Effect of swirl injection parameters on cooling performance of vortex-cooled bipropellant thruster

The cooling performance of a 10N-class gaseous Propane/GOx bi-propellant thruster with vortex cooling was investigated in this experimental study. Injecting oxidizer with a vortex was proposed as a potential cooling method for a semi-thermoplastic constructed thruster and demonstrated as a promising integrated cooling method that can be fabricated using 3D printing technology. Compared to other cooling types, vortex cooling has low system complexity and can be 3D printed as a single solid piece along with a thruster, reducing design complexity, weight, and manufacturing time. The experimental testing examined various injection configurations and their associated parameters to determine the most optimal injection combination. The test collected a comprehensive amount of data to evaluate the cooling performance with respect to varying operational parameters: oxygen-to-fuel ratio, propellant mass flow rate, and injection configuration. The study found that the acrylic chamber operated safely with a proper injection configuration identified maintaining the temperature of the thruster chamber walls below 60 degrees C, lower than the melting point of the acrylic material, with no damage observed. It was found that the downstream swirl injection had more favourable vortex cooling performance than the upstream injection for the scale of the thruster considered in this study.