汽轮机湿气损失抑制方法研究

Research on the suppression method of steam turbine moisture loss

低参数汽轮机在余热回收中有着广泛的应用,为降低汽轮机中的湿气损失,提高运行效率,本文提出了一种添加不凝气体(以氢气为例)的湿气损失抑制方法,并提出了湿气损失定量评估修正模型,同时通过建立hydrogen-steam混合工质凝结流动模型,分析不同氢气组分比对凝结流动特性的影响规律,探明不凝气体对湿气损失的抑制机理。结果表明:不凝气体会改变透平做功过程中凝结激波的形态,使流体域压力和温度发生激变,影响成核及液滴生长过程。当混合工质气中氢质量分数组分比为50%时,流体域内成核区长度减小13.34%,湿气损失降低48.02%,湿气损失系数降低43.4%。这表明氢气可以通过控制非平衡凝结过程有效降低汽轮机湿气损失。

Low-parameter steam turbine is widely used in waste heat recovery.To reduce moisture loss in steam turbine so as to improve operational efficiency,a method to suppress moisture loss by adding non-condensable gas(taking hydrogen as an example)is proposed in this paper.A quantitative assessment and correction model for moisture loss is introduced as well.By establishing a condensation flow model of hydrogen team mixed working fluid,the influence of different hydrogen component ratios on the condensation flow characteristics is analyzed,and the suppression mechanism of non-condensable gas on moisture loss is explored.The results show that the morphology of condensation shocks is altered by non-condensable gas in the process of turbine work,causing abrupt changes in pressure and temperature in the fluid domain,which affects the nucleation and droplet growth processes.When hydrogen mass fraction ratio in the mixed working fluid is 50%,the nucleation length in the fluid domain is decreased by 13.34%,moisture loss is reduced by 48.02%,and the coefficient of moisture loss is decreased by 43.4%.This indicates that hydrogen can effectively reduce steam turbine moisture loss by controlling non-equilibrium condensation process.