Flame characteristics of a high-pressure LOX/H2 rocket combustor with large optical access

Flame dynamics of an injection element operated with LOX/H2, LOX/CNG and LOX/LNG in a sub- and supercritical rocket combustor with large optical access

“…The geometry of the inner surface of the optical access window matches the contour of the combustion chamber wall to minimise disturbance to the symmetry of the flow field in the combustion chamber. 14 The schematic of the combustor configuration is illustrated in Figure 1.…”

“…Higher opening angles are measured for higher values of VR and J, due to the increased shear forces and thus improved mixing. 33,14 The values from the more unstable LPs in the CNG and LNG campaigns do not behave similarly, which can be explained by the excited longitudinal resonance modes of the chamber causing the opening angle to vary dynamically and be generally increased by the upstream compression of the flame by the acoustic oscillations. The dynamic pulsation in the near injector region is also responsible for the large uncertainty in these measurements.…”

“…9 Frequently, the injectors are placed in sub-scale experiments to verify the desired performance before implementing into full-scale engines. 10–19 These experiments can also provide test data to validate CFD tools for use in the design process.…”

“…In addition, a shorter duration of the peak CH* concentration improves the suitability as markers for time-resolved heat release 26 under such conditions and can complement OH* measurements for the assessment of combustion dynamics. 14,24 Although lacking an established proportionality between line-of-sight integrated radiation measurements and q ˙ ′, the correlation of intensity with pressure can give a qualitative indication of the thermoacoustic interaction. Therefore, this article applies OH* and CH* radiation measurements as markers for heat release rate in rocket combustion at pressures well above the validated range.…”

Coaxial-Injector Surrogate Modeling Based on Reynolds-Averaged Navier–Stokes Simulations Using Deep Learning

“…Increasing the numerical modelling reliability is a strategic matter that needs to be addressed in order to reduce the development cost of innovative rocket engines for future launchers, in particular LRE, and thus ensuring access to space. The combustion chamber and injector design are key elements of any rocket engine [1]. High fidelity numerical simulations, and in particular Large Eddy Simulations (LES), have demonstrated their ability to finely describe complex physical phenomena in LRE combustion chambers [2][3][4][5].…”