锥形阀作为一种性能优异的灰控阀，其调节性能对外置换热床的稳定运行十分重要。目前有关锥形阀流量特性的研究尚处于起步阶段，工业上设计和使用锥形阀大都通过经验选取，缺乏可靠理论依据。为此,设计并搭建了带锥形阀的小型流化床实验台，开展不同锥形阀开度x、流化风速u、初始床料高度h、阀体标称尺寸D对应工况实验，以探究开度、流化风速等因素对锥形阀流量特性的影响。为保证实验过程中床层高度及床压的稳定，对给料机流量与频率关系进行标定，从而可通过调节给料机流量使得其与阀流量保持动态平衡关系。在实验前通过马尔文粒度分析等，测得了实验颗粒的尺寸分布、堆积密度、真实密度等物理性质。实验结果表明,锥形阀开度x与阀流量之间基本呈线性关系，这与流通面积与开度之间呈现的近似线性关系相匹配，此外在实验中存在满开度使得流量达到饱和流量，进一步增大开度流量保持不变。对阀内颗粒流动进行了分析，认为锥形阀本质上属于孔口流动系统，进一步发现锥形阀流量由进料流量和出料流量决定，给出了饱和流量点出现的理论解释并分析各因素对进料和出料流量的影响。实验中发现流化风速u对阀流量影响较小,流化风速从2.5umf增加到5umf，流量仅增大2%左右，同时发现床压基本不随流化风速变化。初始床料高度h的增加主要影响床压，进而对锥形阀流量造成影响，随着h的增大，饱和流量Gm及对应的满开度xm也有小幅度增加，同时Gm的增加幅度大于xm。不同标称尺寸下，锥形阀的流量变化规律相似，饱和流量与阀体标称尺寸s之间大致呈现出2.1次方关系，满开度与阀体尺寸之间近似呈线性关系，结果可用于工业过程中锥形阀的设计与运行控制。

The cone valve is a kind of excellent ash-control valve,whose regulation performance is of great importance to the stable operation of external heat exchanger.At present,the research on the flow characteristics of cone valves is still in its infancy stage.Most industrial designs and ultilization of cone valve are based on experience,lack of reliable theoretical basis.A small fluidized bed experimental bench was designed and built to understand the relationship between the flow rate and the valve opening x,flow rate u,initial height of bed material h and nominal valve size D.To keep the stability of bed inventory and bed pressure,the realtionship of feeder flow and frequency is calibrated,the feeder frequency is adjusted to keep the dynamic equilibrium of feeder flow and valve flow.The particle distribution,bulk density and true density is obtained with measurement.The experiment result shows that with the increase of valve opening,the flow rate increases linearly to the saturation point and then maintains constant,which matches well with previous study and the linearly relationship between the valve flow area and valve opening.The inner particle flow of cone valve is analysed to give an explanation to the saturation point.The cone valve is considered as orifice system,and it is found that the flow rate is determined by valve feeding flow and processing flow.The fluidized velocity has little influence on the flow rate comparing to other influence factors,the flow rate increases about 2% when fluizied velocity increases from 2.5 u mf to 5 u mf,and the bed pressure does not change with the fluidized velocity.The initial height of bed material has a positive effect on the bed pressure,the saturation flow and full openning have a slight increase with the increase of the initial height of bed material.The relationship between saturation flow and nominal valve size presents a power of 2.1 and the discharge variation of valve flow is similar under different nominal valve sizes,the experimental results could be used in the industrial design and operation of cone valve.

1 孔口流动系统

2 实验系统  

3.2 阀流量随流化风速u变化关系

3.3 阀流量随床层高度h变化关系

3.4 阀流量随阀体标称尺寸D变化关系

4 结论