The Effect of Geometric Deformation on Tubes and Fins on the Heat Transfer Performance of Automotive Coolers

The aim of this paper is to investigate the effect of deformation in the tubes and fins of a car engine cooler on heat transfer parameters during the cooling process. Circular finned tubes in a staggered arrangement in a laboratory cooling circuit of a car engine are studied experimentally. In terms of heat transfer performance, a non-deformed cooler is compared with 20%, 40%, and 60% deformed cooler cores when using air cooling by a cooler fan (CF) and a ram-air fan located in front of the cooler (RAF). The temperature parameters of the coolant and the cooler surface and the values of heat transfer rate, heat transfer coefficient, thermal efficiency, efficiency factor, and Nusselt number are evaluated. Deformation of the cooler core decreases the cooler’s heat dissipation capacity. The combination of a deformed cooler and ram-air cooling is ineffective for maintaining the optimum operating temperature of the coolant, especially under slow-speed driving conditions or at higher ambient temperatures. The cooler fan cooling reaches heat transfer coefficients that are 1.2 to 3.2 times higher and average Nusselt numbers that are 28.2% to 58.5% higher compared to ram-air cooling. Maximum deformation of the cooler core causes a 37% and 40% decrease in the heat transfer coefficient compared to the non-deformed cooler. Efficiency factors of 0.6 and 0.5 for CF and RAF cooling at maximum deformation can lead to significant problems with engine overheating.