Simulation of room flows with small ventilation openings by a local grid-refinement technique

Abstract

Small ventilation openings in large rooms constitute a numerical resolution difficulty in indoor air flow simulation. A local grid-refinement technique is introduced to add local grid points in the small-opening regions. The method requires a relatively small increase in computer storage. A multi-grid algorithm, which turns out to be an efficient and accurate solves is used to solve the discrete system of equations on both global and local grids. A method for implementing the wall function in the solution procedure is described. Solutions of a three-dimensional isothermal mixing ventilation problem at Reynolds number of 5000 are compared with the experimental results in the literature. The method is then applied in a three-dimensional scaled model room ventilated by a plaque diffuser. The calculations show good agreement with the smoke visualisations of the flow pattern close to the diffuser. The method can be used to predict air flows with more realistic ventilation openings and more applications in large enclosures are expected in the future.

Get full access to this article

View all access options for this article.

References

Gosman A.D. , Nielsen P.V. , Restivo A. and Whitelaw J.H.

The flow properties of rooms with small ventilation openings

J. Fluids Engineering 102(?) 316-323 (1980)

Sandberg M. , Blomqvist C. and Mattsson M. Turbulence characteristics in rooms ventilated with a high velocity jet Air Movement and Ventilation Control Within Buildings, Proc. 12th AIVC Conf, Ottawa, Canada (24-27 September 1991)

Li Y. , Sandberg M. and Fuchs L.

Effects of thermal radiation on air flow with displacement ventilation: an experimental investigation

Energy and Buildings 19 263-274 (1993)

Tu J. Three-dimensional overlapping grids and multigrid methods for flow calculations in complex IC engine geometries PhD thesis Department of Mechanics, The Royal Institute of Technology, Stockholm, Sweden TRITA-GAD 92:19 (1992)

Rai M.M.

A relaxation approach to patched-grid calculations with the Euler equations

J. Comput. Phys. 66 99-131 (1986)

Brandt A.

Multi-level adaptive solutions to boundary-value problems

Mathematics of Computation 31 333-390 (1977)

McCarthy D.R. and Swanson R.C.

Embedded mesh multigrid treatment of two-dimensional transonic flows

Applied Mathematics and Computation 13 399-417 (1983)

Fuchs L.

A local mesh-refinement technique for incompressible flows

Computers and Fluids 14(1) 69-81 (1986)

Thompson M.C. and Ferziger J.H.

An adaptive multigrid technique for the incompressible Navier-Stokes equations

J. Comput. Phys. 82 94-121 (1989)

10.

Srinivasan K. and Rubin S.G.

Segmented multigrid domain decomposition procedure for incompressible viscous flows

International Journal for Numerical Methods in Fluids 15 1333-1355 (1992 )

11.

Lemke M.

Fast adaptive composite grid methods on distributed parallel architectures

Communications in Applied Numerical Methods 8 609-619 (1992)

12.

Li Y. , Fuchs L. and Holmberg S.

Methods for predicting air change efficiency

Proc. Roomvent '92, Aalborg, Denmark (2-4 September 1992)

13.

Bai X.S. and Fuchs L.

Fast multigrid method for 3-D turbulent incompressible flows

Int. J. Num. Meth. Heat Fluid Flow 2(2) 127-137 (1992)

14.

Brandt A. and Dinar N.

Multi-grid solutions to elliptic flow problems

Numerical Methods for Partial Differential Equations Proc. Advanced Seminar, Math. Res. Center, University of Wisconsin, October 1978 ed. S Parter (New York: Academic Press) ( 1979) pp53-147

15.

Li Y. , Fuchs L. and Holmberg S. An evaluation of a computer code for predicting indoor air flow and heat transfer Air Movement and Ventilation Control Within Buildings: Proc. 12th AIVC Conf, Ottawa, Canada pp123-136 (24-27 September 1991)

16.

Restivo A. Turbulent flows in ventilated rooms PhD thesis Department of Mechanical Engineering, Imperial College, London (1979)

17.

Li Y. Simulation of flow and heat transfer in ventilated rooms PhD thesis Department of Mechanics/Applied Computational Fluid Dynamics, Royal Institute of Technology , Stockholm, Sweden (1992)