Star Grain Regression under Spin Induced Acceleration Effect

2011 ◽  
Vol 110-116 ◽  
pp. 451-456 ◽  
Author(s):  
Hlaing Tun Soe ◽  
Hong Jun Xiang

Spinning is used in some of solid rocket motors to increase the flight trajectory precision or for stability requirements. The angular acceleration due to the spin effect increases the burning rate of solid propellant and changes the motor performance by increasing the operating pressure and decreasing the burning time. So it is important to know the grain regression taken place in the solid propellant rocket motor in the acceleration field. In this study, we represent the grain regression analysis of two-dimensional axis-symmetric star grain configuration of the solid propellant rocket motor under spin induced acceleration effect to study how the spin affects on the internal ballistics of the solid rocket motor. Grain regression is done by two methods - geometrical approach and numerical approach. The burning rates on the propellant surface are different with its radial distance, acceleration vector angle and surface slope when the rocket is spinning. With the different burn rates on the propellant surface, the propellant surface perimeter and port area are computed by using the numerical method, and the results are compared with that of constant burn rate.

Author(s):  
Fredrik Haglind ◽  
Henrik Edefur ◽  
Stefan Olsson

Traditionally, air-launched missiles are powered by a turbojet engine, rocket motor or a ramjet engine. A novel concept that may offer advantages over these concepts is the Air Turbo Rocket (ATR), which is a combined cycle engine, featuring a cycle where the turbine is isolated from the core engine flow entirely and powered by a separate gas generator. This paper is aimed at assessing the suitability of the solid propellant ATR as power source for a tactical air-launched missile. The ATR cycle is designed to achieve optimum performance, and a suitable solid propellant is selected. In addition, a turbojet and a solid rocket motor are designed for the same requirements, and the performances of these three engine concepts are compared. The ATR offers high thrust to weight and thrust to frontal area weight ratios, throttleability, and a wide speed-altitude operating envelope. The calculations suggest that, provided that the afterburning cooling issues can be solved, it would be reasonable to design the ATR such that a stoichiometric fuel/air mixture is obtained in the afterburner. For the Mach number range evaluated here, the ATR may offer advantages over the turbojet and the solid propellant rocket motor.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Wei Xianggeng ◽  
Bo Tao ◽  
Wang Pengbo ◽  
Ma Xinjian ◽  
Lou Yongchun ◽  
...  

Unexpected pressure rise may occur in the end-burning grain solid rocket motor. It is generally believed that this phenomenon is caused by the nonparallel layer combustion of the burning surface, resulting in the increase of burning rate along the inhibitor. In order to explain the cause of this phenomenon, the experimental investigation on four different end configurations were carried out. Based on the X-ray real-time radiography (RTR) technique, a new method for determining the dynamic burning rate of propellant and obtaining the real-time end-burning profile was developed. From the real-time images of the burning surface, it is found that there was a phenomenon of nonuniform burning surface displacement in the end-burning grain solid rocket motor. Through image processing, the real-time burning rate of grain center line and the real-time cone angle are obtained. Based on the analysis of the real-time burning rate at different positions of the end surface, the end face cone burning process in the motor working process is obtained. The closer to the shell, the higher the burning rate of the propellant. Considering the actual structure of this end-burning grain motor, it is speculated that the main cause of the cone burning of the grain may be due to the heat conduction of the metal wall. By adjusting the initial shape of the grain end surface, the operating pressure of the combustion chamber can be basically unchanged, so as to meet the mission requirements. The results show that the method can measure the burning rate of solid propellant in real time and provide support for the study of nonuniform combustion of solid propellant.


Author(s):  
J. Richard ◽  
T. Morel ◽  
F. Nicoud

Large solid propellant rocket motors may be subjected to aero-acoustic instabilities arising from a coupling between the burnt gas flow and the acoustic eigenmodes of the combustion chamber. Given the size and cost of any single firing test or launch, it is of first importance to predict and avoid these instabilities at the design level. The main purpose of this paper is to build a numerical tool in order to evaluate how the coupling of the fluid flow and the whole structure of the motor influences the amplitude of the aeroacoustic oscillations living inside of the rocket. A particular attention was paid to the coupling algorithm between the fluid and the solid solvers in order to ensure the best energy conservation through the interface. A computation of a subscaled version of the Ariane 5 solid propellant engine is presented as illustration.


1975 ◽  
Author(s):  
D. E. Coats ◽  
J. N. Levine ◽  
G. R. Nickerson ◽  
T. J. Tyson ◽  
N. S. Cohen ◽  
...  

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