| With the increasingly high performance requirements of aero-engines,the temperature in front of the vortex of the engine is getting higher and higher,and the working environment of the hot components is getting worse.So turbine blades need more advanced and efficient cooling technology,which has higher requirements for the design of internal cooling passages and internal cooling structures.In this paper,the influence of curvature on the flow and heat transfer characteristics of the internal cooling channel of turbine blades is mainly studied,and the rib heights of the internal cooling channel are optimized with Nusselt number and comprehensive heat transfer coefficient as objective functions.The main research contents are as follows.Firstly,by comparing the calculated results of different turbulence models with the experimental data,it is verified that v2f turbulence model can accurately predict the turbulent flow in the internal cooling channel of turbine blades.On this basis,the dynamic characteristics,convective heat transfer characteristics and comprehensive heat transfer performance of the internal cooling channel around the rib with different curvature K and Reynolds number are analyzed.When Re is constant,the curvature K has little influence on the average Nusselt number,but has great influence on the resistance coefficient f.Compared with the straight channel,the variation range of the average Nusselt number is-0.87%～28.3%,and that off is-22.24%～88.41%.When K=-2 and Re=100 000,the comprehensive heat transfer coefficient Nu/Nu0/(f/f0)increases by 32.78%at the maximum,and the comprehensive heat transfer coefficient Nu/Nu0/(f/f0)1/3 increases by 9.5%at the maximum.Based on the idea of inverse problem optimization,this paper takes Nusselt Number Nu,resistance coefficient f,comprehensive heat transfer coefficients Nu/Nu0/(f/f0)1/3 and the maximum temperature difference of the bottom wall as objective functions,and uses the simplified conjugate gradient method to optimize all rib heights of the two-dimensional straight channel model at the same time and the other four rib heights with the first rib height fixed.Due to the entrance section effect,there is no optimal rib configuration with the Nusselt number as the objective function to optimize five rib heights at the same time,and optimal rib configurations are achieved with other performance parameters and the cooling performance is effectively improved.Multi-parameter optimizations for rib arrangements are implemented by integrating the simplified conjugate-gradient algorithm with the turbulent flow and heat transfer model.Different environments have different performance requirements.In this paper,the optimal rib arrangements can be obtained under different performance requirements,which provides theoretical guidance for the research and development of turbine ribs with high heat transfer performance. |
