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Local resistance of fluid flow across sudden
contraction in small channels |
| Hang GUO,Ling WANG,Jian YU,Fang YE,Chongfang MA,Zhuo LI, |
| Key Laboratory of Enhanced
Heat Transfer and Energy Conservation, Ministry of Education of China,
College of Environmental and Energy Engineering, Beijing University
of Technology, Beijing 100124, China；Key Laboratory of Heat
Transfer and Energy Conversion, Beijing Municipality, Beijing University
of Technology, Beijing 100124, China; |
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Abstract The pressure drop caused by flow area contraction in microchannels has been experimentally studied in this paper using the tiny gap pressure measurement method. The working fluid was deionized water at room temperature at near-atmospheric pressure. Three test sections with area ratios of 0.284 and 0.274 and at different tube diameter sizes were used. The experimental results show that the abrupt contraction coefficient Kc decreases with the Reynolds number increasing, and it is much higher than that of conventional tubes in laminar flow. The widely-applied correlation Kc=0.5(1−σ)0.75 could not predict the contraction coefficient of turbulent flow in the micro tubes. The Kc decreases as the tube diameter increases. The transition from laminar to turbulent flow is not obvious when the diameter of the small tube is 0.32mm.
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| Keywords
microchannels
pressure drop
abrupt contraction
loss coefficients
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Issue Date: 05 June 2010
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Wu P Y, Little W A. Measurementof friction factors for the flow of gases in very fine channels usedfor microminiature Joule-Thompson refrigerators. Cryogenics, 1983, 23(5): 273―277
doi: 10.1016/0011-2275(83)90150-9
|
|
Peng X F, Peterson G P, Wang B X. Frictional flow characteristicsof water flowing through rectangular microchannels. Experimental Heat Transfer, 1994, 7(4): 249―264
|
|
Kohl M J, Abdel-Khalik S I, Jeter S M, et al. An experimentalinvestigation of microchannel flow with internal pressure measurements. International Journal of Heat and Mass Transfer, 2005, 48(8): 1518―1533
doi: 10.1016/j.ijheatmasstransfer.2004.10.030
|
|
Tang G H, Li Z, He Y L, et al. Experimental study of compressibility,roughness and rarefaction influences on microchannel flow. International Journal of Heat and Mass Transfer, 2007, 50(11,12): 2282―2295
|
|
Abdelall F F, Hahn G, Ghiaasiaan S M, et al. Pressure drop causedby abrupt flow area changes in small channels. Experimental Thermal and Fluid Science, 2005, 29(4): 425―434
doi: 10.1016/j.expthermflusci.2004.05.001
|
|
Chalfi T Y, Ghiaasiaan S M. Pressure drop caused by flow area changes incapillaries under low flow conditions. International Journal of Multiphase Flow, 2008, 34(1): 2―12
doi: 10.1016/j.ijmultiphaseflow.2007.09.004
|
|
Yu J, Li Z, Ma C F. Experimental study of pressure loss dueto abrupt expansion and contraction in mini-channels. In: Proceedings of the 13th International Heat Transfer Conference, Sydney: BegellHouse, Paper number: MIC-19, 2006
|
|
Li Z, Yu J, Ma C F. Local resistances of single-phase flowacross abrupt expansion and contraction in small channels. Journal of Chemical Industry and Engineering, 2007, 58(5): 1127―1131 (in Chinese)
|
|
Li Z, Yu J, Ma C F. Characteristics of pressure drop forsingle-phase and two-phase flow across sudden contraction in microtubes. Science in China Series E, 2008, 51(2): 162―169
doi: 10.1007/s11431-007-0030-4
|
|
Kays W M. Loss coefficient for abrupt changes in flow cross sectionwith low Reynolds number flow in single and multiple tube systems. Transaction of ASME, Journal of Fluids Engineering, 1950, 72: 1067―1074
|
|
Geiger S E. Sudden contraction losses in single and two-phase flow. Dissertation for the Doctoral Degree. University of Pittsburgh, 1964
|
|
Idel’cik I E. Handbook of Hydraulic Resistance, 2nd ed. New York: Hemisphere Publishing Corporation, 1986
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