Preliminary performance sensitivity study for a 3.5 kN H₂O₂/Kerosene liquid bipropellant rocket engine.
Ichor is an early-stage propulsion study for a pressure-fed, bipropellant liquid rocket engine targeting 3.5 kN sea-level thrust using hydrogen peroxide (H₂O₂) as oxidiser and kerosene as fuel.
The objective of this preliminary phase is to map the sensitivity of key performance parameters — specific impulse, chamber temperature, characteristic velocity and thrust coefficient — to the two primary design variables: oxidiser-to-fuel ratio and chamber pressure.
Six parametric sweeps across O/F ratio (5–8) and chamber pressure Pc (1–4 bar), generated with RPA & NASA CEA, post-processed in MATLAB. The ★ marks the global maximum in each space.
Thermochemical equilibrium calculations were carried out with RPA (Rocket Propulsion Analysis) and NASA CEA, post-processed in MATLAB. The sweep spans O/F ratios from 5 to 8 and chamber pressures from 1 to 4 bar, with the nozzle expansion ratio ε as an additional free parameter — producing the performance sensitivity maps shown above.
The design point was selected at O/F = 6.4 and Pс = 3.5 bar, which maximises specific impulse while keeping chamber temperature within structural material limits. The analysis revealed that Isp is relatively insensitive to chamber pressure above ~2 bar, but the thrust coefficient Cf is strongly Pc-dependent — a critical finding for the injector and feed-system sizing.