Numerical investigation on vortex cooling flow and heat transfer characteristics for gas turbine blade with variable coolant chamber cross-sectional shapes

Abstract

In this paper, according to the actual size of gas turbine blade interior space, eight vortex cooling models with different cross-sectional shapes of coolant chambers are established. Rectangular, Circle, Trapezoidal up, Trapezoidal down, Ellipse up, Ellipse down, Sine up and Sine down are the eight coolant chamber shapes. Functions of variable coolant chamber structures on vortex cooling flow and heat exchange characteristics are numerically analyzed by verifying the Standard k- ω turbulence model and conducting grid independence analysis. Research results show that the heat exchange ability of Sine up coolant chamber is the best compared with the other coolant chambers. The cool air enters the vortex chamber at a faster speed and impacts on the target surface to form a high-pressure area and a low-temperature swirl. The more the cool air moves downstream, the greater the turbulent kinetic energy becomes, which is more conducive to the heat transfer. Therefore, Sine up coolant chambers have the highest thermal performance factor. Due to the low drag coefficient and high target surface average Nusselt number of Ellipse up, its thermal exchange performance is second only to that of Sine up. Circle coolant chamber will not bring favorable factors to engineering application because of the slowest flow speed and the worst heat exchange capacity. For Trapezoidal up and Trapezoidal down, the flow velocity, pressure distribution, turbulent kinetic energy intensity and heat transfer uniformity are almost the same as Rectangle coolant chamber. The models of Ellipse down and Sine down coolant chambers exhibit less turbulent kinetic energy strength to heat transfer and higher temperature in the vortex chamber, and it is not suggested for cooling system optimal design.