Leak Simulation And Detectiomodel Of Heating Network

In recent years, the leakage control of heating network has been the attention of the countries of all over the world. Leak of the heating network not only causes the economic loss, but also affects the people’s life. It’s difficult to diagnosis and localization the leakage as the result of the complex topology and its buried way. This paper based on transient slow, mathematically modeled heating pipe network compensation leaky components and valves which are under pressure mutation, and then based on the s lowly transient flow theory, using the method of system identification, established the leak model of heating network to a theoretical study.Heating pipe network composed of many elements components,in it the square compensator and valve are two importa nt and easily leak components. According to the principle of constant resistance, this paper converted the square compensator into a short pipe which have small diameter to simulate and observed the compensator pressure fluctuations in the pressure mutatio n, at the same time according to the independent wave propagation and the principle of superposition waves, the paper studies the characteristics of the valve. By contrast the end valve and the intermediate valve pressure changes in single valve and double valves adjustment, the paper find a reasonable way for valve arrangement. Finally, the paper reproduced an accident condition of a heating pipe network in Harbin.In order to simplify the hydraulic calculation, the complex heating network can be expressed to a simple and intuitive network map by the graph theory. And the paper established a hydraulic model of heating network which is based on slowly transient flow theory. When the leakage accident conditions of pipe network is simulated, assuming that the leakage occurs in the node or nearby node, the leakage discharge is regarded as a part of the node discharge, the extent of leakage is expressed with the leakage area, and the leakage discharge is calculated through the orifice flow formula. Using matrix method exports the analytic expression which is seen leakage as the dependent variable, and solves the expression discretely. A simple example is the completed by the hydraulic simulation of the model calculations.As the heating network running status affects the pipe flow and node pressure, so the paper used these two parameters as the monitoring parameter. Introduction of system identification theory in existing heating network leakage model, then the paper established the heating pipe network leakage detection model based on Bayes theory. By using a real network and bring two different programs into the leakage detection model, then the model c alculated the probability of leaks were 0.738 and 0.852, it is a good location to find the leak and the extent of the leak, the result verify the reliability of heating network leakage detection model.