Numerical Investigation Of Aerodynamic Performance Of A High Loaded Blade In Different Turbine

Development of the high loaded blade is significant in energy saving and emissionreduction, Now high loaded blade has been gradually used in steam turbines, gasturbines and aircraft engines, which can help to decrease processing costs and increasethe reliability of the unit. design of the blade determines the efficiency and performanceof the unit in different applications.In this paper, a high loaded blade designed by Harbin Turbine Company Limited isapplied in the middle stage of ultra supercritical units. Its aerodynamic performance issimulated to assess the effect of its design with Ansys CFX. The results show that withthe incidence varied from-40degree to40degree aerodynamic load increases, and losscoefficient decreases to the minimum when the incidence is0degree，then losscoefficient increases. Three-dimensional separation line lift height of passage vortex inthe suction side has a gradual increase in the suction side, such as three-dimensionalseparation line lift height near the tip varied from2.8percent of the height of the bladeto16.9percent, three-dimensional separation line lift height near the hub varied from2.8percent of the height of the blade to30.1percent, which shows upper passage vortexintensity is stronger than the lower passage vortex. after all, the blade has a goodincidence performance between-20degree to20degree. With the outlet Mach numbervaried from0.1to0.6, the blade gradually has the after-loaded trend, and loss coefficientdecreases until the Ma number is0.4，then loss coefficient increases, three-dimensionalseparation line lift height is declining.Then the middle section of the blade was chosen as the based two-dimensionalcascade, aerodynamic performance of the blade is analyzed in different Reynoldsnumber after its aerodynamic load is increased. Numerical study was conducted toinvestigated the boundary layer development and separation mechanism using dimpleunder conditions of low Reynolds. The results show that the dimple on the suction sideof the blade could promote the starting point of the transition ahead, change itsturbulence intensity and the size of the separation bubble on the condition of lowReynolds number, the dimple at the separated point can achieve the best control effect.With Reynolds number or free stream turbulence intensity increases, the length of theseparation bubble gradually reduce, the thickness of separation bubble gradually thin,the separation point moves back, so there is an appropriate point to dimple which willhave the best control effect in different Reynolds number and turbulence intensity.