预启式调节阀振动的试验研究

Experimental study on vibration of pilot-cage type control valve

预启式调节阀是一类新型的过程控制调节阀,在某些工况条件下会出现强烈振动。为了揭示其振动机理,采用微型压力传感器和三向加速度传感器,在不同的调节阀开度和压差工况下,分别测量阀芯底部流体脉动压力和阀杆振动加速度响应。对脉动压力时域信号进行幅值分析,对加速度时域信号进行谱分析。试验分析表明:调节阀内流体流动的不稳定性是引起调节阀振动的主要原因。在大开度(70%～100%)及其对应的大压差(0.25～0.27 MPa)工况下,流场最不稳定,脉动压力幅值明显增大,阀杆振动较大。需要进一步研究调节阀结构参数变化对振动的影响。

Pilot-cage type control valve produces intensive vibration under some operation conditions.In order to reveal the vibration mechanism,three micro pressure sensors and a three-direction accelerometer were used to measure the flow pulsating pressure on the bottom of the valve-core and the acceleration response of the valve-stem under the operation cases of different valve openings and pressure differences.Amplitude analysis for the time-domain signal of pulsating pressure and spectrum analysis for the time-domain signal of acceleration response were carried out respectively.Experiment results show that the pulsating pressure amplitude at the measuring point of the bottom center of the valve-core is greater than that at the measuring point of the bottom circumference;the pulsating pressure amplitude at each measuring point increases generally with the increasing of the pressure difference under different openings and with the increasing of the opening under different pressure differences.Experiment analysis indicates that the instability of the fluid flow in the valve is the main cause of valve vibration.In the case of large opening（70%～100%） and corresponding large pressure difference（0.25～0.27 MPa）,the flow field is the most unsteady,and the pulsating pressure amplitude increases obviously and the valve-stem vibration is quite great.Further study on the effect of structural parameter change on valve vibration is necessary.