Preliminary Engine Test Preparation
A small test engine was constructed to evaluate green-flame propellant performance under actual combustion chamber conditions. The engine was designed for 5-10 second burn duration with integrated instrumentation for chamber pressure, wall temperature, and thrust measurement. The test was intended as a proof-of-concept demonstration of green-flame propellant combustion in an engine environment.
Thermal Management Failure
Engine startup proceeded normally, but chamber wall temperatures rapidly exceeded design limits. Thermocouple data showed wall temperatures reaching 1500K within 2 seconds of ignition, significantly higher than predicted. The green-flame combustion produced unexpectedly high heat flux to chamber walls. Thermal stress on the engine structure became severe, and internal instrumentation began failing as temperatures climbed.
Nozzle Erosion and Damage
The engine nozzle throat experienced severe erosion during the test. Post-test inspection revealed throat diameter had increased by approximately 15%, indicating significant material loss. The erosion pattern was non-uniform, suggesting chemical attack rather than simple thermal erosion. Analysis of eroded material showed evidence of reaction with the nozzle material itself, indicating the green-flame combustion products were chemically aggressive at high temperature.
Test Termination and Next Steps
The engine test was terminated after 3 seconds of operation due to structural integrity concerns. The unexpectedly high heat flux and nozzle erosion represent critical design challenges. Chamber cooling system redesign is required, and alternative nozzle materials must be evaluated for chemical resistance. Laboratory work is underway to characterize the chemical composition of high-temperature combustion products and their interaction with candidate chamber materials. Fundamental understanding of green-flame combustion chemistry at engine conditions is needed before further engine testing can be safely conducted.