Multiple Parallel Flow Evaporator Numerical Simulation And Performance Optimization

Multi-port extrudeded tube heat exchangers with flat microchanneltubes and high performance folded louvered fins are thinked of as a kindof cost-effective compact heat exchanger. Multi-unit parallel flow typeheat exchangers are new type multi-port extrudeded tube heat exchangerbased on band-tube heat exchanger, and they have been widely used inautomotive condensers. Because of their superior performance they arenow being considered for use in automotive evaporators, residentialair-conditioners etc, and they will be one of the potential alternatives forreplacing the conventional finned-round heat exchangers.The heat transfer and pressure drop characteristic of louvered finsare numerically investigated, and the results of experimental andnumerical simulation are compared, and they have good consistency.Simulations are performed for varying fin pitch, louver pitch, louverangle, and the impact of these geometries on heat transfer and pressuredrop is analyzed. The energy balance method has been used to set upmathematic model, the effects of major parameters on multi-unit parallelflow type evaporator were analyzed. The results of the investigationssuggest that the overall performance of fins can be improved withdecrease of fin pitch; there are optimized louver pitch and louver angle,and the overall performance of fins is the best, when fin pitch vary, theoptimized louver pitch is different, while the optimized louver angle isthe same; the heat transfer performance of evaporator could be improvedby increasing refrigerant mass flow rate, increasing pass number anddecreasing mini-channel dimension, but the increase is more and moreslower, and pressure drop in tube also increase; the ratio of the tubesnumber in each pass also influences heat transfer performance andpressure drop in tube of evaporator, and there is a optimal ratio, heattransfer quantity is maximal, pressure drop in tube is minimum; the angleof evaporator inclination has the effect on pressure drop in tube.The results of this work are of significance for the optimal design ofmulti-unit parallel flow type evaporator.