Investigation of Inlet Condition Effect on Flow and Turbulence Characteristics in Subsonic Jets from Conical and Chevron Nozzles Using RANS/ILES High Resolutions Method

Abstract

Effect of Mach number and temperature on subsonic jets flow with a combined highresolution RANS/ILES method (Reynolds Averaged Navier-Stokes - RANS, Implicit Large Eddy Simulation - ILES) was investigated. Cold Mj=0.985 T0=300К and hot Mj=0.548 T0=858.6К jets were considered (Mj – Mach number at the nozzle exit and T0 – total temperature at the nozzle inlet). Conical and two chevron nozzles with angle of chevrons to the nozzle axis α=5° and α=18.2° were investigated. The jet flow calculations were carried out together with flow calculation in nozzles. Computation grids were Meshes for simulations (2.8-3.2)×106 cells. Investigated cases were compared by average velocity and velocity fluctuations at the jet axis and at the mixing layer. The magnitude of velocity fluctuations at the jet axis and at the mixing layer for hot jets is higher than for cold jets. It leads to increasing expansion angle of the mixing layer inward the jet axis. This is why the initial part length of hot jets becomes shorter than in cold jets. Comparison of simulations with the experimental data of other authors showed a good agreement by flow and turbulences characteristics.