Hydraulic Condition Analysis And Performance Prediction Research On Large Heat Supply Network

As China’s central heat supply network develops gradually to a large-scale, hydraulic imbalance phenomenon is becoming much obviously, also it brings many questions such as low efficiency, poor quality and high pump energy consumption. So to research on the hydraulic condition variation of the heat supply network is significant for reducing hydraulic imbalance and can make heat supply network operating economically.Taking Shijiazhuang’s Yuhua ring-shaped heat supply network for example and establishing the network model, this paper makes comprehensive analysis of hydraulic conditions.To find out the rules of the network’s flow distribution and the pump energy consumption, this paper makes different schemes for the states of communicating valves, it comes to conclusion that the communicating valves in big ring can influence the whole network’s flow, but the communicating valves in small ring can only influence the small ring’s users; When communicating valves are all closed, the pump energy consumption is the lowest and when they are all open, the pump energy consumption is highest.The paper simulates heat users’ flow change when pipe segment in different position is fault and calculates the maximum limited flow coefficient and each heat users’ valve opening.It shows that the nearer the fault pipe distance the heat source, the maximum limited flow coefficient is bigger; When the further distance pipe is fault, the network can offer flow in turn, so each heat users’ hydraulic imbalance degree can between 0.85-1.15.The paper simulates the flow distribution of the heat supply network when heat users in different position is closed,and also researches on the flow rules when different numbers of heat users is closed. The result shows that when the users near the heat source is closed, it has more influence in the flow change of the network than the remote users closed; It fits the relationship between the diminish flow ratio of the network and the operation speed of the circulating water pump.The paper summarizes three kinds of flow control valves: globe valve, ball valve and butterfly valve and search on their influence to the network. The result shows heat users using butterfly valves can make the flow of the heat supply network the most stable.