Defence Research and Development Laboratory

About: Defence Research and Development Laboratory is a facility organization based out in Hyderabad, India. It is known for research contribution in the topics: Turbulence & Mach number. The organization has 404 authors who have published 420 publications receiving 4183 citations. The organization is also known as: DRDL.

Fracture toughness of nitramine and composite solid propellants

Abstract: Test results of compact tension (CT) specimens, are presented for fracture toughness evaluation of nitramine (in extruded and slurry cast conditions) and composite solid propellants. For notched strength evaluation of cracked configurations, failure assessment diagram is generated utilizing the inherent flaw model. Testing of solid propellant CT specimens need specialized facilities as the spring force of the clip-on type crack opening displacement (COD) gauge, generally used for metallic materials, is high enough to open-up the crack even before commencement of actual test. Therefore, a non-contacting type video extensometer was employed. Fracture toughness of the extruded nitramine propellant is found to be higher, compared to those of slurry cast nitramine and composite propellants.

Heat Management in Supersonic/Hypersonic Vehicles Using Endothermic Fuel: Perspective and Challenges.

Abstract: In this study, an in-depth analysis has been performed on various technoengineering aspects of hydrocarbon cracking under supercritical conditions toward developing an endothermic fuel. The paper is segregated into several sections with specific emphasis. The major areas covered in this work include physicochemical characteristics of different endothermic fuels, supercritical pyrolysis of hydrocarbon fuels, phenomena of coking, and its suppression from an application viewpoint. The influence of various parameters (e.g., temperature, pressure, catalysts, space-time, etc.) on fuel conversion, endothermicity, and coke propensity has been emphasized in detail. The typical value of endothermic heat sink capacity for different fuels consisting of C8 to C15 hydrocarbons ranges from 500 to 1150 kJ/kg over temperature and pressure ranges of 550-750 °C and 25-55 bar, respectively. The effectiveness of various additives/initiators in improving endothermicity has been screened for wide ranges of temperature and pressure. Physicochemical properties like distillation characteristics, hydrocarbon composition, °API gravity, and sulfur content of different hydrocarbon fuels are compared in a single window. Most of the findings are abridged meticulously with relevant tables and plots. Toward the end, we have highlighted the critical issues/challenges on the experimental findings and prospective.