The parallel flow heat exchanger with mini-channel is used as the major radiator for fuel cell vehicle (FCV) to dissipate the waste heat, product by fuel cell stack, from the coolant, a glycol-water mixture with volume concentration of 50%, to the air. Under the operating conditions with varied inlet temperatures of air and coolant, coolant volume flow rate and air velocity, the flow and heat transfer characteristics of the heat exchanger is investigated experimentally. Then, a dimensionless parameter, κ, is defined to quantify the influences of the condition parameters on heat transfer and pressure drop. The trends of coolant-side Nusselt number Nu and friction factor f with Reynolds number Re are investigated. It is observed that the flow transition from laminar to turbulent in the mini-channels (D=2.685 mm) of the heat exchanger occurred at the critical Reynolds number , Rec=1 750, which is lower than that in conventional channels and higher than that in micro-channels. Furthermore, the coolant-side correlations are developed in different forms for laminar and turbulent flows to predict the heat transfer coefficients and friction factors. The correlation of air-side friction coefficient fa is also present. Great agreements between the predicted and experimental values are observed. The deviations of Nu and f are within [-7.06%,5.93%] and [-3.95%,4.11%]. And the errors of fa ranged from -2.22% to 3.62%. Base on these correlations, a mathematical model is built to predict performance of FCV radiators under various operating conditions, especially some extreme but significant conditions that could not realize at labs.
WANG Ting
,
GU Bo
,
QIAN Cheng
,
MA Hongtao
. Experimental and Theoretical Analysis for Heat Transfer and Flow Performance of Mini-channel Parallel Flow Heat Exchanger in Vehicle[J]. Journal of Mechanical Engineering, 2016
, 52(4)
: 141
-147
.
DOI: 10.3901/JME.2016.04.141
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