MapleSim Hydraulics Library from Modelon
Poppet Lift Conical Sharp Edge Conical poppet lift with sharp edge seat
This is a template model for a conical poppet lift with sharp edge seat.

Flow Area


When the poppet is far from the seat, the flowarea between the two chambers is limited by the area between the seatside rod and the seat.
As the poppet moves nearer, the flowarea is limited by the seat and the poppet.
The flow area, , is the area (excluding top and bottom area) of the truncated cone with base radius , top radius , and slant height , as seen in the picture.
where is the distance from the seat to the poppet center and is the seat radius.


Chamber Volumes


The chamber volumes (poppet side) and (seat side) are calculated using the following quantities:
The initial volume (when the poppet lift is closed) on both poppet side (V01) and seat side (V02) are known.
The seatside volume is
where
cone 1 has base radius and top radius
cone 2 has base radius and top radius
cone 3 has base radius and top radius
and is the distance the poppet has been lifted from its initial position.
The poppetside volume, , is calculated from .


Implementation


This model calculates the volumes on both sides of the poppet lift, the mass flow between the two sides and the force . Pressure is calculated in volume components connected to connector and .


Variables


Name

Value

Units

Description

Modelica ID




Relative position of flange_a wrt support_a

s_rel_a




Relative position of flange_b wrt flange_a

s_rel_ab




Force acting in positive direction of flange_a

f




Flow coefficient

lambda




Absolute value of volume flowrate

qunsigned




Volume flowrate in l/min

qLmin




Distance from poppet center/poppet to seat

X




Poppet lift

lift




Static flow forces

fflow




Defines direction of flow forces

cosalpha




Effective orifice area

flowarea




Orifice area (no saturation)

flowarea_nom




Hydraulic diameter

D




Volume, poppet side

V1




Volume, seat side

V2




Temperature

T




Pressure difference over the valve

dp




Pressure, poppet side

p1




Pressure, seat side

p2




Fluid density in the chamber

rho




Fluid viscosity in the chamber

nu


[1]


Gas saturation pressure

p_sat




Absolute pressure, used for all property calls

p1_abs




Absolute pressure, used for all property calls

p2_abs





Xmax




Cone 1 used for calculating chamber volumes

VTruncCone1




Cone 2 used for calculating chamber volumes

VTruncCone2




Cone 3 used for calculating chamber volumes

VTruncCone3



[1]


Connections


Name

Description

Modelica ID



supportA



supportB



flangeA



flangeB

oil

Fluid property model

oil



portA



portA1





Parameters



General Parameters


Name

Default

Units

Description

Modelica ID




Element length

L

reverse



Reverse the sign convention, see documentation for details

reverse




Poppet radius

R


[1]


Conical seat/poppet angle

theta




Throat radius

r




Rod radius, poppet side

Rrod_1




Rod radius, seat side

Rrod_2




Poppet lift in neutral position

lift_0




Piston length

l_piston


[2]


Volume, poppet side, when closed valve

V01


[2]


Volume, seat side, when closed valve

V02




minimum distance between poppet center and seat in basic case, otherwise set as 0

Xmin

transition type



Type of transition

TransitionType




Laminar part of flow model

k1




Turbulent part of flow model

k2




Discharge coefficient

Cdmax




Critical flow number

lambdac





XmaxStart





XmaxNominal




Temperature offset from system temperature

dT_system



[1]
[2]


Constant Parameters


Name

Default

Units

Description

Modelica ID


[1]


Maximum flow area

flowareamax


[2]


Rod area, poppet side

Arod_1


[3]


Rod area, seat side

Arod_2




distance from seat to poppet center

X_0



[1] 2_
[2]
[3]


