Technical Brief: Asymptotic Temperature Distribution in a Simulated Combustion Chamber

2006 ◽  
Vol 129 (7) ◽  
pp. 894-898 ◽  
Author(s):  
Anand B. Vyas ◽  
Joseph Majdalani

In an axisymmetric model of a solid rocket motor, a cylindrical combustion chamber with porous walls is considered. For a posited range of operating parameters, the energy equation is perturbed and linearized using the dimensionless Péclet number. The possibility of circumventing chemical reactions while retaining the essential physics of the problem is explored. This is accomplished by artificially introducing a distributed heat source above the propellant surface. The resulting energy equation is then solved to zeroth order. The analytical solution and corresponding temperature maps are verified qualitatively using comparisons with numerical simulations of the combustion chamber.

Author(s):  
Yumin Xiao ◽  
R. S. Amano ◽  
Timin Cai ◽  
Jiang Li ◽  
Guoqiang He

Abstract It has been a challenge to investigate how to trace particles in a solid rocket motor (SRM) using aluminized composite solid propellant and submerged nozzle. In using CFD simulations, the boundary conditions for the ejecting particles constrain their trajectories, hence these affect the two-phase flow calculations, and thus significantly affect the evaluation of the slag accumulation. The RTR (X-ray Real-time Radiography) technique is a new method to detect the particles in a firing SRM. A method was developed to simulate the particle ejection from the propellant surface. The moving trajectories of metal particles in a firing combustion chamber were measured by using the RTR high-speed motion analyzer. Numerical simulations with different propellant-surface boundary conditions were performed to calculate particle trajectories. Through this study an appropriate surface velocity condition on the propellant surface was discovered. The method developed here can be used for the future CRM research.


2005 ◽  
Vol 127 (9) ◽  
pp. 1057-1061 ◽  
Author(s):  
Yumin Xiao ◽  
R. S. Amano ◽  
Timin Cai ◽  
Jiang Li

Use of aluminized composite solid propellants and submerged nozzles are common in solid rocket motors (SRM). Due to the generation of slag, which injects into a combusted gas flow, a two-phase flow pattern is one of the main flow characteristics that need to be investigated in SRM. Validation of two-phase flow modeling in a solid rocket motor combustion chamber is the focus of this research. The particles’ boundary conditions constrain their trajectories, which affect both the two-phase flow calculations, and the evaluation of the slag accumulation. A harsh operation environment in the SRM with high temperatures and high pressure makes the measurement of the internal flow field quite difficult. The open literature includes only a few sets of experimental data that can be used to validate theoretical analyses and numerical calculations for the two-phase flow in a SRM. Therefore, mathematical models that calculate the trajectories of particles may reach different conclusions mainly because of the boundary conditions. A new method to determine the particle velocities on the solid propellant surface is developed in this study, which is based on the x-ray real-time radiography (RTR) technique, and is coupled with the two-phase flow numerical simulation. Other methods imitate the particle ejection from the propellant surface. The RTR high-speed motion analyzer measures the trajectory of the metal particles in a combustion chamber. An image processing software was developed for tracing a slug particle path with the RTR images in the combustion chamber, by which the trajectories of particles were successfully obtained.


AIAA Journal ◽  
1978 ◽  
Vol 16 (11) ◽  
pp. 1123-1124
Author(s):  
Warren C. Strahle ◽  
John C. Handley

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yanjie Ma ◽  
Futing Bao ◽  
Lin Sun ◽  
Yang Liu ◽  
Weihua Hui

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.


Author(s):  
Jeevan Sapkota ◽  
Yi Hua Xu ◽  
Hai Jun Sun

Pintle technology is currently a versatile technology used in a solid rocket motor (SRM) to control the desired thrust by changing the nozzle throat area, while effectively controlling the chamber pressure at the same time. The sudden movement of the pintle can induce rapid changes in the flow field and the occurrence of pressure oscillations inside the combustion chamber. The analysis of such rapid changes is essential to design an efficient controllable pintle rocket motor for a better thrust regulation. Two-dimensional axisymmetric models with mesh generation and required boundary condition were designed to analyze the effects of three different pintle head shape models in SRM thrust regulation effect. Dynamic mesh method was used with specific velocity for moving plug/pintle in the numerical analysis of SRM thrust regulation. The effects of different pintle head models on the flow field, combustion chamber pressure, mass-flow rate, thrust and Mach number were investigated. According to the analysis of total pressure response time, the simulation data revealed that circular pintle head model responded faster among three different models. According to the thrust effect, parabolic pintle has the maximum value of thrust and the greatest total pressure recovery coefficient among all pintle head models.


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.


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