Rotational Effects on Heat Transfer for In-Line Jet Impingement Array in a Mid-Span Turbine Channel: An Experimental Study

Abstract

This study examined heat transfer for a 3x11 inline impinging jet array within a rotating channel that simulates the turbine blade cooling in mid-span region. The heat transfer on the impingement surface was investigated using Thermochromic Liquid Crystals and a thin-foil heater under steady-state conditions. The influence of impingement distance (L/D=2, 4, 6) and Rotation number (Ro=0.0-0.0083) was examined at a constant Reynolds number of Re=10,000. Results indicate intricate relationships between impingement distance, Coriolis forces, and crossflow. Increased rotation numbers generally diminish heat transfer on both of leading and trailing sides relative to the stationary condition. At a small L/D of 2, crossflow effects predominated over rotational effects, resulting in gradual decrease in downstream region. In contrast to distances L/D=4 and 6, the Nusselt number declined rapidly in the upstream region, whereas the influence of rotation lessened in the downstream region.