Experimental Research Of Balancing Device Regulation Characteristics

With the expansion of the HVAC system and the application and development of variable flow system,The hydraulic imbalance has been brought some serious problems such as the comfort and energy consumption.Balancing device of the water system in HVAC as a important hydraulic balance regulating device,has attracted more and more attention from the industry.Because of the difference of the structure and working characteristics of balancing device,this paper not only analyses the flow characteristic of regulating valve and the characteristic parameters such as valve power degree,flow coefficient,etc,but also lay a theoretical foundation for the research of balancing device.Then from the structure and working principle of the dynamic and static balance valve,the paper makes a contrast analysis of the three kinds of balancing device in the multidrop parallel loop control characteristic,and according to the characteristics of air conditioning terminal devices,the control valve at the end of the balancing device was analyzed,and choose the best way to match.But in order to better understand the regulation of balance device features,through constructing test bench,this paper respectively tested:1.The opening of a static balancing valve and the relationship between flow rate and pressure difference,analysis the characteristics of flow,resistance and air-pocket,and concluded that:(1)the flow characteristic of static balancing valve approximate linear.(2)the flow coefficient is related to the opening and Reynolds number,when the Reynolds number is greater than3′10~4,the flow coefficient is constant;And the drag coefficient is straight-through type globe valve resistance coefficient of about 1.61～1.97 times,and it is much more than general stop valve,so replace applications need to consider its produce resistance loss;Air-pocket index decreases with the decrease of the opening,the valve is not better to work in the opening of 40%.2.Dynamic flow balance valve opening and the flow and the relationship between the pressure difference,and analyze the job characteristics in the experiment,it is concluded that the test valve characteristic curve change trend of first increases,when the lateral pressure difference is greater than 30k Pa started the change is slow,and traffic and the opening basic linear relation.3.Dynamic differential pressure balance valve and the changes of pressure difference and flow rate and analyze its operating characteristics in the experiment,it is concluded that the test valve characteristic curve along with the increase of flow rate of the whole is on the decline,and the lateral pressure difference in the flow of about 3.5-11.5m~3/hrange trend change slowly.