| In the modern gas turbine,the inlet temperature of the turbine blade is often very high.When the high temperature exceeds the maximum limit of the blade material,it will cause damage to the blade.Therefore,a reasonable cooling method should be used to cool the blade.Film cooling technology is one of the effective cooling methods of turbine blades,and it is widely used in various fields.The cutting area of the tail edge of the turbine blade is small,and the high temperature gas is prone to heat and stagnant,which leads to the rise of the temperature.It is very easy to crack and damage the blades,which will affect their normal work.Therefore,the reasonable design of the structure on the trailing edge blade is of great significance,and the heat transfer and cooling characteristics of trailing edge blade can be improved.In this paper,the heat transfer,the cooling characteristics and the flow mechanism of the three kinds of structures are studied by numerical simulation.They are without land,tright angle land and oblique angle land.The cooling effect of the trailing edge blade under the influence of the three factors and the three levels are studied by orthogonal analysis,which provides a reference for the design of the overall cooling structure of the trailing edge blade.Firstly,three three-dimensional physical models of different structures are established.The right angle ribs and the inclined ribs were set up.The influence of different blowing ratios on the convection heat transfer coefficient,temperature distribution and cooling efficiency of the three kinds of the trailing edge blade structures is studied by constant numerical simulation.The results show that when the blowing ratio changes in the range of 0.5~1.5,the convection heat transfer coefficient of the wall surface of the three structures increases graduallywith the increase of the blowing ratio.The closer to the outlet,the greater the influence of the blow ratio.Under these conditions,the cooling effect of Under the same conditions,the cooling effect of the trailing edge blade structure with land is better than that without land.Secondly,the unsteady numerical calculation is made for the structure of the three kinds of trailing edge blades.Starting from the temperature field,the variation of temperature with time is compared between three structures in one period.From the vorticity field,we reveal the formation mechanism of wake vortices in an instantaneous way,and study the variation rule of vorticity with the time in the same section of three structures in one period.The results show that in a period of time,the temperature distribution of the trailing edge of the structure without land is lower than that of the structure with land,and the effect of cooling film coverage is better.The position of the wake vortex of the blade without land is slightly ahead of the structure with land,which reduces the adherence of the tail edge of the blade after the flow of the jet,and the coverage area of the cooling gas film decreases,and the cooling efficiency is becoming lower and lower as the time changes.Therefore,the cooling effect of the trailing edge with land is better than the structure without land.Finally,nine orthogonal schemes with three factors and three levels are established,The influence of different factors on the cooling effect of the trailing edge blade and the order of the main and secondary effects are compared and analyzed,so as to determine the best scheme of the tail edge structure of the blade.The results show that the order of the three factors on the trailing edge blade is that the blowing ratio is greater than the land elongation length,and the land elongation length is greater than the land opening angle.The trailing edge blade of the structure with that the blower ratio is 1.5,the land opening angle is 100 degrees and the land extension length is 3L/4 has the highest cooling.Therefore,reasonable design of the structure of the trailing edge blade is helpful to improve its cooling efficiency. |
PDF Full Text Request