Session: 15-04 Turbulated Cooling

Paper Number: 128221

128221 - Effect of Rotation on 45-Degree Broken V-Ribs in a 2 Pass Square Channel 

A common way of achieving Heat transfer augmentation within cooling channels, is by employing ribs. The ribs promote an increase in local wall turbulence by periodically breaking the fluid flow, thereby greatly enhancing the heat transfer. With gas turbines, pressurized cooling air is circulated through internal cooling channels in order to remove heat from the blades. The gas turbine blade can be viewed as 3 distinct sections, namely; the leading edge, mid-chord region, and the trailing edge. The trailing edge usually employs array pin-fins cooling techniques and the most effective technique used to cool the leading edge is by using jet impingement. Rib-turbulators are the most commonly used cooling configurations in the mid-chord portion of the turbine blade. As the turbine blades rotate, the Coriolis and Buoyancy forces affect the fluid flowing through these channels, thereby causing a non-uniformity in heat transfer distribution between the pressure side and suction side of the turbine blade internal cooling channels. The aim of this paper is to experimentally investigate the effect of rotation on 45 degree Broken-V shaped ribbed turbulators in a, 2-pass rotating channel and to compare the performance against continuous V-ribs and smooth channel with no rib-turbulators, using Thermochromic Liquid Crystals. The channel has an aspect ratio of 1:1, with ribs present on both the trailing and leading side, the rib to pitch to height ration p/e maintained at 6.3 and the rib height to hydraulic diameter ratio is 0.1. Experiments are carried out for Reynolds numbers varying from 10,000-100,000, and for Rotation numbers of 0, 0.05, and 0.1.

Presenting Author: Srinath V. Ekkad North Carolina State University

Presenting Author Biography: Madhusudan is a PhD student at the department of Mechanical and Aerospace Engineering at NC State university, working on gas turbine cooling.

Authors:

Madhusudan Pallikaranai Thirumalai North Carolina State University
Srinath V. Ekkad North Carolina State University