Experimental Study Mechanism Of Pumping Melting Ice Of Diversion Channel In High Altitude And Cold Regions

In the Northwest high altitude and cold regionsof China, the ice damageprevention of diversion hydropower station is a key issue that must be considered in winter. Because of ice damage, huge economic loss and safe hidden trouble has produced every year. Among conventional ice damage prevention measures, Pumping Melting Ice(hereinafter referred to as PMI) is the ideal measure to solve this problem for diversion hydropower station. The principle of PMI is: High temperature groundwater is used to inject diversion channels, the temperature of water in channel will be increased, the generation of water ice will be prevented. At the same time, channel flow will be increased for power generation. PMI for ice damageprevention of channel has already put into practice in many hydropower stations of northwest China, and has achieved good results. But little research on PMI has accomplished at home and abroad, and most research are concentrated on prototype testing and theoretical introduction, experimental research about PMI is rarely described.This article take Hongshanzui Hydropower’s diversion channels that are in operation in winter forthe prototype observation object. Based on prototype observation and model test method, the key factors and operating mechanism of PMI are researched, theoretical basis and technical support are provided for PMI’ application in diversion hydropower station in winter. At the same time, diversion hydropower station’s safe operation in high altitude and cold regionscould be protected in full winter, and the ecological environment of the native population, live production are of great significance.On the basis of prototype observation and outdoor model tests, this paper has researched the mechanism of PMI. The main of results in the paper are as follows:(1)A systematic summary and analysis of ice conditions in present situationat home and abroad was studied in this paper on the basis of describing the evolution of river ice and ice damage types.(2)By use of PMI test model, channel water’s temperature, ice density and water velocity changes along the channel withoutextra well water were analyzed by model tests. The results show that: the temperature of the water and water velocity decreases along the channel, but the ice density increases along the channel.(3)The model test were carried out in different situation of channel flow discharge, well flow discharge, channel water temperature and well water temperature. The warming effect of the channelflow on the situation of various factors was analyzed. Channel mixing water temperature is proportional to well water flow discharge and water temperature, the channelwarming effectis more obvious on the basis of more well flow discharge or higher water temperature. Channel mixing water temperature is inversely proportional to channel flow discharge, with more channel flow discharge, the warming effect of well water is diluted, the effect is notobvious. Channel mixing water temperature is proportional to channel water temperature, and the lower the channel water temperature is, the lower the mixing water temperature is.(4)The variation of water temperature, ice water density and ice water flow velocity along thediversion channel were compared. The results showed that: ice density is inversely proportional to channel water temperature, flow velocity is inversely proportional to ice density, flow velocity is proportional to water temperature, and change in water temperaturedelayedcompared tochange in flow velocity. On the basis of PMI channel model tests results in this paper, combined with the actualoperation of project, PMI scheme for other hydropower could be achieved. Hydropower could solve the problem of ice damage automaticallyin an inexpensive premiseultimately.