The nonlinear characteristics of pneumatic butterfly valve are very prominent
The nonlinearity of pneumatic butterfly valve is very obvious. Without considering the nonlinearity of pneumatic butterfly valve data, the radius of the two throttling orifices is expanded to be the same as the vertical diameter of the additional air chamber. That is, the influence of throttling orifices is eliminated. The method of phase plane diagram is used to study the nonlinearity of pneumatic butterfly valve. The initial displacement value is always at the flat street position, and the initial velocity value is from 0 to 0.12 π m/s, The phase trajectory curve family of the vibration equation is drawn according to the drawing method of the phase plan, as shown in Figure 2. It can be seen that the initial value xo=0. Vo=0) is the singular point of the phase trajectory. At this time, it is the static equilibrium point of the vibration system: the phase trajectory corresponding to each group of initial values is a locking ring. Therefore, the free vibration of the ball valve is periodic: with the increase of the initial speed, The phase trajectory loop gradually changes from the approximate i four shape to the egg shape. It indicates that the vibration of the system is close to linear vibration when the initial kinetic energy of the system is small. The nonlinearity of the vibration is very significant when the initial kinetic energy is large