Numerical Simulation And Analysis Of Turbine Blade Cooling Process

In recent years,air film cooling technology has become an important way of high temperature gas turbine.But high temperature gas at the outlet of the combustion chamber is usually between 15% and 20% of turbulence.Accompanied by about 20% to 30% at the same time,the temperature of axial and radial is uneven distribution.This makes the flow process of gas become very complicated.The influence of blade shape and channel has brought more difficulties to the research of air film cooling.So it is very difficult to study the air film cooling under the real condition.This paper uses GAMBIT to establish the geometric model of the gas turbine static blade leading edge which with three and five rows of cooling air hole in film cooling process.By using jet hole parts adopt the method of partial encryption local mesh encryption method.The boundary conditions is set according to the actual cooling process,and then import the fluid calculation software FLUENT,the k-? turbulence model was used to simulate the film cooling process.The effects of structural parameters such as mainstream gas flow velocity,different cooling jet hole with different arrangement,blade jet angle,jet radius and blowing ratio on the cooling process were investigated.The result shows that: the addition of the cooling flow jet hole will form a layer of air film on the surface of the blade.So it reduced the temperature of the fluid around the blade.The leaves made the cooling effect better.When the hole is the same,the main speed is 2m / s,5m / s and 10 m / s,the cooling effect is inversely proportional to the main velocity.That is to say,the faster the mainstream speed is,the greater the disturbance to the jet speed becomes.So the cooling effect becomes worse.The cooling effect is better than that of the jet hole with the same aperture.In this simulation range,we find that when the main gas flow speed is the same,the cooling fluid speed is faster,the cooling effect of the film is better.With the increase of the jet angle,the cooling effect is enhanced and then decreased.The average variation range of the film temperature is 750-850 K and the jet angle is 90 °.The best film cooling effect is 500 K.With the increase of the radius of the jet hole,the cooling effect is gradually enhanced.When the jet hole becomes too large,the mechanical strength of the blade is reduced,the safety of the equipment is affected.What's more,with the increase of the radius of the jet hole,the whole gas outlet temperature is reduced and the thermal efficiency of the gas is decreased.In this paper,I selected the radius of the jet hole 3.5mm for the best jet hole within the simulation range.It shows that with the increase of jet cooling gas and high temperature gas blowing ratio,the effect of air film cooling is enhanced,but the gas outlet temperature is reduced and the thermal efficiency of gas is decreased.In this paper,the blowing ratio M = 1.5 is the best condition.