| Summary: | WINICE is a project carried out by researchers at Aalto University and Lappeenranta University. The project aims at investigating wasterwater purification through formation of thin ice layers by natural freezing in regions with cold climate, such that the process is more energy efficient than existing common purification methods. The scope of the project includes purification of wasterwater through formation of thin pure ice sheet in a tank, cutting of the ice sheet into ice pieces, removal of the ice pieces and their transport for further processing. This thesis focuses on a method for collection of the ice pieces after they are cut into pieces. For the collection process, a floodgate located centrally along the width of the tank is opened to generate an outward flow of water, which causes the ice piece to move along with the water. The ice piece is separated and the water is then is pumped back into the tank for refreezing. The scope of this thesis is studying the feasibility of the removal process, effects of reducing ice sheet length on the time taken to extract the ice piece (reach time) and analysis of reach time as a function of ice piece’s initial from the floodgate. The simulation of the ice piece motion is divided in two parts: simulation of water flow under the influence of ice sheet of fixed length, and simulation of a rectangular ice piece motion using the imported water flow field. The ice piece motion simulation is done for several initial positions using flow fields corresponding to different ice sheet lengths. However, the final simulation flow field from an interpolated case of several cases is needed to account for several distortions in the reach time contours. It is found that the floodgate is capable of extracting ice pieces from even farthest positions in the tank and that most of the time to completely empty the tank, would be spent on removing the ice pieces at the farthest positions from the floodgate. This time can be further reduced by using a wider floodgate. There are oscillations ...
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