Spray characteristics of gelled propellants in novel impinging jet injector

To improve the atomization quality of gelled propellants, a chamber similar to a Helmholtz resonator was installed in an impinging jet injector to introduce disturbances on the atomized fluid. The spray formation of gelled propellant from impinging jet injectors with a Helmholtz resonator-like chamber was examined experimentally. A high-speed camera was used to record the detailed information of the liquid sheet breakup process. Installing a resonator chamber in the impinging jet injector always tends to decrease the breakup length of the liquid sheet, but rarely does the installation influence the flow rate of the injector. The breakup length of liquid sheet is minimal when the diameter ratio of chamber to exit equals 4. To obtain a shorter breakup length, the ratio of chamber inlet diameter to outlet diameter should be close to the value of 1, but cannot equal 1 because the mass flow rate is decreased when this ratio equals 1. The effect of the ratio of length to diameter of the chamber is minor. Although the breakup length is minimal, when the ratio of chamber length to diameter is between the value of 1 and 1.5, the mass flow rate is also decreased.