H112A - Linear heat conduction unit - kau · the wall of a thick cylinder (Radial energy flow) and...

King Abdulaziz University

Faculty of Engineering, Rabigh

Dep. of Chemical & Mat. Engineering

H112A - Linear heat conduction unit

Objectives

• To measure the temperature distribution for steady state

conduction of energy through a uniform plane wall and

demonstrate the effect of a change in heat flow.

• To understand the use of the Fourier Rate Equation in

determining rate of heat flow through solid materials for one

dimensional, steady flow of heat.

• To measure the temperature distribution for steady state

conduction of energy through a composite plane wall and

determine the Overall Heat Transfer Coefficient for the flow of

heat through a combination of different materials in use.

• To determine the thermal conductivity k of a metal specimen.

Continuous homogenous sample

Procedure

1. Following the basic OPERATING PROCEDURE smear the faces of

the heated and cooled sections with thermal conducting paste and

clamp them together without any intermediate section in place.

2. Again following the above procedure ensure the cooling water is

flowing and then set the heater voltage V to 90 volts.

3. Monitor temperatures T1, T2, T3, T6, T7, T8 until stable.

4. When the temperatures are stabilised record: T1, T2, T3, T6, T7, T8,

V and I.

5. Reset the heater voltage to 120 volts and repeat the above procedure

again recording the parameters T1, T2, T3, T6, T7, T8, V and I when

temperatures have stabilised.







Technical Data

Heated Section

Material: Brass, 25mm diameter,

Thermocouples T1, T2, T3 at 15mm

spacing

Thermal Conductivity:

Approximately 121 W/m K

Cooled Section

Material: Brass, 25mm diameter,

Thermocouples T6, T7, T8 at 15mm

spacing



Brass Intermediate Specimen

Material: Brass, 25mm diameter x

30mm long. Thermocouples T4, T5

at 15mm spacing centrally

spaced along the length.



Stainless Steel Intermediate

Specimen

Material: Stainless steel, 25mm

diameter x 30mm long. No

thermocouples fitted.



Fourier’s law of heat conduction




H112B - Radial heat conduction unit

Objectives • To measure the temperature distribution for steady state conduction

of heat energy through the wall of a thick cylinder (Radial energy flow) and demonstrate the effect of a change in heat flow.

• To understand the use of the Fourier Rate Equation in determining rate of heat flow for steady state conduction of heat energy through the wall of a thick cylinder (Radial energy flow) and using the equation to determine the constant of proportionality (the thermal conductivity k) of the disc material.

• To observe unsteady state conduction of heat and to use this in observation of the time to reach stable conditions.

Temperature distribution across cylinder

Procedure1. Follow the basic OPERATING PROCEDURE2. Again following the above procedure ensure the cooling water is

flowing and then set the heater voltage V to approximately 100 volts. If however the local cooling water supply is at a high temperature (25-35℃ or more) then it may be necessary to increase the voltage supplied to the heater.

3. This will increase the temperature difference between the hot centre and cool circumference of the disc.

4. Monitor temperatures T1, T2, T3, T4, T5, T6 until stable.5. When the temperatures are stabilised record:

T1, T2, T3, T4, T5, T6, V, I.6. Increase the heater voltage by approximately 50 volts and repeat

the above procedure again recording the parameters T1, T2, T3, T4, T5, T6, V, I when temperatures have stabilised.

7. Increase the heater voltage by approximately 50 volts and again repeat the above procedure recording the parameters T1, T2, T3, T4, T5, T6, V, I when temperatures have stabilised.

8. If time is available, the procedure may be repeated further noting that the maximum safe temperature for T1 is 100℃

9. When completed, if no further experiments are to be conducted reduce the heater voltage to zero.

10. shut down the system as detailed in the operation section11. Heat transfer rate from the heater

Q = V×I

Technical Data Material: Brass Outside diameter: 0.110 mDiameter of heated brass core: 0.014 mThickness of disc: 0.0032 mRadial position of thermocouples:T1 = 0.007 mT2 = 0.010 m

T3 = 0.020 mT4 = 0.030 mT5 = 0.040 mT6 = 0.050 m

Thermal conductivity of brass disc (From supplier specification) 121 W/Mk

Fourier’s law on cylinder




H112C – Law of radiant heat transfer and

radiant heat exchange

6. Schematically this produces a system as

shown below.

7. Ensure that the radiation shield is in position

in the radiometer aperture and station the

radiometer in the 900mm position.

8. The radiometer should be left for several

minutes after handling with the radiation

shield in position to ensure that residual

heating has dissipated.

9. Follow the Operating procedure, but do not

increase the supply voltage to the heater

from the zero condition.

10. Monitor the W/m2 digital display and after

several minutes, the display should reach a

minimum.

11. Finally, ‘Auto-Zero’ the radiometer by

pressing the right hand Å button twice.

12. Leave the radiation shield in position and

rotate the voltage controller clockwise to

increase the voltage to maximum volts.

13. Select the T5 position on the temperature

selector switch and monitor the T5

temperature.

Objectives

• To show that the intensity of radiation on a surface is

inversely proportional to the square of the distance of the

surface from the source of radiation (To demonstrate the

inverse square law for thermal radiation)

• To show that the intensity of radiation varies as the fourth

power of the source temperature (To demonstrate the

Stefan-Boltzmann Law.)

• To show that the intensity of radiation measured by the

radiometer is directly related to the radiation emitted from

a source by the view factor between the radiometer and the

source.

• To determine the emissivity of radiating surfaces with

different finishes, namely polished and grey (silver

anodised) compared with matt black.

• To demonstrate how the emissivity of radiating surfaces in

close proximity to each other will affect the surface

temperatures and heat exchanged.

• To show that the illuminance of a surface is inversely

proportional to the square of the distance of the surface

from the light source.

Procedure

1. Following the basic OPERATING PROCEDURE and

INSTALLATION PROCEDURE

2. Install the heated plate C1(10) at the left hand side of the

track and install the radiometer C1(12) on the right hand

carriage C1(2).

3. No items are installed in the left hand carriage for this

experiment but one of the black plates should be placed

on the bench and connected to thermocouple socket T4.

Technical Data

Stefan-Boltzmann Constant

σ = 5.67 x 10-8 W/m2 K4

Temperature locations

T1 Black Plate

T2 Black Plate

T3 Grey Plate

T4 Polished Plate

T5 Heated Plate




H112D - Combined convection and

radiation

Objectives

• Determination of the combined (radiation and convection) heat

transfer (Qr + Qc) from a horizontal cylinder in natural convection

over a wide range of power input and corresponding surface

temperature.

• Measuring the domination of the convective heat transfer coefficient

hc at low surface temperatures and the domination of the radiation

heat transfer coefficient hr at high surface temperatures.

• Determination of the effect of forced convection on the heat transfer

from the cylinder at varying air velocities.

• Determination of the local heat transfer coefficient around the

cylinder.

Cylinder

Procedure

1. Following the basic OPERATING PROCEDURE ensure that the

heated cylinder is located in its holder at the top of the duct and that

the cylinder is rotated so that the thermocouple location is on the

side of the cylinder. This is shown schematically below.

2. Follow the Operating Procedure. Rotate the voltage controller to give

a 50-volt reading.

3. Select the temperature position T2 using the rotary selector switch

and monitor the temperature.

4. Open the throttle butterfly on the fan intake but do not turn on the

fan switch, as the fan will not be used for this experiment.

5. When T2 has reached a steady state temperature record the

following:

T1, T2, V, I.

6. Increase the voltage controller to give an 80-volt reading, monitor T2

for stability and repeat the readings.

7. Increase the voltage controller to give a 120-volt reading, monitor T2


8. Increase the voltage controller to give a 150-volt reading, monitor T2


9. Finally, increase the voltage controller to give approximately a 185-

volt reading, monitor T2 for stability and repeat the readings.

Technical Data

Cylinder diameter D = 0.01m

Cylinder Heated Length L = 0.07m

Cylinder effective heated area

As = 0.0022m2

Effective air velocity local to

cylinder due to blockage effect Ue =

Ua x 1.22

Heat lost due to natural convection

Radiant component

Total heat transfer from the cylinder

Overall heat transfer coefficient




H112E - Extended surface heat transfer

6. A pin of length L diameter D and cross-sectional

area A (Perimeter P) and thermal conductivity k

is heated at one end. It has a total surface area

As and is in an ambient at temperature Ta.

Schematically this produces a system as shown

below.

7. it is possible to develop the following

differential equation to describe conditions

along the bar.

8. Then the equation can be written

9. By applying the boundary conditions it can be

shown that

10. The equation may be re-written as

Objectives

• Measuring the temperature distribution along an extended

surface and comparing the result with a theoretical analysis.

• Calculating the heat transfer from an extended surface resulting

from the combined modes of free convection and radiation heat

transfer and comparing the result with a theoretical analysis.

• Determining the constant of proportionality (the thermal

conductivity k) of the rod material.

Procedure

1. Following the basic OPERATING PROCEDURE and set the

voltage controller to give a 120 volt reading.

2. Select the temperature position T1 using the rotary selector

switch and monitor the temperature REGULARLY until T1

reaches approximately 80°C then reduce the heater voltage to

3. approximately 70 volts. This procedure will reduce the time

taken for the system to reach a stable operating condition.

4. It is now necessary to monitor temperature T1 to T8 until all

the temperatures are stable.

5. When T1 through T8 have reached a steady state temperature

record the following: t1 to t9, V and I .

6. If time permits increase the voltage to a 120 volt reading,

repeat the monitoring of all temperatures and when stable

repeat the above readings.

7. Once readings have been completed the voltage may be

reduced to zero in order to allow the rod to cool. Finally, turn

off the main switch. The theory being demonstrated, sample

observations and calculations are shown in the following

example.

Technical Data

Heated Rod Diameter D = 0.01m

Heated Rod Effective Length L =

0.35m

Heated Rod Effective Cross

Sectional Area

As = 7.854 x10-5 m2

Heated Rod Surface Area A =

0.01099 m2

Thermal Conductivity of Heated

Rod Material k = 121W/mK

Stefan Boltzmann Constant σ =

5.67 x 10-8 W/m2K




H112F - Radiation errors in temperature measurement

6. Repeat the above procedure at heater voltages of

180 and 230 volts

7. Completely close the throttle butterfly on the fan

intake and then turn on the centrifugal fan.

8. Adjust the throttle until a velocity of

approximately 0.5m/s is indicated.

9. Observe the temperatures T1 to T5 and when

stable record T1, T2, T3, T4, T5, V and I.

Objectives

• To demonstrate how temperature measurements can be

affected by radiant heat transfer to a sensor from its

surroundings and to show.

• The effect of temperature difference between the sensor

and its surroundings.

• The effect of air velocity

• The effect of sensors size.

• The effect of sensor emissivity on the measurement error.

• To demonstrate methods for reducing the errors in

temperature measurement that are due to radiation from a

source, which is visible to the measurement sensor.

• Use of a radiation shield between the sensor and the source

of radiation.

• Design of a radiation resistant thermometer.

Procedure

1. Following the basic OPERATING PROCEDURE and

INSTALLATION PROCEDURE connect the Radiation Errors

in Temperature Measurement H112F to the Heat Transfer

Service Unit H112.

2. Ensure that the radiation shield is not fitted.

3. Follow the Operating procedure, but do not increase the supply

voltage to the heater from the zero condition.

4. Set the temperature selector switch to display temperatures T1,

T2, T3, T4 and T5 and record the values. Open the throttle

butterfly but do not turn on the centrifugal fan at this point.

Rotate the voltage controller clockwise to increase the heater

voltage to 80 Volts. Select the T5 position on the temperature

selector switch and monitor the T5 temperature.

5. Also monitor temperatures T2 to T4 until these reach a stable

temperature. When the temperatures are stable record T1, T2,

T3, T4, T5, V and I. Rotate the voltage controller clockwise to

increase the voltage to 120 Volts. Again allow the

temperatures to stabilise and then record T1, T2, T3, T4, T5, V

and I.




H112G - Unsteady state heat transfer unit

Objectives

• To Using analytical transient-temperature/heat flow charts to

determine the thermal conductivity of a solid cylinder from

measurements taken on a similar cylinder but having a different

thermal conductivity.

• To Investigation of the effect of shape, size and material properties on

unsteady heat flow. Using analytical transient-temperature heat flow

charts to analyse the results obtained from different solid shapes.

• Investigation of the Lumped Thermal Capacitance method of

transient temperature analysis.

T3 vs Time graph

Procedure

1. Install the Unsteady State Heat Transfer Unit H112G as detailed in

INSTALLATION UNSTEADY STATE HEAT TRANSFER UNIT

H112G WITH HEAT TRANSFER SERVICE MODULE

2. Follow the OPERATING PROCEDURE onwards in order to

establish the following operating conditions:-

3. Install the 30mm diameter brass cylinder in the shape carrier G1(6).

4. The water bath temperature T1 should be stabilised at approximately

80 to 90 ℃.

5. Set the circulating pump to speed 3 and therefore the water flow

velocity in the flow duct.

6. Record the starting condition temperatures and then plunge the shape

in the flow duct.

7. Then record temperatures and time as detailed in section of the

Operating Procedure.

8. Typical observations are shown.

9. If time permits the procedure may be repeated for the other shapes

supplied.

Technical Data

Brass Test Shapes

Thermal conductivity k: 121 W m-1

K-1

Specific Heat Capacity c: 385 J kg-1

Density ρ 7930 kg m-3

Thermal Diffusivity

ρ =3.7 x10-5 m2s-1

Stainless Steel Test Shapes

Thermal conductivity k: 16.3 W m-1

K-1

Specific Heat Capacity c 460 J kg-1

Density ρ 8500 kg m-3

Thermal Diffusivity

ρ = 0.45 x10-5 m2 s-1




H112H - Thermal conductivity of liquids and gases unit

Objectives

• Determination of the incidental heat transfer.

• Determination of the thermal conductivity of a liquid or a gas.

Thermal conductivity of air

Procedure

1. Before using the unit to determine a thermal conductivity, it is

necessary to determine the extent of the "incidental" heat transfer.

This includes all heat transfers from the element in the plug OTHER

than that transferred by conduction through the fluid under test.

2. The incidental heat transfer includes,

3. Heat conducted from the plug to the jacket by the 'O' ring seals.

4. Heat radiated from the plug to the jacket.

5. Heat losses to the surroundings from the exposed ends of the plug.

Calibration

1. Calibration is most conveniently carried out using air (whose thermal

conductivity is well known) in the radial space:

2. Prepare the unit as under "Operation", with air in the radial

clearance.

3. Adjust the variable transformer to about 60V.

4. Observe the plug and jacket surface temperature and when these are

stable, note their values and the voltage.

5. Increase the electrical input to about 100V and when stable repeat

the observations.

6. Repeat at other voltages up to the maximum.

Heat conducted through air

Electrical Input

Incidental Heat Transfer

Technical Data

Nominal Radial Clearance between

Plug and Jacket: 0.30mm

Effective Area A of Conducting

Path through Fluid : 0.0133m2

1. Power Plug

2. Thermocouple t1

3. Thermocouple t2

4. Logger Thermocouple t1

5. Logger thermocouple t2

6. Cooling water in/out

7. Coolling water in/out

8. Test fluid inlet

Specimen calibration curve




H112J - Perfect gas law demonstration

Objectives

• Collecting Data For Any Configuration, Using The Optional Data

Acquisition System

• Reviewing Recorded Data Using the Data Logging Software

• Investigation of the First law of Thermodynamics by Determination

of the Heat Capacity Ratio γ for air.

• Investigation of the Perfect Gas Law through an Isothermal Process.

• Investigation of the Perfect Gas Law through the Change in

Temperature of a Fixed Volume.

Pressure Display

The digital pressure display shows both

positive pressure in the pressure vessel

and vacuum in

the vacuum vessel. The pressures are

selected using the pressure sensor

selector switch. In both

cases the display shows a positive value.

• Pressures above atmospheric in the

pressure vessel are shown as positive

and below as negative.

• Pressures BELOW atmospheric in the

vacuum vessel are shown as

POSITIVE and above as negative.

Procedure

1. The following procedure will utilise the pressure cylinder to

undertake an adiabatic expansion.

2. Record the local ambient atmospheric pressure using a locally

supplied barometer or equivalent

3. Follow the procedure “Using the Pump to Pressurise the Large

Pressure Cylinder”.

4. The cylinder pressure may be allowed to reach the pressure switch

maximum (35kN/m2 ) or any convenient pressure between this and

atmospheric. Note that with very low pressures observation of the

results is more difficult.

5. Before starting the pump refer to the section relating to use of the

data acquisition system. Start the data recording system as the pump

is started and the change in pressure the large cylinder may be

observed on both the computer and the digital display if the pressure

cylinder is selected.

6. Refer to the procedure “Creating a Step Change in the Large

Pressure Cylinder or Smaller Vacuum Cylinder” and refer in detail to

the section “Step Change To or From Atmosphere”.

7. Observe the digital displays(temperature T1 and pressure) to ensure

that the system has reached temperature and pressure stability before

opening any valves.

8. Create the step change by rapidly opening and closing ball valve to

atmosphere.

9. Observe the drop in both pressure and temperature T1. Allow the

system time for T1 to return to the original condition(which should

be close to ambient t) and for the pressure to stabilise.

10. Once stable again the procedure may be repeated from the existing

pressure and temperature.

11. Depending upon how far and for how long the ball valve is opened

each time there may be opportunity to obtain several sets of readings

before the pressure cylinder returns to atmospheric pressure.

Technical Data

Ratio of Specific Heats for Air γ:

1.4

Gas Constant For Air R = 287 kJ/kg

K

Volume of Large Pressure Cylinder

0.0225 m3

Volume of Smaller Vacuum

Cylinder 0.01225 m3

Volume ratio: 1.841

1. Pressure cylinder

2. Vacuum Cylinder

3. Pressure Control and Display Console

4. Vacuum Pump Coupling

5. Pressure Pump Coupling

6. Needle Valve

7. Vacuum Cylinder Thermocouple

8. Pressure Cylinder Thermocouple

9. Ball Valve

10. Vacuum Cylinder Ball Valve




H112M - Marcet boiler

Objectives

• Investigation of the pressure-temperature relationship for

Water/steam.

• Investigation of the Clausius- Clapeyron equation using the Pressure-

temperature relationship for steam.

• Investigation of steam quality by throttling.

Procedure

1. Refer to the operating procedure. Ensure in particular that the boiler

contains sufficient water.

2. Record the local ambient atmospheric pressure using a locally

supplied barometer or equivalent. Record the starting condition

Temperature T1 and Pressure.

3. If the pressure is to be recorded from a sub-atmospheric pressure

then refer to the “Second Time Use When the Boiler is In Vacuum”

procedure.

4. Increase the heater to full power and monitor the increasing

temperature and pressure. At relevant intervals record both the

pressure and temperature.

5. It is recommended that either whole units of pressure or whole units

of temperature are selected as the recording points as this makes

reference to steam tables easier.

Pressure

1. The gauge pressure indicated by the bourdon tube pressure gauge is

“relative” to atmospheric pressure.

2. Atmospheric pressure varies depending upon weather conditions and

location(sea level or high altitude) and therefore it would be

impractical to present the pressure-temperature relationship for water

in terms of gauge pressure as the readings would vary.

3. Therefore it is normal to refer pressures to an absolute vacuum. This

can be achieved either by using a pressure gauge that is internally

evacuated and sealed or by adding the local atmospheric pressure to

the pressure measured by a standard pressure gauge.1. Boiler

2. Sight Glass

3. Pressure Gauge

4. Throttle Valve

5. Pressure Switch

6. Safety Valve

7. Water fill / Drain

8. Throttle Valve Vent Coupling

9. Safety Valve Vent Coupling

10. Pressure Transducer (*Only fitted if

HC112MA is Purchased).

Pressure Switch

The pressure switch is factory set to

operate at or below 900kN/m2

gauge pressure. This turns off the

heater inside the boiler.




H112P - Free and forced convection from flat, finned and pinned plates

Objectives

• To Demonstrate the Relationship Between Power Input and Surface

Temperature in Free Convection

• To Demonstrate the Relationship Between Power Input and Surface

Temperature in Forced Convection.

• To Demonstrate the use of Extended Surfaces to Improve Heat

Transfer From the Surface.

• To Determine the Temperature Distribution Along an Extended

Surface.

Procedure

1. Ensure the instrument console main switch is sin the off position.

Ensure the fan is switched off.

2. For the natural convection experiments the fan will not be used.

3. If the flat (pinned or finned) plate is not in position, open the toggle

clamps. Replace with the flat(pinned or finned) plate and close the

toggle clamps. Note that with the plate heat exchangers the power

leads exit from the top of the plates. Refer to the diagram.

4. No air velocity will be measurable under natural convection

conditions unless specialized instrumentation is available.

5. Switch on the main switch and set the heater voltage to minimum.

6. The objective with the steady state method is to obtain the same T1

surface temperature on each of the heat exchangers and determine

the steady state power input required to achieve this. From factory

tests under “typical” conditions the following heat inputs were

required to maintain T1.

7. When the temperature T1 has stabilised(this may take 10’s of

minutes) record the actual temperature T1, the actual voltage V and

the ambient air temperature T9. If either the Finned or Pinned plates

are in position the pin temperatures (T2,T3,T4) or fin temperatures

(T2, T3, T4) may be recorded.

8. Before removing the heat exchanger from the duct turn on the fan

and cool the heat exchanger .

9. Note that this cooling procedure may be used to quickly demonstrate

to students the increased heat transfer coefficient due to forced

convection if the voltage setting is left at the natural convection

condition and the fan turned on to give maximum flow.

10. T1 will be seen to rapidly fall from the natural convection condition.

11. Finally reduce the heater voltage to zero and allow to cool before

removing the plate from the tunnel and replacing with one of the

alternative plates.

12. Test results from the steady state method are obtained.

1. Main Switch

2. Instrument Fuse

3. Fan Switch

4. Air Velocity Display (m/s)

5. Air Velocity Sensor(Hot Wire

Anemometer)

6. Duct

7. T5 Air Temperature

8. Heated Plate

9. Air Throttle

Steady State Method

If time permits, or for a student project

the steady state experimental procedure

may be adopted. This allows the heat

transfer rate from the three heat

exchangers to be compared at similar hot

plate temperatures. Due to the

requirement for small adjustments and

the time taken to assess stability the

experimental period can be long.

Transient Method

However for a rapid demonstration the

transient method may be adopted where a

fixed heat input is applied.

With this method the slope of the

temperature rise is an indication of the

rate of heat transfer from the plate.

Technical Data

Duct Cross Sectional Area Ad =

0.01278 m2

Pinned Plate Thermocouple

Locations (distance from surface)

T2:10, T3:30, T4:50

Finned Plate Thermocouple

Locations (distance from surface)

T2:10, T3:30, T4:50




H112Q - Thermoelectric heat pump

Objectives

• Investigation of the effects upon the surface temperature of either face

of the module with increasing power. (Peltier Effect)

• Investigation of the effect upon heat transfer direction of reversing the

polarity of the power supply to the module. (Thomson or Lenz

Effect).

• Investigation of the variation in open circuit voltage across the

module due to the variation in surface temperature difference.

(Seebeck Effect).

• Investigation of the power generating performance of the module with

a steady load and increasing temperature difference.

• Estimation of the coefficient of performance of the module when

acting as a refrigerator.

Procedure

1. It is assumed that the H112Q Thermoelectric Heat Pump Module has

being installed and commissioned.

2. The following experiment demonstrates that if supplied with DC

power the peltier module will cool the upper block.

3. If no external heat is supplied (by the cartridge heater in the upper

block) then the block temperature(T1) will reach a very low value.

4. Turn on the main switch of the H112 Heat Transfer Service unit and

turn the H112 Heater power control to zero (or disconnect the multi-

way plug).

5. Ensure cooling water is flowing through the water cooling

connections to the lower block.

6. Ensure that the DC Power Connectors are red to red and black to

black both ends.

7. Ensure the Load switch is down(on) and the Cooling/generating

switch is set to cooling.

8. Turn on the H112Q control console main switch and set the DC

power control to a low voltage(e.g. 0.5V on the dc voltmeter).

9. Monitor the top block temperature T1. When T1 and T2 are stable

record T1 through to T4 and the DC current and Voltage.

10. Increase the DC voltage in small increments and repeat the

monitoring procedure, recording the data when stable. Repeat the

procedure until the maximum Dc voltage is reached.

11. As may be seen as the supply voltage and current are increased the

upper block temperature t1 reduces considerably as heat is extracted

from the block.

12. The voltage may be increased if required but care must be taken as

the top block(being heated) does not have any water cooling.

13. As may be seen, if compared with the typical data the T1 and T2

temperature trends are reversed showing that the heat transfer has

been reversed.

1. Main Switch

2. DC power control

3. DC voltmeter

4. Cooling / Generating switch

5. DC Ammeter

6. Load Lamp

7. Load switch

8. DC power connectors

9. Cooling water hoses

10. DC power connectors

11. Heater cable

Thermocouples

The 4 thermocouples from the peltier

module are numbered and must be

connected to the H112 console.

T1 Cold Side temperature

T2 Hot Side Temperature

T3 Water Inlet Temperature

T4 Water Outlet Temperature

Technical data

Nominal Peltier cooling capacity 82W @ 15V




H112R - Stirling cycle engine

Objectives

• Demonstration of a direct conversion of heat energy into shaft power

using a Stirling Cycle.

• Investigation of the Stirling cycle performance under load.

• Investigation of the parameters affecting the cycle performance and

cycle efficiency.

Procedure

1. The following experiment demonstrates the way in which direct

heating of the air charge in the Stirling engine results in a mechanical

power output.

2. Turn on the main switch of the H112 Heat Transfer Service unit and

turn the H112 Heater power control to zero.

3. Ensure cooling water is flowing through the water cooling

connections.

4. Turn the heater power control on the H112 Transfer Service unit

slowly clockwise until a current of approximately 0.500 amps is

shown on the H112 Ammeter.

5. Monitor the temperature of the heater TH on the heater temperature

display as this approaches 350°C increase or reduce the power input

to maintain the TH temperature in the 350-380°C range.

6. Now ensure that the load adjuster is set so that the belt brake is

loose. Rotate the flywheel in a clockwise direction, as before and the

pressure of the air acting on the power piston should be felt assisting

in rotation of the flywheel as the piston moves outwards along the

power cylinder. This is the effect of the expanding-heated air moved

by the displacer.

7. If the flywheel is spun in a clockwise direction the engine should

turn slowly and reach a stable speed.

8. Now slightly increase the heater power so that the heater temperature

TH increases slightly and observe the rotational speed of the engine.

This should slowly increase with TH.

9. Though the belt brake is not being used to load the engine it can be

seen that the heat put into the system by the electric heater is being

converted to mechanical energy in order to maintain rotation of the

flywheel.

10. In this condition the engine is only generating power to overcome its

own internal friction.

11. Note that the heater has a maximum temperature limit of 600°C and

when the heater temperature display

12. reaches 600°C there will be an audible click from the display . At

that point the current displayed on the digital current meter will drop

to 0000 as the power is disconnected. The power is re-connected

automatically as the temperature falls to below 599°C.

1. Stirling cycle engine

2. Load cell display

3. Tachometer indicator

4. Heater temperature display

5. H112R heater power connection

6. Heater terminal enclosure

7. heater cylinder

8. Cooling water inlet

9. Flywheel

10. Belt brake

11. Power cylinder

12. Load Adjuster

13. Crankshaft

15. Cooling water drain

16. cold side thermocouple

17. tachometer sensor (hidden)

The Torque Φ developed by the engine

can be calculated

The shaft power W can be calculated

from

Technical data

Radius of Belt Brake Wheel r = 20mm




H112S - Boiling heat transfer module

Objectives

• Visual demonstration of convective, nucleate and film boiling.

• Determination of heat flux and surface heat transfer coefficient up to

and beyond the critical

• condition at constant pressure.

• Investigation of the effect of pressure on critical heat flux.

• Demonstration of filmwise condensation and measurement of overall

heat transfer coefficient.

• Demonstration of the cause of liquid carry over or priming in boilers.

• Determination of the pressure temperature relationship of a pure

substance.

• Investigation of the effect of air in a condenser.

• Demonstration of the law of partial pressures.

Procedure

1. Observe the normal operating procedure before starting this

procedure.

2. Turn on the electrical and water supplies and adjust both to very low

settings (<20 Watts). Allow the digital t1 temperature indicator to

stabilise. Observe this and the liquid temperature t2 at frequent

intervals.

3. It is assumed that the chamber is air free at this point(observed

pressure on the pressure gauge = Saturation pressure at t2).

4. Carefully watch the liquid surrounding the heated cylinder.

Convection currents will be observed, and at the same time liquid

will be seen to collect and drip on the condenser coils, indicating that

evaporation is proceeding although at a low rate. Increase the heat

input in increments by adjusting the heater control , keeping the

vapour pressure at any desired constant value by adjusting the

condenser water flow rate by the water flow control and meter.

5. Nucleate boiling will soon start and will increase until vigorous

boiling is seen, the temperature difference (t1-t2) between the liquid

and metal being still quite moderate (<20K).

6. Increase the heat input, and at between 300 and 400 Watts the nature

of the boiling will be seen to change dramatically and at the same

time the metal-liquid temperature difference will rise quickly.

1. Chamber

2. Water cooled condenser

3. Heated cylinder

4. Water flow control and meter

5. Chamber pressure gauge

6. Charging/drain valve

7. Air vent valve

8. Wattmeter

9. Heater control

10. Main switch

11. t 1 temperature indicator

Technical Data

Dimensions of heating surface:

Effective length = 42mm

Diameter = 12.7mm

Surface area = 0.0018m2

(including area of end)

Condenser surface area: 0.032m2

Maximum permitted surface

temperature: 220℃Heater cut out temperature:

160℃Dimensions of glass chamber:

Nominal internal diameter = 80mm

Length = 300mm

Volume = 0.0015m3

Specific heat capacity of water:

4.18 kJ kg-1 K-1




H102A - Concentric heat tube exchanger

Technical Data

• Inner tube material: stainless steel

• Outside diameter: 0.012m

• Wall thickness: 0.001m

• Outer tube material: Clear acrylic

• Inside diameter: 0.022m

• Wall thickness: 0.003m

• Active heat transfer section length: 2X0.3180m

• Active heat transfer section area: 0.02198m2

Thermocouple Stations Co-current and

Counter current flow:

Thermocouples sense the stream

temperatures at the four fixed stations: -

T1 – Hot Water INLET to Heat Exchanger

T2 – Hot Water RETURN from Heat

Exchanger

T3 – Cooling Water INLET to Heat

Exchanger

T4 – Cooling Water RETURN from Heat

Exchanger

Objectives

• Demonstrating indirect heating or cooling by transfer of heat from

one fluid stream to another when separated by solid wall.

• Performing an energy balance across a concentric tube heat

exchanger and calculating the overall efficiency at different fluid

flow rates.

• Demonstrating the differences between counter-current flow and

co-current flows

• Investigating the effect of changes in hot fluid and cold fluid flow

rate on the temperature efficiencies and overall heat transfer

coefficient.

Procedure

1. Install concentric tube heat exchanger H102A as detailed in

installation guide.

2. Connect the cold water circuit to give counter current flow

according to installation guide.

3. Follow operational procedure to establish the operational

conditions.

4. Turn on main and heat switch.

5. Set hot temperature controller to 60℃.

6. Set cold water flow rate to 15 g/sec.

7. Set hot water flow rate to 50g/sec.

8. Monitor the steam temperatures and the hot and cold flow rates to

ensure these too remain close to the original setting.

9. Record T1, T2, T3, T4, T5, T6, V(cold), V(hot).

10. Adjust cooling water flow control so cold water flow is

approximately 30g/sec.

11. Maintain hot water flow rate at approximately 50g/sec.

12. Allow conditions to stabilize and repeat the above stated procedure

to ensure correct results.

13. Procedure can be repeated with different hot and cold water flow

rates and different hot water inlet temperature if required.

Calculations:

Example of calculation is as under

Reduction in hot temperature fluid: T1-T2 = 59.3-53 = 6.2K

Reduction in cold temperature fluid: T4-T3 = 30.9-15.4

= 15.5K

1. Thermocouple sockets 9. Hot water in/out

2. Main switch 10. cold water in/out

3. Heater switch 11. Fill and sight tube

4. RCCB 12. Vent 13. Tank drain valve

5. Water temperature control

6. Temperature indicator

7. Cooling water flow meter

8. Hot water flow meter




H102B – Plate heat exchanger

Technical Data

• Plate Material: 316 Stainless

steel

• Plate overall dimensions:

0.072m x 0.189m

• Total heat transfer area:

0.024m2

• Number of plates: 4

• Number of channels on hot side:

2

• Cold side: 1

• Weight – Full 0.846kg

• Weight – empty 0.776kg

1. Thermocouple sockets 12. Vent

2. Main switch 13. Tank drain valve

3. Heater switch

4. RCCB





9. Hot water in/out

10. Cold water in/out

11. Fill and sight tube

Objectives

• Demonstration of indirect heating or cooling by transfer of heat

from one fluid stream to another when separated by a solid Wall

(fluid to fluid heat transfer)

• Performing an energy balance across a plate heat exchanger and

calculating the overall efficiency at different fluid flow rates

• Demonstrating the differences between counter-current flow (flows

in opposing directions) and co-current flows (flows in the same

direction) and the effect on heat transferred, temperature

efficiencies and temperature profiles

• Determining the overall heat transfer coefficient for a plate heat

exchanger using the logarithmic mean temperature difference to

perform the calculations (for counter-current and co-current flows).

• Investigating the effect of changes in hot fluid and cold fluid flow

rate on the temperature efficiencies

Procedure

1. Install the Plate Heat Exchanger H102B as detailed in

INSTALLATION / Heat Exchanger Installation guide and connect

the cold water circuit to give Counter-Current flow as detailed in

the guide.

2. Follow the operational procedure detailed in the main manual in

order to establish the operating conditions.

3. Turn on the ‘MAIN SWITCH’ and ‘HEATER SWITCH’

4. Set the hot water temperature controller to 60 ̊C.

5. Set the cold water flow rate Vcold to 15g/sec

6. Set the hot water flow rate Vhot to 35g/sec.

7. Allow the conditions to stabilise and record the observations.

Calculations

For the example result, the calculations are as follows.

Reduction in Hot fluid temperature Δt hot = T1 - T2

= 51.8 - 41.5

= 10.3 K

Increase in Cold fluid temperature Δt cold = T4 – T3

=37.4 - 15.0

= 22.4 K

The test results show the effect upon the temperature differences when

the flow rates through a simple heat exchanger are varied.




H102C – Shell and tube heat exchanger

Technical Data

• Tube Material: Stainless steel

• Tube Outside Diameter:

0.00476m

• Tube Wall Thickness: 0.0006m

• Number of tubes in bundle: 7

• Effective length of tube bundle:

0.205m

• Effective heat transfer area:

0.0187m2

• Shell Material: Clear

Borosilicate (Pyrex type glass)

• Shell Inside Diameter: 0.075m

• Shell Wall Thickness: 0.01m

• Number of baffles: 2



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives

• To demonstrate indirect heating or cooling by transfer of heat from

one fluid stream to another when separated by a solid wall (fluid to

fluid heat transfer).

• To perform an energy balance across a shell and tube exchanger

and calculate the overall efficiency at different fluid flow rates.

• To investigate the effect of changes in hot fluid and cold fluid flow


coefficient.

• To investigate the effect of driving force (difference between hot

stream and cold stream temperature) with counter-current and co-

current flow.

• To determine the overall heat transfer coefficient for a shell and

tube heat exchanger using the logarithmic mean temperature

difference to perform the calculations (for counter-current and co-

current flows).

Procedure

1. Install the Shell and Tube Exchanger as detailed in

INSTALLATION / Heat Exchanger installation guide and connect


the same guide.

2. Follow the OPERATING PROCEDURE detailed in the main

manual in order to establish the operating conditions.




6. Set the hot water flow rate V hot to 50g/sec.

7. The procedure may be repeated with different hot and cold flow


8. Monitor the stream temperatures and the hot and cold flow rates to

ensure these too remain close to the original setting. Then record

the following: T1, T2, T3, T4, Vhot and Vcold

9. Then adjust the cold-water flow valve so that Vcold is

approximately 35g/sec. Maintain the Hot water flow rate at

approximately 50g/sec.

10. Allow the conditions to stabilise and repeat the above

observations.






H102D – Jacketed vessel with coil and stirrer

Technical Data

• Vessel wall inside diameter:

0.1524m

• Vessel wall outside diameter:

0.1542m

• Coil tube outside diameter:

0.0063m

• Coil tube bore diameter:

0.0049m

• Effective length of coil tube:

1.15m



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives




• To investigate the heating characteristics of a stirred vessel

containing a fixed batch of liquid when heated using hot fluid

circulating through a submerged coil.

• To investigate the heating characteristics of a stirred vessel

containing a fixed batch of liquid when heated using hot fluid

circulating through an outer jacket.

• To investigate the change in overall heat transfer coefficient and

logarithmic mean temperature difference as a batch of fluid in the

vessel changes temperature.

• To perform an energy balance, calculate the overall efficiency and

determine the overall heat transfer coefficient for a continuous flow

in a stirred vessel when heated using a submerged coil.

Procedure

1. Install the Jacketed Vessel with Coil and Stirrer H102D as detailed

in installation guide and connect the hot water circuit Using the

Outer Jacket as detailed in the same guide.

2. Adjust the overflow in the vessel to the 1-litre height.

3. Configure the Cold Water Circuit following.



5. Turn on the ‘MAIN SWITCH’ and replenish the hot circuit as the

jacket fills.

6. Turn on the ‘HEATER SWITCH’.




10. Turn stirrer ON, speed to 100%.

11. Make T5 probe 15mm below surface.

CALCULATIONS

For the example result the calculations are as follows.

Reduction in Hot fluid temperature Δt hot = T1 – T2 = 70.2 – 64.2

= 6.0 K


=32.5 – 14.1

= 18.4 K




H102E – Extended concentric tube

Heat exchanger

Technical Data

• Inner Tube Material: Stainless

steel

• Outside Diameter: 0.012m

• Wall Thickness: 0.001m

• Outer Tube Material: Clear

Acrylic

• Inside Diameter: 0.022m


• Active Heat Transfer Section

Length 4 x 0.3180 = 0.636m

• Area 2x 0.02198= 0.04396 m2



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives




• To perform an energy balance across a concentric tube heat

exchanger and calculate the overall efficiency at different fluid

flow rates.

• To determine the overall heat transfer coefficient for a concentric


difference to perform the calculations (for counter-current and co-

current flows).



coefficient.

• To investigate effect of driving force (difference b/w hot and cold

stream temperature) with counter-current and co-current flow.

Procedure

1. Install the Concentric tube Heat Exchanger as detailed in


the cold water circuit to give Counter- Current flow as detailed in

the same section.






6. Set the hot water flow rate V hot to 30 g/sec.



the following: T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, Vcold and V

hot

8. Then adjust the ‘COOLING WATER FLOW CONTROL’ so that

Vcold is approximately 10g/sec.

9. Maintain the Hot water flow rate V hot at approximately 30g/sec.

10. Allow the conditions to stabilise and repeat the above

observations.



Co-current and Counter-current flow


temperatures at the fixed stations: -

T1 Hot stream out (on H102 Panel)

T5 Intermediate hot

T7 Intermediate hot

T10 Intermediate Hot




H102F – Extended plate heat exchanger

Technical Data

• Plate Material: 316 Stainless

steel

• Plate overall dimensions:

0.072m x 0.189m

• Total heat transfer area 0.048m2

• Number of plates: 2x4



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives




• To perform an energy balance across a plate heat exchanger and

calculate the overall efficiency at different fluid flow rates

• To demonstrate the differences between counter-current flow (flows

in opposing directions) and co-current flows and the effect on heat

transferred, temperature efficiencies and temperature profiles

through a plate heat exchanger.

• To determine the overall heat transfer coefficient for a plate heat

exchanger using the logarithmic mean temperature difference to

perform the calculations.



coefficient.

Procedure

1. Install the Plate Heat Exchanger as detailed in INSTALLATION /

Heat Exchanger Installation guide and connect the cold water

circuit to give Co-Current flow as detailed in the same section.










CALCULATIONS

For the example result the calculations are as follows.


= 60.1 – 48.5 = 11.6 K


=47.9 – 16.6 = 32.3 K

The test results show the effect upon the temperature differences when

the flow rates through a simple heat exchanger are varied.

Co-current and Counter-current flow


temperatures at the fixed stations: -

T1 Hot stream out (on H102 Panel)

T6 Intermediate hot

T2 Hot stream return(on H102 Panel)

T3 Cold Out (on H102 Panel)




H102G – Water to water turbulent flow heat exchanger

Technical Data

• Core Tube Material - Copper

• External Diameter (do) =

9.5mm

• Internal Diameter (di) = 7.9mm

• Length = 3 x 350mm

• External Heat transfer area Ao =

0.031m2

• Mean Area = 0.0288m2

• Flow area Si = 49 x 10-6 m2

• Outer Tube Material - Copper

• External Diameter Do =

12.7mm

• Internal Diameter Di = 11.1mm

• Annulus flow area, So = 25.9 x

10-6 m2



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives

• Determination of heat transfer rate, logarithmic mean temperature

difference and overall heat transfer coefficient.

• Determination of surface heat transfer coefficient inside and

outside the tube and the effect of fluid velocity on these.

• Comparison of con-current and counter-current flow in a heat

exchanger.

• Investigation of the relationship between Nusselt Number,

Reynolds Number and Prandtl Number.

Procedure

1. Set the cooling water direction for counter-current flow by

selecting the appropriate cold flow couplings as shown on manual.

2. Check that unit contains water to the correct level.

3. Fully open the hot water flow control valve.

4. Switch on the main switch and heater switch and set the water

temperature control to approximately 70℃.

5. Adjust the hot water flow rate to a convenient value – for example

maximum flow.

6. Adjust the cold water flow to approximately 10-15g s-1 .

7. Make the observations.

Calculations

Mean hot water temperature = (t7+t10)/2

Actual Flow( Litres/minute) = Indicated Flow + (T10 *0.0041) -

0.0796

Temperature Distribution

This can be found through logarithmic mean temperature difference

For the heat exchanger in the counter-current flow arrangement:

The Overall Heat Transfer Coefficient, U, may be obtained from,

Temperature distribution diagram

1. Heat Exchanger

2. Hot Water

Flowmeter

3. Hot Flow

Control

4. Hot Flow From

H102

5. Hot Flow

Return to H102

7. H102G

Securing Nuts




H102H – Coiled concentric tube heat exchanger

Technical Data

• Inner Tube material: Copper

• Outside Diameter: 0.0214m


• Outer Tube material: Steel

• Inside Diameter: 0.0194m


• Active Heat Transfer Section

Length: 1.61m

• Area: 0.108m2



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives




• To perform an energy balance across a concentric tube heat

exchanger and calculate the overall efficiency at different fluid

flow rates.

• To demonstrate the differences between counter-current flow (flows

in opposing directions) and co-current flows (flows in the same

direction) and the effect on heat transferred, temperature

efficiencies and temperature profiles through a concentric tube heat

exchanger.

• To determine the overall heat transfer coefficient for a concentric


difference to perform the calculations.



coefficient.

• To investigate the effect of driving force (difference between hot

stream and cold stream temperature) with counter-current and co-

current flow.

Procedure

1. Install the Coiled Concentric tube Heat Exchanger as detailed in



the same section.









the following:

T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, Vcold and V hot







H102K – Film and dropwise condensation module

Technical Data

• Dimensions of each Condenser:

Length 90mm

• Diameter 12.7mm Surface Area

37 cm2 (3.7 x 10-3 m2)

• Internal Volume of Steam

Chamber (empty): 1840cm3

• Internal diameter of chamber

glass Cylinder: 76mm

• Normal Water Capacity: 500cm3

• Surface Area of Heating

Element: 144cm2



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives

• Visual demonstration of film wise and dropwise condensation, and

of nucleate boiling.

• Measurement of heat flux and surface heat transfer coefficient in

both film wise and dropwise condensation at pressures up to

atmospheric.

• Demonstration of the effect of air in condensers.

• Investigation of the effect of air in condensers.

• Investigation of the saturation pressure/temperature relationship for

H2O between about 20°C and 100°C.

• Demonstration of Daltons Law of Partial Pressures.

Procedure

1. Select and connect the heat exchanger that is to be demonstrated

first.

2. Having checked that there is sufficient water in the chamber to

cover the element by about 20mm, switch on the heater and

increase the water temperature (t1) to about 90-95°C.

3. Carry out the air extraction procedure as detailed in mannual and

then carry on heating until t1 reaches the desired value - say

100°C.

4. Adjust the condenser water flow rate to 50 g/s (maximum flow)

and adjust the heater power output until the steam temperature t5

is constant at the desired value say 100℃.

5. Observe the condensation process and then change over to the

other condenser and establish the same steam temperature t5 with

the cooling water flow rate at maximum (50g/s)

Condensation processes:

• Dropwise condensation: The steam condenses on the surface

forming a large number of static beads which grow in size. When a

bead reaches a certain size it breaks away and rapidly runs down

• the surface, gathering all the static beads in its path.

• Film wise condensation: The surface of the condenser is covered

with an unbroken film of liquid which steadily increases in

thickness as it flows downward. The smooth surface of the liquid

film indicates that flow within it is probably laminar and that there

will be little or no mixing of the hot outer layer with the cooler

inner layer close to the condenser surface. In this case, heat transfer

from the condensing steam (on the outer layer of the film) to the

metal surface is by conduction through the film of liquid.

Thermocouple Locations

t5 Steam / Saturated water

t6 Dropwise/ Film wise Condenser surface

t7 Cooling Water into Condenser

t8 Cooling Water leaving Condenser

Temperature drop across condenser shell

1. Chamber

2. Heater

3. Drain/Fill Valve

4,5. Dropwise &

Film wise

Condenser

6. Steam Baffles

7. Pressure Gauge

8. Pressure Relief

Valve

9. Air Extract

Valve Extractor

20,21. Water Inlet

& Outlet hose




H102M – Water to air heat exchanger



3. Heater switch

4. RCCB





9. Hot water in/out



Objectives




• To calculate the overall efficiency at different fluid flow rates

• To determine the overall heat transfer coefficient for a water to air

heat exchanger using the logarithmic mean temperature difference

to perform the calculations

Procedure

1. Install the Water to Air Heat Exchanger as detailed in

INSTALLATION manual.


manual in order to establish the following operating conditions.



5. Set the fan speed to its minimum speed.

6. Set the hot water flow rate Vhot to 50g/sec.


Calculations

For the example result, the calculations are as follows.


= 71.2 - 69.8

= 1.4 K


=51.7 – 19.5

= 32.2 K

Efficiency of the heat exchanger

Temperature efficiency of the hot and cold stream

Mean temperature efficiency

1. Cooling Fan

2. hot side air

thermocouple

T6

3. hot water

out coupling

4. hot water in

coupling

5. Cooling Fan

Power Supply

6. Speed

controller

7. Water to Air

Heat

Exchanger

8. Hot out

Hose

9. Hot return

Hose

10. Hot water

flow control

11.

Thermocouple

sockets

Technical data

Internal Plate Material: Aluminum

Overall dimensions 0.12m x 0.135m

Total heat transfer area 0.2025m2

H112A - Linear heat conduction unit - kau · the wall of a thick cylinder (Radial energy flow) and...

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Transcript of H112A - Linear heat conduction unit - kau · the wall of a thick cylinder (Radial energy flow) and...