Card 9 - VOID_REGION Thermal Void Region Definition

This optional card specifies the parameters and options for defining a void region that creates a thermal coupling between a group of selected elements and a void non-geometric element.

Parameters: KODE, N1, T1, T2, T3

KODE

KODE is the code VOID_REGION (or 91)

N1

N1 is the VOID_REGION card ID, which is the uid in the solver XML file. Cards with the same ID reference the same void region.

T1 = HTC

T1 = HTC (or 4) specifies a heat transfer coefficient connecting the void region selection with the associated void non-geometric element.

  • If the heat transfer coefficient is constant, then its value is specified in T2.
  • If the heat transfer coefficient is table dependent, then T2 is a table multiplier and T3 has the form Tn (e.g., T25) where n is a table number referencing the TABTYPE or FIELDTYPE cards. The dependent variable on the TABTYPE card must be COND.
  • If the heat transfer coefficient is calculated using an expression, then T2 is an expression multiplier and T3 has the form En (e.g., E25) where n is an expression number referencing the EXPRESSION card.

T1 = FACTOR

T1 = FACTOR (or 8) specifies an area correction factor. This input corrects the convective area.

  • If the area correction factor is constant, then its value is specified in T2.
  • If the area correction factor is table dependent, then T2 is a table multiplier and T3 has the form Tn (e.g., T25) where n is a table number referencing the TABTYPE and FIELDTYPE cards. The dependent variable on the TABTYPE card must be NUMBER.
  • If the area correction factor is calculated using an expression, then T2 is an expression multiplier and T3 has the form En (e.g., E25) where n is an expression number referencing the EXPRESSION card.

T1 = NAME

T1 = NAME (or 6) specifies the region name in T2.

T1 = OVERRIDE

T1 = OVERRIDE (or 9) specifies an area override. This input overrides the convective area.

  • If the area override is constant, then its value is specified in T2.
  • If the area override is table dependent, then T2 is a table multiplier and T3 has the form Tn (e.g., T25) where n is a table number referencing the TABTYPE and FIELDTYPE cards. The dependent variable on the TABTYPE card must be NUMBER.
  • If the area override is calculated using an expression, then T2 is an expression multiplier and T3 has the form En (e.g., E25) where n is an expression number referencing the EXPRESSION card.

T1 = PRESSURE

T1 = PRESSURE (or 3) specifies a pressure for the void region.

  • If the pressure is constant, then its value is specified in T2.
  • If the pressure is table dependent, then T2 is a table multiplier and T3 has the form Tn (e.g., T25) where n is a table number referencing the TABTYPE or FIELDTYPE cards. The dependent variable on the TABTYPE card must be PTOTAL.
  • If the pressure is calculated using an expression, then T2 is an expression multiplier and T3 has the form En (e.g., E25) where n is an expression number referencing the EXPRESSION card.

T1 = ROT_FX

T1 = ROT_FX (or 5) specifies that the void region temperatures are corrected for rotational effects. The ID of the referenced ROT_FX cards is specified in T2.

T1 = SELECTION

T1 = SELECTION (or 1) specifies that the void region is made up of a selection of elements that are represented by the group name T2.

T1 = THICK

T1 = THICK (or 7) specifies the area for internal edges. This input is used to compute the convective area when the void region is applied to internal edges.

If thicknesses are subtracted, then T2 = SUB.

If thicknesses are added, then T2 = ADD.

T1 = VOID_ELEM

T1 = VOID_ELEM (or 2) specifies that the void region selection is coupled to a void non-geometric element represented by the VOID_NONGEOM cards. The ID of the referenced VOID_NONGEOM cards is specified in T2.

Code example

$ ------------------
$ Thermal Void Loads
$ ------------------
$
VOID_NONGEOM 3 MAT 2
VOID_NONGEOM 3 HEAT_LOAD  1.000000E+01
VOID_NONGEOM 1 CAP_METHOD SPECIFY_CAP
VOID_NONGEOM 3 VOLUME  0.000000E+00
VOID_NONGEOM 3 CAPACITANCE  0.000000E+00
VOID_NONGEOM 3 REGION 1 101
VOID_NONGEOM 3 REGION 2 202
$
$ ------------
$ Void Regions
$ ------------
$
$ Thermal Void(1)                                                              
NAME2 Thermal Thermal Void(1)
NAME Thermal        801       1200       1 
$
$ Void Region1
VOID_REGION 101 SELECTION Thermal
VOID_REGION 101 PRESSURE  1.013250E+05
VOID_REGION 101 HTC  5.000000E+04
VOID_REGION 101 ROT_FX 1
ROT_FX 1 ROT_FXS NEGLECT_ROT
ROT_FX 1 SWIRL DEL_TEMP
ROT_FX 1 SWIRL_DEL_TEMP  0.000000E+00
$ Void Region2                                                              
NAME2 Therma_ Thermal Void(2)
NAME Therma_       1201       1600          1
VOID_REGION 202 SELECTION Therma_
VOID_REGION 202 PRESSURE  1.013250E+05
VOID_REGION 202 HTC  1.000000E+05
VOID_REGION 202 ROT_FX 2
ROT_FX 2 ROT_FXS NEGLECT_ROT
ROT_FX 2 SWIRL DEL_TEMP
ROT_FX 2 SWIRL_DEL_TEMP  0.000000E+00

Notes

This option supports the INPF format for pre-NX11 voids, and is described in more detail in the T1 = VOID_ELEM description. It will still be supported, but if this line is present, then no REGION cards may exist in the corresponding VOID_NONGEOM cards, and none of the references to void expression functions may reference regions.