【摘要】 针对高强化发动机的热负荷问题,寻求适当的冷却水量、压力及合理的流场分布是柴油机冷却水腔设计的重要一环。本文以某船用柴油机气缸盖-气缸套冷却水腔为研究对象,通过冷却系统一维仿真得出边界条件,利用FLUENT软件对冷却水腔的冷却水流场进行数值模拟。通过对三维流场的分析,对水腔的压力损失、流场分布给出了恰当的评估并指出了流动优化的方向。为研究发动机冷却水腔内存在的过冷沸腾传热现象,借助于空泡份额(单位容积中气泡所占的百分比)的概念,提出和建立了一种基于单相流的沸腾传热计算方法。更多还原

【Abstract】 For matching the requirement of thermal load of the compact engine,seeking for the appropriate mass flow,pressure and velocity distribution is an important part of design of diesel engine cooling jacket.In this paper,CFD simulation of the cylinder head-block cooling jacket of a marine diesel engine is employed by using FLUENT software,the boundary condition are provided by 1-D simulation of cooling system.Base on the analysis of the three-dimension flow field,the pressure losses and flow field distribution of the cooling jacket are evaluated,and the optimize direction is showed.Aiming at the heat-transfer phenomenon of sub-cooled boiling in cooling water jacket of engine,a new computational model of boiling heat transfer which is based on single-phase flow is presented and established by means of the concept of void fraction(the percentage of vapor in unit volume).更多还原