Study On The Transportation Reservation Of Ring-shaped Heating Networks In Accident Conditions

As the urbanization process of the cities in the country continues to deepen,the urban population is increasing,and the scale of building construction is also increasing.Therefore,in the case of central heating,the heating network is required to have better heating capacity and larger heating area and better stability.In addition to lower cost heating technology is also must.Due to the advantages of good hydraulic stability,operational reliability and flexibility of the ring-shaped heating network,the planning and laying of the ring-shaped heating network begins in the transformation of the old network and the construction of the new network and received the attention of people.However,due to the lack of corresponding design planning,construction management,operation adjustment and other technologies,the use of the ring network for district heating is hindered.Therefore,the research on the ring-shaped heating network should be deeper and more systematic.This paper mainly studies the transportation capacity of the ring-shaped heating network under the accident condition,and takes the single heat source and single-ring-shaped heating network as the research object.The main research contents include: establishing a single-heat source and single-ring-shaped heating network model based on polar coordinate system,performing hydraulic calculation of design working conditions on the model network,and performing hydraulic calculation on accident conditions without changing the initial design pipe diameter.Through the hydraulic analysis of the accident conditions,under the premise of meeting the requirements of the limit heating,the layout of the network under the initial design pipe diameter is studied;in the case of the ringshaped heating network accident,if the limit is to be met for the heat requirement,it is necessary to carry out the calculation of the diameter expansion of the ring main pipe,determine the research method of the pipe network conveying capacity,and propose the definition of the reserve capacity of the conveying capacity.The paper studies the influence of factors such as the number of nodes,the radius of the ring network,the heating coefficient of the limit on the reserve coefficient of the transport capacity,the relationship between the reserve coefficient of the transport capacity and the material characteristic coefficient.The calculation example of the single-ring-shaped heating network using a single heat source is based on the discrete The actual pipe diameter analysis of the transport capacity reserve coefficient and material property coefficient and other indicators,verified the approximation between the theoretical analysis of continuous variables.In this paper,through the theoretical derivation of the model network,the change rule of the reserve coefficient of the accidental transport capacity of the ring-shaped heating network is basically the same as that obtained by the case network.It can be explained that the basis of this paper is based on the ring network model of the polar coordinate system can be used to study the transportation capacity of the ring-shaped heating network.Based on the theoretical model,this paper quantifies the contradiction between reliability and economy,and provides quantitative reliability and economic indicators for the reliability design of the ring network,have certain reality and effectiveness.