One-Dimensional Combustion Instability Studies with Moving Boundaries in an End-Burning Test Motor

2002 ◽  
Author(s):  
Kerem Pekkan ◽  
Ahmet Ucer
Keyword(s):  
Combustion Instability ◽  
Moving Boundaries ◽  
One Dimensional

Numerical simulation of gas-solid two-phase reaction flow with multiple moving boundaries

2015 ◽  
Vol 25 (2) ◽  
pp. 375-390 ◽  
Author(s):  
Qiao Luo ◽  
Xiaobing Zhang
Keyword(s):  
Numerical Simulation ◽  
Physical Phenomenon ◽  
Great Influence ◽  
Moving Boundaries ◽  
Charge Weight ◽  
Phase Reaction ◽  
Two Phase ◽  
Content Type ◽  
One Dimensional ◽  
Chamber Volume

Purpose – In engineering applications, gas-solid two-phase reaction flow with multi-moving boundaries is a common phenomenon. The launch process of multiple projectiles is a typical example. The flow of adjacent powder chambers is coupled by projectile’s motion. The purpose of this paper is to study this flow by numerical simulation. Design/methodology/approach – A one-dimensional two-phase reaction flow model and MacCormack difference scheme are implemented in a computational code, and the code is used to simulate the launch process of a system of multiple projectiles. For different launching rates and loading conditions, the simulated results of the launch process of three projectiles are obtained and discussed. Findings – At low launching rates, projectiles fired earlier in the series have little effect on the launch processes of projectiles fired later. However, at higher launching rates, the projectiles fired first have a great influence on the launch processes of projectiles fired later. As the launching rate increases, the maximum breech pressure for the later projectiles increases. Although the muzzle velocities increase initially, they reach a maximum at some launching rate, and then decrease rapidly. The muzzle velocities and maximum breech pressures of the three projectiles have an approximate linear relationship with the charge weight, propellant web size and chamber volume. Originality/value – This paper presents a prediction tool to understand the physical phenomenon of the gas-solid two-phase reaction flow with multi-moving boundaries, and can be used as a research tool for future interior ballistics studies of launch system of multiple projectiles.

Asymptotic approach to combustion instability

2005 ◽  
Vol 363 (1830) ◽  
pp. 1247-1259 ◽  
Author(s):  
Xuesong Wu
Keyword(s):  
Combustion Instability ◽  
Parametric Instability ◽  
Acoustic Mode ◽  
Sound Waves ◽  
Asymptotic Approach ◽  
Reaction Heat ◽  
Weakly Nonlinear ◽  
One Dimensional ◽  
Entire Flow ◽  
Asymptotic Formulation

This paper presents an asymptotic approach to combustion instability in premixed flames under the assumptions of large activation energy and small Mach number. The entire flow consists of four distinct yet fully interactive sub-regions, which accommodate the chemical reaction, heat transport, hydrodynamics and acoustics, respectively. A reduced system was derived to describe the intricate coupling between the flame and acoustics that underlies the combustion instability. The asymptotically reduced system was employed to study the weakly nonlinear interaction between the Darrieus–Landau instability and the longitudinal acoustic mode of the combustion chamber. The general asymptotic formulation includes the influence of enthalpy fluctuation in the oncoming mixture. It is shown that one-dimensional enthalpy fluctuation, through its interaction with flame, produces sound waves, and may cause parametric instability of the flame. The mutual coupling between the sound wave and parametric instability is analysed at the instability thresholds.

Beurling's projection theorem via one-dimensional Brownian motion

1996 ◽  
Vol 119 (4) ◽  
pp. 729-738 ◽  
Author(s):  
Wendelin Werner
Keyword(s):  
Brownian Motion ◽  
Harmonic Measure ◽  
Moving Boundaries ◽  
Hitting Times ◽  
One Dimensional ◽  
Projection Theorem ◽  
Radial Projection ◽  
Alternative Approach

AbstractWe prove some elementary intuitive estimates on moving boundaries hitting times by one-dimensional Brownian motion (in ℝ and on the circle). These results give an alternative approach to Beurling's radial projection theorem on harmonic measure in a disc.

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