Low-order model studies of combustion instabilities in a DVRC combustor

Abstract

Experimental and numerical studies on Discrete Variable Resonant Combustor (DVRC) are presented with the main objective of investigating the acoustic role of oxidizer manifold. In the experimental set up the longitudinal single element combustor is characterized by the unchoked interface between oxidizer manifold and the combustor. The numerical study\ud is carried out with two different approaches. One is based on linearized Euler equations, the other is based on quasi-1D Euler equations and allows to introduce perturbation on different quantities, i.e. mass flow rate boundary condition or heat release source term. Resonant frequencies and modal shapes are computed with both approaches and show good agreement with experimental data, provided that the perturbation, in the second approach, is applied within the combustion chamber and thus the manifold damping effect is limited. The manifold damping effect is clearly observed in the nonlinear regime which is discussed by the analysis of the solution obtained with the quasi-1D solver forcing with large perturbation different quantities

Reduced-Order Modeling of Model Rocket Combustors

“…Commonly adopted simplifications in reduced-fidelity models include reduced chemical reaction mechanisms [11][12][13] and low-dimension approximation. 12,14 Although failing to predict finer details of the flow, these methods can often be tuned for specific problems and provide satisfying accuracy in critical properties such as pressure, velocity and heat release for LRE modeling. However, the tuning process is typically empirical and iterative, involving calibration based on experiment or high-fidelity simulation data.…”

Optical Diagnostics in a High-Pressure Combustor with Gaseous Oxygen and Kerosene

“…The continuously variable resonance combustor used a gascentered swirl-coaxial injector with a variable length oxidizer post in the injector, allowing for tunable resonant responses [13]. This rig evolved into the discretely variable resonance combustor, with an updated injector mechanism [14]. Both of these rigs operate at pressures up to 4.1 MPa, with either CH 4 or liquid hydrocarbon fuels.…”

Three-Dimensional Numerical Analysis of Longitudinal Thermoacoustic Instability in a Single-Element Rocket Combustor

“…Typically, the longitudinal combustion instability has mostly been examined systematically at Purdue University (Smith et al, 2006(Smith et al, , 2010bYu, 2009;Wierman et al, 2012). Various scaled combustors with a single injector have been applied to study the longitudinal combustion instability mechanisms, including the Discretely Variable Resonance Combustor (DVRC (Frezzotti et al, 2014)), Continuously Variable Resonance Combustor (CVRC (Yu et al, 2008)), and Full-Flow Staged Combustor (Lemcherfi et al, 2019). A careful design of the acoustic coupling between the injector and combustion chamber allows exciting unstable combustion easily.…”