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  • 1. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 31 AN EXPERIMENTAL STUDY OF HEAT TRANSFER IN A PLATE HEAT EXCHANGER Omar Mohammed Ismael*, Dr. Ajeet Kumar Rai**, HasanFalah Mahdi*, Vivek Sachan** *Ministry of Higher Education and Scientific Research, Republic of Iraq **Department of Mechanical Engineering, SSET, SHIATS-DU, Allahabad (U.P) INDIA-211007 ABSTRACT Experiments were conducted to determine the laminar convective heat transfer characteristics for fully developed flow of hot and cold fluid in alternate ducts. Experiments were conducted on a three channel 1-1 pass plate heat exchanger. Hot fluid was made to flow in the central channel to get cooled by water in the outer channels in parallel and counter flow arrangements. Reynolds number was fixed at 1666.5 for milk and for the cooling water also. The average heat transfer coefficient of the milk-water system is 17% higher compared with water-water system in the counter flow arrangement. Key words: Plate Heat Exchanger, Heat Transfer Coefficient. INTRODUCTION A heat exchanger is a device that is used to transfer thermal energy (enthalpy) between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. In heat exchangers, there are usually no external heat and work interactions. Typical applications involve heating or cooling of a fluid stream of concern and evaporation or condensation of single- or multi component fluid streams. In other applications, the objective may be to recover or reject heat, or sterilize, pasteurize, fractionate, distill, concentrate, crystallize, or control process fluid. In a few heat exchangers, the fluids exchanging heat are in direct contact. In most heat exchangers, heat transfer between fluids takes place through a separating wall or into and out of a wall in a transient manner. In many heat exchangers, the fluids are separated by a heat transfer surface, and ideally they do not mix or leak. Such exchangers are referred to as direct transfer type, or simply recuperate. In contrast, exchangers in which there is intermittent heat exchange between the hot and cold fluids—via thermal energy storage and release through the exchanger surface or matrix are referred to as indirect transfer type, or simply regenerators. Such INTERNATIONAL JOURNAL OF ADVANCED RESEARCH IN ENGINEERING AND TECHNOLOGY (IJARET) ISSN 0976 - 6480 (Print) ISSN 0976 - 6499 (Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME: www.iaeme.com/ijaret.asp Journal Impact Factor (2014): 7.8273 (Calculated by GISI) www.jifactor.com IJARET © I A E M E
  • 2. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 32 exchangers usually have fluid leakage from one fluid stream to the other, due to pressure differences and matrix rotation/valve switching. Common examples of heat exchangers are shell-and tube exchangers, automobile radiators, condensers, evaporators, air pre-heaters, and cooling towers. If no phase change occurs in any of the fluids in the exchanger, it is sometimes referred to as a sensible heat exchanger. There could be internal thermal energy sources in the exchangers, such as in electric heaters and nuclear fuel elements. Combustion and chemical reaction may take place within the exchanger, such as in boilers, fired heaters, and fluidized-bed exchangers. Mechanical devices may be used in some exchangers such as in scraped surface exchangers, agitated vessels, and stirred tank reactors(1) and the detailed of classification is given by shah (2). Heat exchangers are devices used to transfer heat between two or more fluid streams at different temperatures. Heat exchangers find widespread use in power generation, chemical processing, electronics cooling, air-conditioning, refrigeration, and automotive applications. A plate type heat exchanger, as compared to a similar sized tube and shell heat exchanger, is capable of transferring much more heat. This is due to the large area that plates provide over tubes .Plate heat exchangers are used for transferring heat for any combination of gas, liquid and two-phase streams. Plate heat exchangers can be classified as casketed plate, spiral plate or lamella(3).Extended surface heat exchanger Extended surface heat exchangers are generally fins or appendages added to the primary heat transfer surface (tubular or plate) with the aim of increasing the heat transfer area. The two most common types of extended surface heat exchangers are plate-fin heat exchangers and tube-fin heat exchangers. Consist of a stack of parallel thin plates that lie between heavy end plates. Each fluid stream passes alternately between adjoining plates in the stack, exchanging heat through the plates. The plates are corrugated for strength and to enhance heat transfer by directing the flow and increasing turbulence. These exchangers have high heat-transfer coefficients and area, the pressure drop is also typically low, and they often provide very high effectiveness. However, they have relatively low pressure capability. A plate type heat exchanger consists of plates instead of tubes to separate the hot and cold fluids. EXPERIMENTAL SETUP AND PROCEDURE The photograph of the experimental setup, fabricated to investigate the heat transfer characteristics of the plate heat exchanger channels for same flow conditions are shown in (Fig.1).It includes a hot water loop, a coolant loop and a measurement system. The hot water loop and coolant loop comprise water tanks containing heater, pump and temperature indicator. A flow straightener is installed at the entrance and exit of the test section to maintain the uniformity of the flow. The test section of the plate heat exchanger has three ducts. The geometrical characteristics are given in the table1. Two different cases of parallel and counter flow arrangements have been made. Hot fluid (milk) was made to flow through the central channel and cold fluid (water) through the two outer channels. Copper-Constantan thermocouples are used to measure the temperature of the fluids at the inlet and outlet of the heat exchanger. Table 1: Geometrical characteristics of plate heat exchanger Sl. No Parameters Value 1 Length of the test section, L 100 cm 2 Width of the test section, a 10 cm 3 High of the test section, b 5 cm
  • 3. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 33 Fig.1: Plate Heat Exchanger The experimental data was used to calculate the heat exchanger rate, convective heat transfer coefficient, Nusselt number and Peclet number of each of the involved fluids. Heat removal rate; Heat transferred from an elemental part of the exchanger is: The local heat transfer coefficients for the fluids are determined from: where the bulk temperature is given by, the average heat transfer coefficient by, Therefore, it can be shown that Each channel has equal flow area and wetted perimeter givenby, And hence hydraulic diameter of the channel is given by, Dh = 4Ao/P with appropriate second suffix in flow area. The relevant flow- and fluid-properties are found from Specific flow rates for the fluids; Reynolds number of the fluids; The overall heat transfer coefficient Observations and Results: Experimentation is done with hot fluid as milk and as water separately with cold fluid as water in parallel and counter flow arrangements.Numbers of observations were taken on the setup for a fixed inlet temperature of hot and cold fluids. Values are tabulated as shown below.
  • 4. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 34 Table 2: The temperature and properties for counter flow with hot milk in the Centre Thi Tho Tci Tco ρρρρ kg/m2 Cph kJ/kg K K W/mK µ Ns/m Cpc kJ/kg K 70 55 35 36 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 55 35 36 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 56 35 37 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 56 35 38 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 55 35 37 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 55 35 37 1.02998 1009.7543 0.02977 0.00002 1004.3509 70 55 35 37 1.02998 1009.7543 0.02977 0.00002 1004.3509 Table 3: The temperature and properties for parallel flow with hot milk in the Centre Thi Tho Tci Tco ρρρρ kg/m2 Cph kJ/kg K K W/mK µ Ns/m Cpc kJ/kg K 70 58 33 37 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 58 33 37 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 59 33 38 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 59 33 39 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 59 33 39 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 58 33 38 1.02998 1009.7543 0.02977 0.00002 1004.0496 70 58 33 38 1.02998 1009.7543 0.02977 0.00002 1004.0496 Table 4: The temperature and properties for parallel flow with hot water in the Centre Thi Tho Tci Tco ρρρρ kg/m2 Cph kJ/kg K K W/mK µ Ns/m Cpc kJ/kg K 70 48 28 32 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 48 28 32 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 48 28 33 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 49 28 33 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 49 28 34 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 49 28 34 1.02998 1009.7543 0.02977 0.00002 1003.30035 70 49 28 34 1.02998 1009.7543 0.02977 0.00002 1003.30035 Table 5: The temperature and properties counter for flow with hot water in the Centre Thi Tho Tci Tco ρρρρ kg/m2 Cph kJ/kg K K W/mK µ Ns/m Cpc kJ/kg K 70 54 34 39 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 56 34 43 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 57 34 45 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 57 34 47 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 58 34 48 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 59 34 48 1.02998 1009.7543 0.02977 0.00002 1004.2001 70 59 34 48 1.02998 1009.7543 0.02977 0.00002 1004.2001
  • 5. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 35 Table 6: Result for parallel flow with hot water in the Centre Re V m/s LMTD C, k h W /m2 .K Nu εεεε Effectiveness Heat flow Q( w ) 1666.5 0.0485 26.9407 98.485 2265.61 0.5271 5553.64 1666.5 0.0485 26.9407 98.485 2265.61 0.5271 5553.64 1666.5 0.0485 26.223 101.18 2327.6 0.5272 5553.64 1666.5 0.0485 26.9407 94.009 2162.63 0.5032 5301.21 1666.5 0.0485 26.223 96.581 2221.8 0.5032 5301.21 1666.5 0.0485 26.223 96.581 2221.8 0.5032 5301.21 1666.5 0.0485 26.223 96.581 2221.8 0.5032 5301.21 Table 7: Result for counter flow with hot water in the Centre Re V m/s LMTD C, k h W /m2 .K Nu εεεε Effectiveness Heat flow Q( w ) 1666.5 0.0485 24.663 78.241 1799.89 0.4469 4039.02 1666.5 0.0485 25.323 60.676 1533.85 0.391 3534.14 1666.5 0.0485 25.968 60.374 1388.89 0.3631 3281.7 1666.5 0.0485 25.968 60.374 1388.89 0.3631 3281.7 1666.5 0.0485 25.968 55.7307 1282.05 0.3351 3029.26 1666.5 0.0485 27.2207 48.736 1121.15 0.3072 2776.82 1666.5 0.0485 27.2207 48.736 1121.15 0.3072 2776.82 Table 8: Result for counter flow with hot milk in the Centre Re V m/s LMTD C, k h W /m2 .K Nu εεεε Effectiveness Heat flow Q( w ) 1666.5 0.0485 26.1904 69.073 1588.98 0.4308 3786.57 1666.5 0.0485 26.1904 69.073 1588.98 0.4308 3786.57 1666.5 0.0485 26.1904 64.468 1483.05 0.4021 3534.14 1666.5 0.0485 25.564 66.045 1519.35 0.4021 3534.14 1666.5 0.0485 25.564 70.763 1627.87 0.4308 3786.57 1666.5 0.0485 25.564 70.763 1627.87 0.4308 3786.57 1666.5 0.0485 25.564 70.763 1627.87 0.4308 3786.57 Table 9: Result for parallel flow with hot milk in the Centre Re V m/s LMTD C, k h W /m2 .K Nu εεεε Effectiveness Heat flow Q( w ) 1666.5 0.0485 28.248 51.113 1144.5 0.3261 3022.22 1666.5 0.0485 28.248 51.113 1144.5 0.3261 3022.22 1666.5 0.0485 28.248 46.853 1049.13 0.298 2770.37 1666.5 0.0485 27.633 47.896 1022.47 0.2989 2770.37 1666.5 0.0485 27.633 47.896 1022.47 0.2989 2770.37 1666.5 0.0485 27.633 52.250 1169.97 0.3261 3022.22 1666.5 0.0485 27.633 52.250 1169.97 0.3261 3022.22
  • 6. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 36 CONCLUSIONS An experimental set up of heat exchanger was made of Al sheet for heat transfer study. The test section was formed by three identical channels with hot fluid in the middle and cold fluid in the adjacent channels. A milk-water and water-water fluid combinations are selected in parallel and counter flow arrangements of the heat exchanger. It is observed that counter flow arrangement of milk-water combinations is 29.4% more effective than their parallel flow arrangements. Further, milk-water fluid combination in counter flow is 13.2% more effective than water-water fluid combination. Future scope of work: The rate of heat transfer rate can be further increased by having high thermal conductivity fluids or by use of Nano particles of high thermal conductivity materials in the het transfer fluids. Plates of the plate heat exchangers can be corrugated at suitable angles to enhance the heat transfer between the fluids. REFERENCES 1. Shah, R. K. andSekulic D. P. 2003“Fundamentals of Heat Exchanger Design” John Wiley &Sons,Inc 2. Shah, R. K., 1981, Classification of heat exchangers, in Heat Exchangers: Thermal- Hydraulic Fundamentals and Design, S. Kakac¸ , A. E. Bergles, and F. Mayinger, eds., Hemisphere Publishing,Washington, DC, pp. 9–46. 3. SadikKakaç, Hongtan Liu 2002. Heat Exchangers: Selection, Rating, and Thermal Design, Second Edition,CRC Press 4. Shah, R. K., 1991, Industrial heat exchangers—functions and types, in Industrial Heat Exchangers,J-M. Buchlin, ed., Lecture Series No. 1991-04, von Ka´rma´n Institute for Fluid Dynamics, Belgium. 5. Shah, R. K., 1994, Heat exchangers, in Encyclopedia of Energy Technology and the Environment, A.Bisio and S. G. Boots, eds., Wiley, New York, pp. 1651–1670. 6. Shah, R. K., and W. W. Focke, 1988, Plate heat exchangers and their design theory, in Heat TransferEquipment Design, R. K. Shah, E. C. Subbarao, and R. A. Mashelkar, eds., Hemisphere Publishing,Washington, DC, pp. 227–254. 7. Bejan, A.,Heat Transfer, 1993, Wiley, New York, NY. 8. Kakac, S. (ed.),Boilers, Evaporators, and Condensers, 1991, Wiley, New York,NY. 9. Kakac, S. and Liu, H., Heat Exchangers: Selection, Rating, and Thermal Performance, 1998, CRC Press, Boca Raton, FL. 10. Kays, W.M. and London, A.L.,Compact Heat Exchangers, 1984, McGraw-Hill, New York, NY. 11. Kern, D.Q. and Kraus, A.D., Extended Surface Heat Transfer, 1972, McGraw-Hill, New York, NY. 12. L. B.Wang, Y. H. Zhang, Y. X. Su, and S. D. Gao, “Local and Average Heat/Mass Transfer over Flat Tube Bank Fin Mounted In-Line Vortex Generators with Small Longitudinal Spacing”, Journal of Enhanced Heat Transfer ,Vol. 9, pp.77–87, (2002). 13. W. R. Pauley and J. K. Eaton, “ The Effect of Embedded Longitudinal Vortex Arrays on Turbulent Boundary Layer Heat Transfer”, Transactions Of The ASME, Journal Of Heat Transfer, Vol.116, pp.871-878,(1994). 14. Han,J.C. ,“Heat transfer and friction in channels with two opposite rib-roughened walls. ”, Transaction of the ASME, Vol. 106, Nov,(1984).
  • 7. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 6480(Print), ISSN 0976 – 6499(Online) Volume 5, Issue 4, April (2014), pp. 15. Mustafa S Mahdi and Ajeet Kumar Rai of single phase liquid to liquid shell and tube heat exchanger’’ Mechanical Engineering & Technology 16. ShiveDayalPandey, V.K. Nema of nanofluids a coolant in a corrugated plate heat exchanger “ science 38 (2012) 248–256 17. Shah, R. K., 1991, Compact heat exchanger technology and applications, in Heat Exchanger Engineering, Vol. 2, Compact Heat Exchangers: Techniques for Size Reduction, E. A. Foumeny P. J. Heggs, eds., Ellis Horwood, London, pp. 1 18. N.G.Narve and N.K.Sane, Symmetrical Triangular Fin Arrays”, International Journal of Advanced Research in Engineering & Technology (IJARET), Volume 4, Issue 2, 2013, pp. 271 0976-6480, ISSN Online: 0976 19. Ajeet Kumar Rai, Shahbaz Ahmad and Sarfaraj Ahamad Idrisi, and Heat Transfer Study o Engineering & Technology (IJMET), Volume 0976 – 6340, ISSN Online: 0976 AUTHOR’S DETAIL Omar Mohammed B.Sc. in the year 2010 conditioning Eng. Tech education and scientific research in 2014 in Mechanical School of Engineering and Technology, Agriculture Technology & S Dr. A. K. Rai his M.Tech Degree from MNNIT Allahabad in Design of Process Machines and Ph.D. from SHIATS PantNagar from 2003 to 2005. He ha assistant Profes international journals. He has delivered expert lectures in many national and International conferences. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 6499(Online) Volume 5, Issue 4, April (2014), pp. 31-37 © IAEME 37 Mustafa S Mahdi and Ajeet Kumar Rai “A practical approach to design and optimization of single phase liquid to liquid shell and tube heat exchanger’’ International Journal Mechanical Engineering & Technology, 3(3), 378 – 386 (2012). V.K. Nema “Experimental analysis of heat transfer and friction factor of nanofluids a coolant in a corrugated plate heat exchanger “Experimental thermal and fluid , Compact heat exchanger technology and applications, in Heat Exchanger Engineering, Vol. 2, Compact Heat Exchangers: Techniques for Size Reduction, E. A. Foumeny P. J. Heggs, eds., Ellis Horwood, London, pp. 1–29. N.G.Narve and N.K.Sane, “Heat Transfer and Fluid Flow Characteristics of Vertical Symmetrical Triangular Fin Arrays”, International Journal of Advanced Research in echnology (IJARET), Volume 4, Issue 2, 2013, pp. 271 - 6480, ISSN Online: 0976-6499. Ajeet Kumar Rai, Shahbaz Ahmad and Sarfaraj Ahamad Idrisi, “Design, Fabrication of Green House Dryer”, International Journal of Mechanical Engineering & Technology (IJMET), Volume 4, Issue 4, 2013, pp. 1 - 6340, ISSN Online: 0976 – 6359. ohammed Ismael is born in Baghdad in April 1987, he received his in the year 2010 from the department of Refrigeration and Air ditioning Eng. TechTechnical College,of Baghdad,Ministry of higher ucation and scientific research, Republic of Iraq. He completed in Mechanical Engineering (Thermal Engineering) form School of Engineering and Technology, Sam Higginbottom Institute of culture Technology & Sciences, Allahabad, U.P, India. is born in 1977, Distt. Ballia (Uttar Pradesh) India. He received his M.Tech Degree from MNNIT Allahabad in Design of Process Machines and Ph.D. from SHIATS- DU Allahabad in2011. He has been in GBPUAT PantNagar from 2003 to 2005. He has Joined SHIATS-DU Allahabad as assistant Professor in2005. He has published more than 25 papers in international journals. He has delivered expert lectures in many national and International conferences. International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 – © IAEME practical approach to design and optimization International Journal of xperimental analysis of heat transfer and friction factor xperimental thermal and fluid , Compact heat exchanger technology and applications, in Heat Exchanger Engineering, Vol. 2, Compact Heat Exchangers: Techniques for Size Reduction, E. A. “Heat Transfer and Fluid Flow Characteristics of Vertical Symmetrical Triangular Fin Arrays”, International Journal of Advanced Research in 281, ISSN Print: “Design, Fabrication International Journal of Mechanical - 7, ISSN Print: April 1987, he received his the department of Refrigeration and Air- Ministry of higher e completed his M .Tech. Engineering (Thermal Engineering) form Shepherd igginbottom Institute of lia (Uttar Pradesh) India. He received his M.Tech Degree from MNNIT Allahabad in Design of Process Machines He has been in GBPUAT DU Allahabad as sor in2005. He has published more than 25 papers in international journals. He has delivered expert lectures in many national and