TY - JOUR

T1 - A 2-D CFD model of oscillatory flow with jets impinging on a random wire regenerator matrix

AU - Ibrahim, Mounir B.

AU - Zhang, Zhiguo

AU - Wei, Rong

AU - Simon, Terrence W.

AU - Gedeon, David

PY - 2002

Y1 - 2002

N2 - This paper describes the CFD portion of an overall plan to examine a modern type of Stirling engine regenerator matrix both computationally and experimentally. An experimental program has already started at the University of Minnesota (UMN) to examine a stacked-screen regenerator. A 2-D axisymmetric computational model was developed to simulate the UMN rig encompassing a piston/cylinder, cooler tube, plenum, regenerator matrix and heater. The CFD-ACE+, a commercial CFD-code, has been utilized for this study. A systematic approach was taken where CFD results were obtained for the following: 1) Turbulence modeling (low Re k-ε) of a unidirectional pipe flow with sudden expansion (expansion ratio D/d=1.95). Good agreement was achieved with the experimental data; 2) Laminar flow with porous media for a flow over and through a stack of rectangular parallel plate fins (porosity=0.579 & permeability =2.28E-08 m -2). Good agreement was achieved with published CFD data; 3) Good agreement was achieved for prediction of the oscillatory velocity field, in the plenum, with the UMN data and without the regenerator matrix where a low Re k-ε turbulence model was used; 4) Results for the oscillatory flow data with the regenerator matrix in place showed that the laminar flow model overpredicted the centerline velocity (as expected), since the flow is turbulent. The laminar flow model with permeability of 1.65E-08 m -2 seems to show velocity uniformity in the matrix as early as 15 screen-layers deep into the regenerator matrix (from the cooler side). This is consistent with the UMN temperature data. A combined study of a turbulence model and a porous media model is underway to provide accurate data both in the plenum and the regenerator matrix. Our next step is to apply this model and include the energy equation to predict not only velocity but also temperature profiles as well.

AB - This paper describes the CFD portion of an overall plan to examine a modern type of Stirling engine regenerator matrix both computationally and experimentally. An experimental program has already started at the University of Minnesota (UMN) to examine a stacked-screen regenerator. A 2-D axisymmetric computational model was developed to simulate the UMN rig encompassing a piston/cylinder, cooler tube, plenum, regenerator matrix and heater. The CFD-ACE+, a commercial CFD-code, has been utilized for this study. A systematic approach was taken where CFD results were obtained for the following: 1) Turbulence modeling (low Re k-ε) of a unidirectional pipe flow with sudden expansion (expansion ratio D/d=1.95). Good agreement was achieved with the experimental data; 2) Laminar flow with porous media for a flow over and through a stack of rectangular parallel plate fins (porosity=0.579 & permeability =2.28E-08 m -2). Good agreement was achieved with published CFD data; 3) Good agreement was achieved for prediction of the oscillatory velocity field, in the plenum, with the UMN data and without the regenerator matrix where a low Re k-ε turbulence model was used; 4) Results for the oscillatory flow data with the regenerator matrix in place showed that the laminar flow model overpredicted the centerline velocity (as expected), since the flow is turbulent. The laminar flow model with permeability of 1.65E-08 m -2 seems to show velocity uniformity in the matrix as early as 15 screen-layers deep into the regenerator matrix (from the cooler side). This is consistent with the UMN temperature data. A combined study of a turbulence model and a porous media model is underway to provide accurate data both in the plenum and the regenerator matrix. Our next step is to apply this model and include the energy equation to predict not only velocity but also temperature profiles as well.

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M3 - Conference article

AN - SCOPUS:23844458358

SN - 0146-955X

SP - 511

EP - 517

JO - Proceedings of the Intersociety Energy Conversion Engineering Conference

JF - Proceedings of the Intersociety Energy Conversion Engineering Conference

T2 - 2002 37th Intersociety Energy Conversion Engineering Conference, IECEC

Y2 - 29 July 2002 through 31 July 2002

ER -