Numerical prediction of aerothermodynamic effects on a reentry vehicle body flap configuration

Paper number

IAC-06-D2.6.08

Author

Mr. Marco Di Clemente, CIRA Italian Aerospace Research Centre, Italy

Coauthor

Dr. Marco Marini, CIRA Italian Aerospace Research Centre, Italy

Coauthor

Mrs. Sara Di Benedetto, CIRA Italian Aerospace Research Centre, Italy

Coauthor

Mr. Antonio Schettino, Italy

Coauthor

Dr. Giuliano Ranuzzi, CIRA Italian Aerospace Research Centre, Italy

Year

2006

Abstract

Flow separation over re-entry vehicles’ control surfaces is a typical phenomenon caused by shock wave boundary layer interaction which can deteriorate control surface efficiency and cause high thermo-mechanical loads in the proximity of flow reattachment. As far as today only few studies have been performed to analyse the phenomenon in high enthalpy conditions. 
Within the EXPERT program, funded by European Space Agency, a number of experiments to be performed in the CIRA Plasma Wind Tunnel “Scirocco”, representative of the capsule flight conditions with respect to the shock wave boundary layer interaction phenomenon occurring around the 20-deg open flap, has been designed: PWT driving conditions, model configuration and attitude have been defined, by means of a massive CFD activity performed by using the CIRA code H3NS, in order to allow for the duplication of characteristic parameters (viscous interaction parameter, rarefaction parameter, reference pressure and heat flux) of the interaction to reproduce on a full scale flap model both pressure and heat flux levels estimated in critical flight conditions. All this in order to develop an extrapolation-to-flight methodology for such flows since the full duplication of flow characteristic numbers (Mach, Reynolds, Damkhöler) and state of the gas is not feasible in ground facilities. 
Considering the model that has been designed for this experimental test campaign the effects of catalysis on complex three dimensional shock wave boundary layer interaction will be presented. The model reproduces the full scale EXPERT 20deg flap, mounted on a holder composed by a flat plate with rounded leading and lateral edges; in order to be consistent with the EXPERT capsule, it will be built by using the same materials to manufacture its different parts: i.e. PM1000 for the flat plate and C-SiC for the flap. This choice has caused a discontinuity of the catalytic properties, being PM1000 a metallic alloy with moderately high recombination coefficients and C-SiC a low catalytic material, that has a not negligible influence on the thermal loads acting on the flat plate ahead the flap. In fact, following the flow direction in the separation bubble, the particles composing the air mixture “feel” a discontinuity between a low and a high catalytic material, thus forcing a sudden recombination with a strong energy release and a consequent heat flux increase.
The effects of catalysis will be analyzed considering the available recombination coefficients (exponential fits of temperature) for the materials of interest or modelling PM1000 as fully catalytic and C-SiC as non catalytic, to obtain a conservative estimation of the heat flux on the flat plate. 

Abstract document

IAC-06-D2.6.08.pdf

Manuscript document

IAC-06-D2.6.08.pdf (🔒 authorized access only).

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