 Wysłany: Sob 10:55, 09 Kwi 2011 Temat postu: Modulation of low-pressure pulse jet mechanism and |
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| Modulation of low-pressure pulse jet mechanism and vibration simulation modulator
Equation J. 3.1.1 Continuous flow equation under the law of conservation of mass, of a control volume, the amount of inflow and outflow and is zero. Consider liquid compressibility and system leakage, flow continuity equation can be established, that a plant AQ + CLAp0 · (6) where, Ef is the fluid bulk modulus, Pa; CL for the leakage coefficient; Vi is i-a control chamber volume, rrl3; Ap for the orifice pressure drop, Pa. 3.1.2 Throttle modulator every equation in the calculation of the flow orifice, due to the different throttle position to be judged and calculated according to the corresponding z position of each orifice flow, flow formula is Q = C (+ o), / Ap. (7) where, c is with the throttle, the fluid properties of the coefficient, · m5; for the spool displacement, m; z0 initial position for the spool, m. Control the flow resistance of the resistance is small compared with the throttle, can be neglected. 3.1.3 spool dynamics equations of motion according to Newton's law, the dynamic equation of motion for the spool, | 2,. , |,, M + B half = ΣFi. (  dt-u £ where the quality of the spool i, kg; B with the velocity of the drag coefficient, kg · S ~; ΣFi total load for the valve, N. 3,2 Preliminary results spool vibration simulation of the modulator valve chamber and flow channel of the relevant structures, and physical and mechanical properties of drilling fluid system pressure modulator input parameters such as simulation model calculations. Modulator parameters are as follows: the system working pressure of 20MPa, the orifice discharge coefficient is 0.9, fluid bulk modulus is 2.3GPa, drilling fluid density 1020kg/m3, drilling fluid viscosity 16mPa · S . Calculated by Newtonian fluid. Through simulation, calculate the hydraulic system modulator valve chamber in the different pressure changes, and the spool in the hydraulic high-frequency motion under the action of the process and results. Figure 2 shows the main modulator valve and control valve have a resonance in the motion curve. The results showed that: ① the modulator and the orifice of the chamber and adjust the pressure to establish reasonable; ② play the role of the mainstream of opening and closing the main valve and the only change from the role of the control valve to control the movement is coordinated,scarpe nike 2011, in the system together under pressure-driven resonance, the main valve can be closed the next stop point to achieve the purpose of the mainstream; ③ the main valve closed and open time for the mainstream fluid 2 ~ 3ms, basically the moment of opening and closing; ④ spool vibration frequency of about 20Hz, only points off the main valve in the next time 10Iris mainstream, while the vibration period is about 45ms, the basic indicators of compliance requirements of low-pressure pulse jet _2J, that the structural parameters of the modulator is reasonable. Book the main valve control valve modulator in Figure 2 the main valve and control valve hydraulic simulation results 4 Conclusion resonant design of the full-size low-pressure pulse jet modulator coordination of the main valve and control valve vibration of the work is feasible, the vibration frequency of the modulator, the main valve opening and closing time and the next stop point of time off the mainstream performance indicators and other important basic compliance requirements of low-pressure pulse jet. Major low pressure pulse modulator block works is relatively simple, but the vibration performance to achieve the desired low-voltage pulse a reasonable target, must continue to improve the structural parameters of the modulator and hydraulic operating parameters. The actual work of the modulator and the model simulation performance and reliability of indicators yet to experiment. |
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