Sökning: "transient numerical modelling of diffusion"

Hittade 5 avhandlingar innehållade orden transient numerical modelling of diffusion.

  1. 1. Alternative methods for analysing moisture transport in buildings : Utilisation of tracer gas and natural stable isotopes

    Författare :Kjartan Gudmundsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tracer gas; water vapour permeability; diffusion; surface diffusion; isotopic analysis; deuterium; oxygen-18; fractionation; vapour barrier; transient numerical modelling of diffusion; Building engineering; Byggnadsteknik;

    Sammanfattning : New methods, based on tracer gas measurements and isotopicanalysis can be used to evaluate the moisture properties ofbuilding materials and provide the means for forensic analysisof the origins and history of excessive water in buildings, theimmediate practical consequences of which will be the abilityto improve the moisture performance of constructions. It is shown, in theory and through measurements how thewater vapour permeability of porous building materials can witha good degree of accuracy be estimated with tracer gasmeasurements that provide an efficient alternative to the cupmethod. LÄS MER

  3. 2. Moisture Transport in Porous Media. Modelling Based on Kirchhoff Potentials

    Författare :Jesper Arfvidsson; Avdelningen för Byggnadsfysik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; moisture distribtion; wood drying; wood; diffusion coefficient; numerical modelling; moisture flow; Moisture; transient measurements; periodic boundary condition; penetration depth; sorption coefficient; non-linear moisture flow; calculation model; anisitropy; Kirchhoff potentials; evaluation; moisture transport; Building construction; Byggnadsteknik;

    Sammanfattning : The work presented in this thesis is focused on the development of the new concept to describe isothermal moisture transport using Kirchhoff potentials. The first four papers deal with moisture transport in porous media using Kirchhoff potentials. The last three papers deal with wood. LÄS MER

  4. 3. Numerical Modelling of Some Engineering Heat Transfer Problems

    Författare :Daniel Eriksson; Värmeöverföring; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energy research; Energiforskning;

    Sammanfattning : Engineering heat transfer problems are very often of a complex nature and most often no analytical solutions exist. One way to create solutions to such problems is to apply numerical methods. This study concerns heat transfer problems with coupled conduction, convection and thermal radiation. LÄS MER

  5. 4. Moisture and Chloride Transport in Concrete

    Författare :Filip Nilenius; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multiscale modelling; mass transport; coupled diffusion; statistical volume element; interfacial transition zone.; computational homogenization; mesoscale;

    Sammanfattning : Material properties pertaining to the physical phenomena of mass transport in concrete are important for the durability of concrete structures, and they can ultimately be derived from material heterogeneities found at different subscales. On the mesoscale level, these heterogeneities are mainly characterized by the presence of embedded aggregates in the cement paste, together with cracks. LÄS MER

  7. 5. Combination of optical methods for studies in combustion and wave propagation

    Författare :Roger Mattsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimentell mekanik; Experimental Mechanics;

    Sammanfattning : In this thesis, different optical methods were combined for studies of combustion processes in gases and transient wave propagation in plates and water. Pulsed TV holography was used in all these projects. LÄS MER