Liquid Fuel Injection Strategy to Reduce Sensitivity to Liquid Physical Properties

摘要

Changes in fuel properties can alter injection and distribution of the fuel ahead of the combustion process. JP-8 properties can vary from batch to batch and with temperature. Furthermore, alternative fuels may have different physical properties than the baseline JP-8 fuel. By mitigating the dependency of the fuel injection process on liquid physical properties, better control of the subsequent combustion process can be attained, and fuels can be changed in an engine with more confidence that performance won't be affected. This presentation summarizes a strategy that has been developed for liquid fuel injection using plain jets that reduce the sensitivity of the injection process to liquid physical properties such as viscosity, surface tension, and density. CFD simulations and detailed experiments were carried out to understand and confirm the desired performance results associated with decoupling the injection process from liquid physical properties. Laser sheet imaging, high speed video, and laser diffraction drop sizing were used in the experimental validation. The results show that the strategy utilized (1) significantly reduces sensitivity of the injection process to changes in fuel properties and (2) enhances atomization (i.e., reduces droplet size) compared to a baseline configuration.