Study On Plate-Fin Heat Exchange For Engine Waste Heat Utilization

Energy is the basis of national stability and social development.my country’s oil is seriously dependent on abroad,and most of which are used in traffic fields,but the transformation efficiency of the vehicle engine is only about 40%,and most of the energy is discharged into the atmosphere in the form of thermal energy.In order to improve energy utilization efficiency,the plate fin heat exchanger in the engine exhaust gas heat recovery system is studied,and the plate fin heat exchangers are analyzed and studied from structural parameters,operating parameters,and strengthen heat transfer.By reviewing the literature,the research status of engine exhaust gas heat recovery technology and plate fin heat exchanger is summarized.Analysis of the heat transfer model of the plate fin heat exchanger,on this,discuss the evaluation criteria,based on heat transfer equation,analyze the enhanced heat transfer,and study how to improve heat transfer coefficients.Using a three-dimensional software to build a plate fin heat exchanger model,mesh division and model verification,using control variable method,flat-wire heat exchanger structural parameters for straight,zigzag and ripple three different types of fins Through simulation of simulation,the relationship between fin structural parameters and heat transfer performance and flow resistance characteristics are studied.The results show that with the increase in the height of the fin,the better the integrated performance of the fins.In the study of the heat exchange parameters,the engine’s exhaust gas temperature,the inlet speed of the heat exchanger and the influence of the type on heat exchange performance are analyzed by the evaluation criteria.The results show that the higher the engine exhaust gas temperature,the better the heat transfer performance;the inlet speed of the cold working effect has less impact on the heat transfer performance of the fins.Based on the theory of enhanced heat transfer and the limitations of the fin structure,a tapered baffle structure is proposed for straight fins and zigzag fins;the porous structure and corrugated fins are combined to form corrugated porous fins.The research results show that by improving the structure,the heat transfer performance of the flat and corrugated fins has been improved,but the flow resistance inside the fins is also increased,which is not conducive to engine exhaust emissions;the improved structure of the sawtooth fins is not only The heat transfer performance can be improved,and the internal pressure drop of the heat exchange core can also be reduced.In the study of the work quality,the temperature of the fins of the fins by water is used as the temperature of the cold fluid,but the amount of heat transfer of the fins is large,but the boiling of ethanol and 95% alcohol solution is low,and the temperature is fast,more It is easy to vaporize,so ethanol and 95% alcohol solution are more suitable as circulating power generation.