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Investigation on a Novel Coaxial Microinjector with Application to Liquid Micropropulsion System

Principal Investigator(s): 

Abstract: 

Micro-fabrication technologies have made possible to develop micro-scale energy conversion and chemical processing systems. Micro-power generators (combustion chamber volume ∼ 10-20 mm3), which burn hydrogen or hydrocarbon fuels, have the potential to be more compact and longer-lived than chemical batteries as a portable power source. The development process of Miniature Kill Vehicles (MKVs) and micro-satellites will greatly benefit from the advancement of micro-fabricated propulsion systems. Since storable liquid bipropellant systems offer the most performance (Specific Impulse, Isp, as high as 450s, high thrust to weight ratio) and possess most versatility (pulsing, restart, variable thrust), the MKVs could effectively utilize liquid bipropellant micro-rockets for their divert propulsion, orbital maneuvering and attitude control systems for higher effectiveness, better range, maneuverability, and kill performance. However, successful miniaturization of propulsion components demands more complete and broader understanding of micro-fluid dynamics and micro-combustion phenomena associated with the micro-rocket design. This project is aimed at investigating the details of the flow dynamics and the combustion behavior of micro-injectors and to create theoretical backgrounds and empirical databases for micro-injector design. The liquid fueled combustor will then be used to demonstrate the hot firing performance under relevant conditions of the micro-rocket assembly and determine performance assessment and improvement. The primary objective of this three year project is to develop a novel coaxial swirl micro-injector technology which can be used for the divert propulsion and attitude control systems of Miniature Kill Vehicles (MKVs). The specific objectives are to:

  • Develop a coaxial swirl micro-fuel injector assembly which is capable of mixing and burning storable liquid/gas propellants. The effects of injector geometry and operating conditions on mixing characteristics will be examined.
  • Hot firing of the micro-rocket injector and the total micro-rocket assembly and determine the performance.
  • Obtain the injector performance in micro-rocket assembly for different liquid/gas fuel/oxidizers (ethanol-oxygen, RP1-oxygen and monomethylhydragine-nitrogen tetroxide) combinations. Analyze the data for practical implementation of the results.