scholarly journals Burning Rate Enhancement Analysis of End-Burning Solid Propellant Grains Based on X-Ray Real-Time Radiography

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Wei Xianggeng ◽  
Bo Tao ◽  
Wang Pengbo ◽  
Ma Xinjian ◽  
Lou Yongchun ◽  
...  
Keyword(s):  
Burning Rate ◽  
Real Time ◽  
Solid Propellant ◽  
Burning Surface ◽  
Rocket Motor ◽  
Operating Pressure ◽  
Solid Rocket Motor ◽  
X Ray ◽  
The Real ◽  
Solid Rocket

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.

Star Grain Regression under Spin Induced Acceleration Effect

2011 ◽  
Vol 110-116 ◽  
pp. 451-456 ◽  
Author(s):  
Hlaing Tun Soe ◽  
Hong Jun Xiang
Keyword(s):  
Solid Propellant ◽  
Rocket Motor ◽  
Spin Effect ◽  
Geometrical Approach ◽  
Operating Pressure ◽  
Solid Rocket Motor ◽  
Solid Propellant Rocket ◽  
Solid Rocket ◽  
Propellant Rocket ◽  
Propellant Surface

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.

Solid Rocket Motor Internal Ballistics Simulation Considering Complex 3D Propellant Grain Geometries

2018 ◽  
pp. 146-169
Author(s):  
Guilherme Lourenço Mejia
Keyword(s):  
Solid Propellant ◽  
Structural Integrity ◽  
Combustion Process ◽  
Burning Surface ◽  
Chamber Pressure ◽  
Computational Tool ◽  
Solid Rocket Motor ◽  
Rocket Motors ◽  
Internal Ballistics ◽  
Solid Rocket

Solid rocket motors (SRM) are extensively employed in satellite launchers, missiles and gas generators. Design considers propulsive parameters with dimensional, manufacture, thermal and structural constraints. Solid propellant geometry and computation of its burning rate are essential for the calculation of pressure and thrust vs time curves. The propellant grain geometry changes during SRM burning are also important for structural integrity and analysis. A computational tool for tracking the propagation of tridimensional interfaces and shapes is then necessary. In this sense, the objective of this work is to present the developed computational tool (named RSIM) to simulate the burning surface regression during the combustion process of a solid propellant. The SRM internal ballistics simulation is based on 3D propagation, using the level set method approach. Geometrical and thermodynamic data are used as input for the computation, while simulation results of geometry and chamber pressure versus time are presented in test cases.

scholarly journals A New Erosive Burning Model of Solid Propellant Based on Heat Transfer Equilibrium at Propellant Surface

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yanjie Ma ◽  
Futing Bao ◽  
Lin Sun ◽  
Yang Liu ◽  
Weihua Hui
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Burning Rate ◽  
Rocket Motor ◽  
Solid Rocket Motor ◽  
Erosive Burning ◽  
Computational Data ◽  
And Performance ◽  
Solid Rocket ◽  
Propellant Surface

Erosive burning refers to the augmentation of propellant burning rate appears when the velocity of combustion gas flowing parallel to the propellant surface is relatively high. Erosive burning can influence the total burning rate of propellant and performance of solid rocket motors dramatically. There have been many different models to evaluate erosive burning rate for now. Yet, due to the complication processes involving in propellant and solid rocket motor combustion, unknown constants often exist in these models. To use these models, trial-and-error procedure must be implemented to determine the unknown constants firstly. This makes many models difficult to estimate erosive burning before plenty of experiments. In this paper, a new erosive burning rate model is proposed based on the assumption that the erosive burning rate is proportional to the heat flux at the propellant surface. With entrance effect, roughness, and transpiration considered, convective heat transfer coefficient correlation proposed in recent years is used to compute the heat flux. This allows the release of unknown constants, making the model universal and easy to implement. The computational data of the model are compared with different experimental and computational data from different models. Results show that good accuracy (10%) with experiments can be achieved by this model. It is concluded that the present model could be used universally for erosive burning rate evaluation of propellant and performance prediction of solid rocket motor as well.

NON-STATIONARY BEHAVIOR OF A SOLID PROPELLANT CHARGE FOR NOZZLELESS SOLID ROCKET MOTORS UNDER GAS-DYNAMIC LOAD

2021 ◽  
pp. 48-59
Author(s):  
I.G. Voropaeva ◽  
◽  
A.A. Kozulin ◽  
L.L. Min’kov ◽  
E.R. Shrager ◽  
...  
Keyword(s):  
Burning Rate ◽  
Solid Propellant ◽  
Solid Mechanics ◽  
Stokes Equations ◽  
Combustion Products ◽  
Conjugate Problem ◽  
Navier Stokes ◽  
Solid Rocket Motor ◽  
Propellant Charge ◽  
Solid Rocket

The numerical solution to a conjugate problem of an unsteady flow of combustion products in a flow path of the nozzleless solid rocket motor (SRM) and the oscillation of a solid propellant charge under the action of the forces directed from combustion products is considered. The Navier-Stokes equations for a compressible viscous gas are used to mathematically describe the flow of the combustion products. To model the charge oscillations, the equations of solid mechanics are applied, which take into account the propellant hyperelasticity. Pressure distributions and the propellant burning rate along the charge channel are presented for different models of the propellant burning rate. It is revealed that at the stage of SRM design, the use of the burning rate law, determined by pressure in the head of the combustion chamber, is more preferable in order to assess the internal ballistic characteristics. The solution to the conjugate problem shows that in the nozzleless SRM with the propellant having low Young's modulus, resonance can occur, which causes uncontrolled charge oscillations.

NUMERICAL SIMULATION OF INTRA-CHAMBER PROCESSES IN A SOLID ROCKET MOTOR WITH ACCOUNT FOR BURNING SURFACE MOTION

2021 ◽  
pp. 90-105
Author(s):  
A.E. Kiryushkin ◽  
◽  
L.L. Minkov ◽  
Keyword(s):  
Numerical Simulation ◽  
Numerical Algorithm ◽  
Burning Surface ◽  
3D Models ◽  
Stationary Regime ◽  
Rocket Motor ◽  
Chamber Pressure ◽  
Solid Rocket Motor ◽  
Solid Rocket ◽  
Motor Operation

The axisymmetric solid rocket motor (SRM) with an “umbrella” shape is considered in this paper. The numerical algorithm based on the inverse Lax-Wendroff procedure for a gas dynamic equation and on the level-set method for tracking the burning surface is overviewed for internal ballistics problems. Assuming that the propellant combustion proceeds in a quasi-stationary regime and a mass flow from the burning surface depends on the pressure raised to the power of parameter ν, the numerical computations of intra-chamber combustion product flows during the main-firing phase are carried out using the numerical algorithm developed for “umbrella”-shaped SRM at different parameter values. The approximation convergence of flow parameters in a case of the stationary propellant surface and average intra-chamber pressure for all the time of motor operation is examined. The numerical simulation results are obtained and analyzed for different “umbrella” inclination angles. Though the developed algorithm has been applied to the motors with a specific shape, it can also be used for propellant grains of different shapes and is easily extended to 3D models.

scholarly journals Transient Burning Rate Model for Solid Rocket Motor Internal Ballistic Simulations

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
David R. Greatrix
Keyword(s):  
Burning Rate ◽  
Solid Phase ◽  
Burning Surface ◽  
Solid Rocket Motor ◽  
Principal Mechanism ◽  
Conservation Result ◽  
Burning Model ◽  
Solid Rocket ◽  
Transient Burning Rate ◽  
Experimental Firing

A general numerical model based on the Zeldovich-Novozhilov solid-phase energy conservation result for unsteady solid-propellant burning is presented in this paper. Unlike past models, the integrated temperature distribution in the solid phase is utilized directly for estimating instantaneous burning rate (rather than the thermal gradient at the burning surface). The burning model is general in the sense that the model may be incorporated for various propellant burning-rate mechanisms. Given the availability of pressure-related experimental data in the open literature, varying static pressure is the principal mechanism of interest in this study. The example predicted results presented in this paper are to a substantial extent consistent with the corresponding experimental firing response data.

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