Mixed laminar convection in Trombe wall channels
- Mechanical Engineering and Mechanics, Old Dominion Univ., Norfolk, VA 23455 (US)
The two-dimensional, steady, combined forced and natural convection in a vertical channel is investigated for the laminar regime. To simulate the Trombe wall channel geometry properly, horizontal inlet and exit segments have been added to the vertical channel. The vertical walls of the channel are maintained at constant but different temperatures while the horizontal walls are insulated. A finite difference method using up-wind differencing for the nonlinear convective terms, and central differencing for the second order derivatives, is employed to solve the governing differential equations for the mass, momentum, and energy balances. The solution is obtained for stream function, vorticity, and temperature as the dependent variables by an iterative technique known as successive substitution with overrelaxation. The flow and temperature patterns in the channel are obtained for Reynolds numbers and Grashof numbers ranging from 25 to 100 and 10,000 to 1,000,000, respectively. Both local and overall heat transfer coefficients are computed for the channel aspect ratio varying from 5 to 15. For a given value of Grashof number, as the Reynolds number is increased, the flow patterns in the vertical channel exhibit a change from natural convection like flow patterns in which a large recirculating region is formed in the vertical part of the channel, to a forced flow type pattern. This is also the case with isotherms. The size of the recirculating region in the channel increases with increasing value of Gr/Re/sup 2/. At low Reynolds number, the stream function, and isotherms are qualitatively similar to those reported for the natural convection in rectangular slots.
- OSTI ID:
- 6496514
- Journal Information:
- J. Sol. Energy Eng.; (United States), Journal Name: J. Sol. Energy Eng.; (United States) Vol. 110:1; ISSN JSEED
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
142000* -- Solar Energy-- Heat Storage-- (1980-)
99 GENERAL AND MISCELLANEOUS
990230 -- Mathematics & Mathematical Models-- (1987-1989)
CONVECTION
DIFFERENTIAL EQUATIONS
ENERGY BALANCE
ENERGY SYSTEMS
ENERGY TRANSFER
EQUATIONS
EQUIPMENT
FINITE DIFFERENCE METHOD
FORCED CONVECTION
GEOMETRY
HEAT TRANSFER
HEATING SYSTEMS
ITERATIVE METHODS
MASS TRANSFER
MATHEMATICS
NATURAL CONVECTION
NUMERICAL SOLUTION
PASSIVE SOLAR HEATING SYSTEMS
REYNOLDS NUMBER
SOLAR EQUIPMENT
SOLAR HEATING SYSTEMS
TROMBE WALLS
TWO-DIMENSIONAL CALCULATIONS
WALLS