Semester of Graduation

Fall 2022


Master of Science in Mechanical Engineering (MSME)


Mechanical and Industrial Engineering

Document Type



With interest in space travel and space-related science increasing in recent years, significant efforts to reduce the cost and increase the safety of rocket motors have become commonplace. Liquid rockets are currently the most commonly used system, but there is interest in the reduced complexity of hybrid rockets. For these hybrid rocket motors to become the norm, extensive research on their complex boundary layer combustion needs to be performed. Modeling these hybrid systems is of much interest to companies developing rocket motors; ultimately, small-scale experiments will help validate their behavior. This paper covers the application of a near-infrared tunable diode laser absorption spectroscopy system implemented on a hybrid rocket combustor to study the system’s behavior. The TDLAS system was first implemented on a flat flame burner to adjust the settings and code to ensure that it was functioning correctly. The TDLAS system was able to capture the general trends of the flat flame burner but failed to calculate the temperature and mole fraction values accurately. This is believed to come from flow rate uncertainties and assumptions resulting from the removal of atmospheric interference. The TDLAS system was then transplanted onto a custom hybrid combustor to begin taking data. Distortion of the TDLAS signal within the combustion made it difficult to capture accurate temperature and water mole fraction values, but a connection between the lasers’ timescale and fluid fluctuations was established. Hardware limited the sampling rate of the laser and prevented it from running above 2kHz. It was hypothesized that running the laser upwards of 5kHz within a hybrid combustor of this scale may be necessary to ensure that the distortion effects are entirely removed from the signal.



Committee Chair

Menon, Shyam