Study On The Construction Of Hydraulic Model Of Urban Pipe Network And Evaluation Method Of Fire Water Supply Capacity

Water supply network system is an important lifeline project in the city.It not only provides water for people's daily life and production,but also shoulders the heavy responsibility of fire fighting.The water supply network hydraulic model can help the management of information management and operation status of the pipeline network.It is the most direct and effective technical method for the urban water supply department to carry out design,operation,management,optimization,and risk prediction of the pipeline network.The evaluation of urban fire water supply capacity based on the hydraulic model of the water supply network is an expansion of the hydraulic model of the water supply network.At present,China is in a period of rapid urbanization and industrialization.The risk of fire increases continuously.The demand for fire safety is also increasing year by year.Studying how to quickly and efficiently assess the water supply capacity of water supply pipe network can provide the initial and later renovation of the pipe network.On the basis of this,this not only provides guarantees for the safety of urban life production,but also promotes social development and economic construction.It can also provide certain technical support for future research on urban pipe network fire water supply capacity assessment methods.The research direction of this paper is the construction of the urban water supply network hydraulic model and the evaluation of the water supply capacity of the pipeline network based on the hydraulic model.The main contents include:(1)Research on the design method of fire water quantity in town.Through the analysis of relevant norms of China's "fire fire water and fire hydrant system technical specifications",fire flow design of domestic regulations exist irrational value,unable to meet the development needs of the city,the design value is obviously lower than the actual fire demand and lower than the foreign value standard problem.Then three kinds of calculation methods of fire water design in foreign countries are introduced in detail,namely,ISO method,ISU method and IITRI method.By comparing four calculation methods through two examples,it is concluded that although the calculation of ISO is more complex,the obtained results are closest to the actual water demand of fire,and the practicability and accuracy are the highest.(2)Research on the establishment of hydraulic model of water supply network in cities and towns.The hydraulic system model is composed of nodes,pipes,pumps,valves,tanks and towers the five basic components of the system,the modeling problem is to combine the network system components,and gives the corresponding numerical,mapping to mathematics,is to solve the energy equation and the continuity equation of two equations constitute the theoretical basis of network hydraulic model the.In this paper,the gradient algorithm is used to solve the equation group,and the hydraulic theoretical foundation for the construction of the hydraulic model of the pipe network is explained.Then,it compares and analyses the commonly used modeling software at home and abroad,and selects two software WaterGEMS and EPANET according to the needs of the subject.The WaterGEMS software has the function of convenient modeling,but there is poor and not because the printing effect is completely free,so the application range of the defect,while the EPANET is completely free,with a strong hydraulic simulation,calculation functions and rich graphical output function,but not for rapid modeling of complex network.Therefore,this topic will be the two software are combined to supply ERON County of Lijiang city network as an example,using WaterGEMS to establish the hydraulic model,applying EPANET to China fire code requirements for the standard,five fire control point selection,using single and multi-point fire simulation assessment of fire water supply capacity network.The results show that the fire water supply capacity of ERON County pipe network mostly meets the requirements of China's fire code,and there are some nodes that fail to meet the specifications when there are multiple fires.(3)The research on the method of evaluating the water supply capacity of urban pipe network.This part introduces the evaluation methods of fire water supply capacity of existing municipal pipelines,which are NFPA method,hydraulic model based trial method and Boulos method.The advantages and disadvantages of each method are also analyzed.The NFPA method is simple in calculation,but in order to ensure the accuracy of the need to spend a lot of manpower and resources,but also may affect the normal operation of the network;hydraulic model trial method has complicated calculation process based on Boulos method;there were many times of iteration,commercial software applications,so there is the problem of limited application scope.This paper is based on a new evaluation method for fire water supply capacity of the municipal pipe network based on Newton iteration is proposed.The method is transformed into the optimization problem of water supply capacity assessment of municipal pipe network,the network quality and energy conservation equation for nonlinear constraints,using Newton iterative solution,involves fewer parameters,with higher computing efficiency.Taking a water supply network hydraulic model as an example,the Boulos method is compared with the evaluation method based on Newton iteration proposed in this paper.The results show that the proposed Newton iteration method can more effectively evaluate the fire water supply capacity of the pipe network.(4)The water supply capacity of the water supply network in Qujing is evaluated by using the pipe network modeling method and Newton iterative method proposed in this paper.The municipal water supply network in Qujing city of Yunnan Province as an example,determine the fire flow value and evaluation standard in China according to the fire code recommendation method,single point and multi point fire fire simulation of two kinds of condition assessment methods of Qujing city network fire water supply capacity evaluation,the final results show that the fire water supply pipe network capacity can meet the requirements of specification;then 5 fire control points of fire flow are calculated by using ISO method,and then use the Newton iterative method based on Calculation of fire flow points are presented in this paper,comparing the two calculation results show that the fire flow by the two methods of the value of income difference,and the calculation method based on Newton iteration is more efficient,again to prove the feasibility of this method;the maximum value of the final result from the two methods,with the same fire simulation condition using hydraulic.The model has evaluated the fire water supply capacity of Qujing city pipeline network.The results show that the fire water supply capacity of Qujing water supply network can still meet the needs of fire under the demand of larger fire,and it is a safe and reliable water supply network.