Improved Design Of Turbine Blade Composite Cooling Structure Based On Pipeline Network

Gas turbine is widely used in aviation,spaceflight,navigation,ground power generation and other fields to generate power,but with the development of technology,people pay more and more attention to the improvement of comprehensive performance of gas turbine,including the parameters such as thermal efficiency,thrust weight ratio,power and so on.The results show that these parameters are largely dependent on the increase of inlet gas temperature,accompanied with the blade material can not bear such high inlet gas temperature,and then affect the strength and reliability of gas turbine,so advanced cooling technology is needed to effectively cool the blades.The traditional design method of turbine is the initial design of turbine,calculation and analysis,modification,and then reanalysis of the continuous iterative process.But because of the continuous increasing of inlet gas temperature,the internal cooling channel of turbine blades are becoming more and more complicated,a single continuous calculation and improvement has greatly increased the turbine design cycle.So the optimization design method is proposed,but this method is generally based on the full three-dimensional numerical simulation,optimize once at least a month,or even several months,which can not achieve the purpose of rapid design.Based on pipeline network of our research group in this paper,the optimization design platform based on pipeline network is established.The computation time is greatly reduced based on one-dimensional fast calculation.The verification shows that it can be used to predict the temperature distribution of the turbine blade wall,thus,the design period of the inner cooling passage of turbine blade is greatly reduced.In this paper,Mark ? blade is used to conjugate heat transfer numerical validation,the results of the five turbulence models are compared with the experimental results,the calculation precision,convergence speed and the difficulty degree of mesh partition and other factors are considered,the k-? turbulence model is chosen as the turbulent model for subsequent numerical calculation.The full three dimensional conjugate heat transfer calculation of a high pressure turbine rotor blade was carried out by using CFX software,the causes of the high temperature zone and the zone of temperature gradient is too large in the turbine blade are analyzed,and then modification measures are proposed.The modified effect of the modified turbine blade is analyzed by three-dimensional conjugate heat transfer calculation,and the modified blade is used for the prototype of the next optimization design.The results show that,after modification,the cooling air distribution of the turbine blade tends to be rationalized,the maximum wall temperature decreases,the minimum temperature increases,and the wall temperature distribution tends to be more homogeneous compared with the prototype.The network topology of the modified blade is divided,and the conjugate heat transfer based on pipeline network is carried out,relevant parameters are obtained,an optimization platform based on iSIGHT software platform is established by using the obtained documents.Multi-Island Genetic Algorithm(MIGA)is chosen as the optimization method in this paper.The rib height,rib spacing,rib angle and the diameter of the film hole,the imping hole and the through hole are chosen as the optimization parameters,The minimization of the maximum wall temperature is chosen as the optimization target,the optimization parameters are obtained for the secondary modified turbine blade.The three dimensional conjugate heat transfer calculation is carried out on the secondary modified turbine blade,and the results are compared with those of the modified turbine blade.The results show that the size of the cooling structure of the secondary modified turbine blade is more matched with the cooling gas,the maximum temperature of the blade wall is significantly reduced without increasing the cooling gas rate,and the utilization rate of the cool air is improved.