Design And Research On Pressure Independent Constant Air Flow Control Valve

The pressure independent constant air flow control valve can automatically adjust the flow area to adapt to the changes of the pressure differential of the valve.In the range of working pressure,the air volume through the valve can be controlled at the pre-set value.Thus,it has been widely applied in the workplaces that needs accurate control of airflow such as operating room in hospital,biology and chemistry laboratory,cleanroom and so on.At present,the domestic market of the valve is monopolized by some foreign enterprises.Because domestic manufacturers do not grasp core technology of the valve,which makes domestic valve product at a disadvantage in the market competition.In recent years,with the rapid development of HVAC industry in China,the need of market for the valve is in a constant increasing.The core technology of the valve urgently needs to be researched further.This paper proposes a designing scheme of the pressure independent constant air flow control valve,based on mechanical self-force principle,establishes 3D entity model,flow mathematical model,numerical calculation model,analyzes the distribution of flow field of the valve,corrects the parameter of the valve port curve.The main investigates of this thesis includes as follows:The pressure independent constant air flow control valve with simple structure,good flow capacity and high control precision is presented based on the flow field distribution of the valve.The valve is composed of valve body,valve element,axle of valve element,spring,regulating stem,support frame and some other mechanisms.It can respond to the changes of valve pressure differential with the help of spring to adjust the air volume by changing flow area.According to the relationship between air volume and pressure drop of the valve,it is designed and calculated,which mainly includes the design of the valve port and mechanical self-force regulating device.3D entity model of the pressure independent constant air flow control valve is established by Solidworks software,simulation calculation is made by Ansys software,the rule of the flow field distribution and flow coefficient variation of the valve are analyzed,and calculation formulas of the flow and parameter of the valve port curve are corrected in this paper.The testing device of flow distribution and performance for the valve is constructed,which can verify the simulation results and characteristics of the pressure independent constant air flow control valve by measuring the pressure distribution and air volume value under various operating modes.Also,the feasibility of design scheme of the constant air flow control valve in this paper in the design of other calibers is explored,by designing and calculating the valve with different calibers.