TY - JOUR
T1 - Unsteady flow evolution and combustion dynamics of homogeneous solid propellant in a rocket motor
AU - Apte, Sourabh
AU - Yang, Vigor
N1 - Funding Information:
This work was sponsored partly by the Pennsylvania State University and partly by the California Institute of Technology Multidisciplinary University Research Initiative under ONR Grant No. N00014-95-1-1338. The use of ARSC supercomputers in Alaska is also appreciated.
PY - 2002/10
Y1 - 2002/10
N2 - A time-resolved numerical analysis of combustion dynamics of double-base homogenous solid propellant in a rocket motor is performed by means of a Large-Eddy Simulation (LES) technique. The physiochemical processes occurring in the flame zone and their influence on the unsteady flow evolution in the chamber are investigated in depth. A five-step reduced reaction mechanism is used to obtain the two-stage flame structure consisting of a primary flame, a dark zone, and a secondary flame in the gas phase. It is observed that, for homogeneous solid propellant combustion, the chemical time scale is much greater than the smallest turbulence time scale, rendering a highly stretched and thickened flame. The chemical reactions proceed at a slower rate than turbulent mixing, and propellant combustion may be locally treated as a well-stirred reactor. The flowfield in the chamber consists of three regions of evolution: the upstream laminar regime, the central transitional section, and the fully developed turbulent regime further downstream. A theoretical formulation exploring the chamber flow and flame dynamics is established to study the intriguing phenomenon of combustion instability. The work done by Reynolds stresses, vorticity-flame interactions, and coupling between the velocity field and entropy fluctuations may cause resonance effects and excite pressure oscillations leading to self-sustained unsteady motions within the chamber.
AB - A time-resolved numerical analysis of combustion dynamics of double-base homogenous solid propellant in a rocket motor is performed by means of a Large-Eddy Simulation (LES) technique. The physiochemical processes occurring in the flame zone and their influence on the unsteady flow evolution in the chamber are investigated in depth. A five-step reduced reaction mechanism is used to obtain the two-stage flame structure consisting of a primary flame, a dark zone, and a secondary flame in the gas phase. It is observed that, for homogeneous solid propellant combustion, the chemical time scale is much greater than the smallest turbulence time scale, rendering a highly stretched and thickened flame. The chemical reactions proceed at a slower rate than turbulent mixing, and propellant combustion may be locally treated as a well-stirred reactor. The flowfield in the chamber consists of three regions of evolution: the upstream laminar regime, the central transitional section, and the fully developed turbulent regime further downstream. A theoretical formulation exploring the chamber flow and flame dynamics is established to study the intriguing phenomenon of combustion instability. The work done by Reynolds stresses, vorticity-flame interactions, and coupling between the velocity field and entropy fluctuations may cause resonance effects and excite pressure oscillations leading to self-sustained unsteady motions within the chamber.
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U2 - 10.1016/S0010-2180(02)00397-8
DO - 10.1016/S0010-2180(02)00397-8
M3 - Article
AN - SCOPUS:0036772016
SN - 0010-2180
VL - 131
SP - 110
EP - 131
JO - Combustion and Flame
JF - Combustion and Flame
IS - 1-2
ER -