Effect of jet's inlet temperature field excitation on heat transfer by turbulent impinging jet: an investigation based on Large Eddy Simulations

In this paper, the effect of inlet temperature field excitation on the impinging jet heat transfer has been investigated using Large Eddy Simulation (LES). There are several experimental and numerical studies on the inlet velocity field excitations of a turbulent impinging jets, however, the temperature field excitation has not been done before. The Reynolds number (Re) of the jet is 23000 and dimensionless jets outlet to target wall distance is two. To ensure a good quality of the simulation, the non-excited jet is simulated first. From the simulation, It is found that the Strouhal number corresponding to the preferred mode of the unexcited jet is 0.328. The jets inlet temperature field is then excited with three different frequencies. The heat transfer enhancement is found to be possible with inlet temperature field excitation; however, the improvement depends crucially on the excitational frequencies.