基于ANSYS燃气轮机排气引射器优化设计

Optimization Design of Gas Turbine Exhaust Ejector Based on ANSYS

摘要: 为了探究最佳尺寸的排气引射器对燃气轮机箱体的冷却效果，应用计算流体动力学理论，建立某船用燃气轮机箱装排气引射器体模型，并通过ANSYS对不同喷嘴距以及不同混合室直径的船用燃气轮机排气引射器进行仿真。结果表明，随着喷嘴距的增加其引射效率在不同混合室直径下变化规律不一，较小混合室直径的引射效率变化不明显，而较大混合室直径变化规律先增加后逐渐变化不明显，当喷嘴距达到1 m时效果最好；而随着混合室直径增加，不同喷嘴距其引射系数变化规律都先增加后减少，当混合室直径为1.8 m时为最佳。当船用燃气轮机排气引射器选用喷嘴距为1 m，混合室直径为1.8 m时，能够达到最大的引射效率为38.12%，此时对于箱体的冷却效果为最佳，其满足了工业型燃气轮机零组件的使用要求和天然系统的防爆要求。

Abstract: In order to explore the cooling effect of the exhaust ejector with the best size on the gas turbine box, the computational fluid dynamics theory was applied to establish a model of the exhaust ejector in-stalled in a marine gas turbine box, and the exhaust ejector of marine gas turbine with different nozzle spacing and different mixing chamber diameter was simulated through ANSYS. The results show that as the nozzle distance increases, the variation of injection efficiency varies under different mixing chamber diameters. The change in injection efficiency is not significant for smaller mixing chamber diameters, while the change in diameter of larger mixing chambers first increases and then gradually changes. The best effect is achieved when the nozzle distance reaches 1 m; as the diameter of the mixing chamber increases, the variation pattern of the injection coefficient for dif-ferent nozzle distances first increases and then decreases. When the diameter of the mixing cham-ber is 1.8 m, it is optimal. When the nozzle spacing of the marine gas turbine exhaust ejector is 1 m and the mixing chamber diameter is 1.8 m, the maximum injection efficiency can be achieved at 38.12%. At this time, the cooling effect of the box is the best, which meets the requirements for the use of industrial gas turbine components and the explosion-proof requirements of natural systems.