Solid-propellant Combustion Instability and the Role of Velocity Coupling PDF Download
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Author: Louis A. Povinelli
Publisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 60
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Book Description
Pressure and velocity coupling effects on combustion stability in solid propellant burning.
Author: Louis A. Povinelli
Publisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 60
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Book Description
Pressure and velocity coupling effects on combustion stability in solid propellant burning.
Author: Louis A. Povinelli
Publisher:
ISBN:
Category : Chemical kinetics
Languages : en
Pages : 49
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Book Description
Author: Merrill W. Beckstead
Publisher:
ISBN:
Category :
Languages : en
Pages : 207
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Book Description
The objectives of the program were: To develop an understanding of the role of velocity-coupled combustion response in solid propellant combustion instability, to evaluate various methods for quantitatively measuring this response, and to select the most appropriate method for future development and evaluation. The study was divided into three phases: Supporting analyses to provide direction for the experimental phases; a phenomenological study to determine relative effects of propellant combustion in an oscillatory environment; and the evaluation of test techniques to find a quantitative tool for characterizing velocity coupling. (Modified author abstract).
Author: R. S. Brown
Publisher:
ISBN:
Category :
Languages : en
Pages : 145
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Book Description
Studies are being conducted to define and characterize the basic fluid mechanics and heat transfer mechanism controlling the coupling between acoustic and radial profiles of the mean and oscillatory velocity are being measured at several axial stations in a cold flow rocket simulator. Recent studies have concentrated on measuring the structure of the acoustic waves and how this structure relates to the oscillatory heat flux data reported earlier. In particular, the radial profiles of the magnitude and phase (relative to the head end acoustic pressure) of the acoustic velocity have been measured at several axial stations. At low acoustic pressures (i.e., 0.05%) the acoustic waves extend across the entire cross-section in the region upstream of the transition in the mean velocity profile. Nonplaner and nonlinear behavior is also observed in the near surface regions. Downstream of the velocity transition, the acoustic waves do not penetrate through the near wall turbulence. At higher acoustic pressures (i.e., 0.4%) the upstream nonlinearities increase in magnitude and extend across the entire port. Downstream of the velocity transition the core nonlinearities decay while the linear component penetrates through the turbulence to the wall. Originator-supplied keywords include: Velocity coupling; and Combustion instability.
Author: Joseph D. Baum
Publisher:
ISBN:
Category :
Languages : en
Pages : 45
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Book Description
An existing nonlinear instability model has been extended and improved to allow it to more realistically treat the longitudinal shock wave type of combustion instability frequently encountered in tactical solid rocket motors. Results obtained utilizing this model to investigate limiting amplitude and velocity coupling phenomena in solid rocket motors are presented. An advanced finite difference integration technique capable of accurately describing shocks and contact discontinuities has been incorporated into the computer program, as well as an improved heat conduction solution, an heuristic velocity coupling model, and a spectral analysis capability. Solutions of wave propagation and shock formation and propagation in a variable area duct and a solid propellant rocket motor are presented; as are a number of solutions demonstrating that limiting amplitude is independent of the characteristics of the initial disturbance. Results of a preliminary study of nonlinear velocity modulated limit cycles are presented, as are results that demonstrate the primarily traveling wave nature of nonlinear wave propagation in solid rocket motors, and the complexity of the phase relationships between pressure, burning rate, and velocity oscillations are presented. Finally, the effect of a threshold velocity on non-linear velocity coupled instability was explored, and some of the results are also presented. (Author).
Author: R. S. Brown
Publisher:
ISBN:
Category :
Languages : en
Pages : 199
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Book Description
The fluid mechanics of the coupling between acoustic waves and the solid propellant combustion have been studied in a cold flow simulation of a solid propellant rocket motor. The axial variation of the oscillatory heat flux shows substantial deviations from the behavior expected from both the linear and nonlinear heuristic models of velocity coupling that are currently used in combustion stability analyses. Keywords: solid propellants, combustion, acoustics, instability.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722159733
Category :
Languages : en
Pages : 50
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Book Description
A multi-dimensional numerical model has been developed for the unsteady state oscillatory combustion of solid propellants subject to acoustic pressure disturbances. Including the gas phase unsteady effects, the assumption of uniform pressure across the flame zone, which has been conventionally used, is relaxed so that a higher frequency response in the long flame of a double-base propellant can be calculated. The formulation is based on a premixed, laminar flame with a one-step overall chemical reaction and the Arrhenius law of decomposition with no condensed phase reaction. In a given geometry, the Galerkin finite element solution shows the strong resonance and damping effect at the lower frequencies, similar to the result of Denison and Baum. Extended studies deal with the higher frequency region where the pressure varies in the flame thickness. The nonlinear system behavior is investigated by carrying out the second order expansion in wave amplitude when the acoustic pressure oscillations are finite in amplitude. Offset in the burning rate shows a negative sign in the whole frequency region considered, and it verifies the experimental results of Price. Finally, the velocity coupling in the two-dimensional model is discussed. Chung, T. J. and Park, O. Y. Unspecified Center NAG8-627...
Author: T. J. Chung
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
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Book Description
Analytical models are developed for the multi-dimensional combustion instability analysis of solid propellant rocket motors. This research was motivated by the need for improvement of the current practice in combusiton instability analysis. For example, the burning rates and response functions are affected by the extremely complex flowfield. The flow is three-dimensional or at least two-dimensional in axisymmetric geometries; vortex motions and turbulent flows must be adequately calculated; the coupling mechanism of acoustic and hydrodynamic wave oscillations and particle damping should be clarified. These flowfield phenomena, after all, are originated from the flame zone activities - oscillatory behavior of all field variables such as temperature, velocity, pressure, density of the gas, and fuel fractions. The response functions, which serve as boundary conditions for the flowfield can be calculated from the first and second order perturbation eigenvalue analyses of the flame zone governing equations. The effect of velocity coupling appears, naturally, in the second order (nonlinear) solutions. All calculations are carried out using the finite element method. Some of the findings are summarized.
Author: Martin Summerfield
Publisher: Elsevier
ISBN: 0323163351
Category : Science
Languages : en
Pages : 713
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Book Description
Solid Propellant Rocket Research
Author: Martin Summerfield
Publisher: AIAA
ISBN: 9781600863967
Category : Solid propellants
Languages : en
Pages : 922
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Book Description
