Advanced Optical Patternator for Performance Prediction of Bipropellant Thrusters

We develop an advanced optical patternator method to predict bipropellant thruster characteristic exhaust velocity, aiming to bridge the gap between cold-flow diagnostics and hot-fire performance prediction. The method combines scattered light and planar laser-induced f luorescence techniques to achieve non-contact, high-resolution spray characterization that overcomes fundamental limitations of conventional mechanical patternators. Experiments conducted under well-controlled conditions support our theoretical analysis, revealing that the optical approach achieves performance equivalent to mechanical patternators across a wide range of mixture ratios. Furthermore, the predicted characteristic velocities show excellent agreement with hot-firing test data, confirming the validity of the proposed framework. The proposed optical method offers real-time measurement capabilities with approximately 90% reduction in evaluation time and achieves performance prediction within 5.2% error of hotf ire test results, demonstrating its utility for reducing development costs while maintaining quantitative reliability for thruster design applications.