The Numerical Simulation Study Of District Heating Network

The district heating system is one of the most important fundamental infrastructures of modern cities, which can not only save a lot of resources and protect the environments but also realize high efficient heat supply to users. With the expansion of city construction and increasing customers, the central heating network has become a dominating form of supplying central heating in the north of China in winter.The central heating system is a complicated large variable control system, which is affected by various factors in reality. The change of any part operation, several consumers using quantity of heat or network structure can influence other consumers, even the whole system. Hydraulic maladjustment is a prevalent phenomenon in heat supply network, so how to avoid the problem and achieve hydraulic balance play an important role in improving heat-supply quality and saving a great sum of money.The method which integrates theoretical analysis, numerical simulation and experiment is adopted to research the hydraulic condition of the district heating network in the paper,which can be achieved as follows:The article summarizes development of the district heating system at home and abroad, the district heating system is studied by using commercial computational fluid dynamic software of FLUENT in the paper. As the accurate mathematical model about the central heating system established, the characteristic of the first and second heating network pressure distribution in the stable working condition is achieved by the numerical simulation based on the standard k-εmodel. Meanwhile, which is used to analyze the change law of the quantity flow, pressure in the district heating system when hydraulic maladjustment appears. Compared with the experimental test data, the simulation result is validated on the base of the standard k-εmodel calculations and the hydraulic analysis of the heating network, which can be used for reference in the further study of heating system optimization. In addition, based on the deep research of laws of fluid flow and pressure change, the heat transfer numerical simulation study of the plate heat exchanger in the laboratory heating network is investigated. The change law of the pressure, temperature in plate heat exchanger is analyzed, which provide the reference for thermal model of the district heating system.