Ignition thresholds of HTP-ethanol bipropellants with an electrothermal mesh igniter
Kyoungeun Lee (Georgia Institute of Technology)
Prakhar Jindal (TU Delft - Aerospace Engineering)
Sebastien Reichstadt (The Exploration Company)
B. V.S. Jyoti (TU Delft - Aerospace Engineering)
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Abstract
Reliable low-power ignition is essential for replacing toxic hypergolic propellants with green bipropellant systems in spacecraft propulsion. This work experimentally evaluates a Nickel–Chromium (NiCr) thermal wire mesh igniter for high-test peroxide (HTP) with ethanol and Jet A in two laboratory configurations: open premixed surface ignition and confined spray-through hot-mesh ignition. Each power condition was repeated five times, and thresholds were defined as the minimum power producing at least 80% self-sustained ignition success (≥ 4/5). In the open configuration, ethanol–HTP and Jet A–HTP reached self-sustained ignition at 12.5 W and 10.0 W, respectively, corresponding to an estimated pre-contact mesh temperature of approximately 420 ∘C and 380 ∘C, respectively. In the confined configuration, thresholds decreased to 10 W for ethanol–HTP and 7.5 W for Jet A–HTP, corresponding to approximately 380 ∘C and 320 ∘C, respectively. Ignition delay time, estimated from 240 fps video, decreased from approximately 500–700 ms near threshold to 50–75 ms at the highest tested powers. The results indicate that NiCr mesh ignition can provide repeatable, low-power ignition of HTP-based green bipropellants, while confinement improves ignition by increasing heat retention and reactant residence near the heated mesh.
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