vapour transfer coefficients

[marijke]

dear all,

i have a question regarding how the vapour transfer coefficients are calculated in wufi. i supposed that the vapour transfer coefficients were constant as they are derived from the heat transfer coefficients (which are constant) using the lewis - relation. however, when i ask their values as an output of my simulation i see that they are not constant.
can someone help me with this?
furthermore i wondered if it is possible to insert your own values for the vapour transfer coefficients (and the heat transfer coefficients).
thanks in advance.

best regards,
marijke steeman

university of ghent, belgium

[Manfred Kehrer]

Dear Marijke,

the vapor transfer coefficient (derived from heat transfer coefficient) will be calculated to a sd value to add the additional user defined sd value. This calculation will be done for a Temperature of 10°C. This sd value goes to the calculation kernel and will be transformed to a water vapor transfer coefficient after every iteration step by using the current surface temperature. Therefore you will always have transient values for the transfer coefficient, if the surfaces temperature changes.

Sorry, at the time transient user defined values for heat and vapor transfer are not possible.