船用燃气轮机预旋系统增压设计及仿真

Design and Simulation of Pre-swirl System Supercharging in Marine Gas Turbine

为了提高船用燃气轮机进口燃气压力和温度,涡轮冷却空气应当具备更大的压力来满足叶片表面气膜冷却的需求。本文优化现有的预旋系统,通过在供气孔入口布置增压叶轮,减少气流经预旋喷嘴射入盘腔和经盘腔进入供气孔的突扩损失。运用数值计算的方法对预旋系统模型进行研究,所采用的计算模型和冷吹实验与1.0设计工况数据对比具有较好的精度。研究表明:增压预旋系统和常用预旋系统具有相似的流场结构,但预旋腔内形成的涡更小,有效抑制了气流在腔内的总压损失;在增压叶轮和结构改进的作用下,冷气相对总压提高2.90%,绝对总压提高4.59%,同时增压所产生的温升变化较小,提高了冷却空气的冷却能力。

In order to improve the inlet gas pressure and temperature of marine gas turbines,the turbine cooling air needs to possess higher pressure to meet the demand for blade surface film cooling.This study optimizes the existing pre-swirl system by incorporating supercharging impeller at the intake holes,reducing the cavity losses of the air flow entering the disk cavity through the pre-swirl nozzles and exiting into the supply holes.Numerical calculations are employed to investigate the pre-swirl system model,and the adopted computational model exhibits good accuracy when compared with cold wind blowing experiments and 1.O working condition data.Research shows that supercharging pre-swirl system and the conventional pre-swirl system exhibit similar flow field structures,but the vortices formed in the preswirl cavity of the supercharging system are smaller,effectively suppressing the total pressure losses in the cavity;with the effect of the supercharging impeller and structural improvements,the relative total pressure of the cooling air increases by 2.90%,and as the absolute total pressure increases by 4.59%,the temperature rise remains essentially unchanged,thereby improving the quality of the cooling air.