Session: 11-01 Combustor-turbine interactions

Paper Number: 123899

123899 - Influence of Dilution and Effusion Flows in Generating Variable Inlet Profiles for a High-Pressure Turbine 

Elevated flow temperatures and pressures exiting gas turbine combustors affect the efficiency and durability of the high-pressure turbine stage. Understanding the effects that result from the upstream dilution and effusion flow interaction in creating the combustor exit profiles are important to advancing gas turbine performance. This paper presents common combustor features, such as dilution jets and effusion cooling, and how they interact to guide the design of a non-reacting profile simulator capable of producing a wide range of non-uniform temperature and pressure profile shapes representative of those entering high-pressure turbine stages. The new simulator device was designed for modular installation into the Steady Thermal Aero Research Turbine (START) facility at the Pennsylvania State University. The START laboratory is a continuous-duration, steady-state turbine facility that houses a single-stage test turbine and operates at engine-relevant Reynolds and Mach numbers. Computational fluid dynamics (CFD) simulations using Reynolds-averaged Navier Stokes (RANS) modeling were conducted with a two-level design of experiments (DOE) approach to determine a number of engine-representative target profiles with temperature shapes that are mid-radius peaked, outer diameter (OD) peaked, inner diameter (ID) peaked, along with a uniform profile. The features of the simulator included interchangeable liner panels with multiple rows of dilution jets and wall effusion cooling to allow various hole diameters and patterns to be studied. The dilution jets not only generate elevated turbulence levels but are also used to tailor the flow temperature profiles in the radial and circumferential directions. Independent control of air mass flow distributions as well as flow temperatures is accomplished within the simulator using the START infrastructure. Results from the DOE indicated the main contributor to the temperature profile shape at the near-wall locations between 0-15% and 85-100% radial span was the injection temperature of the effusion flow, while between 15-45% and 55-85% radial span the main contributor was the injection temperature of the second-row dilution jets, and between 45-55% radial span the main contributor was the diameter of the first-row dilution holes. A sensitivity analysis of the results determined which factors significantly affected the profile shape so that the target profiles could be produced.

Presenting Author: Chad Schaeffer The Pennsylvania State University

Presenting Author Biography: Chad Schaeffer is a Ph.D. candidate at The Pennsylvania State University in the Department of Mechanical Engineering. His current research at the Steady Thermal Aero Research Turbine (START) Lab includes applying CFD to design a combustor profile simulator to be used with the experimental turbine rig.

Authors:

Chad Schaeffer The Pennsylvania State University
Michael Barringer The Pennsylvania State University
Stephen Lynch The Pennsylvania State University
Karen Thole The Pennsylvania State University