Abstract
The aerodynamic and thermal behaviour of multiperforated zones in combustors is essential to the development of future combustion chambers. Detailed databases are therefore crucial for the validation of RANS/LES solvers, but also regarding the derivation of heat transfer correlations used in 0D/1D in-house codes developed by engine manufacturers. In the framework of FP7 EU SOPRANO Program, the test-rig used in a previous study is modified to be compatible with anisothermal conditions. The plate studied is a 12:1 model with a 90∘ compound angle injection. A heating system is used to generate a moderate temperature gradient of about 20 K between the secondary hot flow and the main cold flow. The aerodynamic field is acquired by a PIV 2D-3C (Stereo Particle Image Velocimetry) system. The surface heat transfer coefficient is derived based on surface temperature distribution acquisitions. Several heating power levels are tested, which allows evaluating the convective heat transfer coefficient and reference temperature through a linear regression. Measurements are conducted on both sides of the plate, which also gives access to those quantities on the injection/suction sides. From a numerical point of view, the configuration is studied using the unstructured ONERA in-house CEDRE solver with an advanced Reynolds Stress Model. A systematic comparison is presented between the experimental and numerical database. Due to the high blowing ratio, the film protection is low in the first rows, with a convective heat transfer coefficient enhancement around three, and freestream cold air brought close to the wall by vortices created at injection. After four rows, the film is building up, leading gradually to a better insulation of the wall. The comparison with the numerical simulation exhibits a qualitative agreement on the main flow structures. However, the mixing between the jets, the film and the freestream is underestimated by the calculation.
Highlights
Cooling in modern combustion chambers involves the use of multiperforated liners which allow creating a cold film protection and reduce the heat load received by the wall.To model the corresponding heat transfer, detailed databases are required for the validations of RANS/LES solvers, and regarding the derivation of heat transfer correlations used in 0D/1D in-house codes developed by engine manufacturers
Due to the high blowing ratio, the film protection is low in the first rows, with a convective heat transfer coefficient enhancement around three, and freestream cold air brought close to the wall by vortices created at injection
In the framework of the EU FP7 SOPRANO program, a test rig was developed to study the aerothermal field around a 12:1 scale multiperforated plate, with 90 deg compound angle injection
Summary
Cooling in modern combustion chambers involves the use of multiperforated liners which allow creating a cold film protection and reduce the heat load received by the wall. The influence of compound angle injection on film cooling effectiveness was first investigated for one or two rows. They compared their results with streamwise injection holes, showing enhanced adiabatic effectiveness and lower heat transfer rates for the configuration with compound angle injection They emphasized the concept of Net Heat Flux Reduction Crouzy [14] presented results obtained on a realistic configuration, where various aerothermal conditions were tested for different tubular configurations Parameters such as the yaw angle, the spacing between holes, and the chamber preswirl rate were varied, and the respective cooling efficiencies were compared. To the best of our knowledge, there is no study in the literature currently presenting a combined fluid dynamics/heat transfer detailed database of the flow encountered around a multiperforated plate for anisothermal conditions and a 90◦ compound injection. This simulation, carried out with a standard k-ω SST turbulence model and with an advanced Reynolds Stress Model, aims at better understanding the main flow characteristics and should be seen as a first step before future works on the evaluation of Reynolds Stress Models, more suitable for such complex flows
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