Reciprocating heat engine with superadiabatic combustion in porous media

摘要

A new method of energy conversion from combustion heat to mechanical power has been proposed on the basis of superadiabatic combustion in a porous medium. The system consists of two pistons and a thin porous medium in a cylinder; one being a displacer piston and the other a power piston. These create reciprocating motions with a phase relation, similar to those of an ordinary Stirling engine. By means of the reciprocating flow system, the residual combustion gas enthalpy is effectively regenerated to induce enthalpy increase in the mixture through the porous medium, which provides heat storage. A one-dimensional numerical calculations has been performed based on the one-step reaction model having the Arrhenius reaction rate expression. Due to heat recirculation, the maximum temperature is higher than the theoretical one in free space. The thermal efficiency is higher than those of the conventional Otto and diesel cycles under a range of low compression ratios.