Koya UniversityFaculty of Engineering

School of Chemical & Petroleum EngineeringChemical Engineering department

MECHANICAL FLUID

EXPERIMENT NUMBER FIVE

STATIC & DYNAMIC PRESSURE

Instructor: Mr. Ali & Miss. HawzheenAuthor Name: Aree Salah Tahir

Experiment Contacted on: 19/Nov/2013Report Submitted on: 26/Nov /2013

Group:A

The aim of this experiment:

The aim of this experiment is to find the dynamic pressure in a moving fluid using piezometer and pitot tube. By calculating its static pressure and its totalpressure.

Introduction:

When a fluid is in motion it’s affected by two types of pressure which are dynamic and static pressure. Static pressure is the pressure in still liquids and in this experiment it’s used to calculate the dynamic pressure in moving fluids, for finding the static pressure we use the piezometer. Dynamic pressure (velocity pressure) is the kinetic energy per unit volume of a fluid particle, it’s the difference between the total pressure (also called stagnation pressure) andstatic pressure.

Theory:

To find the dynamic pressure we have to find two other pressures at first, which are static and the total pressure because the total pressure is the sum of both dynamic and static pressure, thus dynamic pressure is the difference between the total and the static pressure.Prandtl’s tube is a sort of combination of both the piezometer and the pitot tube which are for finding the static and dynamic pressures in a moving fluid.Pdyn. =1/2 PV2The dynamic pressure is also called velocity pressure, the dynamic pressure rises with square of the flow speed.

In fluid dynamics, Stagnation pressure (total pressure) is equal to the sum of the free-stream dynamic pressure and free-streamstatic pressure.

𝑃𝑑𝑦𝑛/𝛾 =𝑃𝑡/𝛾−𝑃𝑠/𝛾𝑣 = √(2𝑃𝑑𝑦𝑛/𝜌)

Procedure:Preparing:

Before the actual measurement the manometer must be prepared and vented;1. Connect the outputs of the prandtl’s tube by the connecting hoses to the dual water manometer.2. Close all cocks of the pipe system, and the vent valves on the water manometer.3. Switch on the pump and open the pipe system inlet cock.4. Open the lower vent valves of the water manometer:The pipe section and connecting hoses are vented by the water flow.When there are no longer air bubbles in the connecting hoses, close the lower vent valve simultaneously, then close the inlet cock and open the drain cock.

Performing the experiment:Carefully open the upper vent valve and inlet cock, observing the waterlevel: No water should emerge from the upper vent valve.Read of the two heads of water Pt and Ps.High pressures can be adjusted by means of the inlet. If lower pressuresare to be measured, reduce the inlet cock and adjust the head of the water with the drain cock.

TOOLS:

1:twin tube manometers,

2: tank,

3:digital pressure display,

4:pressure sensor,

5:supply tank with submersible pump,

6:Pitot tube,

7:differential pressure manometer,

8:pipe section,

9:hydrostatic pressure in liquids,

10: pressure vessel,

11:pressure vessel,

12:Bourdon tube manometer,

13:diaphragm manometer

Discussion:

As the velocity increases all of dynamic, static and total pressure increases but for dynamic pressure it increases with square of the flow velocity.