Performance of a Rotating Detonation Rocket Engine with Various Convergent Nozzles and Chamber Lengths

Energies

StephenA. Danczyk¹  JohnW. Bennewitz¹  WilliamA.Hargus¹  MathiasC. Ross²  RichardD. Smith³  BlaineR. Bigler⁴ 

[1] Air Force Research Laboratory, Edwards, CA 93524, USA;Department of Mechanical and Aerospace Engineering, UCLA, Los Angeles, CA 90095, USA;GHKN Engineering LLC., Kirkland, WA 98034, USA;Jacobs Technology Group, Air Force Research Laboratory, Edwards, CA 93524, USA;

关键词: rotating detonation rocket engine;    detonation;    counter-propagation;    wave dynamics;    injection recovery;   

DOI  :  10.3390/en14082037

来源: DOAJ

【 摘 要 】

A rotating detonation rocket engine (RDRE) with various convergent nozzles and chamber lengths is investigated. Three hundred hot-fire tests are performed using methane and oxygen ranging from equivalence ratio equaling 0.5–2.5 and total propellant flow up to 0.680 kg/s. For the full-length (76.2 mm) chamber study, three nozzles at contraction ratios ${ϵ}_c$ = 1.23, 1.62 and 2.40 are tested. Detonation is exhibited for each geometry at equivalent conditions, with only fuel-rich operability slightly increased for the ${ϵ}_c$ = 1.62 and 2.40 nozzles. Despite this, counter-propagation, i.e., opposing wave sets, becomes prevalent with increasing constriction. This is accompanied by higher number of waves, lower wave speed $U_{\mathrm{wv}}$ and higher unsteadiness. Therefore, the most constricted nozzle always has the lowest $U_{\mathrm{wv}}$. In contrast, engine performance increases with constriction, where thrust and specific impulse linearly increase with ${ϵ}_c$ for equivalent conditions, with a 27% maximum increase. Additionally, two half-length (38.1 mm) chambers are studied including a straight chamber and ${ϵ}_c$ = 2.40 nozzle; these shortened geometries show equal performance to their longer equivalent. Furthermore, the existence of counter-propagation is minimized. Accompanying high-fidelity simulations and injection recovery analyses describe underlying injection physics driving chamber wave dynamics, suggesting the physical throat/injector interaction influences counter-propagation.

【 授权许可】

Unknown