CFD Analysis of Solid Rocket Motors


Book Description

Determination of the grain geometry is an important and critical step in the design of solid propellant rocket motors. Because, the performance of the rocket is greatly effect by the burning surface area of the solid propellant. The performance prediction of the solid rocket motor can be achieved easily if the burn back steps of the grain are known. In this study, grain burn back analysis for 3-D star grain geometries was investigated. The method used was solid modeling (ANSYS(r) - DM, PRO-E and GAMBIT) of the propellant grain for predefined intervals of burn back. In this method, the initial grain geometry was modeled parametrically using ANSYS software. For every burn step, the parameters were adapted and the new grain geometry was modeled, for analysis three cases of grain geometries was considered during the combustion. By analyzing these geometries, burn area change of the grain geometry was obtained. Using this data and internal ballistic parameters, the performance of the solid propellant rocket motor in terms of motor pressure was achieved.













Advanced Multi-Phase Flow Cfd Model Development for Solid Rocket Motor Flowfield Analysis


Book Description

A Navier-Stokes code, finite difference Navier-Stokes (FDNS), is used to analyze the complicated internal flowfield of the SRM (solid rocket motor) to explore the impacts due to the effects of chemical reaction, particle dynamics, and slag accumulation on the solid rocket motor (SRM). The particulate multi-phase flowfield with chemical reaction, particle evaporation, combustion, breakup, and agglomeration models are included in present study to obtain a better understanding of the SRM design. Finite rate chemistry model is applied to simulate the chemical reaction effects. Hermsen correlation model is used for the combustion simulation. The evaporation model introduced by Spalding is utilized to include the heat transfer from the particulate phase to the gase phase due to the evaporation of the particles. A correlation of the minimum particle size for breakup expressed in terms of the Al/Al2O3 surface tension and shear force was employed to simulate the breakup of particles. It is assumed that the breakup occurs when the Weber number exceeds 6. A simple L agglomeration model is used to investigate the particle agglomeration. However, due to the large computer memory requirements for the agglomeration model, only 2D cases are tested with the agglomeration model. The VOF (Volume of Fluid) method is employed to simulate the slag buildup in the aft-end cavity of the redesigned solid rocket motor (RSRM). Monte Carlo method is employed to calculate the turbulent dispersion effect of the particles. The flowfield analysis obtained using the FDNS code in the present research with finite rate chemical reaction, particle evaporation, combustion, breakup, agglomeration, and VOG models will provide a design guide for the potential improvement of the SRM including the use of materials and the shape of nozzle geometry such that a better performance of the SRM can be achieved. The simulation of the slag buildup in the aft-end cavity can assist the designer to improve the design of ...




An Automated Fluid-Structural Interaction Analysis of a Large Segmented Solid Rocket Motor


Book Description

A new analysis procedure has been used to evaluate the propellant grain/flow stability of a new, five-segment Space Shuttle solid rocket booster. The fluid-structural interaction (FSI) analysis of the ETM-3 motor used PYTHON, a powerful programming language, and FEM BUILDER, a pre- and post processor developed by ATK Thiokol Propulsion under contract to the AFRL, to automatically couple the ABAQUS structural solver with FLUENT, the computational fluid dynamics (CFD) solver. This iterative process automatically used the results of one solver as the inputs to the other solver until convergence to a solution was obtained. The ETM-3 motor was basically an reusable solid rocket motor (RSRM) with an additional center segment added. The additional segment and greater nozzle diameter increased mass flow and mach number in the motor. Because of this harsher flow environment, it was necessary to conduct a detailed FSI analysis to ensure propellant grain stability against boot-strapping. This paper details the FSI analysis work done for ETM-3. The analyses conducted and documented in this report assumed linear elastic material behavior and steady state fluid behavior without time response in either the structural or fluid models.




Engineering of Solid Rocket Motors


Book Description

In the last few years, the aerospace industry has grown exponentially for both military and civil applications. This book explores the systems engineering, production processes and performance issues which happen constantly during solid rockets operations and flight. It also discusses state of the art experiments and techniques, as well as many recent developments. The book will appeal to rocket scientists, students and lecturers, senior scientists and professors.