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RELATIONSHIP BETWEEN HEAT AND MASS TRANSFER COEFFICIENTS AT THE SURFACE OF POROUS MATERIALS USED IN CIVIL ENGINEERING.

COUPLAGE ENTRE TRANSFERTS DE CHALEUR ET DE MASSE A LA SURFACE DE MATERIAUX POREUX UTILISES EN GENIE CIVIL.

Author(s) : PERRIN B., DAROLLES D.

Type of article: Article

Summary

FOR A GIVEN EXPERIMENTAL ASSEMBLY, A DETAILED AIR FLOW STUDY ENABLED ONE TO EVALUATE, FOR TWO SELECTED VELOCITIES, THE AVERAGE CONVECTIVE EXCHANGE COEFFICIENT USING A NUSSELT COEFFICIENT. DURING THE DRYING OF THE MORTAR AND CLAY IN CONTACT WITH THE AIR FLOW, TEMPERATURE VARIATIONS WERE RECORDED AT THE SURFACE AND INSIDE THE MATERIALS, AS ALSO THEIR MASS EVOLUTION. DURING THE FIRST DRYING STAGE, THE SUPERFICIAL WATER CONTENT OF THE MATERIAL IS HIGHER THAN THE CRITICAL WATER CONTENT, IT IS THEN POSSIBLE TO CALCULATE THE AVERAGE MASS EXCHANGE COEFFICIENT, KNOWING THE WATER VAPOUR PRESSURES AT THE INTERFACE. THE RATIO BETWEEN THE AVERAGE EXCHANGE COEFFICIENTS APPEAR TO BE INDEPENDENT OF AIR FLOW CONDITIONS BUT NOT EQUAL TO THE FORESEEABLE RATIO FOR LOCAL COEFFICIENTS. THIS DIFFERENCE SHOWS THE INFLUENCE OF BIDIMENSIONAL EFFECTS OF SURFACE EXCHANGES.

Details

  • Original title: COUPLAGE ENTRE TRANSFERTS DE CHALEUR ET DE MASSE A LA SURFACE DE MATERIAUX POREUX UTILISES EN GENIE CIVIL.
  • Record ID : 1989-0782
  • Languages: French
  • Source: Rev. gén. Therm. - vol. 27 - n. 323
  • Publication date: 1988

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