This link extends GunnsFluidConductor with several additional functions:

• It scales its effective conductivity with a given valve position (0-1). See a further description of this position term below.
• It adds a leak-thru malfunction for leaking through a closed valve.
• It models convective heat flux between the valve/pipe walls and the fluid passing through it.

The link does not modify the mixture of the fluid passing through it.

The GunnsFluidValve can be hooked up to nodes in exactly the same ways that regular fluid conductors can.

Port Connection Rules (These are limitations on the port connection to nodes that the link enforces in run-time):

• Ports 0 and 1 cannot connect to the same non-Ground node.

Other Rules (These are extra rules you should always try to follow):

• Same as GunnsFluidConductor.

Configuration Data Parameters:

• maxConductivity: Same as GunnsFluidConductor.
• expansionScaleFactor: Same as GunnsFluidConductor.
• The following 3 parameters govern the convection heat transfer between the valve/tube wall and the fluid passing through it. This effect is optional - leaving thermalLength or thermalDiameter = 0 turns this effect off.
  • thermalLength (default = 0.0 (m), must be >= 0): This is the length of an equivalent circular cross-section pipe for the heat convection effect. The longer this length, the more heat will exchange between the wall and the fluid, and the more the fluid exit temperature will approach the wall temperature.
  • thermalDiameter (default = 0.0 (m), must be >= 0): This is the diameter of an equivalent circular cross-section pipe for the heat convection effect. Heat exchange increases with decreasing diameter.
  • surfaceRoughness (default = 0.0 (m), must be >= 0): This is the average surface roughness height of the inner surface of an an equivalent circular cross-section pipe for the heat convection effect. Heat exchange increases with increasing roughness. Note that a roughness of zero does not cause zero convective heat flux. Roughness values are documented for materials used in the construction of systems we typically simulate with GUNNS. Roughness is typically many orders of magnitude smaller than the tube diameter. Machined steel has a roughness typically on the order of 1E-6 m, for instance.

Input Data Parameters:

• malfBlockageFlag (default = false): Initial state of the blockage malfunction activation flag. This malfunction reduces the effective conductivity from the maxConductivity value.
• malfBlockageValue (default = 0.0, must be (0-1)): Initial state of the blockage malfunction value. A value of 0.0 is the same as no blockage at all, and 1.0 completely blocks all flow and isolates the port nodes from each other (although parallel flow paths still apply).
• position (default = 0.0, must be (0-1)): Initial valve position.
  • A value of 1.0 is fully open (effective conductivity = maxConductivity), and a value of 0.0 is fully closed (effective conductivity = 0).
  • This link does not change its own valve position, and it must be updated from outside, like from a valve controller aspect via the sim bus, etc.
  • Note that flow rate through fluid conductors, and hence valves, is linearly proportional to the effective conductivity, effective conductivity is linearly proportional to this valve position, and therefore flow rate is linear with valve position. This valve position is effectively the fraction of max cross-sectional area open to the flow. Depending on the physical valve type, this position is not the same thing as the angular position of the valve handle, etc. Any needed conversion between the physical position of a piece of valve hardware and this fluid position term must be done outside this link object, such as in a valve controller model.
• malfLeakThruFlag (default = false): Initial state of the leak-thru malfunction activation flag.
• malfLeakThruValue (default = 0.0 (kg/s), must be >= 0): The initial flow rate of the leak-thru malfunction.
• wallTemperature (default = 0.0 (K), must be >= 0): The initial tube wall temperature for heat convection calculations.

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