EXPERIMENTAL STUDY ON DROPLETS IN IMPINGING-JET SPRAYS GENERATED UNDER FLASH-BOILING CONDITIONS
Impinging-jet injectors, where two or more liquid streams collide in a gaseous environment, are critical for atomisation and mixing in rocket engine combustion, including those operating in near-vacuum conditions during orbital restarts. Under such conditions, rapid phase changes known as flash boiling can occur, significantly altering liquid stream formation, collision dynamics, and spray characteristics. This study investigates the effects of flash-boiling on droplet size distributions in sprays generated by two impinging jets and compares them to analogous single (free) jets. Droplet sizes were measured using a shadowgraphy technique with a long-distance microscope. The results revealed that flash-boiling not only reduces droplet sizes near the injector but also enhances spray dispersion due to intensified stream disintegration. These indicate possible implications for combustion efficiency in aerospace propulsion systems based on impinging-jets injection systems.
Topic: Engine combustion
Author: Hernan Amaya Gonzalez
Co-authors: Bartosz Kaźmierski, Łukasz Boruc, Łukasz Jan Kapusta
