Experimental research of high-temperature and high-pressure water jet characteristics in ICRC engine relevant conditions

Abstract

The internal combustion Rankine cycle (ICRC) concept provides a potential solution for future high thermal efficiency and low emission powertrains, and direct water injection (DWI) proved to be the key parameter for ICRC optimization. This paper was dedicated to investigating the fundamental mechanisms of water spray characteristics under different water injection control parameters. In order to do so, an experimental test system was carefully designed and built based on the Bosch and Schlieren methods: the Bosch method is utilized to measure the effect of injection and ambient pressure on water injection characteristics, and the Schlieren method is utilized to investigate the impact of water injection and ambient temperature on water spray and evaporation processes. The experimental results indicate that both control parameters show important effects on water injection and spray characteristics. The water injection and ambient pressure show significant impacts on steady-state flow quantity and cyclic water injection quantity, and the water injection and ambient pressure affect the evaporation ability of water vapor within the spray which leads to a different variation trend during the initial, developing, and developed water spray stages. The results of this work can be used as fundamental supplements for ICRC, steam assistant technology (SAT), and DWI-related ICEs experimental and numerical researches, and provide extra information to understand the DWI process within engine-relevant conditions.