Conjugate Heat Transfer Effects on a Realistic Film-Cooled Turbine Vane

Abstract

A conjugate heat transfer solver has been developed and applied to a realistic film-cooled turbine vane for a variety of blade materials. The solver used for the fluid convection part of the problem is the Glenn-HT general multiblock heat transfer code. The solid conduction module is based on the Boundary Element Method (BEM), and is coupled directly to the flow solver. A chief advantage of the BEM method is that no volumetric grid is required inside the solid — only the surface grid is needed. Since a surface grid is readily available from the fluid side of the problem, no additional gridding is required. This eliminates one of the most time consuming elements of the computation for complex geometries. Two conjugate solution examples are presented — a high thermal conductivity Inconel nickel-based alloy vane case and a low thermal conductivity silicon nitride ceramic vane case. The solutions from the conjugate analyses are compared with an adiabatic wall convection solution. It is found that the conjugate heat transfer cases generally have a lower outer wall temperature due to thermal conduction from the outer wall to the plenum. However, some locations of increased temperature are seen in the higher thermal conductivity Inconel vane case. This is a result of the fact that film cooling is a two-temperature problem, which causes the direction of heat flux at the wall to change over the outer surface. Three-dimensional heat conduction in the solid allows for conduction heat transfer along the vane wall in addition to conduction from outer to inner wall. These effects indicate that the conjugate heat transfer in a complicated geometry such as a film-cooled vane is not governed by simple one-dimensional conduction from the vane surface to the plenum surface, especially when the effects of coolant injection are included.

BEM/FDM conjugate heat transfer analysis of a two-dimensional air-cooled turbine blade boundary layer

“…In order to improve gas turbine engine thrust-to-weight ratio, turbine inlet temperature must be increased and turbine cooling flow rates must be reduced. On the other hand, the higher pressure ratio cycles of compressor leads to the higher compressor outlet temperature, which increases the temperature of the cooling air for turbine cooling [1]. So in the procedure of turbine engine designing, except for the aerodynamical efficiency, another important factor is the temperature distribution of gas turbine engine.…”

Fluid-structure interaction analysis applied to thermal barrier coated cooled rocket thrust chambers with subsequent local investigation of delamination phenomena

“…For example, in the work of Heidmann et al [6], the interface conditions are transferred in a reverse manner compared to the approach that is followed in the present study, where heat §ux is tranferred from the §uid analysis to the structural analysis and temperature is transfered from the structural side to the §uid side, respectively.…”

“…In the discipline of turbomachinery, a lot of studies focus on conjugate heat transfer analyses (see, e. g., [6,7]) which di¨er algorithmically in the details of the coupling strategy from the present approach. For example, in the work of Heidmann et al [6], the interface conditions are transferred in a reverse manner compared to the approach that is followed in the present study, where heat §ux is tranferred from the §uid analysis to the structural analysis and temperature is transfered from the structural side to the §uid side, respectively.…”

Thermal Analysis of a Film Cooling System with Normal Injection Holes Using Experimental Data

“…To predict the life and safety of hot components such as combustors, vanes, and blades, it is necessary to estimate the metal temperature of the film cooling system in an appropriate thermal environment. In recent years, several investigators [10][11][12] have attempted a conjugated analysis of heat conduction in turbine blades. In these conjugate analyses, blade surface temperatures and thermal stresses are predicted.…”