scholarly journals Investigation of effect on cross-flow heat exchanger with air flow non-uniformity under low Reynolds number

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770808 ◽  
Author(s):  
Kai Shen ◽  
Zhendong Zhang ◽  
Ziqing Zhang ◽  
Youwen Yang
Keyword(s):  
Reynolds Number ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Low Reynolds Number ◽  
Air Flow ◽  
Cross Flow ◽  
Calculation Model ◽  
Flow Heat ◽  
Air Flows ◽  
Low Reynolds

In this study, the theoretical and experimental study of a cross-flow heat exchanger is carried out based on the theory of porous media under low Reynolds number. The accuracy of the mathematical calculation model is verified by experiments. Pressure drop in air side and efficiency of heat exchanger are analyzed with mathematical models of various non-uniform air flows under low Reynolds number. The responses are found influences of air flow non-uniformity on pressure drop and efficiency of heat exchanger have certain rules. The difference in pressure drops between non-uniform air flows and evenly distributed air flows is linearly related to variance [Formula: see text] of non-uniformity. And the increasing rate of resistance energy consumption difference between non-uniform air flows and evenly distributed air flows is approximately linearly related to the relatively non-uniform coefficient squared [Formula: see text] of non-uniformity. The descent range of heat transfer efficiency has exponential relation to the relatively non-uniform coefficient [Formula: see text].

Analysis of Flow Mal-Distribution in a Cross-Flow Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 1428-1432 ◽  
Author(s):  
Krishna P. Mohan ◽  
Shekar M. Santosh ◽  
M. Ramakanth ◽  
M.R. Thansekhar ◽  
M. Venkatesan
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Cross Flow ◽  
Flow Distribution ◽  
Ansys Fluent ◽  
Commercial Code ◽  
Uniform Flow Distribution ◽  
Flow Heat ◽  
Channel Assembly ◽  
Uniform Fluid

Flow mal-distribution is defined as the non-uniform fluid flow distribution among the parallel channels having a common header. Flow mal-distribution is present in every header channel assembly. This mal-distribution has a significant effect on the performance of the heat exchanger by increasing the pressure drop and affecting the heat transfer characteristics. However, in designing a heat exchanger, a uniform flow distribution in each channel is assumed. The present work attempts to reduce the flow mal-distribution in a cross flow heat exchanger. A numerical analysis is done using a commercial code ANSYS FLUENT 3D and the results are validated experimentally. A parametric study is done by changing the size of the channels within the heat exchanger so as to reduce the flow mal-distribution. The effect of varying channel size on flow mal-distribution and pressure drop across the heat exchanger is studied and a geometry with reduced flow mal-distribution is found.

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