i want to make a simulation of piston pump with drain valve and inlet valve .i use the event to define the control the valve's motion.when i define the pressure-inlet and pressure-outlet,the Residual curve of continuity keep 1. i change the pressure-inlet and preeesure-outlet to wall,and initial the flow field by 0.6MPa,but the contours of pressure display 0. why?

Sorry, but I will have question What do you use to define the valve motion? It is not clear for me. I have to define a movement, and maybe it can be useful for me. Thanks.

by UDF to define the valve motion