STM Journals Peer-reviewed research from Consortium e-Learning Network

Journal of Experimental & Applied Mechanics

Experimental Investigations of Mass Flow Rate on Regression Rate of Hybrid Rocket

  1. DR. PRAMOD KUMAR DASH
  2. Jhumki Nandi
  3. Shruthi R. Giri

Abstract

A number of practical hybrid propulsion systems developed for booster and upper stage application,at different Centers across the globe. The regression rate of hybrid fuel plays an important role ondevelopment of viable hybrid propulsion system. In the present investigation an effort has been madeto study the regression rate behavior of PVC-DBP((C 2 H 3 Cl) n )-DBP(C 16 H 22 O 4 ) hybrid fuel burning inthe stream of gaseous oxygen using two different Swirl Injectors and a conventional Shower HeadInjector. In all the cases, the oxygen injection has been varied from 20bar (290 psi) and 40.68 bar(590 psi). The local regression rate has been determined all along the grain length, measuring theremaining web at each locations of the grain and assuming a uniform fuel consumption rate in smallinterval of burning time of ten seconds or less. The local regression rate has been found to increasewith injection pressure at each location of grain for all the cases. The average regression rate ofPVC-DBP-DBP hybrid fuel has been found to increase with injection pressure, however this value ishighest for Swirl Injector, SWA and lowest for Shower Head Injector, while Swirl Injector SWBresulted in values in between. The dependence of average regression rate on the injection pressurehas been found to follow a power law relationship. The fuel mass consumption rate has also beenfound to increase with injection pressure and to follow a power law variation with injection pressure.However, mass consumption rate is more pronounced in case of Swirl Injectors, and the pressureexponent for Swirl Injectors have been found to be more than twice than that of Shower HeadInjector, similar to the case of average regression rate. The data have been analyzed in the light ofavailable combustion models and have been matched with experimental results. The Swirl Injectorshave been found to enhance the fuel regression, and, for the same oxidizer mass flow rate, it isexpected to result in higher thrust levels. The visual recordings indicate lower combustion efficiencyand movement towards fuel rich exhaust with condensed smoke; however, with the increase ininjection and combustion chamber pressure, higher combustion efficiency has been obtained withhigher regression rate as presented in Figure and table.

Keywords

Support