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CONTENTS

• INTRODUCTION

• NANO PARTICLE PRODUCTION

• WHY NANOFLUIDS

• SPECIFIC BAFFLE ARRANGEMENT AND BAFFLE

SPACING

• ROLE OF BAFFLE CUT

• GEOMETRY OF BAFFLES

• ANALYSIS

• RESULT

• EXPERIMENTAL RESULTS

• CONCLUSION

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INTRODUCTION

• TO IMPROVE THE EFFICIENCY OF STHE

• INCREASE HEAT TRANSFER AREA

• INCREASING NUMBER OF TUBES

• PROVIDING FINS

• EQUIPMENT BECOME BULKY

• INCREASE TIME OF CONTACT OF FLUID ELEMENT PASSING

THROUGH THE HEAT EXCHANGER

• PROVIDING BAFFLES

• USE SOLID PARTICLES (HIGH THERMAL CONDUCTIVITY) IN

CONVECTIONAL FLUID

• LEAD TO FOULING, SEDIMENTATION, INCREASED PRESSURE

DROP

• THUS NANO FLUID

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STHE WITH BAFFLE ANGLE

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NANOPARTICLE PRODUCTION

• RAPID PYROLYSIS

• IN THE PRESENCE OF SURFACTANTS (TOPO, OA)

• SHAPE DEPEND ON

• SURFACTANTS, OPTIMIZING PARAMETERS

• SHAPE STUDIED BY HIGH RESOLUTION

TRANSMISSION ELECTRON MICROSCOPE

• TECHAI G2 (200KV) MICROSCOPE6

WHY NANOFLUIDS

• REDUCES FOULING, SEDIMENTATION,

CLOGGING OF FLOW CHANNELS DUE TO POOR

SUSPENSION STABILITY, EROSION OF HEAT

TRANSFER DEVICE, AND INCREASING IN

PRESSURE DROP.

• THE SUSPENDED NANOPARTICLES INCREASE

THE SURFACE AREA AND THE HEAT CAPACITY

OF THE FLUID.

• THE SUSPENDED NANOPARTICLES INCREASE

THE EFFECTIVE (OR APPARENT) THERMAL

CONDUCTIVITY OF THE FLUID.7

• THE DISPERSION OF NANOPARTICLES FLATTENS

THE TRANSVERSE TEMPERATURE GRADIENT OF

THE FLUID.

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WHY SPECIFIC BAFFLE ARRANGEMENT

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THE MAIN ROLES OF A BAFFLE IN A SHELL AND TUBE

HEAT EXCHANGER ARE TO:

• HOLD TUBES IN POSITION (PREVENTING SAGGING),

BOTH IN PRODUCTION AND OPERATION

• PREVENT THE EFFECTS OF VIBRATION, WHICH IS

INCREASED WITH BOTH FLUID VELOCITY AND THE

LENGTH OF THE EXCHANGER

• DIRECT SHELL-SIDE FLUID FLOW ALONG TUBE

FIELD. THIS INCREASES THE EFFECTIVE HEAT

TRANSFER CO-EFFICIENT OF THE EXCHANGER

• IN A STATIC MIXER, BAFFLES ARE USED TO

PROMOTE MIXING.

• IN A CHEMICAL REACTOR, BAFFLES ARE OFTEN

ATTACHED TO THE INTERIOR WALLS TO

PROMOTE MIXING AND THUS INCREASE HEAT

TRANSFER AND POSSIBLY CHEMICAL REACTION

RATES

10

BAFFLE SPACING

• BAFFLE SPACING IS AMONG THE MOST

IMPORTANT PARAMETERS USED IN THE DESIGN

OF SHELL AND TUBE HEAT EXCHANGERS.

• CLOSER SPACING CAUSES HIGHER HEAT

TRANSFER, BUT THIS LEADS TO POOR STREAM

DISTRIBUTION AND HIGHER PRESSURE DROP.

• ON THE OTHER HAND, HIGHER BAFFLE SPACING

REDUCES THE PRESSURE DROP, BUT THIS WILL

ALLOW MORE LONGITUDINAL FLOW, WHICH

DECREASES THE COEFFICIENT OF HEAT

TRANSFER.

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• IT IS, THUS, DIFFICULT TO REALIZE THE

ADVANTAGE OF BAFFLE ARRANGEMENTS.

• DP PROPOTIONAL TO 1/B4 AND H TO 1/B0.55

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GEOMETRY

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• DOTL : DIAMETER OF CIRCLE TOUCHING THE

OUTER SURFACE OF OUTERMOST TUBES.

• DCTL : DIAMETER OF CIRCLE PASSING THROUGH

THE CENTERS OF OUTERMOST TUBES.

• LBB: DIAMETRIC CLEARANCE BETWEEN TUBE

BUNDLE AND SHELL INSIDE DIAMETER.

• QCTL: THE ANGLE INTERSECTING DCTL DUE TO

BAFFLE CUT.

• QDS: THE ANGLE INTERSECTING DS DUE TO

EXTENDED BAFFLE CUT.

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BAFFLES SPACING TO BAFFLE WINDOW

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• Connection with the baffle

window dimensioning, the

maximum baffle spacing

should not exceed the shell

diameter Ds.

So, Bmax = Ds

ROLE OF BAFFLE CUT ON FLOW DISTRIBUTION

• IF THE BAFFLE CUT IS TOO SMALL, THE FLOW WILL JET

THROUGH THE WINDOW AREA AND FLOW UNEVENLY

THROUGH THE BAFFLE COMPARTMENT.

• IF THE BAFFLE CUT IS TOO LARGE, THE FLOW WILL

SHORT-CUT CLOSE TO THE BAFFLE EDGE AND AVOID

CROSS-MIXING WITHIN THE BAFFLE COMPARTMENT.

• A BAFFLE CUT THAT IS EITHER TOO LARGE OR TOO

SMALL CAN INCREASE THE POTENTIAL FOR FOULING IN

THE SHELL.

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• THIS REQUIRES A BAFFLE

CUT THAT IS LESS THAN

ONE-HALF OF THE SHELL

INSIDE DIAMETER.

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BAFFLE CUT

• BAFFLE CUT IS THE HEIGHT OF

THE SEGMENT THAT IS CUT IN

EACH BAFFLE TO PERMIT THE

SHELL SIDE FLUID TO FLOW

ACROSS THE BAFFLE.

• THIS IS EXPRESSED AS A

PERCENTAGE OF THE SHELL

INSIDE DIAMETER.

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• ALTHOUGH THIS, TOO, IS AN IMPORTANT

PARAMETER FOR STHE DESIGN, ITS EFFECT IS

LESS PROFOUND THAN THAT OF BAFFLE

SPACING.

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SEGMENTAL BAFFLE CUT GEOMETRY

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• SEGMENTAL BAFFLE CUT

HEIGHT :LBCH

• ASSUMING THAT THE

SEGMENTAL BAFFLE IS

CENTERED WITHIN THE

SHELL INSIDE DIAMETER.

• THE SMALL DIFFERENCE BETWEEN THE SHELL

AND BAFFLE DIAMETER IS CALLED THE

CLEARANCE LSB AND IT IS IMPORTANT FOR

LEAKAGE CORRECTIONS

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STUDY DONE AT

• DEPARTMENT OF MECHANICAL ENGINEERING,

UNIVERSITY OF MALAYA, 50603 KUALA LUMPUR,

MALAYSIA

• PROF. M.M. ELIAS ,PROF. I.M. SHAHRUL , PROF.I.M.

MAHBUL , PROF. R. SAIDUR , PROF.N.A. RAHIM

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ANALYSIS

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• HEAT EXCHANGER OPERATED WITH BOEHMITE

ALUMINA (ALOOH) NANOPARTICLES OF 0 TO 1 %

VOLUME CONCENTRATION WHICH ARE

SUSPENDED IN A MIXTURE OF WATER/ETHYLENE

GLYCOL (50/50 MIXTURE OF ETHYLENE GLYCOL

AND WATER) AT 365 K WERE USED.

• BOTH FLUIDS ARE UNMIXED

• SINGLE PASS TUBE CROSS FLOW HEAT

EXCHANGER IS USED

• MASS FLOW RATE IS CONSTANT TO GET LAMINAR

FLOW

• E-TYPE SHELL AND TUBE HEAT EXCHANGER IS USED

• ALOOH PRESENT IN MANY FORMS (PLATELETS,

BLADES, CYLINDRICAL AND BRICKS)

• NANOFLUIDS AND FLUE GAS ARE THE WORKING

FLUID

• FLUE GAS INCLUDE NITROGEN (60.3%), WATER

(24.4%), CARBON DIOXIDE (12.1%), AND OXYGEN

(3.2%).

• CONSTANT MASS FLOW RATE IS MAINTAINED TO GET

LAMINAR FLOW24

SPECIFICATIONS OF E TYPE STHE

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Parameter Value

Tube inside diameter 22.9mm

Tube outside diameter 25.4 mm

Shell inner diameter 2090 mm

Total number of tubes 1024

Pitch 1.75

Baffle spacing 1776 mm

Shell thickness 14mm

Length 5m

Flue gas mass flow rate 26.3 kg/s

Nanofluid mass flow rate 35 kg/s

Nanofluid inlet temperature 30⁰C

Flue gas inlet temperature 100⁰C

RESULTS

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1. EFFECTS OF OVERALL HEAT TRANSFER

COEFFICIENT-DIFFERENT BAFFLE ANGLE

• FOR ALL THE SHAPES, THE OVERALL HEAT TRANSFER

COEFFICIENT INCREASES WITH THE INCREASE OF

VOLUME CONCENTRATION.

• NANOFLUID WITH EVERY NANO-PARTICLE SHAPE OF

200 BAFFLE ANGLE SHOWS GREATER OVERALL HEAT

TRANSFER COEFFICIENT COMPARED WITH OTHER

BAFFLE ANGLES.

• FOR COMPARING THE ALL FOUR TYPES OF BAFFLE

ANGLES, NANOFLUID CONTAINING CYLINDRICAL

SHAPE NANOPARTICLE SHOWS BETTER OVERALL

HEAT TRANSFER COEFFICIENT IN COMPARISON

WITH OTHER SHAPES.

• THE OTHER SHAPES BRICKS, BLADES, AND

PLATELETS. BLADES AND PLATELETS SHOW

ALMOST SIMILAR INCREASING TREND FOR ALL

BAFFLE ANGLES WITH THE INCREASE OF VOLUME

CONCENTRATION

• LOWEST PERFORMANCE WAS FOUND FOR

PLATELETS SHAPE BASED NANOFLUID AMONG THE

OTHER CONSIDERED NANOPARTICLES SHAPES

FOR ALL BAFFLE ANGLES.

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28

20° 30°

40° 50°

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EFFECTS OF OVERALL HEAT TRANSFER COEFFICIENT-

SEGMENTED BAFFLES

• FOR SEGMENTAL BAFFLES,NANOFLUID HAVING

CYLINDRICAL SHAPE SHOWS HIGHER OVERALL HEAT

TRANSFER COEFFICIENT

• THE OVERALL HEAT TRANSFER COEFFICIENT BY

USING NANOFLUID WITH CYLINDRICAL SHAPE FOR

SEGMENTAL BAFFLE IN CORRESPONDING TO 1 VOL.%

CONCENTRATION IS FOUND 2.5% AND

• IT IS 1.2% HIGHER THAN 400 AND 500 BAFFLE ANGLES

RESPECTIVELY, AND 17.8% AND 6.8% LOWER THAN 200

AND 300 BAFFLE ANGLES RESPECTIVELY.

• ALL THE CASES SEGMENTAL BAFFLES AND

BAFFLE ANGLE OVERALL HEAT TRANSFER

COEFFICIENT IS ESTABLISHED HIGHER FOR 200

BAFFLE ANGLE.

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0°

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2. EFFECTS OF HEAT RATE-DIFFERENT BAFFLE

ANGLE

• HEAT TRANSFER RATE MOSTLY DEPENDS ON

EFFECTIVENESS

• HEAT TRANSFER RATE IS FOUND HIGHER FOR

NANOFLUID CONTAINING CYLINDRICAL SHAPE

• RATE IS LOWER FOR PLATELETS SHAPE.

• AT 1 VOL.% CONCENTRATION, HEAT TRANSFER

RATE FOR CYLINDRICAL SHAPE IS FOUND 0.5%

GREATER THAN PLATELETS SHAPES.

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20° 30°

40° 50°

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EFFECTS OF HEAT RATE-SEGMENTED BAFFLE

• FOR SEGMENTAL BAFFLES, NANOFLUID HAVING

CYLINDRICAL SHAPE SHOWS HIGHER HEAT

TRANSFER RATE

• THE HEAT TRANSFER RATE AT 1 VOL.%

CONCENTRATION, CYLINDRICAL SHAPE NANOFLUID

IS FOUND APPROXIMATELY 0.5% HIGHER THAN

BOTH BLADES AND PLATELETS SHAPE NANOFLUID.

• NANOFLUID HAVING CYLINDRICAL SHAPE FOR

SEGMENTAL BAFFLE IS FOUND 0.8% AND 8.95%

HIGHER THAN 400 AND 500 BAFFLE ANGLES

RESPECTIVELY

• AND 14.6% AND 6.96% LOWER THAN 200 AND 300

BAFFLE ANGLES RESPECTIVELY IN

CORRESPONDING TO 1 VOL.%

CONCENTRATION.

NANOFLUID CONTAINING BLADES AND

PLATELETS SHAPE PERFORMS ALMOST

SIMILAR INCREASING TREND WITH THE

INCREASE OF VOLUME CONCENTRATION.

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35

0°

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3. EFFECT ON ENTROPY GENERATION-DIFFERENT

BAFFLE ANGLES

• MINIMIZATION OF THE ENTROPY GENERATION

HAPPENS FOR ALL NANOPARTICLE SHAPES WITH

THE INCREASE OF NANOPARTICLE VOLUME

FRACTION.

• THE ENTROPY GENERATION FOR THE 200BAFFLE

ANGLE IS FOUND HIGHER.

• THE MAXIMUM ENTROPY GENERATION RATE FOUND

TO BE AT 0 VOL.% CONCENTRATION (MEANS BASE

FLUID) FOR ALL BAFFLE ANGLES.

• THE MINIMIZATION OF ENTROPY GENERATION IS

FOUND TO SUPERIOR FOR THE CYLINDRICAL

SHAPE IN COMPARISON WITH THE ALL OTHER

SHAPE FOR ALL BAFFLE ANGLES.

• THE MINIMIZATION OF ENTROPY GENERATION IS

FOUND HIGHER FOR THE BRICKS THAN BLADE

AND PLATELETS BUT LOWER THAN THE

CYLINDRICAL SHAPE.

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38

20°

50°

30°

40°

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EFFECT ON ENTROPY GENERATION-SEGMENTED

BAFFLES

• FOR SEGMENTAL BAFFLES, THE MINIMIZATION OF

ENTROPY WILL OCCURRED WITH THE

INCREASING OF NANOPARTICLE VOLUME

FRACTION

• THE ENTROPY GENERATION RATE DECREASES

WITH INCREASE OF THE VOLUME

CONCENTRATION AND THE

• MINIMIZATION OF ENTROPY GENERATION

DECREASES WITH THE INCREASE OF BAFFLE

ANGLE.

40

0°

EXPERIMENTAL RESULTS

• (AL2O3, SIO2, CUO, ZNO) HEAT TRANSFER COEFFICIENT

IMPROVE BY 39% WHEN COMPARED WITH WATER

• BY USING 2.5 WT.% OF GRAPHITE NANOPARTICLES 22%

HIGHER CONVECTIVE HEAT TRANSFER IS OBTAINED

• 0.3 VOL.% OF AL2O3 ,TIO2–WATER NANOFLUID SHOWS

BETTER HEAT TRANSFER PERFORMANCE

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CONCLUSION

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• FOR NANOFLUIDS OF CYLINDRICAL SHAPES HAVE

BETTER OVERALL HEAT TRANSFER COEFFICIENT

• THE MAXIMUM OVERALL HEAT TRANSFER

COEFFICIENT WAS FOUND FOR 200 BAFFLE ANGLE

THAN ANY OTHER BAFFLE ANGLE AS WELL AS

SEGMENTAL BAFFLE.

• BY THE USAGE OF 1 VOL.% CONCENTRATION OF

BOEHMITE ALUMINA (ALOOH) NANOPARTICLE SHOWS

THE ENHANCEMENT OF 12%, 19.9%, 28.23% AND

17.85% FOR CYLINDRICAL SHAPE NANOPARTICLE AT

200 BAFFLE ANGLE COMPARED TO 300, 400, 500 BAFFLE

ANGLES AND SEGMENTAL BAFFLE.

• AND THE LOWER OVERALL HEAT TRANSFER

COEFFICIENT WAS FOUND FOR BLADES AND

PLATELETS SHAPES OF THE NANOPARTICLES,

• THE HEAT TRANSFER RATE FOR EVERY SHAPE OF

NANOPARTICLES WAS FOUND HIGHER FOR 200

BAFFLE ANGLE BY COMPARED WITH THE OTHER

BAFFLE ANGLE AND SEGMENTAL BAFFLES.

• BY THE USAGE OF 1VOL.% CONCENTRATION OF

BOEHMITE ALUMINA (C-ALOOH) NANOPARTICLE

SHOWS THE INCREMENT OF 8.2%,15.37%, 22.3%

AND 14.6% FOR CYLINDRICAL SHAPE

NANOPARTICLE AT 200 BAFFLE ANGLE COMPARED

TO 300, 400, 500BAFFLE ANGLES AND SEGMENTAL

BAFFLE.

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• THE NANOFLUIDS HAVING BLADES AND

PLATELETS SHAPES OF NANOPARTICLES

SHOWED LOWER HEAT TRANSFER RATE.

• THE ENTROPY MINIMIZATION RATE WAS FOUND

TO BE HIGHER FOR THE CYLINDRICAL SHAPE

COMPARED TO ANY OTHER SHAPES AT AN 200

BAFFLE ANGLE.

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REFERENCE

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ALUMINUM OXIDE NANOFLUIDS IN DIESEL ELECTRIC GENERATOR AS

JACKET WATER COOLANT, APPL. THERM.

2. S. CHOI, ENHANCING THERMAL CONDUCTIVITY OF FLUIDS WITH

NANOPARTICLES, IN: D.A.SIGINER, H.P. WANG (EDS.), DEVELOPMENTS

APPLICATIONS OF NON-NEWTONIAN FLOWS, ASME, NEW YORK, 1995, PP.

99–105. FED-VOL 231/MD-VOL 66.

3. I.M. MAHBUBUL, R. SAIDUR, M.A. AMALINA, LATEST DEVELOPMENTS ON

THE VISCOSITY OF NANOFLUIDS, INT. J. HEAT MASS TRANSFER 55 (4) (2012)

877–888.

4. J.-Y. JUNG, C. CHO, W.H. LEE, Y.T. KANG, THERMAL CONDUCTIVITY

MEASUREMENT AND CHARACTERIZATION OF BINARY NANOFLUIDS, INT. J.

HEAT MASS TRANSFER 54 (9–10) (2011) 1728–1733.

5. J. LEE, K. HWANG, S. JANG, B. LEE, J. KIM, S. CHOI, C. CHOI, EFFECTIVE

VISCOSITIES AND THERMAL CONDUCTIVITIES OF AQUEOUS NANOFLUIDS

CONTAINING LOW VOLUME45

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