Effect of Nano-Sized Energetic Materials (nEMs) on the Performance of Solid Propellants: A Review

As a hot research topic, nano-scale energetic materials have recently attracted much attention in the fields of propellants and explosives. The preparation of different types of nano-sized energetic materials were carried out, and the effects of nano-sized energetic materials (nEMs) on the properties of solid propellants and explosives were investigated and compared with those of micro-sized ones, placing emphasis on the investigation of the hazardous properties, which could be useable for solid rocket nozzle motor applications. It was found that the nano-sized energetic materials can decrease the impact sensitivity and friction sensitivity of solid propellants and explosives compared with the corresponding micro-sized ones, and the mechanical sensitivities are lower than that of micro-sized particles formulation. Seventy-nine references were enclosed.

Prediction of thermal ablation in rocket nozzle using CFD and FEA

To protect the structural part of the rocket nozzle, an insulation liner is provided at its inner surface. Charring ablators are used for this purpose. The thickness of the insulation liner is one of the major design considerations of the nozzle. In the present analysis, an attempt has been made to predict thermal erosion (ablation) in the insulation liner through numerical studied CFD and FEA. The problem is modeled in ANSYS software. Fluid flow analysis is performed using the fluent module that works on the finite volume method, and the transient thermal module is used for the thermal analysis that works on the finite element method. Appropriate mesh convergence, residual convergence, and time step convergence exercises are made and the numerical results are verified with the analytical solution wherever possible. The possibility of reduction of thermal load due to the presence of char in ablator liner is considered and the thermal resistance in the region exposed to melting point temperature is altered to permit the propagation of thermal loads to the current pyrolysis front at any instant. The concept of this work is useful in the prediction of thermal ablation in rocket nozzles and in selecting the required thickness of the insulation layer.