船用柴油机多缸流动不均匀性的数值模拟与优化

采用数值模拟方法建立整机冷却水腔三维模型,研究大型船用柴油机的多缸流动不均匀性问题。分析了进出口位置和不同进口流量对流量不均匀度的影响。结果显示:冷却水腔进出口位置对各缸不均匀性有较大影响;进口位置布置于V型机端面中部,且出口位置靠近机体轴向中部,均有利于使各缸压力损失均匀并提高进水均匀性。对原冷却水腔结构优化后,流量不均匀度从7.10%下降至3.91%;各缸流量不均匀度基本不随进口流量的增加而变化;且A、B两列气缸流量基本一致。

Numerical Simulation and Design Optimization of Multi-Cylinder FlowNon-uniformity in Marine Diesel Engines

In order to study the multi-cylinder flow non-uniformity in large marine diesel engines, the three-dimensional model of cooling water jacket was built up using numerical simulation method. The impact of different locations of cooling water inlet and outlet and varied flow rates of inlet on the flow non-uniformity of cooling water was studied. The results show that the locations of inlet and outlet have great impact on the flow distribution of each cylinder. The inlets located in the central section of the end face and the outlet close to axial middle position for V-type engines both help to uniform the pressure loss and improve the flow uniformity of each cylinder cooling water jacket. After structure optimization of the original cooling water jacket, the flow non-uniformity declines from 7.10% to 3.91%. The flow non-unifor-mity of each cylinder hardly changes with the increase of flow rate, and the cooling water flow of row A and row B keeps consistent.