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*FLUID EXCHANGE PROPERTY
Define the fluid exchange property for flow in or out of a fluid cavity.

This option is used to define the fluid exchange property for flow between two fluid cavities or between a fluid cavity and its environment.

Products: Abaqus/Standard  Abaqus/Explicit  Abaqus/CAE  

Type: Model data

Level: Model  

Abaqus/CAE: Interaction module

References:

Required parameters:

NAME

Set this parameter equal to a label that will be used to refer to the fluid exchange property.

TYPE

Set TYPE=BULK VISCOSITY to define fluid exchange where the mass flow rate is related to the pressure difference by both viscous and hydrodynamic resistance coefficients.

Set TYPE=ENERGY FLUX to define fluid exchange by specifying the heat energy flow rate leakage explicitly. This parameter value applies only to Abaqus/Explicit analyses.

Set TYPE=ENERGY RATE LEAKAGE to define fluid exchange by specifying the heat energy flow rate as a function of temperature difference and pressure. This parameter value applies only to Abaqus/Explicit analyses.

Set TYPE=FABRIC LEAKAGE to define fluid exchange due to fabric leakage.

Set TYPE=MASS FLUX to define fluid exchange by specifying the mass flow rate leakage explicitly.

Set TYPE=MASS RATE LEAKAGE to define fluid exchange by specifying the mass flow rate as a function of pressure difference and temperature.

Set TYPE=ORIFICE to define fluid exchange through a vent orifice. This parameter value applies only to Abaqus/Explicit analyses.

Set TYPE=VOLUME FLUX to define fluid exchange by specifying the volume rate leakage explicitly.

Set TYPE=VOLUME RATE LEAKAGE to define fluid exchange by specifying the volume rate leakage as a function of pressure difference and temperature.

Set TYPE=USER to indicate that user subroutine VUFLUIDEXCH is used in Abaqus/Explicit to define fluid exchange by specifying the mass flow rate and/or heat energy flow rate.

Optional parameters:

CONSTANTS

This parameter applies only to Abaqus/Explicit analyses.

Set this parameter equal to the number of constant values needed as data to define the fluid exchange in user subroutine VUFLUIDEXCH. The default is CONSTANTS=0.

DEPENDENCIES

Set this parameter equal to the number of field variables included in the specification of the coefficients defined by the TYPE parameter. If this parameter is omitted, the coefficients are assumed not to depend on any field variables.

DEPVAR

This parameter applies only to Abaqus/Explicit analyses.

Set this parameter equal to the number of solution-dependent state variables required for user subroutine VUFLUIDEXCH. The default is DEPVAR=0.

Data lines for TYPE=BULK VISCOSITY: 

First line:

  1. Viscous resistance coefficient.

  2. Hydrodynamic resistance coefficient.

  3. Average absolute pressure, if pressure dependent.

  4. Average temperature, if temperature dependent.

  5. First field variable.

  6. Second field variable.

  7. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four):

  1. Fifth field variable.

  2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to specify the viscous and hydrodynamic resistance coefficients as functions of average absolute pressure, average temperature, and other predefined field variables.

Data line for TYPE=ENERGY FLUX: 

First (and only) line:

  1. Heat energy flow rate per unit area.

Data lines for TYPE=ENERGY RATE LEAKAGE: 

First line:

  1. Absolute value of the heat energy flow rate per unit area. (The first tabular value entered must always be zero.)

  2. Temperature difference. (The first tabular value entered must always be zero.)

  3. Average absolute pressure, if pressure dependent.

  4. Average temperature, if temperature dependent.

  5. First field variable.

  6. Second field variable.

  7. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four):

  1. Fifth field variable.

  2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the heat energy flow rate as a function of temperature difference, average absolute pressure, average temperature, and other predefined field variables.

Data lines for TYPE=FABRIC LEAKAGE or TYPE=ORIFICE: 

First line:

  1. Discharge coefficient that is used to modify the exhaust or leakage surface area. The default value is 1.

  2. Absolute pressure, if pressure dependent.

  3. Temperature, if temperature dependent.

  4. First field variable.

  5. Second field variable.

  6. Etc., up to five field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five):

  1. Sixth field variable.

  2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the discharge coefficient as a function of pressure, temperature, and other predefined field variables.

Data line for TYPE=MASS FLUX: 

First (and only) line:

  1. Mass flow rate per unit area.

Data lines for TYPE=MASS RATE LEAKAGE: 

First line:

  1. Absolute value of the mass flow rate per unit area. (The first tabular value entered must always be zero.)

  2. Absolute value of the pressure difference. (The first tabular value entered must always be zero.)

  3. Average absolute pressure, if pressure dependent.

  4. Average temperature, if temperature dependent.

  5. First field variable.

  6. Second field variable.

  7. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four):

  1. Fifth field variable.

  2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to specify the mass flow rate as a function of pressure difference, average absolute pressure, average temperature, and other predefined field variables.

Data line for TYPE=VOLUME FLUX: 

First (and only) line:

  1. Volumetric flow rate per unit area.

Data lines for TYPE=VOLUME RATE LEAKAGE: 

First line:

  1. Absolute value of the volumetric flow rate per unit area. (The first tabular value entered must always be zero.)

  2. Absolute value of the pressure difference. (The first tabular value entered must always be zero.)

  3. Average absolute pressure, if pressure dependent.

  4. Average temperature, if temperature dependent.

  5. First field variable.

  6. Second field variable.

  7. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four):

  1. Fifth field variable.

  2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the volume rate leakage as a function of pressure difference, average absolute pressure, average temperature, and other predefined field variables.

Data lines for TYPE=USER: 

First line:

  1. Enter the values of the fluid exchange constants, eight per line.

Repeat this data line as often as necessary to define all fluid exchange constants.