Numerical investigation of twin-jet impingement with hybrid-type turbulence modeling

• LES & SST–SAS hybrid model were applied for the first time for impinging twin-jets.
• The numerical investigation was carried out for different spacing and Reynolds number.
• Both approaches were not able to produce accurate results for heat transfer.
• SST–SAS produced good results in terms of pressure distribution & velocity.

A Computational Fluid Dynamics (CFD) study of a twin-jet impingement is performed using the Reynolds-Averaged Navier–Stokes (RANS) approach with a dynamic Smagorinsky Large Eddy Simulation (LES). The use of a hybrid RANS–LES (i.e., part of the turbulence is modeled and part of the turbulence is resolved) method potentially offers a compromise between the computational efficiency and the accuracy comparable with that of a pure dynamic LES. In the current study, the SST–SAS (Shear-Stress transport with Scale-Adapted Simulation) k–ω model having hybrid RANS–LES characteristics is utilized for turbulence modeling. Effects of nozzle-to-plate (H/D) and nozzle-to-nozzle (L/D) distances on the pressure distribution and the heat transfer are investigated for 3 × 104 < Re < 5 × 104. Numerical results of SST–SAS and dynamic LES methods are validated against available experimental data. The flow expands radially as H/D increases. Results show that the SST–SAS model can produce fairly accurate results, especially with a lower H/D at which the sub-atmospheric region appears. In addition, the SST–SAS model is capable of predicting the peak values of local Nusselt number at correct locations.