A simplified equation to predict heat transfer in an internal duct of a gas turbine nozzle guide vane

Abstract

This paper presents a simplified formula that can be used to obtain the detailed heat transfer rate and temperature distribution on the surfaces of square and non-square cooling channels of a nozzle guide vane (NGV). Due to the three-dimensional shape of the internally cooling channels, the heat transfer rate can vary substantially between the different sides of the channels. This detailed heat flux and resulting temperature distribution on the walls are important to improve the design of the airfoil as well as to determine the expected usable life of the NGV. This detail heat transfer data is usually obtained by means of a complex three-dimensional simulation of the NGV configuration. Therefore, for design purposes, the heat transfer data on the channel surfaces is often assumed to be the average heat transfer rate on the channel walls. The average heat transfer rate can be obtained by using a simplified heat transfer equation, based on the average Reynolds number in the channel. The simplified formula presented in this paper can be used to obtain the detailed heat transfer rate and temperature distribution on the surfaces of square and non-square cooling channels of a nozzle guide vane (NGV). The simplified formula is based on results obtained from three-dimensional simulations of the heat transfer in the channels and was compared to simulated and experimental data over a range in flow rates and channel geometries. In general, it can be concluded that the formulation produces fast and accurate results over a wide range of applications. Copyright © 2000 John Wiley & Sons, Ltd.