Hypergolic Reactive Boundaries

Hypergolic propellants demonstrate distinct combustion instabilities when compared to other mixtures such as liquid oxygen and methane or hydrogen. The extremely short time scales, typically near 2 ms, over which hypergolic propellants go from impacting one another to igniting produce heating rates one the order of a million degrees Kelvin per second. Such heating rates are highly desirable for many space applications but are also challenging to manage and diagnose. Under certain conditions, the magnitude and time scales associated with the energy released during the combustion of hypergolic propellants can create high pressure oscillations and uneven heat transfer. If these pressure and heat transfer variations are large enough, they can couple with injection processes and rapidly build a feedback mechanism which often results in catastrophic hardware failure. Building on my growing expertise with hypergolic propellants such as Mixed Oxides of Nitrogen (MON) and monomethylhydrazine (MMH), the most common hypergolic propellants in current space systems, I propose to investigate the initiation mechanisms of the high-pressure oscillations observed with hypergolic propellants with a detailed study of physical confinement, backflow, and heat soak-back on the reactions between MMH and MON. I propose a four-year research plan to understand the effects of a reactive boundary on an injector and combustion chamber surfaces. The research would be completed at Purdue University’s Maurice J. Zucrow Laboratories under the advisory of Professor Pourpoint. In the proposed research, I would mimic the surfaces of a wetted injector face and combustion chamber by creating a thin film of MMH on a wicking plate while injecting MON onto the wicking plate. The setup will use a clear, quartz combustion chamber with the ability to be temperature and pressure controlled. A high-speed camera will be used to visualize the pressure spikes occurring on the wicking plate. The wicking plate itself will have an embedded thermocouple rake to measure the temperature distribution on the plate, with interchangeable plates varying length and diameter. The experimental setup will be kept small, around 3-4 inches in diameter, for ease of manufacturing, to minimize the use of propellant, and the safe operation of the experiment. Between each experiment, the residues on the wicking plate will be investigated using a suite of analytical tools available at Purdue. The proposed experiments will make use of high frequency pressure measurements and videos in the visible and IR wavelengths and a high-speed streak camera available to probe gas phase regions. These high frequency diagnostic tools are paramount for the proposed work. They will be completed by UV and IR spectrometry of reaction products and, as needed, complementary CFD models of reactions to help me identify condensed and gaseous species within the early stages of the hypergolic ignition events. Determining the effects of combustion instabilities directly correlates with the NASA Technology Roadmap TA 2: In-Space Propulsion Technologies for chemical propulsion (TA 2.1) with the main goal to enhance current or future missions through improvements in performance, reliability, and safety. Combustion instabilities are common throughout every engine, with failures dating back to Apollo 11; however, hypergolic instabilities are unique given the reactivity of Hypergols. Despite Hypergols being not well characterized, they are used in a wide variety of engines – ranging from small scale moon lander thrusters or heavy launch vehicles like the Ariane 5. A current example of hypergolic thrusters is NASA’s Thrusters for the Advancement of Low-Temperature Operation in Space (TALOS), where injector and combustion chamber designs were impacted by reactive boundary interactions.

This is early/mid-stage (TRL 2) — the most realistic path in is NASA SBIR/STTR, which funds small businesses and research institutions to develop technology aligned with NASA's needs (equity-free, phased funding). Check whether a current SBIR/STTR solicitation topic overlaps with this project's technology area, or contact the project directly (above) to ask.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.