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Investigation on the Effect of Thrust Chamber Geometric Parameters on the Performance of NTO/MMH Thrusters
P. Arun Kumar1, C. Rajeev Senan2, B. Ajith3, M. Ponnuswamy4, P. Balachandran5

1Dr. P. Arun Kumar, Group Head, Spacecraft Propulsion Engines Group (SPEG), Liquid Propulsion Systems Centre, Valiamala P.O, Trivandrum (Kerala), India.
2C. Rajeev Senan, Engineer-SF, Spacecraft Propulsion Engines Group (SPEG), Liquid Propulsion Systems Centre, Valiamala P.O, Trivandrum (Kerala), India.
3B. Ajith, Engineer-SE, Spacecraft Propulsion Engines Group (SPEG), Liquid Propulsion Systems Centre, Valiamala P.O, Trivandrum (Kerala), India.
4M. Ponnuswamy, Engineer-SE, Spacecraft Propulsion Engines Group (SPEG), Liquid Propulsion Systems Centre, Valiamala P.O, Trivandrum (Kerala), India.
5Dr. P. Balachandran, Principal, Pinnacle School of Engineering and Technology, Areeplachy P.O, Anchal, Kollam (Kerala), India.

Manuscript received on 10 October 2017 | Revised Manuscript received on 18 October 2017 | Manuscript Published on 30 October 2017 | PP: 105-115 | Volume-7 Issue-1, October 2017 | Retrieval Number: A5201107117/17©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: Hypergolic bipropellant radiation cooled thrusters utilizing Mono-methyl Hydrazine and Nitrogen Tetroxide are commonly used in spacecraft missions for attitude and orbit control. The performance index of a rocket engine is the specific impulse which is a function of combustion efficiency, known as C* efficiency, and the nozzle efficiency. An experimental investigation is carried out to evaluate the effect of combustion chamber design parameters on performance(C*efficiency) for varied injector spray and atomisation characteristics as well as injection pressures. Analytical model with empirical correlation available in the literature is used as a tool for understanding the physical process in the combustion chamber and predicting C* efficiency which was validated with experiments. Design variables considered are characteristic length and the contraction ratio. Cold flow evaluation of the injector using simulant water was done to evaluate the droplet size and injection velocity, which is normalised to the propellant flow conditions. Hot test for 10s using the stainless steel chamber was done at sea level with instrumentation for chamber pressure, mass flow rate of propellants and throat temperature. Results show that for a given injection and operating conditions, there exists a range of L* and contraction ratio where C*efficiency will be optimum and less sensitive. Trends in throat temperature measured are also evaluated. This paper presents the details of the investigation
Keywords: Hypergolic Bipropellants, C* Efficiency, L*, Contraction Ratio

Scope of the Article: High Performance Computing