Study On The Recession Rule Of Turbine Performance In Marine Salt Spray Atmospheric Environment

As the core component of gas turbine,turbine plays a decisive role in the performance of gas turbine.With the increasing attention paid by the state to maritime rights and interests,the training and patrol of ships and shipborne aircraft in the ocean are gradually normalized.Affected by marine salt spray environment,high-pressure turbine is prone to hot corrosion,resulting in turbine blades from smooth to rough.In addition,the turbine corrosion is often accompanied by ablation,which leads to the change of turbine blade geometry.Therefore,it is of great significance to explore the degradation law of turbine performance in marine salt fog environment for subsequent turbine design,operation and maintenance and avoiding major losses.In this thesis,the turbine with hot corrosion and ablation is studied by numerical simulation.The following research is carried out in this thesis:Firstly,the working conditions of E~3 high pressure stage turbine experimental point are numerically simulated,and the calculated results are compared with the experimental values to verify the reliability of the numerical simulation results.Then,the working conditions of different outlet back pressure at 110%,100%,90%and 80%of the design speed of the turbine are numerically simulated.The effects of outlet back pressure and speed on turbine performance and internal flow field were investigated.Secondly,the hot corrosion degree of the turbine at different time is simulated by the numerical change of the roughness at different chord positions of the blade,and the influence of different hot corrosion degree on the performance of the turbine is analyzed;Then,the internal flow field at the highest efficiency point of the original model and turbines with different degrees of hot corrosion is analyzed in detail.The effects of hot corrosion on turbine performance and internal flow field were investigated.Finally,through the combination of hot fluid structure coupling calculation and physical model data extraction,the influence of ablation on turbine geometry is determined.On this basis,the numerical simulation calculation of the turbine after ablation is carried out to explore the influence of ablation on turbine performance.Then,the working conditions of hot corrosion and ablation of the turbine are simulated,and the internal flow field at the working point with the highest efficiency is compared and analyzed.The effects of hot corrosion and ablation on turbine performance and internal flow field were investigated.The results show that the hot corrosion increases the blade surface roughness,enhances the eddy current strength in the channel,and leads to the early separation of the suction surface flow of the moving blade.Increasing the tip leakage flow leads to the increase of the working medium flow loss and the deterioration of the turbine performance;The deeper the degree of hot corrosion,the more serious the deterioration of turbine performance.Ablation leads to the change of turbine guide vane geometry,the flow disorder of guide medium at the blade leading edge,the increase of secondary flow loss and the decline of turbine performance.The combined action of hot corrosion and ablation leads to the disorder of flow at the leading edge of the blade,the increase of secondary flow loss in the channel and the deterioration of turbine performance.