Most of the flows occurring in the engineering systems are turbulent and their accurate numerical analysis is still challenging, especially when combined with the heat transfer. One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied also in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to its origin are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason. The authors are interested in construction of the numerical model assuring the results as close as possible to the experimental one and then modelling the transport processes in the heat exchanger. The most difficult area to model is the stagnation region, where the thermal effects are strongly affected by the conditions in the pipe/nozzle/orifice, from which the jet is originated. In the following article, summary of authors’ findings, regarding significance of the velocity profile or turbulence intensity at the inlet, are presented. In addition, qualitative analysis of the heat transfer enhancement is included, in relation to the inlet conditions.