传热
二冲程发动机
冲程(发动机)
往复运动
流量(数学)
燃烧
四冲程发动机
机械
汽车工程
废气
废气再循环
热机
汽油机
内燃机
机械工程
工程类
热力学
燃烧室
物理
化学
有机化学
气体压缩机
作者
José Manuel Luján,Héctor Climent,Pablo Olmeda,Víctor Daniel Jiménez
标识
DOI:10.1016/j.applthermaleng.2014.04.045
摘要
Heat transfer from the hot gases to the wall in exhaust systems of high-performance two-stroke engines is underestimated using steady state with fully developed flow empirical correlations.This fact is detected when comparing measured and modelled pressure pulses in different positions in the exhaust system.This can be explained taking into account that classical expressions have been validated for fully developed flows, a situation that is far from the flow behaviour in reciprocating internal combustion engines.Several researches have solved this phenomenon in four-stroke engines, suggesting that the unsteady flow is strongly linked to the heat transfer.This research evaluates the correlations proposed by other authors in four stroke engines and introduces a new heat transfer model for exhaust systems in two-stroke, high performance, gasoline engines.The model, which accounts for both the entrance length effect and flow velocity fluctuations, is validated against experimental measurements.Comparisons of the proposed model with other models are performed, showing not negligible differences in the scavenge process related parameters.
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