[Numerical simulation of dynamic characteristic of exhalation valve plate in pressure oxygen mask].

ABSTRACT

Objective. To find out the reason of "dithering" of exhalation valve plate in pressure oxygen mask under high overpressure condition. Method. Dynamic model of the exhalation valve plate in pressure oxygen mask was established. Aerodynamic force on the plate was determined by flowfield computing. The dynamic characteristic of the exhalation valve plate was analyzed by experimental measurement [correction of measurment] integrated with numerical simulation. Result. The movement of valve plate could be simulated with the method proposed, and the course of the"dithering" was found out. Conclusion. The "dithering" of the valve plate can be averted by cutting down the area of the film or increasing the diameter of the valve pedestal moderately.