The paper presents a computational study of the NPP ventilation system check valve aerodynamics, namely, a numerical simulation of the air flowing through the open valve with the subsequent determination of the relationship between the reactive torque acting on the valve closure axles and the input air velocity.This numerical simulation of the air flowing through the check valve was performed using the ANSYS CFX program. In the computation, different operating modes of the check valve were considered when the air flow was passing through it. The valve operating modes were set depending on changes in the input air velocity. As a result of aerodynamic computation, the values of pressure and velocity components were obtained over the entire valve volume.Reactive forces were calculated in the ANSYS Mechanical program. The reactive forces acting on the valve body form a torque at the gate axles. When adjusting the check valve to the actual flow rate, it is necessary to know this torque value and compensate for it. As a result of a series of computations of reactive forces, a relationship was found between the torque value of the valve’s working element axles and the input air velocity.
The inertance hydraulic converter relies on fluid inertance to modulate flow or pressure and is considered to be a competitive alternative to the conventional proportional hydraulic system due to its potential advantage in efficiency. As the quantification of fluid inertance, the suction flow characteristic is the crucial performance indicator for efficiency improvement. To explore the discrepancy between the passive inertance hydraulic converter featured by the check valve and the active inertance hydraulic converter driven by an equivalent 2/3 way fast switching valve in regard to suction flow characteristics, analytical models of the inertance hydraulic converters were established in MATLAB/Simulink. The validated models of the respective suction components were incorporated in the overall analytical models and their suction flow characteristics were theoretically and experimentally discussed. The analytical predictions and experimental measurements for the current configurations indicated that the active inertance hydraulic converter yields a larger transient suction flow rate than that of the passive inertance hydraulic converter due to the difference of the respective suction components. The suction flow characteristic can be modulated using the supply pressure and duty cycle, which was confirmed by experimental measurements. In addition, the suction flow characteristics are heavily affected by the resistance of the suction flow passage and switching frequency. There is a compromise between the resistance and switching frequency for inertance hydraulic converters to achieve large suction flow rate.
Study of functional characteristics for safety system check valve using scaled model
