Numerical study of gas film cooling with coolant injection though a triangular shaped nozzle with a recess
N.N. Kozyulin, M.Yu. Khrebtov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: numerical simulation, film cooling, trapezoid shaped nozzle, direct cooling scheme, thermal adiabatic efficiency
Abstract
The paper presents the results of numerical simulation for a near-wall film cooling with gas ejection though a nozzle shaped as a cavity with triangular cross-section (with arranged recess). The flow downstream the recess induces the main flow detachment and generates the coherent vortex structures with a constant frequency of shed vortex (in the zone of mixing with the coolant jet). These vortex structures interact with the wall and improve the coolant spreading in the horizontal direction. This also facilitates the jet flow leaning to the surface at high injection numbers. The cavity’s triangular shape facilitates the lower generation of streamwise vortices that separate the nearwall stream from the surface. The study was conducted for a wide range of coolant injection number. The wall boundary conditions are adiabatic. We determined the injection parameters range suitable for practical applications for the described design. The developed system has a separate vortex shedding frequency and the system is sensitive to the external impact at this frequency. Thus, this approach is a candidate for arrangement a real active control system for film cooling.
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