大功率船用汽轮机排汽缸的改型设计

Modified Design of Exhaust Cylinder of High-Power Marine Steam Turbine

采用SST湍流模型对某型大功率船用汽轮机排汽缸的内部流动情况进行分析,研究排汽缸内部流动结构特点,并提出新型的加速扩张排汽缸结构。对新型排汽缸结构与旧排汽缸的数值模拟结果进行对比分析,结果表明:加速扩张排汽缸可使排汽缸内部的通道涡在发展中强度加速下降;加速扩张排汽缸可使得排汽缸的全压损失系数明显下降,且随着排缸内质量流量的增加,排汽缸的全压损失系数不断增加,其相对于原排汽缸的损失减小效果更加明显;排汽缸通流的面积变化速率是影响排汽缸内通道涡强度的重要因素,该数值的增加能够有效抑制通道涡在排汽缸内的发展,减小排汽缸的总压损失。

The SST turbulence model is used to analyze the internal flow situation of the exhaust cylinder of a high-power marine steam turbine.The characteristics of the internal flow structure of the exhaust cylinder are studied.A new type of accelerated expansion exhaust cylinder structure is proposed.A comparative analysis of the numerical simulation results between the new exhaust cylinder structure and the old structure shows that accelerating the expansion of the exhaust cylinder can accelerated the strength reduction of the channel vortices inside the exhaust cylinder during development.Accelerating the expansion of the exhaust cylinder can significantly reduce the total pressure loss coefficient of the exhaust cylinder.As the mass flow rate inside the exhaust cylinder increases,the total pressure loss coefficient of the exhaust cylinder continues to increase,which has a more significant reduction effect compared to the original exhaust cylinder.The rate of changing in the flow area of the exhaust cylinder is an important factor affecting the strength of channel vortices in the exhaust cylinder.Increasing this value can effectively suppress the development of channel vortices in the exhaust cylinder can reduce the total pressure loss of the exhaust cylinder.