Designing of frazil ice test rig

Abstract: A large part of electricity in Sweden is produced by hydropower plants, which are a safe and pollution-free source for electricity production. In the cold season, when the temperature of water decreases to below zero, water can be frozen and different types of ice will be generated. Frazil Ice is one type of ice that is made by turbulent water. This type of ice flows into rivers and blocks trash racks. Trash racks prevent the entrance of different things such as leaves, woods, stones and fishes into the turbines, but when they are blocked by the ice, water cannot go through them, thus turbines cannot work. Träbena is a hydropower station located at the Ätran River in south Sweden, and it suffers from frazil ice problems during the winter. To solve this problem, a heating system has been installed on the trash rack to melt frazil ice. Currently, the heating system works manually, but for energy saving, an automatic switch has been designed with a capacity sensor to detect the frazil ice thus turning the heating system either on or off. A test rig should be designed to test the sensor’s performance as well as to discover the best program for that sensor. In this research, following certain constraints such as cold store and trash rack dimensions, a test rig has been designed to test the frazil ice detector, using different variables such as temperature and water flow. The model of the test rig has been evaluated by static analysis, and water flow has been simulated to show how the water becomes turbulent in the test rig.