Over the years, we have done research in a number of topical areas, including shock and kinetics interaction, turbulent combustion modeling and turbine combustor flow computations, injector flows, film cooling and cavity heat transfer of turbines, nozzle flows, seal dynamics, porous media fluid flow and heat transfer and turbomachinery and injector optimization. We summarize a current topic motivated by liquid rocket propulsion in the following.
Fluid Flow and Heat Transfer Through Porous Media for Liquid Rocket Applications
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| Rigimesh material | Rigimesh Schematic |
Porous materials are often used for the injector face plate of liquid propellant rocket engines (LPRE). Fuel bleeds through the porous plate to aid in cooling of the injector face by transpiration while helping injection of fuel at the same time. For example, in P&W’s RL10 engine and Space Shuttle Main Engine (SSME), Rigimesh is used. Rigimesh is formed by pressing layers of sintered stainless steel wire meshes. In the case of SSME, a 0.25” thick plate with about 9% void space is used. Rigimesh can qualitatively be classified as a dense, non-uniform, fibrous porous media.
In such porous fluid flow problems, direct numerical simulation of the fluid flow accounting for all geometric details is very costly if not impossible. Thus modeling efforts in this area dating back to Darcy’s experimental study in 1856, have mostly aimed at empirically correlating the pore level flow effects to the bulk fluid motion. The most commonly used approach is to add source terms to the global transport equation of mass, momentum and energy and relate these source terms back to empirically found parameters corresponding to the porous material being used.
To develop predictive capabilities for such porous media flow problems, a first principle-based, multi-scale modeling strategy is developed. The effect of porous media on the macroscopic fluid flow structures is accounted for via local volume averaged governing equations. The resulting set of transport equations, at the global domain level, contains closure terms representing the statistical flow characteristics around the pores. Our approach is based on the local volume averaging method. This method follows the notion of investigating the flow properties averaged over local volume elements and produces an unclosed set of governing equations. Most porous media can be thought of as a matrix of repeating pore patterns. We can calculate the closure terms for different flow speeds and pore patterns observed. These results can be interpolated to obtain the closure term evaluations throughout the porous medium. Thus, we can avoid the computational cost of direct simulation yet we can produce accurate numerical predictions completely free of empiricism. In the present approach, these closure terms in the global fluid flow equations are deduced via direct computation of the fluid flow in individual, representative pores.
Researchers: Emre Sozer
References:
- Sozer, E., Shyy, W., "Modeling of Fluid Dynamics and Heat Transfer Through Porous Media for Liquid Rocket Propulsion", AIAA-2007-5549, 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Cincinnati, OH, July 8-11, 2007
- Clutter, J.K., Mikolaitis, D.W. and Shyy, W., "Reaction Mechanism Requirements in Shock-Induced Combustion Simulations", Proceedings of the Combustion Institute, Vol. 28, (2000), pp. 663-669, Twenty-Eighth International Symposium on Combustion, Edinburgh, Scotland, July 30 - August 4th.
- Shyy, W. and Ebert, M.P., "Heat Transfer and Fluid Flow in Rotating Sealed Cavities", Advances in Heat Transfer, Vol. 35, (2001), pp. 173-248, J.P. Hartnett, T.F. Irvine, Jr., Y.I. Cho and G.A. Greene (eds.), Academic Press, New York.
- Schuchkin, V., Osipov, M., Shyy, W. and Thakur, S., "Mixing and Film Cooling in Supersonic Duct Flows", International of Heat and Mass Transfer, Vol. 45, (2002), pp. 4451-4461.
- Vaidyanathan, R., Tucker, P.K., Papila, N., Shyy, W., "CFD-Based Optimization for a Single Element Rocket Injector", Journal of Propulsion and Power, Vol. 20, (2004), pp. 705-717; an earlier version was presented in the 41st Aerospace Sciences Meeting & Exhibit, Paper No. 2003-0296, (2003).