A One-Dimensional Combustion-Path Model for Wave-Speed Deficits and Axial Force in Non-Premixed Rotating Detonation Rocket Engines

A one-dimensional combustion-path model is developed to relate wave-speed deficits to axial-force production in non-premixed rotating detonation rocket engines. Incoming propellant is partitioned into full detonation, attenuated-front combustion, parasitic combustion, and unmixed afterburning. An empirical common attenuation length is calibrated against wave-speed data and coupled to filling and mixing. Under the adopted closure, only the full-detonation fraction supplies front-supporting heat release, whereas both front-processed fractions contribute to injector-face overpressure force. All paths remain included in the common pressure and injection-momentum terms. Using literature-based pressure and measured wave count, comparisons with 15 operating points from seven combustor configurations yield an apparent mean absolute error of 0.025 in the Chapman–Jouguet-normalized wave-speed ratio. The mean absolute percentage error is 18.1% for the three sea-level and flight-derived specific-impulse cases. The seven Purdue cases give 2.3%, but, because their pressure input comes from the same thrust measurement, they are a consistency check; the ten-case value is 7.1%. Despite agreement in overall wave-speed levels, the model reproduces only 13.8% of the wave-speed decrease at fixed wave count. The framework provides a compact representation of distinct contributions to wave support and axial force, while identifying unresolved operating-condition dependence and limitations in the force closure.