Local Heat Transfer Coefficient Measurements on an Engine-Representative Internal Cooling Passage

Abstract

Spatially resolved heat transfer measurements of turbomachinery components can lead to more accurate metal temperature distributions, leading to better predictions of thermal stresses in the blade and, ultimately, blade life. The increased fidelity of the spatially resolved data also provides a data set, which can delineate the complex fluid and heat transfer processes for the purpose of numerical validation. This research applies transient liquid crystal experiments on stationary engine-representative internal cooling passages with a filleted rectangular cross section and staggered 45 deg ribs on two opposing walls. The ribs have a rounded profile and span half the width of the passage. Pressure loss measurements and spatially resolved heat transfer coefficients have been collected over the full surface of the test section over a range of Reynolds numbers (18,000-105,000) for three aspect ratios (1∶2, 1∶3, and 1∶4). The experimental results were compared to widely used empirical correlations for ribbed passages with full-width ribs in sharp-cornered passages. The average Nusselt number and friction factor differed from industry-standard correlations by a maximum of 45 and 10%, respectively.

Analytical Thermal Boundary Condition for Quasi-Transient Simulation of Internal Flow Experiments

“…It uses CFD to solve the fluid and the heat flux distribution, with the surface temperature then calculated analytically from incident surface heat flux by applying the impulse response method to solve the semi-infinite one-dimensional conduction equation. The ATBC simulations are compared to both TLC experimental data from a rib roughened passage [18], and also steady state CFD, carried out to industry standard. This paper also redresses some of the conclusions drawn in [17] and provides a true assessment of HTC values appropriate processing method is applied, which are seen to converge quickly.…”

“…The experimental data simulated in this paper are from an aspect ratio 1:3 super-scaled rib roughened internal cooling passage [18,19]. The geometry is typical of that found in a modern gas turbine engine blade.…”

“…The data presented in this paper is unwrapped using the nomenclature in Figure 2, where the terms 'pressure/suction surface' and 'leading/trailing edge' relate to the turbine blade's outer surfaces in the main gas path, and not the local aerodynamics within the cooling passage. Further details of the experimental setup can be found in [18,19].…”

“…Post-processing of the simulation data is then carried out in an experimental-like manner for direct comparison to the experiments [18]:…”

Experimental and Numerical Investigations on the Ignition of RBCC Gas-Oxygen/Kerosene Rocket Ejector

“…However, kerosene is a complex mixture of components. For CFD simulation, some kerosene substitute models have been studied successively to simplify the model and the calculation [20,21]. In this paper, a ten-step quasiglobal chemical kinetics model for kerosene fuel combustion (Table 2) was adopted to conduct chemical reaction rate calculations.…”