Thermoelectric coupling effect of secondary injection on gasoline fuel spray and mixing of a free vibration combustion alternator

Abstract

This article focuses an unconventional energy transducer called free vibration combustion alternator that directly utilizes mechanical vibration to convert fuel combustion heat energy into electrical energy, while studying the impact of secondary injection strategy on fuel spray and mixing in a free vibration combustion alternator. A thermoelectric-mechanical coupling model is developed to take into account the interaction effect between vibration, generation, combustion on fuel spray and mixing in free vibration combustion alternator. Meanwhile, an algorithm method is proposed to iterate the calculation results of vibration and combustion for simulating the effect of the secondary injection strategy on the mixture formation characteristic. The results indicate that the fluctuation of secondary injection ratio affects the free vibration combustion alternator vibration, and then changes the compression ratio and the initial conditions for fuel injection and mixture formation. The free vibration combustion alternator operating in secondary injection proportion of 9:1 condition shows equivalent speed of 2061 r/min, compression ratio of 8.75, fuel evaporation rate of 91.4%, mixing uniformity index of 86.4%, and they are adjusted to 1855 r/min, 7.96, 99.9%, 32.2% respectively when the secondary injection proportion is 1:9. Moreover, a larger secondary injection proportion causes stronger turbulent motion, significantly improving the mixing quality.