Investigation of Density Ratio Effects on Behavior of Injected Jet into a Hot Turbulent Flow, Using Different Turbulence Models

In this research، effects of density differences between a hot cross flow and injected coolant fluid on the flow hydrodynamics and film cooling effectiveness at different velocity ratios were computationally investigated. A computer code was developed using finite volume method and the SIMPLE algorithm on a multi-block، non-uniform staggered grid. Three different turbulence models (standard and SST versions of and) were applied. The simulations were performed at three density ratios of 0. 5، 1، and 2، and three different velocity ratios of 0. 5،1، and 2. The jet into cross flow temperature ratio and the jet Reynolds number were 0. 5 and 4700، respectively. Comparing the obtained results showed that the density ratio effects on the turbulent kinetic energy، especially in the near wall region، is noticeable. Therefore، the convection heat transfer coefficient can be greatly affected by the density ratio. In addition، the density ratio has significant effects on the jet into cross flow penetration in all three directions (streamwise، normal، and spanwise). Moreover، at low velocity ratio (0. 5)، increasing the density ratio reduces the spanwise averaged film cooling effectiveness. At higher velocity ratio (2. 0)، as the density ratio increases، the spanwise averaged cooling effectiveness increases.