flowcontrolvalve-states

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flowcontrolvalve-states

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Iconic Diagrams\Hydraulics\Valves\Basic Valves

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Hydraulics).

Description

FlowControlValve-States

This model describes a flow control valve with with lumped volumes.

FlowControlValve

In this model the flow is modeled by an tanh function. The pressure drop is defined as the pressure where 95% of the desired flow rate is achieved.

 

dp = pa.p - pb.p

phi = if dp > 0 then

 phi*arctanh( (arctan(0.95)/p_drop) * dp) + GLeak * dp;

else

 GLeak * dp

end;

 

Here phi is the desired flow and p_drop is the 95% pressure drop. Gleak is the conductance of laminar leakage flow when the valve is closed. The pressure at both ports has a lower limit that is equal to the vapour pressure. Therefore the actual equations used in this model are:

 

p1_lim = if pa.p < p_vapour then p_vapour else pa.p end;

p2_lim = if pb.p < p_vapour then p_vapour else pb.p end;

dp = p1_lim - p2_lim;

Interface

Ports

Description

pa, pb

Both terminals of the hydraulic component.

Causality

 

fixed volume flow out pa

fixed volume flow out pb

 

Parameters

 

FlowControlValve\phi

FlowControlValve\p_drop

FlowControlValve\GLeak

Va\V

Va\B

Va\p_initial

Vb\V

Vb\B

Vb\p_initial

Desired flow [m3/s]

pressure drop at 95% flow [Pa]

Conductance of the laminar leakage flow [m3/s.Pa], GLeak >= 0!

Volume of oil under pressure [m3]

Effective bulk modulus [Pa]

The starting pressure of the volume [Pa]

Volume of oil under pressure [m3]

Effective bulk modulus [Pa]

The starting pressure of the volume [Pa]