NASA SBIR 2006 Solicitation


SUBTOPIC TITLE:Aerothermodynamics
PROPOSAL TITLE:Gas-Kinetic Navier-Stokes Solver for Hypersonic Flows in Thermal and Chemical Non-Equilibrium

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
3409 N. 42nd Pl.
Phoenix, AZ 85018-5961
(480) 518-0981

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Lei   Tang
3409 N. 42nd Pl.
Phoenix, AZ  85018-5961
(480) 518-0981

TECHNICAL ABSTRACT ( Limit 2000 characters, approximately 200 words)
This SBIR project proposes to develop a gas-kinetic Navier-Stokes solver for simulation of hypersonic flows in thermal and chemical non-equilibrium. The Navier-Stokes solvers adopted in current hypersonic CFD codes like LAURA and GASP use Riemann solver for the convection part and central scheme for the diffusion part. As a result, their integration with DSMC in the transitional and rarefied flow regimes may cause an artificial flow across the interface between CFD/DSMC zones because of the inconsistency in the estimated fluxes. On the other hand, the proposed gas-kinetic BGK solver for the Navier-Stokes equations (BGK-NS) computes the inviscid and viscous fluxes as a single entity, consistent with the DSMC approach. Furthermore, this BGK-NS solver has been demonstrated very accurate for hypersonic heat transfer prediction. The approach has also been successfully extended for solution of the Burnett equations whereas the macroscopic Burnett approach has some numerical difficulties. This SBIR project will further extend this BGK-NS solver to hypersonic flows in thermal and chemical non-equilibrium. In Phase I, a prototype non-equilibrium BGK-NS solver will be developed for the nitrogen shock dissociation cases and then in Phase II, a gas-kinetic CFD counterpart of LAURA will be fully developed and well validated.

POTENTIAL NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
NASA current mission focuses on human lunar and martian exploration. The design of crew exploration vehicles requires a computational tool, which is able to accurately predict hypersonic flows in thermal and chemical non-equilibrium. Compared with the macroscopic CFD approach, the proposed gas-kinetic CFD approach is more suitable for simulation of high-temperature non-equilibrium processes. It is not only accurate for prediction of shock stand-off distances, peaks in thermal loads, skin friction drag, forces and moments on the vehicles, but also ready for extension beyond the continuum flow regime. Such a computational tool can be used for accurate prediction of wake heating, single/multiple rocket plume effects on the vehicle aerodynamics and heating.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
Except Exa's Powerflow code, current commercial CFD software in the market is based on the macroscopic CFD approach, which is not well suited for simulation of non-equilibrium flows. On the other hand, Exa's Powerflow code only works for incompressible flows. The developed gas-kinetic computational algorithm can satisfy people's desire of accurate simulation of high-speed non-equilibrium flows. It can significantly enhance the capability of aerospace industry for accurate prediction of the aerothermal loads on a space vehicle, and can be used to analyze aerobrake systems, to predict leakage flows past seal teeth in gas turbine engines, etc. Such a computational tool is currently lacking in the market.

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Software Tools for Distributed Analysis and Simulation

Form Printed on 09-08-06 18:19