Influence of the Turbulence Scale of Gas Flows on the Heat Exchange Intensity in Channels with Different Cross Sections

The efficient operation of power machines and installations is largely determined by the initially set value of flow turbulence in gas-air systems. Consequently, the level of flow turbulence affects the formation of the boundary layer and the quality of heat transfer in the channels. The main goal of this study was to examine the effect of the turbulence scale on the heat transfer intensity from stationary gas flows in channels of different cross-sections. The research was carried out using numerical modeling of gas dynamics and heat transfer of stationary flows based on the Computational Fluid Dynamics method. Data on the assessment of the effect of flow turbulence scale on heat transfer in channels of different profiles for different gas flow regimes are presented in the paper. It was found that the turbulence scale has an insignificant effect on the change in the heat transfer coefficient in profiled channels. It is shown that the use of a square-shaped channel leads to a decrease in the heat transfer coefficient by an average of 4% in comparison with a circular channel. Conversely, the use of a channel with a triangular cross section causes an increase in the heat transfer coefficient within 10%. The suppression of the heat transfer coefficient along the channel length (downstream) by an average of 26% for all the considered channel profiles is demonstrated. The obtained data are planned to be used to predict thermophysical processes in gas exchange systems of heat engines for various purposes.