Research On Hydraulic Analysis Of Dynamic Distributed Loop Pipe Network

With the improvement of people's living standards,residents' demands for the indoor environment are getting higher and higher.The accelerating process of urbanization has led to a multi-heat source and large-scale development of the heating pipe network.Centralized heating is a livelihood project.Residents place higher demands on the reliability of the heating system.In this case,the ring pipe network It is being used more and more.However,the form of the ring pipe network is r elatively complex with respect to the branch pipe network.The initial investment and operation energy consumption are high,and the operation adjustment is relatively complicated.At the same time,as a energy-saving measure,the distributed power supply and distribution system has been increasingly applied to central heating projects due to its high energy-saving and adjustable features.However,at present,the study of the distributed power supply and distribution system only stays in the branch pipe ne twork.In addition,the application of the distributed power supply and distribution system in the ring pipe network is rarely mentioned at home and abroad.Therefore,it is of great practical significance to carry out the study of the dynamic distributed annular pipe network to reduce the energy consumption of the heating system and satisfy the life heating demand.In this paper,firstly,by referring to the existing research results of the distributed power heating system in the branched pipe network,combined with the characteristics of the ring pipe network,based on the pipe network topology,the system layout and the hydraulic pressure diagram,the distributed power supply is distributed.The differences in the application of the distribution system in the branch and ring pipe networks were compared.The analysis of the example shows that the application of the power distributed secondary pump system in the ring pipe network reduces the energy consumption by 23.9% compared with the traditional centralized heating pipe network.Secondly,based on graph theory and fluid pipe network characteristic equations,using MATLAB software,a single heat source single-loop pipe network and dual heat source single-loop pipe network hydraulic simulation models of the power distribution secondary pump heating system are respectively established.Under the user's design flow,the initial hydraulic intersection is obtained,so that the pipe network achieves hydraulic balance.Several typical conditions,such as simulated design conditions,failure of heat source,failure of a certain section of main line,and shutdown of a user's water pump,were used to analyze the position change of hydraulic junctions in the pipe network and the trend of pipe network pressure changes.The results showed that: the backbone network The flow affects the position of the hydraulic intersection of the pipe network;the effect of the heat source failure and the failure of a certain section of the main line on the hydraulic intersection is greater than the effect of the failure of a certain user branch on the hydraulic intersection;when the hydraulic conditions of the pipe network change After that,the heat source pump must consider the total flow that should be supplied to the backbone network after the operating conditions change.To satisfy their own heating needs,the user needs to adjust the user pump to obtain the heat required by itself;the power distributed dual heat source single loop pipe network heat source mutually For standby,the heating reliability of the pipe network is strengthened.When a certain heat source fails,another heat source can adjust the supply of the backbone network to meet the normal heating of each user in the pipe network,but the user needs to adjust the motor frequency of the user pump.The tubing gets water and meets the user's heat requirements.Finally,based on the flow pressure variation rule for several typical hydraulic conditions and the relatively mature operation regulation theory of the distributed power supply and distribution system in the branched pipe network,the operation regulation of the suitable dynamic distributed annular pipe network is concluded.Strategy: Integrate heat pump and user pump into unified control software to detect changes in pressure and flow at each node of the pipe network.Calculate the new balance based on hydraulic changes in different operating conditions.Derive relevant hydraulic parameters,adjust heat pump and user pump.The motor frequency to meet the dynamic balance of the heating pipe network provides a certain theoretical reference for the design,application and operation regulation of the dynamic distributed ring pipe network.