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Measured and Predicted Effects of Air Flow Non-Uniformity on Thermal Performance of an R-134a Evaporator
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Abstract
Tests have been carried out over a wide range of operating conditions on a single circuit plate-finned tube type of refrigerant evaporator, exchanging heat between ambient air and refrigerant R134a. Uniform and non-uniform air flow distributions were applied with the objective of studying the effects of non-uniformity on heat transfer.
The experimental results revealed that, for a given total volume flow of air, heat transfer performances could be up to 15% better with a non-uniform flow where turbulence levels were also high.
Extensive comparisons were also made between these measurements and predictions from a computer model. This was designed to simulate the thermal behavior of cross-flow heat exchangers on a tube segment-by-segment basis, allowing for flow non-uniformity. Predictions were found to match measurements satisfactorily for test cases involving uniform air flows and a relatively large temperature difference between fluids. In contrast to the measured trends, the simulation results predicted a degradation in heat transfer performance for non-uniform air flow cases.
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Citation
Ryan, A. and Timoney, D., "Measured and Predicted Effects of Air Flow Non-Uniformity on Thermal Performance of an R-134a Evaporator," SAE Technical Paper 970831, 1997, https://doi.org/10.4271/970831.Also In
References
- Kitto, J.B. Robertson J.M. Effects of Mal-Distribution of flow on Heat Transfer Equipment Performance Heat Transfer Engineering 10 1 1989
- Fagan, T.J. The effects of Air-Flow Maldistributions on Air-to-Refrigerant Heat Exchanger performance ASHRAE Transactions 1980
- Chiou, J.P. Thermal performance Deterioration in Crossflow Heat Exchanger due to the Flow Nonuniformity, Transactions of the ASME Journal of Heat Transfer 100 580 1978
- Chiou, J.P. The effect of Air Flow Nonuniformity on the thermal performance of Automobile Air Conditioning Condenser SAE Transactions , ( 830542 ) 1984
- Chiou, J.P. The effect of Air Flow Nonuniformity on the thermal performance of Evaporator of Automobile Air Conditioning System SAE Transactions , ( 840381 ) 1985
- Berryman, R.J. Russell C.M.B. The effect of maldistribution of air flow on Air-Cooled heat exchanger performance Transactions of the ASME, Journal of Heat Transfer 1987
- Rabas, T.J The Effect of Nonuniform Inlet Flow and Temperature Distributions on the thermal performance of Air-Cooled condensers Transactions of the ASME, Journal of Heat Transfer 1987
- Kondo, F. Aoki Y. Prediction method on effect of Thermal Performance of Heat Exchanger due to Non-uniform Air Flow Distribution SAE Transactions , ( 850041 ) 1985
- Domanski, P.A. EVSIM- An evaporator model accounting for refrigerant and one-dimensional air distribution Gaithersburg, MD National Institute of Standards and Technology 1989
- Domanski, P.A. Simulation of an Evaporator with Nonuniform One-Dimensional Air Distribution ASHRAE Transactions 1991
- Wattelet, J.P. Chato J.C. Souza A.L. Christoffersen B.R. Evaporative Characteristics of R-12, R-134a, and a Mixture at low Mass Fluxes ASHRAE Transactions: Symposia 100 1 603 615 1994
- Gray, D.L. Webb R.L. Heat Transfer and Friction Correlations for Plate Finned-Tube Heat Exchangers having Plain Fins Proc. of the eighth international Heat Transfer Conference on Heat Transfer Hemisphere Pub. Corp. 6 2778 2750 1986
- Sheffield, J.W. Wood R.A. Sauer, H.J. Jr Experimental Investigation of Thermal Conductance of Finned Tube Contacts Experimental Thermal and Fluid Science 2 107 121 1989
- Pierre, Bo. Flow Resistance with Boiling Refrigerants- Part I ASHRAE Journal September 1964
- McLinden, M.O. Gallagher J.S. Weber L.A. Morrison G. Ward D. Goodwin A.R.H. Moldover M.R. Schmidt J.W. Chae H.B. Bruno T.J. Ely J.F. Huber M.L. Measurement and formulation of the thermodynamic properties of refrigerants 134a (1,1,1,2-Tetraflouroethane) and 123 (1,l-Dichloro-2,2,2-Triflouroethane) ASHRAE Transactions 1989
- Piao, C. Sato H. Watanabe K. Thermodynamic charts, tables and equations for refrigerant HFC-134a ASHRAE Transactions 1991
- Piao, C. Noguchi M. Sato H. Watanabe K. An improved equation of state for R-134a ASHRAE Transactions 100 1 358 366 1994
- Basu, R.S. Wilson D.P. Thermophysical properties of 1,1,1,2-Tetraflouroethane (R-134a) International Journal of Thermophysics 10 3 591 603 1989
- Zhu, Ming-Shan Wu Jiang Yi-Dong Fu New experimental vapour pressure data and a new vapour pressure equation for HFC-134a Fluid Phase Equilibria 80 99 105 1992
- Klea I.C.I. Chemicals for a Better Future Klea 134a Physical Property Data Sheet, S.I. Units, I.C.I. Klea Runcom, Cheshire 1994
- Kabelac, S. A simple set of equations of state for process calculations and its applications to R-134a and R-152a International Journal of refrigeration 14 217 222 1991
- Jung, D. Radermacher R. Transport properties and surface tension of pure and mixed refrigerants ASHRAE Transactions: Research 1991
- Tanaka, Y. Nakata M. Makita T. Thermal conductivity of gaseous HFC-134a, HFC-143a, HCFC-141b & HCFC-142b International Journal of Thermophysics 12 6 949 963 1991
- McGovern, J.A. Low loss Measurement of oil concentration in a refrigerant-oil mixture in a Liquid Line International Journal of Refrigeration 12. 1989
- Pasqua, P.F. Metastable Flow of Freon 12 Refrig. Eng. 61 1953
- Krakow, K.I. Lin S. Refrigerant Flow Through Orifices ASHRAE Transactions 94 484 506 1988
- Aaron, D.A. Domanski P.A. Experimentation, Analysis and Correlation of Refrigerant-22 Flow Through Short Tube Restrictors ASHRAE Transactions 96 1 729 742 1990