Investigation of heat transfer in packed beds at high temperatures and low Reynold's numbers

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5277272

Huber, M L

At high temperatures in packed bed heat exchangers or reactors, one must consider the contribution of radiative transfer as well as conduction and convection to the total heat transfer process. In this study, the frequency response method was used to investigate heat transfer in a packed bed subject to gas flow at low Reynold's numbers (less than 16). The frequency response method requires the use of a mathematical model for data analysis. A new model was developed, the extended single particle model, which includes axial conduction in the solid, solid-to-solid particle radiative transfer, gas-particle interphase transfer, and is expressed in terms of the surface temperature of the solid. Experiments were performed using four different sizes of alumina spheres, ranging from 0.003175 to 0.01905 m in diameter, with temperatures from 600 to 1300 K and particle Reynold's numbers varying from 0.6 to 15.4. The model was used to obtain estimates of the heat transfer parameters h (gas-to-particle heat transfer coefficient) and k/sub eax/ (effective axial thermal conductivity), using a nonlinear least squares parameter estimation method. The Nusselt number was found to follow Nu = 0.154 Re/sup 1.48/ for 0.6 < Re < 16, and were only weakly dependent on temperature.

• Research Organization: Colorado School of Mines, Golden (USA)
• OSTI ID: 5277272
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer &amp; Fluid Flow
DATA ANALYSIS
ENERGY TRANSFER
FREQUENCY RESPONSE TESTING
HEAT TRANSFER
HIGH TEMPERATURE
MATHEMATICAL MODELS
NUSSELT NUMBER
PACKED BED
REYNOLDS NUMBER
TESTING
VERY HIGH TEMPERATURE