Design and Testing of Lab-scale Red Fuming Nitric Acid/Hydroxyl-terminated Polybutadiene Hybrid Rocket Motor for Studying Regression Rate

Sankaran Venugopal; V. Ramanujachari; K.K. Rajesh

doi:10.14429/dsj.61.873

Sankaran Venugopal Defence Research and Development Laboratory, Hyderabad
V. Ramanujachari Defence Research and Development Laboratory, Hyderabad
K.K. Rajesh Defence Research and Development Laboratory, Hyderabad

DOI: https://doi.org/10.14429/dsj.61.873

Keywords: Hybrid rocket motor, regression rate, oxidiser mass flux, chamber pressure, solid fuel, liquid oxidiser, RFNA, HTPB, red fuming nitric acid, hydroxyl-terminated polybutadiene

Abstract

This paper presents the design of a hybrid rocket motor and the experiments carried out for investigation of hybrid combustion and regression rates for a combination of liquid oxidiser red fuming nitric acid with solid fuel hydroxyl-terminated Polybutadiene. The regression rate is enhanced with the addition of small quantity of solid oxidiser ammonium perchlorate in the fuel. The characteristics of the combustion products were calculated using the NASA CEA Code and were used in a ballistic code developed for predicting the performance of the hybrid rocket motor. A lab-scale motor was designed and the oxidiser mass flow requirements of the hybrid motor for the above combination of fuel and oxidiser have been calculated using the developed ballistic code. A static rocket motor testing facility has been realised for conducting the hybrid experiments. A series of tests were conducted and proper ignition with stable combustion in the hybrid mode has been established. The regression rate correlations were obtained as a function of the oxidiser mass flux and chamber pressure from the experiments for the various combinations.

Defence Science Journal, 2011, 61(6), pp.515-522, DOI:http://dx.doi.org/10.14429/dsj.61.873

Author Biographies

Sankaran Venugopal, Defence Research and Development Laboratory, Hyderabad

Mr S. Venugopal obtained his ME (Mechanical Engg.) from IAT, Poona University in 1986. He is pursuing his PhD (Mechanical Engg.) from JNTU, Hyderabad. Presently he is working as Scientist at the Defence Research and Development Laboratory (DRDL), Hyderabad. His research and work experiences include: Aerodynamics, aerospace structures, manufacturing, system integration, and hybrid propulsion.

V. Ramanujachari, Defence Research and Development Laboratory, Hyderabad

Dr V. Ramanujachari obtained PhD (Mechanical Engg.) from IIT Madras, Chennai in 1993. Presently, he is working as Scientist‘G’ at DRDL, Hyderabad, and is the Project Director of the Hypersonic Technology Demonstration Vehicle (HSTDV) Project. His research and work experiences include: combustion, turbulent two-phase flows and propulsion. He has guided more than 50 ME/MTech and PhD dissertations.

K.K. Rajesh, Defence Research and Development Laboratory, Hyderabad

Dr K.K. Rajesh obtained PhD (Aerospace Engg.) from IIT Madras. Chennai in 2000. He worked as a Lady Davis Postdoctoral Fellow at the Faculty of Aerospace Engineering, Technion, Israel Institute of Technology, Haifa. Presently, he is working as a Scientist at DRDL, Hyderabad. His research and work experiences include: Solid and hybrid propulsion, development, and testing of rocket motors