Numerical simulation of chemically reactive hypersonic flows

To study the atmospheric reentry phase of a space vehicle, it is necessary tounderstand correctly the thermochemical nonequilibrium processes coupled withthe aerodynamic phenomena of this critical phase. In a typical hypersonic flowabout a blunt body, the strength of the bow shock is such that the regionbetween the body surface and shock is the site of intensive thermochemicalprocesses. The different internal energy modes of the molecules are far fromtheir equilibrium state. The energy exchanges between these different modesoccur according to the individual relaxation time associated to eachprocesses. Detailed physico-chemical models for air in chemical and thermalnonequilibrium are needed for a realistic prediction of hypersonic flowfields. One of the key issues in the design of a hypersonic vehicle is theevaluation of aerodynamic heating. Especially, shock-shock interferenceheating phenomena is an important and critical problem in the development ofair-breathing hypersonic vehicles. Of special interest is the Edney type IVinteraction, because it is known to generate the highest local loads inpressure and heat transfer. A number of numerical studies on shock-shockinterference problems have been conducted. Most of these studies, however,assume a perfect gas model. For high-enthalpy hypersonic shock-shockinteractions, however, real gas effects become important. Real gas effects canhave a noticeable impact on flow features, such as shock stand-off distance ina blunt body flow and surface heating rates. Because of their importance, realgas effects have recently been the focus of several studies. An improvedunderstanding of the influences of real gas effects on the shock interactionphenomenon reduces a significant element of risk in the design of hypersonicvehicles.In the framework of the present work, the adaptive CFD code {it QUADFLOW} hasbeen extended for a five components air model. Different thermochemical modelswere implemented. The uncertainties associated with the physico-chemicalmodelling and their influence on the flow fields are discussed with the helpof computational results. Further, an attempt has been made to improve theunderstanding of influence of the real gas effects on the type IV shock-shockinteractions by the present computational study. In this regard, a series ofnumerical simulations of the experiments conducted at GALCIT T5 hypervelocityshock tunnel on shock-shock interactions were carried out. The computedresults are discussed in comparison with the experimental results andcomputational results of DLR FLOWer-Code, which is a non-adaptive RANS-solver.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2006

Author dc:creator

• Kumar, Sanjeev

Contributors dc:contributor

• Olivier, Herbert

• info:eu-repo/classification/ddc/620
• Ingenieurwissenschaften
• Hypersonic Flows
• Chemical Reaction

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-122682%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:60997