Relief Valve $—$ Static model of a relief valve

The Relief Valve component describes a relief valve. The resistance depends on the pressure differential, $\mathrm{Δp}={p}_{A}-{p}_{B}$:

 $\mathrm{Δp}<{p}_{\mathrm{closed}}$ Leakage from high pressure port to low pressure port only. $q=\mathrm{Δp}{G}_{\mathrm{leak}}$ ${p}_{\mathrm{closed}}<\mathrm{Δp}$ $<$ ${p}_{\mathrm{open}}$ Working range. Valve is partially open. ${p}_{\mathrm{open}}<\mathrm{Δp}$ Valve is wide open. $q=\mathrm{Δp}{G}_{\mathrm{open}}$

The mass and flow forces are not included. Use the modifier(s)

VolumeA(port_A(p(start=1e5,fixed=true)))

and/or

VolumeB(port_A(p(start=1e5,fixed=true)))

to set the initial condition(s) for the pressure of the lumped volume(s) $\left[\mathrm{Pa}\right]$.

Events

There is a new boolean reduceEvents (selected by default) in the Advanced section under the Inspector tab. Selecting reduceEvents lets the model use noEvents(expr) to generate fewer events for boolean expressions that should not generate events. In some cases the solver might reduce the stepsize too much and generate a lot of steps. If this happens, try clearing reduceEvents.

Related Components

 Name Description Ideal model of a relief valve, additional information.

Connections

 Name Description Modelica ID ${\mathrm{port}}_{A}$ Layout of port where oil flows into an element ($0<{m}_{\mathrm{flow}}$, ${p}_{B}<{p}_{A}$ means $0<\mathrm{Δp}$) port_A ${\mathrm{port}}_{B}$ Hydraulic port where oil leaves the component (${m}_{\mathrm{flow}}<0$, ${p}_{B}<{p}_{A}$ means $0<\mathrm{Δp}$) port_B $\mathrm{oil}$ oil

Parameters

General Parameters

 Name Default Units Description Modelica ID ${\mathrm{ΔT}}_{\mathrm{system}}$ $0$ $K$ Temperature offset from system temperature dT_system use volume A $\mathrm{true}$ If true, a volume is present at port_A useVolumeA use volume B $\mathrm{true}$ If true, a volume is present at port_B useVolumeB ${V}_{A}$ ${10}^{-6}$ ${m}^{3}$ Geometric volume at port A volumeA ${V}_{B}$ ${10}^{-6}$ ${m}^{3}$ Geometric volume at port B volumeB ${p}_{\mathrm{closed}}$ $1.9·{10}^{7}$ $\mathrm{Pa}$ Valve closed if $\mathrm{Δp}$ smaller pclosed ${p}_{\mathrm{open}}$ $2.05·{10}^{7}$ $\mathrm{Pa}$ Valve wide open if $\mathrm{Δp}$ higher popen ${G}_{\mathrm{leak}}$ $1.11·{10}^{-12}$ $\frac{{m}^{3}}{s\mathrm{Pa}}$ Conductance of leakage of closed valve GLeak ${G}_{\mathrm{open}}$ $1.67·{10}^{-9}$ $\frac{{m}^{3}}{s\mathrm{Pa}}$ Conductance of wide open valve GOpen

 Name Default Units Description Modelica ID reduce events $\mathrm{true}$ reduceEvents