The Combined Effects of Maldistributions of the Inlet Air Temperature and the Induced Flow Nonuniformity on the Performances of Radiator, Heater, and Oil Cooler

A mathematical method for determination of the heat transfer effectiveness of the engine radiator, heater or oil cooler of automobile accounting for the effects of the nonuniformity of the inlet air temperature distribution and the induced nonuniformity of the mass velocity distribution is developed. Using several typical models of the two-dimensional nonuniform inlet temperature distributions of the cooling air flow, the induced nonuniform mass velocity distributions are determined. The heat transfer effectiveness of the unit and its deterioration are calculated for typical operating conditions accounting for this combined effect. A Non-uniformity Factor of the inlet air temperature distribution is suggested as an index for estimating the degree of the deterioration of the thermal performance of the engine radiator, heater or the oil cooler.