Experimental Investigations Of COAX SWIRL Injectors For Hydrocarbons
- Paper number
IAC-07-C4.3.06
- Author
Mr. Robert Wagner, Technical University of Munich, Germany
- Coauthor
Prof. Dr.-Ing. Hans-Peter Kau, Technical University of Munich, Germany
- Coauthor
Mr. Chris Maeding, EADS Astrium GmbH, Germany
- Coauthor
Mr. Philip Martin, EADS Astrium GmbH, Germany
- Coauthor
Mr. Sebastian Soller, Technical University of Munich, Germany
- Year
2007
- Abstract
Further improvements of rocket engines depend on well-founded knowledge about the design of injector elements, as they affect not only the performance, but also influence the reliability and fatigue behaviour of the propulsion system. Since the year 2000, the Institute of Flight Propulsion at the University of technology, Munich, and EADS Space Transportation, Munich, have been conducting a series of test campaigns in order to assess the characterize different coaxial injector design concepts for the propellant combination LOX/Kerosene.
The experiments were conducted at the high pressure combustion test facility of the Institute of Flight Propulsion. Elements were tested in a single element rocket combustor. The usage of kerosene and gaseous oxygen resembles conditions similar to those in the main chamber of an oxidizer rich staged combustion (ORSC) cycle engine like Energomash’s RD-170. The injectors consist of an oxidizer post, which is inserted in a fuel sleeve, thus forming the spirally wound fuel channels. The propellants pass through a recess area before entering the chamber. This design allows for premixing and pre-reaction of fuel and oxidizer and reduces the element’s sensitivity towards transversal or radial combustion instabilities.
Prior to hot fire testing, the hydraulic behaviour of the injectors was investigated in a specially designed spray test chamber using nitrogen as inert gas and kerosene. Optical access to the chamber allowed for an investigation of spray pattern with respect to element setup and operating conditions. The recorded static pressures in the chamber and manifolds of oxidizer and fuel were used to calculate the discharge coefficients of both sides. The results were compared with data from hot fire tests in order to assess the influence of combustion within the elements’ recess. In the experiments, the chamber pressure was varied from 4.0 MPa to 8.5 MPa with mixture ratio ranging from 2.4 to 3.4. The static wall pressure was measured at 4 positions along the chamber wall and was used to estimate the axial distribution of heat release within the chamber. The heat transfer to the water cooled wall was measured integrally over each of the chamber segments, providing a coarse axial profile of heat flux density. From the mass flow rates of fuel and oxygen, the combustion efficiency η c* was calculated taking into account losses due to wall friction, energy losses due to heat transfer to the wall and a variable discharge coefficient of the chamber nozzle. The fingerprint of each element was rounded off by a spectral analysis of the dynamic pressure signals recorded within the combustion chamber and the oxidizer feed line.- Abstract document
- Manuscript document
IAC-07-C4.3.06.pdf (🔒 authorized access only).
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