The 1000 L/min large flow hydraulic system for the hydraulic
support used in a coal mine is a hot
topic at present. The large flow directional valve is one of
the key components for the hydraulic system,
so design of the 1000 L/min large flow directional valve is
very essential. The designed single-channel
valve shows serious hysteresis characteristics in 1000 L/min
large flow condition, but it does not happen
in 16 L/min small flow condition. Based on this phenomenon,
the CFD technology was used to simulate
the flow in the valve. It was discovered that the
single-channel caused unbalanced pressure in the annular
region and on the surface of the valve spool, so the valve
spool is subjected to great radial unbalanced
force. Then a double-channel valve was designed to improve
the pressure distribution. The simulated
radial unbalanced force on the double-channel valve is 67.2%
lower than that of the single-channel
valve. The experimental results showed that the hysteresis
characteristics also disappeared under 1000
L/min large flow condition. So conclusions can be drawn that
the hysteresis characteristics of the singlechannel
valve is due to the radial unbalanced force caused by the
unsymmetrical flow field. Results show
that the maximum radial unbalanced force the valve spool can
withstand is 170 N. What’s more,
symmetrical flow passages have to be taken into account in
large flow conditions. The paper provides
valuable references for the design of large flow valves.
Website: http://www.arjonline.org/engineering/american-research-journal-of-mechanical-and-automation-engineering/
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