Aerodynamic Performance And Partical Deposition Analysis Of Turbine Blade Tip Structure

Gas turbine technology is a crucial development technology in the field of national defense science and technology.And turbine is one of the most important parts of a gas turbine.However,there are some difficulties in the turbine development.F irstly,tip clearance flows in a turbine will cause flow losses.If the leakage flow at the blade tip cannot be effectively controlled,the flow loss will be increased which leads to the decease of the efficiency of a turbine.It also causes heat load increase at the blade tip.That results in strong thermal stress in the tip and casing.Secondly,under non-ideal working conditions,turbines will face the influence of airflow containing sand or dust,leading to the invasion of tiny particles.In the cascade channel,fine particles form deposits causing localized high temperatures,which ultimately results in component damage.According to the problems described above,this study will effectively control the leakage flow in the clearance by changing the tip structure and change the flowpattern near the tip of the blade,thus alleviating the severe heat transfer at the top of the blade.At the same time,the pattern of flow and heat transfer of particles in turbine blades under different tip structures are investigated.In this study,a high-load turbine rotor blade is used as a model to establish a planar cascade.Firstly,the flow and heat transfer coefficient distribution in the flat tip and tip winglet with different gap heights are compared.The control mechanism on the flow loss and the effect on the tip heat transfer of the blade tip structure are analyzed.Then,the effects of different tip thickness of winglet tip structures on the aerodynamic performance and heat transfer characteristics of turbine blades are compared.The tip structure to control the tip leakage flow of the turbine blade with different gap sizes is analyzed.Then,the blade tip wing structure is improved based on previous study.The total pressure loss coefficient at the outlet section and the heat transfer coefficient distribution of the tip of different tip-wing structures are analyzed.It is found that the optimized blade tip structure has improved the aerodynamic performance and heat transfer.That will provide theoretical guidance for the installation of blade tip winglets in actual turbine blades.Finally,the distribution of the trajectories of the particles in the turbine cascade with different blade tip-wing structures is calculated and discussed.The effects of particle diameter on particle motion and deposition are studied.The results show that the reasonable tip-wing structure can reduce the overall flow loss of the turbine blade and reduce the heat load pressure at the top of the blade.The blade tip structure of the turbine blade changes the particle trajectory,but the particle’s own properties affect the trajectory distribution more obviously.