Research On The Key Technologies Of Multi-channel Confluent Water Supply For Urban Fire Fighting Vehicles

Fire water supply is an important component in the fire fighting and rescue operations,and plays a key role to determine its success or failure.Fire water supply is developing in the direction of high efficiency and high stability with the increasing complexity of fire accidents and the increasing number of fire truck dispatching.As the pivotal role of the fire water supply,the multi-channel confluent water supply system is very important to ensure the efficiency of water supply for fire fighting and rescue work.However,factors such as the confluent structure,channel switching,matching with other equipment,and firefighters' operations of the multi-channel confluent water supply system will affect the water supply efficiency.Therefore,it is necessary to study the key technologies such as the law,structure and control of multi-channel confluent water supply to ensure the stability and reliability of concentrated water supply.This subject is supported by the National Key R&D Program of China “Key Technology Research and Product Development of New Multifunctional Urban Fire Fighting Vehicles(No.2016YFC0802908)”.Research on the dynamic characteristics,smooth switching control and optimization of confluent structure are conducted,which is aimed to provide the theoretical support and technical solutions for the continuous and stability water supply.The main contents include:(1)The overall scheme of multi-channel confluent water supply is designed based on the analysis of the characteristics of the multi-channel confluent water supply system.Taking into account the needs of practical applications,the dynamic mathematical model of the system is established using the mechanism method,and the process mechanism is analyzed.The hydraulic model of the system is established based on the transient flow theory of the pressure pipe,combined with complex boundary conditions,the numerical solution method of the system pressure and flow is analyzed.The above analysis process provides a theoretical basis for the subsequent research on the key technologies of multi-channel confluent water supply.(2)Research on the dynamic characteristics of the confluent water supply system.Firstly,an experimental research platform for the multi-channel confluent water supply system is built based on the similarity theory;the simulation research platform of the multi-channel confluent water supply system is established based on the one-dimensional simulation software AMESim.Secondly,combined with the experiment and simulation research platform,the influence of main operating parameters on the output pressure and flow rate of the confluent water supply system under normal working conditions is studied;with the main pipe pressure drop and pressure rise as performance indicators,the influence of working parameters on the output stability of the confluent water supply system under switching conditions is studied.Finally,the influence law of the main operating parameters on the output characteristics of the confluent water supply system under different working conditions is obtained.(3)Carry out research on smooth switching control of confluent water supply system.In order to achieve the system control goal,combined with the dynamic characteristics of multi-channel confluent water supply,the pressure control of multi-channel confluent water supply is explored.A compound control strategy based on variable universe fuzzy PID is proposed.A co-simulation platform is established using AMESim and Lab VIEW,and a variable universe fuzzy PID controller based on fuzzy inference type expansion factor is designed.The comparison with the simulation results of traditional PID and fuzzy PID shows that the designed controller has shorter response time,better tracking performance and stronger anti-interference ability.Based on the experimental research platform,a smooth switching control system is developed,and performance experiments are carried out.The experimental results significantly reduced the pressure fluctuations caused by switching and verified the effectiveness of the control strategy.(4)To carry out numerical analysis and optimization research on the structure of the confluent water supply system.In order to improve the water supply efficiency of the multi-channel confluent structure,a numerical simulation model of the confluent water supply system structure is established based on the completely unstructured grid finite volume method.Based on the above model,the hydraulic characteristics of the multi-channel confluent water supply system are analyzed in detail by two performance indicators of pressure loss and pressure drop.The influence of the diameter of the clustered pipe,the diameter of the main pipe,the distance between channel pipes and the number of parallel pipes on the hydraulic performance of the confluent water supply system is revealed,and the influence mechanism is explained in combination with the flow field distribution.These provide a reference for the design and optimization of the multi-channel confluent structure.Finally,on the basis of the above research,the prototype trial production and performance test of the multi-channel confluent water supply system are completed.The test results show that the prototype of the multi-channel confluent water supply system can meet the continuous and stable water supply demand,and verify the feasibility of the key technologies research method.There are 88 figures,23 tables and 199 references in the dissertation.