Numerical prediction of low frequency combustion instability in a model ramjet combustor
- Engineering Sciences, Inc., Huntsville, AL (United States)
- SECA, Inc., Huntsville, AL (United States)
A numerical analysis has been conducted for low-frequency combustion instability in a model ramjet combustor. The facility is two-dimensional, and is comprised of a long inlet duct, a dump combustor chamber, and an exhaust nozzle. The experiments observed that the combustor pressure oscillation under the particular operating condition did not have much cycle-to-cycle variation. The main resonant frequency occurs at about 65 Hz for this case. In the numerical analysis, a time accurate Computational Fluid Dynamics (CFD) code with a pressure-correction algorithm is used, and the combustion process was modeled with a single step chemistry model and a modified eddy breakup model. A high-order upwind scheme with flux limiter is used for convection terms. The convergence of the linear algebraic equations is accelerated through a preconditioned conjugate gradient matrix solver. The numerical predictions show that the flame oscillates in the combustion chamber at the calculation condition and are justified by the experimental schlieren photographs. The numerical analyses correctly predict the chamber pressure oscillation frequency is over-predicted compared with the experimental data. The discrepancy can be explained by the simplified turbulence and combustion model used in this study, and the uncertainty of the inlet boundary conditions.
- OSTI ID:
- 442728
- Report Number(s):
- CONF-961105-; ISBN 0-7918-1523-4; TRN: IM9712%%153
- Resource Relation:
- Conference: 1996 international mechanical engineering congress and exhibition, Atlanta, GA (United States), 17-22 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the ASME Heat Transfer Division. Volume 4: Natural convection within a horizontal circular cylinder heated from below and cooled from above; Numerical methods for coupled fluid-thermal-structural interaction; Thermal analysis in waste processing and disposal; Heat transfer in fire and combustion systems; HTD-Volume 335; Pepper, D.W. [ed.] [Univ. of Nevada, Las Vegas, NV (United States)]; Douglass, R.W. [ed.] [Idaho National Engineering Lab., Idaho Falls, ID (United States)]; Heinrich, J.C. [ed.] [Univ. of Arizona, Tucson, AZ (United States)] [and others]; PB: 433 p.
- Country of Publication:
- United States
- Language:
- English
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