摘要
通过数值模拟方法研究了船用柴油机排气温度与排气背压变化对水平布置排气管内气液两相逆流特性的影响。结果表明:在相同排气量下,排气温度升高会使水倒流减弱,降低水倒灌发生风险;排气背压增大会使水倒流增强,即增大水倒灌发生风险。除排气速度外,排气的密度、黏度等物性参数也对水下排气管内水倒灌的发生具有重要影响。因此在柴油机排气系统设计中,需考虑排气参数波动对防倒灌的影响;在基于Wallis数的防倒灌设计准则中,需进一步考虑排气黏度对气液逆流极限完全携带点的影响。
In order to prevent marine diesel engine from a damage caused by the water pouring back into the diesel from the exhaust pipe,a numerical simulation study was performed on effects of fluctuations in exhaust temperature and exhaust back pressure on the counter current flow limitation in horizontal exhaust pipes.The result indicates that,under the condition of the same exhaust mass flow rate,the increase in exhaust temperature can weaken water backflow in exhaust pipes while the increase in exhaust back pressure can enhance water backflow.In other words,an increased exhaust back pressure can increase the risk of water intrusion accident while an increased exhaust temperature can not.Meanwhile,the result reveales that,in addition to the gas velocity,the properties of exhaust gas,such as the density and viscosity,have a significant influence on the occurrence of water backflow in exhaust pipes.Therefore,it is suggested to consider the effect of exhaust parameter fluctuation on the prevention of water backflow intrusion in the design of exhaust system,and to consider the effect of gas viscosity on the zero liquid penetration point into the prediction model which is often based on a Wallis number that does not include the viscosity of gas.
作者
马有福
王硕
陆鹏
朱奎
马浩
MA Youfu;WANG Shuo;LU Peng;ZHU Kui;MA Hao(Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China;Shanghai Marine Diesel Engine Research Institute, Shanghai 200090, China)
出处
《内燃机工程》
EI
CAS
CSCD
北大核心
2020年第6期95-100,共6页
Chinese Internal Combustion Engine Engineering
关键词
船用柴油机
水下排气
水倒灌
气液逆流极限
marine diesel engine
exhausting underwater
water backflow
counter current flow limitation
