Application of Slow Time Acceleration on Variable geometry Dual Thrust Motors

Abstract

Numerical Studies have been carried out on a 2D-axisymmetric Dual thrust Solid Rocket Motors(DTMs) to analyze and predict the Pressure transient of the motor with the advent of Slow Time Acceleration Method. Numerical Studies in the field of Solid Propellant Rocket Motors(SRMs) involves many parametric components that needs to be analyzed before computation. One of the key components in parametric analysis for Computational Fluid Dynamics(CFD) are the Time Scales present in the system. Persistent studies in application of CFD solvers in problems involving SRMs would easily show the importance of these time scales and their involvement in ascertaining the physical time required for the computation to complete. In the case of SRMs there exist a large disparity between these time scales and understanding this disparity and successful mitigation of this disparity could essentially decrease the overall physical time and ergo, making the solver more efficient. Slow Time Acceleration is one such methodology which is designed to mitigate this disparity in timescales, by essentially employing multi-scale asymptotics.

Numerical Studies have been carried out on the 2-D axisymmetric variable-geometry Dual Thrust Solid Rocket Motors(DTMs) with high length-to-diameter(L/d) ratio to test the application of Slow Time Acceleration on the internal ballistics properties such as, starting pressure transient using Euler/RANS system of equations with SST K-Omega turbulence Model. The possible occurrence of internal throat choking have been confirmed, as have been stated in previous research. Present Study concentrates on the internal ballistics of DTM as well as other Simple geometry rocket motors with the successful application of slow time acceleration and furthermore, exploring the difficulties as well as the instabilities involved with this method.