الفهرس 
CHAPTER (1): INTRODUTION AND LITERATURE REVIEWOnly 14 pages are availabe for public view
 |  | from | 151 |  |  |
| | | from | 151 | | |
Abstract
Rocket is a general term of a jet propulsions device producing thrust by expelling propellant at a high velocity. Rockets have important role in both the civilian and tactical life, specially in communication, weather monitoring spying, planetary and exploration. To understand the nature of the internal flow field inside the interior cavity in a model of Solid Rocket Motor (SRM) chamber, numerical, analytical and experimental studies of acoustic wave propagation in a simulated SRM chamber are introduced.
The experimental study is carried out in a square cross-sectional channel with two equally permeable sidewalls. An endwall disturbance is imparted using a moving piston located at the head end while the exit end of the channel is opened to the atmosphere. Three different cases are considered. The first case considers only steady injection through the channel porous sidewalls. Axial velocity disturbance at the closed head end with impermeable sidewalls is considered for case (2). The last case considers a combination between steady sidewall injection and axial velocity disturbance generated at the channel head end. Moreover changeable convergent, divergent and convergent-divergent nozzles are mounted at the exit end of the channel to study the behavior of the complex wave interaction mechanism for different variable nozzle geometries.
The unsteady, compressible, two dimensional Navier-Stokes equations in the laminar regime are numerically solved by predictor-corrector MacCormack scheme. An analytical solution for pure acoustic flow is derived from the reduced form of the full Navier-Stokes equations. The numerical and analytical solutions are compared with the experimental data. The comparisons show a reasonable agreement between these three approaches. Moreover, the results show that, the geometry of the variable cross section area part has a significant effect on the generated complex wave pattern inside the chamber.
The existence of a convergent nozzle at the channel open end increases the pressure amplitude inside the channel. This amplitude also increases with the decrease of the convergent nozzle exit height. When the convergent-divergent nozzle is installed, higher harmonics arise and the system natural frequency changes. The existence of a divergent nozzle at the open end decreases the pressure amplitude and at a certain divergence angle the pressure increases. In the present study, the piston-crank shaft mechanism proved uncapable to produce pure sinusoidal wave at the channel head end and higher harmonics can be clearly noted throughout the channel. Steady injection from the channel porous sidewalls decreases the acoustic wave generated inside the chamber.