Dynamical Characteristics Experiments For Continuous Control Valve And Smart Hydraulic Control Methods

Continuous control valves are important flow and energy regulation components for hydraulic balance and local hydraulic parameters control in HVAC system,which has important significances to implement the HVAC system functions and save the running energy consumption.There exist two core problems waiting to be solved in running,one is the lack of quantitative and full descriptions for the valve dynamic resistence characteristics,and another is no dynamic control model for relationship between valve stroke and controlled parameters.The first problem is the essential to cause others,such as valve selection,valve stroke control.The second problem leads to inaccurate valve stroke and repeated actions that make system running not very well,low smart to compensate the perturbation motion,accelerating the valve aging and so on.So it is necessary and important to make research to the problems.However,the current research did not focus on the control valve dynamic characteristics and not effectively solve the problems.It is difficult to calculate the control valve dynamic characteristics with the current theories because of many relative factors,such as valve material,structure,stroke etc.So the paper is organized by making experiments research for valve dynamic characteristics firstly,and analyzing and proposing the valve control strategy and methods from the theories based on experiments data,finally proving the methods and conclusions by experiments.Firstly,the principle of control valve dynamical regulation characteristics experiments system was analysed based on the mathematical model of hydraulic characteristics of fluid network.The design of experiments system and equipment and instruments selection were completed in accordance with the experiments system design methods and the monitor and control system of experiments system was designed and developed independently.The building and debugging work of experiments work were finished,which provides expreimental platforms for follow-up research.Then,the expreimental conditions research of controlvalve dynamical characteristics were made and experiments processed on the experiments system.The experiments data get by the three conditions,equal valve flow,equal valve pressure drop and equal valve stroke,which make up a three-dimensional surface by the valve running status various,the valve flow,valve pressure drop and valve stroke.The valve opening admittance function(discribing the relationship between valve stroke and valve admittance,valve admittance is the reciprocal of valve impedance)structure and parameters get with least squares method and the valve hydraulic characteristics status equation(VHCSE)is developed,which described the connections of valve flow,valve pressure drop,valve stroke.The comparison analyses between control valve characteristics curves and valve opening admittance function show the later quantitatively expresses the valve characteristics for the fully stroke by static parameter ? and dynamic parameter n,and have no harsh restrictions as the former.The valve opening admittance function for unknown characteristics control valve can be got by the field calibration method of control valve dynamic characteristics.A new intellengent control valve was designed according to the VHCSE and control demands.There are two types of control valves tasks,the control for the various target parameters and the compensation for the perturbation motion from the pipe network.The new control algorithm in intelligent valves based on VHCSE can accurately control the valve stroke by monitoring the status various and identifying the pump head lift and impedance of pipe network.The compensation control can keep the hydraulic parameters steady and accurate by dynamic valve stroke compensation.The conclusions have been proved by experiments.The new intelligent control valves obey the valve intelligent judgements characteristics that include the autonomous perception,autonomous calculation,autonomous control,autonomous adjusting and autonomous communication,which have the abilities for smart control.The core development works of new intelligent control valve have been done,including the intelligent valve standard information model,smart control algorithm and network monitoring communication.