Research On Hydraulic Balance And Self-operated Flow Control Valve For Heating Pipe Network

With the continuous promotion of centralized heating,the hydraulic imbalance of the heat pipe network has gradually emerged.As a new type of hydraulic balance regulating equipment,self-operated flow control valve has been gradually popularized in the field of thermal pipe network because of the interaction between its regulating elements and variable flow surface to ensure the constant output flow of the valve.It involves fluid mechanics,structural design,dynamics,solid-flow coupling and other issues,and is a hightech product of fluid machinery.Domestic products in this field are mostly imitation,and the control accuracy of products is low.Based on the horizontal project cooperated with Huaneng Qingdao Thermal Power Co.,Ltd.,this paper studied the theoretical basis of hydraulic balance regulation and self-balancing flow valve.According to the factors affecting the hydraulic balance,a new hydraulic balance regulation method was proposed.According to the movement law of the fluid in the valve,a new self-supporting flow control valve was designed,and its CAE analysis and experimental verification were carried out.The specific research content is as follows:(1)Based on the analysis and research on the causes of hydraulic maladjustment,the methods to solve the hydraulic maladjustment have been analyzed,and adaptive adjustment methods have been proposed according to the existing adjustment methods and the basic theory of hydraulic balance adjustment.(2)The basic structure and working principle of the self-operated flow control valve were introduced in detail.On this basis,the curve equation of variable flow surface of spool and the calculation formula of regulating element spring have been established and deduced,and the geometric relationship among variable flow surface,spring and fluid parameters of spool was determined.(3)According to the above calculation results,three-dimensional modeling of each component of the self-operated flow control valve was performed.The static simulation of the valve flow field was carried out to obtain the pressure and velocity field map of the flow field.The finite element analysis of the valve core components was carried out,and the valve core structure was optimized according to the simulation results.The designed new structure spool adopts a double stroke structure,which expands the adjustment range of the self-operated flow control valve and improves the control precision.(4)The experimental platform of the flow characteristic of the self-operated flow control valve was built,and the working range and control precision of the prototype valve were analyzed.The experimental results show that the control accuracy of the output flow of the prototype valve is less than±4%,which verifies that the flow control valve meets the design requirements and meets the practical application conditions.