Thrust Anomalies at Ignition Transient of Solid Propellant Rockets
- Paper number
IAC-10.C4.2.4
- Author
Prof. Bernardo Favini, Sapienza Università di Roma, Italy
- Coauthor
Dr. Ferruccio Serraglia, European Space Agency (ESA), Italy
- Coauthor
Dr. Viviana Ferretti, Sapienza Università di Roma, Italy
- Coauthor
Prof. Maurizio Di Giacinto, Sapienza Università di Roma, Italy
- Coauthor
Dr. Enrico Cavallini, Sapienza Università di Roma, Italy
- Year
2010
- Abstract
VEGA is the new launcher of the European Space Agency, currently in its final phase of development. Tailored for small payloads and low earth orbit missions, VEGA is a single-body four-staged launcher with three solid propellant rockets and one liquid propulsion upper module. The three SRMs, the first stage P80 (Europropulsion), the second Zefiro 23 (Avio Group) and the third Zefiro 9 (Avio Group) share the same finocyl configuration, characteristics and technologies. A fourth SRM, Zefiro 16 (Avio Group), has been developed in the past as a technological demonstrator of the Zefiro motor family. During the development and the qualification of the Zefiros and P80 SRMs, the characterisation and the analysis of the ignition transient phase has been carried out by a numerical simulation code SPIT (Solid Propellant Rocket Motor Ignition Transient), developed by the authors (SPqR Team). As a matter of fact, these numerical simulations proved to be useful to predict the behaviour of the motors during the ignition phase but also, through the analysis of the experimental results of the performed static firing tests, they can give a very deep insight of the physical phenomenology and the complex succession of events that characterize the ignition transient. In the frame of this analysis a dedicated methodology based on the Hilbert-Huang Transform (HHT) has been developed to investigate the frequency content of experimental and numerical pressure signals. Experimental results and quasi-1D simulations (SPIT) confirmed that the ignition transient can be characterized by strong unsteady phenomena and complex gas dynamic features. In addition to well-known issues that could affect SRMs ignition, as net thrusts and pressure oscillations, over-pressures, hang-fires or misfires, during the Zefiros and the P80 development specific attention has been spent to investigate the effect of the pressuring gas on the acoustic excitation of the motor chamber and to the supersonic chocking effect caused by the pyrogen igniter jets. To further investigate the multi-dimensional phenomena, in particular the igniter jets formation/interaction and the flow-field evolution inside the star-shaped finocyl region, a 3D, compressible, inviscid and multifluid solver, MUG, has been developed by the authors. The full article will discuss these phenomena and will present the comparison between numerical simulations performed with the 3D and the Q1D model and experimental data. These analyses will be particularly focused on the effect of specific gas-dynamics features that can have a relevant impact on the overall SRM behaviour during the ignition transient.
- Abstract document
- Manuscript document
IAC-10.C4.2.4.pdf (🔒 authorized access only).
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