| Summary: | 碩士 === 中華大學 === 機械工程學系碩士班 === 97 === The accumulator (MS-28700-7, MIL-H-5606F) and the hydraulic oil
(Hougto Safe1120) were discussed in the present study. The Nitrogen gas was
pre-filled into the accumulator with a piston ring to separate the liquid and the
gas. The tests were proceeded for different liquid pressure values in the
accumulator, then released the liquid for different orifice diameters and choke by
the solenoid valve. The relationship between the pressure and the volume with
time was obtained.
The relationship between the pressure and the volume will be used to the
UAV catapult system to be the reference of the basic setting condition. From
the result, the pressure of the Nitrogen gas in the accumulator will affect the
volume of filling liquid. The higher pressure of Nitrogen gas will lead the
lower volume of filling liquid, and the few liquid output will influence the
pressure drop obviously. On the contrary, the lower pressure of Nitrogen gas
will lead the higher volume of filling liquid.
The flow rate was influenced by orifice diameters and choke, especially for
the accurate displacement about the volume change. And the accuracy will be
increased by the real experiment with the deduction of error, and the
surrounding effects (temperature and interface friction) should be considered.
From the theoretical and the experimental results, the approximate equation on
pressure and volume was obtained by curve fitting method. Therefore, the
torque, the flow rate and the rotational speed of the liquid pressure motor can be
determined. The flow rate and the pressure were influenced by the orifice
diameters and choke obviously. When the length of the choke is longer, the
pressure drop is increased.
The pressure of the filling liquid (3000psi) in the accumulator was 10 times
than the pre-filled pressure of Nitrogen gas (300psi). By means of the results
we may derive the equation for the relationship between the pressure and the
volume by the curve-fitted method.
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