PHYSICAL AND NUMERICAL MODELING OF THERMOMECHANICAL PROCESSES IN GAS–AIR SYSTEMS OF PISTON ENGINES UNDER GASDYNAMIC-NONSTATIONARITY CONDITIONS

It is well known that as of today, internal combustion engines are the most widespread energy sources among heat engines. Therefore, one relevant problem in the development of world energy is to improve operating processes, and also to modernize systems and elements of piston internal combustion engines with the aim of improving their technical and economic indices. In the present paper, the authors have given new information on nonstationary gasdynamics and local heat transfer of pulsating fl ows in gas–air fl ow ducts of internal combustion engines, and also have proposed methods for improving the processes in intake and exhaust systems. Experimental investigations were conducted on full-scale models of a single-cylinder internal combustion engine with supercharging and without it. Physical features of pulsations of gas fl ows in the engines′ gas–air fl ow ducts have been described. Calculated and experimental dependences of the change in the instantaneous velocity and the pressure of the gas fl ow in the gas–air fl ow ducts with time have been presented. Particular emphasis was placed on an analysis of the intensity of heat transfer in gas–air fl ow ducts of different confi gurations. It has been shown that lateral profi ling of intake and exhaust pipelines exerts a positive infl uence on the technical and economic indices of piston engines without supercharging. A method to reduce pulsations of the pressure and velocity of gas fl ows (on the average, by a factor of 2) in the intake pipeline of a supercharged internal combustion engine has been proposed, which leads to an improvement of the reliability of the entire engine.
   
Author:  L. V. Plotnikov, B. P. Zhilkin, and Yu. M. Brodov
Keywords:  piston engine, gas–air systems, turbosupercharging, pulsating fl ows, nonstationary gasdynamics, local heat transfer, improvement of gas exchange.
Page:  594