Characteristic Features of the Thermomechanics of Gas Flows in the Piston Engine Outlet under Various Gas-Dynamical Conditions

A comparative analysis of the thermomechanical characteristics of a gas in the internal combustion piston engine outlet in the case of stationary and pulsating gas flow regimes was carried out. An estimate of the effect of external turbulence (of the presence of a turbocompressor) in the engine outlet on the thermomechanics of flows pulsating in it has been carried out. It has been established that in the engine outlet the change-over of flow regime from a stationary to a pulsating one leads to an 8–10-fold increase in the turbulence degree, as well as to a change in the heat transfer coefficient by ±25%. It is shown that mounting of a turbocompressor in the engine outlet leads to a 1.5–2.5-fold increase in the hydraulic resistance of the system, to a decrease in the rate of air flow though the system on the average by 11%, and to a 1.5–3.0-fold increase in the turbulence degree at a low flow velocity, as well as to heat transfer intensification by 33% at a high pressure at the output.