FEATURES OF HEAT TRANSFER IN A FLAT POROUS MICROCHANNEL


  • A.A. Avramenko Institute of Engineering Thermophysics, National Academy of Sciences of Ukrain e
  • N.P. Dmitrenko Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine
  • Yu.Yu. Kovetska Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine
  • E.A. Kondratieva Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine
Keywords: heat transfer, microchannel, porous medium.

Abstract

A steady heat transfer process of mixed convection in a flat vertical porous microchannel is considered.

The results of simulation showed that Knudsen number effects are more significant in the neighborhood of the wall where growth of Knudsen numbers is accompanied with the velocity and temperature jumps on wall. With increasing parameter of porosity M (decreasing permeability), the flow velocity decreases and the velocity jump decrease as well.

For all combinations of the criteria Ra, Kn and M increasing Knudsen number reduces heat transfer intensity. This can be attributed to increasing temperature jump on wall which causes deterioration of thermal interaction between the fluid and the wall.

For low Rayleigh numbers increasing parameter M leads to increasing heat transfer since the temperature jump decrease on walls. For large Rayleigh numbers the trend becomes reversed, since for larger parameters M, the near-wall velocity decreases.

For low Rayleigh numbers increasing the Knudsen number leads to decreasing hydraulic resistance coefficient, but with increasing parameter M leads to increasing this coefficient. At high Ra numbers increasing Knudsen number leads to growth of hydraulic resistance, which is due to increasing velocity gradient on the wall.

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Published
2020-04-12
How to Cite
Avramenko, A., Dmitrenko, N., Kovetska, Y., & Kondratieva, E. (2020). FEATURES OF HEAT TRANSFER IN A FLAT POROUS MICROCHANNEL. Thermophysics and Thermal Power Engineering, 42(1), 12-18. https://doi.org/https://doi.org/10.31472/ttpe.1.2020.1
Section
Heat and Mass Transfer Processes and Equipment, Theory and Practice of Drying