Unsteady Analysis of Adiabatic Film Cooling Effectiveness Behind a Row of Circular Holes Fed by Internal Crossflow

Abstract

The adiabatic film cooling effectiveness behind a single row of circular holes fed by internal crossflow was measured by fast-response pressure-sensitive paint technique. During the experiment, the coolant flow was discharged from the coolant holes via either plenum or crossflow channel. The test model has a row of circular holes with 3D spacing, 6.5D entry length, and 35° inclination angle. Two blowing ratios (M = 0.40 and 0.80) were tested with a density ratio of 0.97. A numerical steady-state RANS simulation, using SST k-ω and Realizable k-ε turbulence models, was conducted to understand the internal crossflow behaviors. The unsteadiness caused by the flow structures (counter-rotating vortex pair (CRVP) and horseshoe vortex) was quantified by the root mean square and the cross-correlations. In addition, the proper orthogonal decomposition was used to identify the large-scale unsteady coherent structures and their contributions. The fluctuations of the crossflow feed were asymmetric, which were significantly weaker compared with the plenum case. The CRVP, as the most significant coherent structures, were demonstrated to play the main role in the unsteadiness of the crossflow feed.

Investigation of Film Cooling Vortical Structures Behind a Cylindrical Hole Fed by an Internal Crossflow

“…The physical problem is an experimental work taken from the authors (Qenawy et al, 2019). It was achieved with fast-response pressure sensitive paint (PSP) technique.…”

“…The main objective is to perform a three-dimensional compressible LES approach to provide a detailed evaluation of the identified unsteady flow structures. The simulation was performed on a physical problem taken from the experimental work of the authors (Qenawy et al, 2019). The numerical results were validated by the measured data in terms of cooling effectiveness and flow data.…”