Experimental and numerical investigations on the spray characteristics of liquid-gas pintle injector

Abstract

The spray characteristics of a liquid-gas pintle injector at different total momentum ratios (TMR) are investigated by means of experiment and numerical simulation. Water and nitrogen are used as simulant for liquid fuel ejected out from radial gap and gas oxidizer ejected out from axial annular gap, respectively. A high-speed photography system and Malvern measuring instrument are used to study the spray pattern, spray angle, droplet diameter and spatial distribution. A coupling algorithm between Volume of Fluid and Lagrangian Particle Tracking (VOF-LPT) is applied for spray simulations implemented within the CFD software OpenFOAM. The results indicate that the spray pattern generated by the liquid-gas pintle injector is mainly influenced by gas weber number and divided into three types. The spray angle is dominated by the TMR, and the outer boundary of the spray field is enlarged with the increase of the TMR. In particular, a spray angle formula of liquid-gas pintle injector is given in: cos⁡θ=c/(c+TMR), and c=0.71 with considering the gas jet momentum loss. The droplet diameter and spatial distribution indicate that Sauter Mean Diameter (SMD) decreases in the spray intermediate area with the increase in the aerodynamic force action. The spray structure and diameter distribution obtained by numerical calculation agree well with the experimental results, and can be used to analyze the spray characteristics.