Gas Turbine Blade Heat Transfer and Internal Swirl Cooling Flow Experimental Study Using Liquid Crystals and Three-Dimensional Stereo-Particle Imaging Velocimetry

Abstract

The challenging engineering intricacies related to improving efficiency of a gas turbine engine come with the need to maximize the internal cooling of the turbine blade to withstand the high turbine inlet temperature. Understanding the fluid mechanics and heat transfer of internal blade cooling is, therefore, of paramount importance. This paper presents the impact of swirl cooling flow on the heat transfer of a gas turbine chamber to understand the mechanics of internal blade cooling. The focus is the continuous swirl flow that must be maintained via nonstop injection of tangential flow, whereby swirl flow is generated. The impact of swirl flow considers the velocity fields measured using stereo particle image velocimetry, the wall temperature and the convective heat transfer coefficient measured by liquid crystals. Flow behavior and heat transfer at three Reynolds numbers ranging from 7000 to 21,000 and the average profiles of axial and radial, magnitudes of velocity, and Nusselt numbers are given to research the direct effects of the circular chamber shape. Heat transfer results are measured in a second circular chamber and collected continuously after the system is heat soaked to the required temperature. As part of the results relatively low heat transfer rates were observed near the upstream end of the circular chamber, resulting from a low momentum swirl flow as well as crossflow effects. The thermochromic liquid crystal heat transfer results exemplify how the Nu measured favorably at the midstream of the chamber and values decline downstream.