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Water condensation on cold surfaces

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Hi I am simulating heat and mass transfer with comsol in a closed chamber in order to detect condensation on walls surfaces. At some point I have obtained the water concentration profil as well as the temperature distribution, which I can use to determine the relative humidity. I calculated the relative humidity as the (water vapor pressure/water vapor saturation pressure). Using this concept I have found values of relative humidity that exceeds 100% which is not real since at that value the water vapor starts to condensate. My question is how to limit relative humidity to 100% and determine the quantity of condensed water. Does anyone have any clue how to do this with comsol ?


1 Reply Last Post Oct 3, 2017, 9:35 a.m. EDT
Sergei Yushanov Certified Consultant

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Posted: 6 years ago Oct 3, 2017, 9:35 a.m. EDT

Ahmed,

Comsol has special "Moist Air" feature which includes physical properties of dry air and water vapor mixture, as well as built-in functions for temperature-dependent saturation pressure and latent heat of evaporation. This feature also has predefined variable for relative humidity. This simplifies modeling of the water condensation and you might consider to take a look at the following examples:

https://www.comsol.com/model/condensation-detection-in-an-electronic-device-with-transport-and-diffusion-14397

https://www.comsol.com/model/condensation-risk-in-a-wood-frame-wall-43871

Regards,

Sergei

Ahmed, Comsol has special "Moist Air" feature which includes physical properties of dry air and water vapor mixture, as well as built-in functions for temperature-dependent saturation pressure and latent heat of evaporation. This feature also has predefined variable for relative humidity. This simplifies modeling of the water condensation and you might consider to take a look at the following examples: https://www.comsol.com/model/condensation-detection-in-an-electronic-device-with-transport-and-diffusion-14397 https://www.comsol.com/model/condensation-risk-in-a-wood-frame-wall-43871 Regards, Sergei

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