Numerical Study On Heat Transfer Enhancement Of Turbine Blade With Internal Fin Structure

With the development of the aviation industry,the temperature in front of the engine turbine is constantly increasing,so the development of turbine blade cooling technology is very necessary.This thesis work studies the effect of spoiler ribs on the heat transfer efficiency in square channels,which is based on an extended study of the commonly used turbine blade rib wall channel structure,aiming at finding a better ribbed flow cooling scheme.The flow characteristics and heat transfer characteristics of the spoiler rib cooling were numerically simulated by Fluent software,so we can know the influence of different parameters on the flow field.With the change of the angle of the spoiler rib,the ratio of rib height to rib spacing,the shape of rib cross section and the mode of discontinuity,the layer loss in the square channel is stabilized by the near rib wall surface,causing severe disturbance to the wall surface with different strengths.The incoming stream can carry more heat and strengthen the heat transfer between the fluid and the wall.This process has important academic significance for studying the heat dissipation of turbine blades.Firstly,the optimal ratio of rib height to rib spacing is studied.Eight cases are selected,is 1:4,1:5,1:6,1:7,1:8,1:9,1:10 and 1:12.In the study of this paper,the heat transfer intensity is measured by the Nusselt number of the ribbed wall surface,and the effect of the flow loss of the channel on the efficiency is considered.The simulation results show that when the e/p is 1:6,the average Nusselt number of the ribbed wall surface will reach a peak.When the ratio of rib height to rib spacing is more than 1:6,the fluid can be fully developed and the boundary layer becomes thicker after the fluid is separated from the rib wall by the ribs,whichis not conducive to the exchange of heat.Secondly,on the basis of keeping the ratio of rib height to rib spacing is 1:6,the influence of rib angle change on heat transfer efficiency in cooling passage of turbine blade is calculated and analyzed.The ribs are placed at angles of 0°,10°,20 °,30°,35°,40°,45°,50°,and 60°,then the calculation is performed for a total of 9 angles.The simulation results show that when the flow resistance is the secondary factor,the rib angle of 40 degrees is the most advantageous to enhance heat transfer.Then the influence of rib profile shape is studied.Calculate the ribs of triangular,semi-circular,square,elliptical and trapezoidal cross-section shapes at a selected optimum angle of 40 °,based on a ratio of rib height to rib spacing of 1:6.The results show that the trapezoidal ribs are most beneficial to the improvement of heat transfer capacity,followed by elliptical ribs,square ribs and triangular ribs,while the semicircular ribs have the most limited improvement in heat transfer capacity.Finally,the effect of discontinuous mode of rib on heat transfer efficiency is studied.Under the condition that the optimal angle of rib,the optimal shape of rib section,the optimal ratio of rib height to rib spacing remain unchanged,different discontinuity conditions are selected to calculate.It is hoped that the optimal discontinuity mode can be obtained through the calculation results.