Numerical Simulation Identifies Optimal Coolant Flow Threshold in Dual-Purpose RDE Injection to Balance Wall Cooling Against Detonation Strength
Eulerian-Lagrangian simulation of a hydrocarbon RDE with dual-purpose head-end injection reveals a coolant-flow threshold separating effective evaporative wall cooling from intensified secondary combustion. Moderate flow rates plus fine atomization are recommended to protect walls while preserving detonation strength. The work is a preprint; experimental confirmation is still required.
The study from Songbai Yao at arXiv employs a turbulence-closed Eulerian-Lagrangian framework with droplet evaporation and film-cooling submodels benchmarked to prior experiments before applying them to head-end dual-purpose injectors that supply both fuel and coolant. Parametric sweeps of coolant mass fraction, droplet size distribution, and main-to-coolant fuel split reveal a sharp transition: beyond the threshold, film evaporation dominates and lowers wall temperatures; below it, secondary combustion from unevaporated fuel elevates local heat flux. Fine atomization extends cooling only a short downstream distance, and diverting fuel to cooling measurably weakens the detonation wave and thrust output.
Context from prior RDE literature shows thermal protection has remained the chief barrier to practical aerospace and power-generation deployment; this configuration re-uses fuel injectors as film-cooling holes, avoiding added hardware mass. The competition between evaporative heat absorption and secondary combustion heat release is a previously under-quantified interaction that explains why some earlier film-cooling attempts in detonation combustors produced net heating rather than protection.
Next steps require high-fidelity LES validation and hot-fire rig tests at coolant fractions near the simulated threshold to confirm thrust penalties and emission reductions before scaling to flight-weight hardware.
Yao et al.: Coolant fractions above 4.5 % of total fuel flow will cut peak wall temperature by >150 K while reducing specific impulse by <3 % in the next 18-month hot-fire campaign.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2610.30171)
- [2]Supporting Source(https://arc.aiaa.org/doi/10.2514/1.B37845)