Natural heat and mass transfer in a rectangular enclosure

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6454734

Lai, Wing Tak

The purpose of the dissertation is to provide background work for the investigation of fluid flow in complex geometries which exist in buildings. Both 2- and 3-d investigations were performed. The 2-d configuration is a square enclosure with one vertical surface maintained at high temperature and high moisture content, with the opposite vertical wall kept at low temperature and low moisture content, while the top and bottom surfaces were insulated and impermeable to moisture. The 3-d case was a cubical enclosure which had the boundary conditions of a heated and moist vertical wall, an opposite cooled and dry wall, and surfaces on the top, bottom, front and back that were insulated and impermeable to moisture. The strength of the convective flow was determined by the heat transfer Grashof number (Gr{sub h}) and mass transfer Grashof number (Gr{sub m}). Air and water vapor were employed as the heat and mass transfer fluids. The numerical investigation utilized the Semi-Implicit Method of Pressure Linked Equations Revised (SIMPLER,) iterative technique for the solution of the two- and three-dimensional cases for heat transfer Grashof numbers from 10{sup 3} to 10{sup 6} combined with various magnitudes of the mass transfer Grashof number. A direct solution technique of the hybrid method of successive substitution and Newton-Raphaon methods was employed for the computation of the two-dimensional model with GR{sub h} ranging from 10{sup 6} to 6.5 {times} 10{sup 8} and Gr{sub m} up to 8.7 {times} 10{sup 7}. Experiments were performed to measure the velocity and temperature distributions in a cubical enclosure. The velocities were measured with a Fiber Optic Laser Doppler Velocimetry system, while the temperature measurements were made with a thermocouple probe. Due to the size of the enclosure, the Grashof numbers were limited to magnitudes between 10{sup 7} and 10{sup 9}.

• Research Organization: Minnesota Univ., Minneapolis, MN (USA)
• OSTI ID: 6454734
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320100* -- Energy Conservation
Consumption
& Utilization-- Buildings
AIR
AMBIENT TEMPERATURE
BOUNDARY CONDITIONS
BUILDINGS
CALCULATION METHODS
COMPUTER CODES
CONVECTION
DOPPLER EFFECT
ENERGY TRANSFER
FIBER OPTICS
FLOW MODELS
FLOW RATE
FLUID FLOW
FLUIDS
GASES
GEOMETRY
HEAT TRANSFER
LASERS
MASS TRANSFER
MATHEMATICAL MODELS
MATHEMATICS
MEASURING INSTRUMENTS
MOISTURE
NATURAL CONVECTION
PRANDTL NUMBER
S CODES
TEMPERATURE DISTRIBUTION
TEMPERATURE GRADIENTS
TEMPERATURE MEASUREMENT
THERMAL INSULATION
THERMOCOUPLES
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
VAPORS
VELOCIMETERS
WATER VAPOR