Application of Three-Parametric Differential RANS-Model of Turbulence for Solving the Problems of Gas Flow Energy Separation

The paper describes the numerical study technique for problems of external compressible gas flow around permeable surfaces applying a three-parameter RANS turbulence model. Numerical study of energy separation in the boundary layer on an impermeable and permeable plate with gas injection/suction in the range of Prandtl numbers Pr from 0.05 to 5 showed that temperature stratification increases with decreasing Pr number. Gas injection into a supersonic flow reduces temperature stratification compared to an impermeable plate, while suction increases the effect. The influence of the Prandtl and Mach numbers of the external flow on the value of temperature stratification, which is largely determined by the value of the suction intensity and, consequently, the total flow rate of the sucked gas, is studied. Temperature stratification is most pronounced for gases with small Prandtl numbers. It has been established that with intensive gas suction in the boundary layer on the section of the impermeable plate following the permeable part, the wall temperature drops sharply. The reason for the formation of a zone with a lower wall temperature is the laminarization of the boundary layer on the permeable wall with intensive suction resulting in the asymptotic suction mode. The conducted numerical study confirmed a significant decrease in the wall temperature compared to the temperature of the injected gas for both laminar and, to a lesser extent, a turbulent boundary layer with foreign injection of helium into xenon with a Prandtl number variable along the length compared to a uniform gas injection with a constant Prandtl number. The results of numerous numerical studies of the main elements of the working process in the energy separation device were obtained, which served as a justification for the possibility of energy separation of the gas flow.