Numerical investigation of truncated-root rib on heat transfer performance of internal cooling turbine blades

Abstract

Due to the great heat obtained from the combustion chamber, the turbine blades of a jet engine always operate at high temperatures. Therefore, to minimize the temperature of the turbine rotor and stator blades, the internal cooling system was developed. The original rib called the squared-rib has been developed as a turbulence generator to enhance heat transfer ability. This technique is to cast ribs in the serpentine passage inside the turbine blades. By this technique, the vortex exists in the rear rib region that causes a low heat transfer zone. In this investigation, a new rib configuration called the truncated-root rib was designed to reduce the squared-rib disadvantage. The configuration of the truncated-root rib forms a small extra-passage into which the coolant passes through and the vortex is comparatively removed. To investigate the heat transfer performance and fluid flow characteristic of the internal cooling turbine blades, a parametric study of the truncated-root rib with the height and shapes of the extra-passage was performed using three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model. The numerical results showed that all the heat transfer performance of the truncated-root rib configuration is greater than that of the squared-rib. The Nusselt number in the case of the truncated-root rib increases by 8.56% with the Reynolds number of 37 392, and the thermal performance is 39.24% higher than that of the original shape in the case with Reynolds number 53 697.