In this paper, INTERNAL BALLISTICS of solid rocket motors (SRM), in which the grain is burned from inside (inner burning surface) or from both inside and outside (inner and outer burning surfaces), is numerically simulated. The solution domain includes two passages and a converging-diverging nozzle. It is discretized using a control-volume finite-element method. Governing equations of the quasi one-dimensional Euler flow are integrated over each control volume. The flux-vector components are related to the nodal values using a physical influence scheme. Erosive burning is incorporated in the flowfield calculation using a quasisteady model. In cases with inner and outer burning surfaces, the resulting system of equations deviates from a block tri-diagonal one. Therefore, special care is needed for the efficient solution of this system of equations. To evaluate performance of the present algorithm, transient flow fields of several SRMs with different burning surfaces are simulated, and the results compared with the experimental data and numerical results. The excellent agreement observed in all cases validates the algorithm and approves its accuracy. For SRMs with inner and outer burning surfaces, possibility of their modeling with an equivalent motor is also investigated. In addition, a SRM with area transition along the grain is simulated to demonstrate the general capability of the present code.

INTERNAL BALLISTICS of solid rocket motor is simulated by solving the axisymmetric Navier-Stokes equations on a moving unstructured grid. Then, the flow velocity, pressure, temperature, and other variables are computed for problems with complex geometries and boundary conditions. The dynamic (moving) mesh is used to model flows where the shape of the domain changes with time due to motion of the domain boundaries (burning surfaces).Updating of the mesh is handled automatically at each time step, based on the new position of the boundaries. This study showed that CFD with unstructured dynamic meshing can be a powerful tool for simulating INTERNAL BALLISTICS of solid rocket motors.

In this study, solid rocket motor INTERNAL ballistic, has been investigated. Flow field consists of INTERNAL grain space and converging-diverging nozzle. Axisymmetric, compressible and transient Euler equations have been considered as governing equations and erosive burning has been considered as an important phenomenon in solid rocket motors. Fluent software and its moving mesh capability have been used to flow field modeling. At the first time, an appropriate UDF has been utilized to achieve a good SIMULATION of erosive burning. The results show very good agreement with other numerical results.

The purpose of this research is to evaluate a ground test bed of an orbital transmission engine with pre-evacuation of the engine's INTERNAL space. In the usual tests on the ground, the initial pressure of the engine is atmospheric pressure. While during the orbital mission, the INTERNAL space of the engine may be in the vacuum pressure. Therefore, to ensure the proper performance of INTERNAL BALLISTICS, it is necessary to test the performance by pre-evacuating its INTERNAL space. In this research, first, the suitability of an exhaust diffuser for this type of test is investigated numerically. Then, the unsteady numerical SIMULATIONs have been done by applying the pressure-time profiles of the engine as the boundary condition of the inlet pressure. Investigations show that the two phenomena of flow being supersonic in the diffuser at very low engine pressures and the discharge of the return flow to the vacuum chamber prevent the significant influence of environmental conditions on the flow inside the nozzle. So, from the initial moment to the stable working of the diffuser, the flow in the first half of the nozzle is in the supersonic state. Therefore, the INTERNAL BALLISTICS of the engine is evaluated independently of the conditions of the outside environment.

Background and Purpose: The project of establishing FARAJA ballistic protection equipment laboratory started a decade ago. The structure of this laboratory was predicted based on the requirements of National courthouse institute 010106. Because of misunderstandings in the contract's implementation, this laboratory has not yet been put into operation despite spending a lot of money. The research project of evaluating, updating and upgrading the FARAJA BALLISTICS Laboratory was defined to check the current state of the laboratory, identify deficiencies and solve solutions. Method: With field visits, the condition of the laboratory was checked. By studying the existing standards, the requirements were adapted to the existing equipment, which will be the road map for establishing the laboratory under the title of qualitative and quantitative requirements assessment. Findings: Based on the defects found, it was determined according to the needs and existing structures. The standards were reviewed to determine their requirements. The evaluation of these hardware requirements was done to follow up the solutions to solve it. Conclusion: The hardware for the implementation infrastructure of the National courthouse institute 010106 standard has been specified. This clarification, qualitative and quantitative needs assessment and providing solutions to define executive projects to fix defects are considered.

In the present research, a new model is presented to predict the burning rate of a solid rocket motor (SRM) in the presence of erosive burning phenomenon. This model is based on the Wang model and the major modification is adding the pressure change in the erosive burning rate. In addition, the necessary relations needed to calculate the velocity gradient on the propellant surface in a one-dimensional INTERNAL BALLISTICS code was presented. To assess the new model, the test results of a laboratory motor designed in this research were used. Also, to compare the performance and accuracy of this model with the other models, this motor was simulated with the presented model and the six available models. The results of the comparison indicate that the new model has better accuracy than the other models. The advantage of introducing the pressure effect in the Wang model has been shown. Another advantage of the new model is that this model doesn’ t have any experimental constants dependent on the propellant composition or grain dimensions which is a common defect in popular models such as Lenoir-Robillard model.

The steady state flow of viscous fluid in two dimensional and axisymmetric nozzles in all regimes has been numerically studied using compressible TLNS equations. Implicit delta form of Roe finite difference is used as the numerical scheme. The numerical SIMULATION of two-dimensional transonic flow through a double throat nozzle is studied as a test problem. In order to show ability of the method flow in a plug nozzle is also studied. Due to the strong interaction of shock, the entropy condition in solution of plug nozzle has been modified. The dependency of the solution upon grid refinement has been also studied and the results are validated using the results of previous investigators.

In order to study the dynamic behavior of engines a software was developed; the actual pressure and also the friction forces were considered in the governing equations. Considering the torque as the input, the crank speed and acceleration were calculated. The cylinder gas pressure was detected with a photo sensor installed in the spark plug. The predicted and actual crank velocities were compared and the differences were explained.