Experimental and numerical study of steady forced-convection heat transfer in a spherical annulus
The results of a combined experimental and numerical study of steady forced-convection heat transfer in a spherical annulus with 50/sup 0/C heated water flowing in the annulus, an insulated outer sphere, and a 0/sup 0/C cooled inner sphere are presented. The inner sphere radius is 139.7 mm, the outer sphere radius is 168.3 mm and the radius ratio is 1.2. Measurements of inner sphere heat- flux rate distribution, flow separation angle, annulus fluid temperatures and total heat transfer were made for gap Reynolds numbers from 41 to 1086. The angle of separation along the inner sphere was found to vary as a function of Reynolds number. Measured total Nusselt numbers agreed with results reported in the literature to within 2.0% at a gap Reynolds number of 974 and 26.0% at a gap Reynolds number of 66. Results of numerical calculations of laminar incompressible fluid flow and heat transfer in a spherical annulus are presented. Velocity, temperature, pressure and heat-flux rate distributions are presented for gap Reynolds numbers from 4.4 to 440. It is believed that this is the first experimental study of spherical annulus convective heat transfer in which inner sphere heat-fux distribution has been measured and in which sepration angle was measured by non-visual methods and found to vary as a function of Reynolds number. Also, the numerical analysis is the first solution of the full laminar Navier-Stokes equations for forced-convection heat transfer in a spherical annulus. The computations predict well the experimental trends and qualitative aspects of the flow and heat transfer while underpredicting heat-flux rates by a factor of two or more. It is felt that a turbulence model is necessary to predict more accurately the experimental results.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore National Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7011275
- Report Number(s):
- UCRL-53081
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420400* -- Engineering-- Heat Transfer & Fluid Flow
ANNULAR SPACE
CONFIGURATION
CONVECTION
DATA
ENERGY TRANSFER
EXPERIMENTAL DATA
FLOW RATE
FORCED CONVECTION
HEAT EXCHANGERS
HEAT TRANSFER
HYDROGEN COMPOUNDS
INFORMATION
MEASURING METHODS
NUMERICAL DATA
NUMERICAL SOLUTION
OXYGEN COMPOUNDS
REYNOLDS NUMBER
SPACE
SPHERICAL CONFIGURATION
THEORETICAL DATA
WATER