The Dynamics of Drops Freezing on Cold Surfaces
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The freezing of water droplets is a relevant and topical subject that is starting to get more attention in science since the need for research is growing. Areas of applications are wind-power industry, ice growth on airplane wings and propellers and when studying freezing rain that fall for example on cold roads. The understanding for the freezing process of water droplets is relatively good since there are several experiments performed on the subject, however there is very little written about CFD-simulations. The need for a simple CFD-model is therefore of great importance. The aim of this master thesis is to create a working CFD-model of the freezing process of a water droplet. A solidification model was used in the software ANSYS FLUENT to simulate the freezing process. A 2D- and 3D-model was created, using a half circle with diameter 2 mm and hemisphere with the same diameter respectively. A hexahedral mesh was applied to both models. The droplet "floor" was given a temperature of -20°C and the droplet surface were given an adiabatic condition. A mesh-analysis was performed finding the best suitable mesh for both the 2D- and the 3D-case. The freezing time, when all parameters where kept constant in the 2D-case, was 13.3 s and for the constant 3D-case it was 11.4 s. When varying the specific heat and the thermal conductivity it took 12.4 s and 3.6 s respectively. For the constant 2D-case and when varying the specific heat the freezing time was very close to the freezing time found in experiments. When varying the thermal conductivity the freezing time was much lower, but why this was has to be investigated further. This also has to be done for the constant 3D-case since a coarser mesh than the suggested mesh from the mesh-analysis was used, due to the limited time and data resources.
Place, publisher, year, edition, pages
2013. , 41 p.
Technology, CFD, Freezing, Simulations, Water droplets
IdentifiersURN: urn:nbn:se:ltu:diva-57422Local ID: e1720034-f740-48be-aeea-1e544e17f6a7OAI: oai:DiVA.org:ltu-57422DiVA: diva2:1030809
Subject / course
Student thesis, at least 30 credits
Engineering Physics and Electrical Engineering, master's level
Validerat; 20130722 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved