Pressure Amplification Coefficient of the “Nozzle-Flap” Transducer

The principle of operation of automatic control system of hydraulic actuator based on hydraulic measuring transducer of angular velocity of a “nozzle-flap” type is considered. The aim of the research was mathematical modelling of the influence of geometrical parameters of the measuring converter on its pressure intensification coefficient in the MathCAD program. The research methodology included a theoretical substantiation of the proposed expressions describing the transducer, as well as an analysis of numerical results obtained by numerical simulation in the MathCAD program. Numerical researches of the known pressure intensification coefficient in the interval of diameter changes of nozzle and constant choke of 0.5…1.5 mm at a pressure in the system of 0.5…2.0 MPa showed the presence of extreme character of pressure intensification coefficient changing depending on a flap stroke from the nozzle end. An adequate linear dependence for the pressure intensification coefficient was observed in the section of the flap stroke up to (0.5 h). The highest value of the coefficient of amplification corresponded to a flap stroke of (1 h). An active growth of the area under the pressure intensification coefficient graph occured up to (1.7 h). It should be kept in mind, that when the flap stroke increases more than 0.25 of nozzle orifice diameter, the annular gap no longer functions as an adjustable hydraulic resistance. Thus, for nozzle and constant choke orifice diameters (0.0011; 0.0010 m) the recommended initial clearance is 0.5 h or, based on the purpose of the measuring transducer, can be increased to a value of 1.7 h/2.