Research of liquid outflow from low-emission swirl injectors of a low-thrust liquid rocket engine

The paper justifies the possibility of using cold-flow test data to predict the combustion efficiency for a 13.34 N thruster combustion chamber. The results of modeling working liquid (water) flowing through hydraulic passages of single injection elements and coaxial swirl injectors are presented. We performed the simulation using the Reynolds-averaged Navier-Stokes equations that describe a turbulent flow of a two-phase non-compressible liquid. We used both one-velocity and two-velocity flow models. We modeled the turbulence by the BSL isotopic turbulence model on a computational block-structure grid. The computational grid consisted mostly of HEXA elements. The orientation of the elements coincided with the flow direction in the injector hydraulic channels, which improved the flow resolution accuracy in the boundary layer near the solid wall. We compared the results of calculation with the cold-flow test data. The use of the one-velocity flow model in the design area of a single injector and the two-velocity model in the design area of the mixing element yielded the results that agreed satisfactorily with the cold-flow data.