Description: A technique for measuring velocity in rocket plumes called hydroxyl tagging velocimetry (HTV), which was developed previously and demonstrated on a small rocket engine, is proposed for use on a full scale engine. Specific goals of the program include producing a measurement system that can withstand the high acoustic levels of a relevant full scale rocket engine, development of efficient user-friendly software for processing the raw images to produce velocity data, verifying the performance of the prototype at relevant temperatures and H2O concentrations, and demonstrating it on a full scale rocket engine. The work plan includes tasks to design and construct a rugged prototype HTV system, including supporting analyses required to properly select the laser, camera, and optical components, test the prototype in a laboratory scale flame, and produce acoustic suppression covers and damping systems to enable a demonstration on a large engine.

Benefits: NASA applications include the measurement of rocket performance on SLS engines, such as the Launch Abort engine of the CST-100 crew capsule, and on other NASA programs requiring the direct measurement of velocity from rocket plumes. Also, validation of computer models for rocket engine performance, leading to improvements in efficiency and reduction in cost of hardware development programs.

Non-NASA applications include the measurement of velocity to obtain performance data in engine development programs in the commercial space transportation industry, rockets, missiles, scramjets, and turbine engines, new concepts in propulsion, pulse detonation engines, etc.