Card 6e - Thermal Coupling Request (non-NEARx)

This optional card creates conductances that are fixed or area-proportional between two sets of elements N1 and N2.

Parameters: L, N1S, N1F, N1D, N2S, N2D, HN1, KODE, EXP, P1, VX, VY, VZ

Card 6e is active only if the VUFAC module is run (Card 2a M = 2).

Only the following types of elements are recognized:

  • Card 5a SURFACE elements with emissivity ≥ 0, or flagged as NORAD with the PARAM NORAD Card.
  • 2-node hydraulic or stream elements or 1-node AMBIENT elements.

Solid elements are not recognized.

Electrical couplings may also be created. An electrical coupling is similar to a thermal coupling, except that it takes part in the electrical network calculations, and not in the thermal network calculations. An electrical coupling is a linear thermal coupling that references a table or expression (through the EXP parameter) whose dependent variable on the TABTYPE card is ELECRES. The value of the electrical coupling will be the value of the thermal coupling multiplied by the value interpolated from the table.

L

L is the code AREA (or 11)

The non-NEARx options generate conductances according to a specified numbering scheme.

N1S

N1S defines the N1 elements. It may be an element number or a group name. If N1S is an element number, the N1 elements start with N1S, end with N1F, and are incremented by N1D. N1D = 0 defaults to N1D = 1.

N2S

N2Sdefines the N2 elements that start with N2S and are incremented by N2D, corresponding to N1S and N1D. If N2S is a group name, it is interpreted to be the first element of the group, and it must be a Card 5a element. For the CONVASN and CONVSN options N2S is a table number specifying a time vs temperature behavior.

N2D

N2Dis the identifier ID for the Card 9 DESCRIP when N1S and N2S are group names, or an increment value when N1S and N2S are element numbers.

HN1

HN1 is a coefficient associated with element N1.

KODE = COND

COND (or 1) creates a linear conductance equals to A(N1)*HN1/RL, where RL is the distance between the CG's of N1 and N2.

KODE = CONV

CONV (or 0) creates a linear conductance equals to A(N1)*HN1 between elements N1 and element N2.

EXP (optional) is a conductance multiplier table or expression number. The dependent variable on its TABTYPE Card must be COND.

KODE = CONV1W

CONV1W (or 34) creates a linear 1-way conductance A(N1)*HN1 between elements N1 and element N2. A(N1) is the area of N1. N2 is affected by the N1 elements, while the N1 elements are not affected by N2.

KODE = CONVASN

CONVASN (or 21) creates a linear conductance A(N1)*HN1 between the N1 elements and a SINK element whose temperature history is described by table or expression N2S. The number of the SINK element is assigned during run-time.

  • EXP is an optional table or expression number for a conductance multiplier. The dependent variable on its TABTYPE Card must be COND.
  • N2S is a table number specifying a time vs temperature behavior.

KODE = CONVLP

CONVLP (or 23) creates linear conductances for beam elements. The N1 elements must be beam elements and the resulting conductance is equal to LENGTH(N1)HN1.

EXP is an optional table or expression number for a conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = CONVSN

CONVSN (or 20) creates a linear conductance HN1 between the N1 elements and a SINK element whose temperature history is described by table or expression N2S. The number of the SINK element is assigned during run-time.

  • EXP is an optional table or expression number for a conductance multiplier. The dependent variable on its TABTYPE Card must be COND.
  • N2S is a table number specifying a time vs temperature behavior.

KODE = CSERIES

CSERIES (or 6) creates a conductance A(N1)*HN1 in series with the already existing linear conductance between N1 and N2, thereby reducing it.

EXP is an optional table or expression number for a table-dependent conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = CYLINDASN

CYLINDASN (or 3834) creates free convection coupling(s) from element(s) N1 on the surface of a cylinder, convecting to a SINK element whose temperature history is described by table or expression N2S. The fluid is assumed to surround, i.e., be both above and below the element. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the diameter of the cylinder. The EXP=SELF option is not valid for this correlation.
  • P1 must be the length of the cylinder.
  • VX, VY, VZ are the directional components of the unit axis vector of the cylinder.

KODE = FREE

FREE (or 4) creates a free convection conductance A(N1)*HN1. Heat flow through it is calculated with:

  • EXP = blank defaults to .25.
  • P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate convect. If P1 is unspecified or 0, the thermal solver determines the coupling side, depending on the sides that "see" each other: either TOP or BOTTOM.

KODE = FREECONVASN

FREECONVASN (or 3835) creates a free convection conductance A(N1)*HN1 between the N1 elements and a SINK element whose temperature history is described by table or expression N2S. The SINK element ID is assigned during run-time. The fluid is assumed to surround, i.e., be both above and below the element. Heat flow through it is calculated with:

  • EXP = blank defaults to .25.
  • P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate convect. If P1 is unspecified or 0, the thermal solver determines the coupling side, depending on the sides that "see" each other: either TOP or BOTTOM.

KODE = FORCEDCASN

FORCEDCASN (or 3837) creates forced convection coupling(s) from element(s) N1 on the surface of a cylinder in cross flow, convecting to a SINK element whose temperature history is described by table or expression N2S. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the velocity of the flow.
  • P1 is 0.
  • VX is the diameter of the cylinder.

KODE = FORCEDPASN

FORCEDPASN (or 3836) creates forced convection coupling(s) from element(s) N1 on the surface of a flat plate, convecting to a SINK element whose temperature history is described by table or expression N2S. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the velocity of the flow.
  • P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate convect.
  • VX is the length of the plate in the direction of the flow.

KODE = FORCEDSASN

FORCEDSASN (or 3838) creates forced convection coupling(s) from element(s) N1 on the surface of a sphere in cross flow, convecting to a SINK element whose temperature history is described by table or expression N2S. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the velocity of the flow.
  • P1 is 0.
  • VX is the diameter of the sphere.

KODE = INCCHNLASN

INCCHNLASN (or 3840) creates a free convection coupling from the element(s) N1 on the inner surface of either wall of an inclined open parallel plate channel, convecting to a SINK element whose temperature history is described by the table or expression N2S. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • EXP is the distance between the walls of the channel.
  • P1 is the length of the channel.
  • VX, VY, VZ are the directional components of the vector of the surface normal of the walls of the channel.

KODE = INTER

INTER (or 12) defines the N1 elements to be interface resistance elements.

If N1 is a planar element surface coated onto the surface of a solid element I, and a conductance of value GINI is calculated between them by the COND module, GINI is reduced to GINInew

If N1 lies at the interface of two solid elements then GINI is reduced to:

With this option you can model with zero-thickness planar elements the interface resistance of a thin glue line. If the N1 elements are beams, they must be connected to the edges of planar elements, and their area per unit length should be 1.

EXP is an optional table or expression number for a table-dependent conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = INTERB

INTERB (or 44) defines the N1 elements to be interface resistance elements.

INTERB behaves the same way as the INTER option, except for beam elements. If the N1 elements are interface beam elements between two shell elements, the interface conductance between the two shells is proportional to the length of the interface beam element, not its surface area (as with the INTER option).

If a conductance of value GINI is calculated between the two shell elements by the COND module, GINI is reduced to GINInew:

KODE = INTER2

INTER2 (or 42) creates interface conductances between the N1 and N2 elements where they are connected conductively. Conductive connection means the adjacent elements share the same nodes. The PARAM COND NEW option must be used.

HN1 is the interface conductance value per unit length for shells, per unit area for solids, and interface conductance value for beams.

If N1A is a shell element conductively connected to one of the shell elements of N2, the effective conductance GbN1 between N1A and the beam boundary element that is shared by N1A and the N2 element it is connected to is reduced to GbN1new

L(N1A) is the length of the beam boundary element joining N1A and the element of the N2 group.

If N1A is a solid element conductively connected to one of the solid elements of N2, the effective conductance GbN1 between N1A and the shell boundary element that is shared by N1A and the N2 element it is connected is reduced to GbN1new:

If N1A is a beam element conductively connected to one of the beam elements of N2, the effective conductance of value GbN1 between N1A and the lump mass boundary element that is shared by N1A and the N2 element it is connected is reduced to GbN1new

EXP is an optional table or expression number for a table-dependent conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = INTER2TOT

INTER2TOT (or 43) creates interface conductances between the N1 and N2 elements where they are connected conductively. Conductive connection means the adjacent elements share the same nodes. The PARAM COND NEW option must be used.

HN1 is the total interface conductance value created between the N1 and N2 elements.

If N1A is a shell element conductively connected to one of the shell elements of N2, the effective conductance GbN1 between N1A and the beam boundary element that is shared by N1A and the N2 element it is connected to is reduced toGbN1new:

where:

  • A(N1A) is the area of the boundary element joining N1A and the N2 group.
  • ATOT is the total area of the boundary between the N1 and N2 groups.

If N1A is a solid element conductively connected to one of the solid elements of N2, the effective conductance GbN1 between N1A and the shell boundary element that is shared by N1A and the N2 element it is connected is reduced to GbN1new:

where:

  • A(N1A) is the area of the boundary element joining N1A and the N2 group.
  • ATOT is the total area of the boundary between the N1 and N2 groups.

If N1A is a beam element conductively connected to one of the beam elements of N2, the effective conductance of value GbN1 between N1A and the lump mass boundary element that is shared by N1A and the N2 element it is connected is reduced to GbN1new

where:

  • NTOT is the number of connections where the N1 group joins the N2 group.
  • EXP is an optional table or expression number for a table-dependent conductance multiplier. The dependent variable on its TABTYPE Card must be COND

KODE = INTERTOT

INTERTOT (or 35) defines the N1 elements to be interface resistance elements.

HN1 is the total interface conductance for all the interface elements N1.

If N1 is a planar element surface coated onto the surface of a solid element I, and a conductance of value GIN1 is calculated between them by the COND module, GIN1 is reduced to .

where ATOT1 is the total area of all the N1 elements.

If N1 lies at the interface of two solid elements, then GIN1 is reduced to .

With this option, you can model with zero-thickness planar elements the interface resistance of a thin glue line.

If the N1 elements are beams, they must be connected to the edges of planar elements, and their area per unit length should be 1.

EXP is an optional table or expression number for a table-dependent conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = INTERBTOT

INTERBTOT (or 45) defines the N1 elements to be interface resistance elements.

INTERBTOT is similar to INTERTOT, except for beam elements that lie at the interface of shell elements. For these, the interface conductance is proportional to the length of the beam element, not its surface area (as with the INTERTOT option). If a conductance G1N1 is calculated between the two shells by the COND module, GIN1 is reduced to .

KODE = MERGE

MERGE (or 27) merges elements N1 with the first element of N2, such that the N2 elements are left and the N1 element numbers disappear during Analyzer runs.

As a rule, N2 should only contain a single element.

KODE = PLATEASN

PLATEASN (or 3831) creates free convection couplings from the top/bottom/both sides of elements N1 on a plate to a SINK element whose temperature history is described by table or expression N2S. The fluid is assumed to surround, i.e., be both above and below the element. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the characteristic length. Typically, this should be the distance along the plate connecting its highest and lowest points. Alternatively, EXP may be the code SELF, in which case the vector components VX, VY, and VZ, as well as the characteristic length, are calculated from the geometry of the group N1.
  • P1 may be TOP, BOTTOM, or BOTH, indicating the side of the plate that convects. If P1 is BOTH, two separate thermal couplings are created, one from each side of the plate.
  • VX, VY, VZ are the directional components of the unit vector of the surface normal of the plate.

KODE = PLATEHASN

PLATEHASN (or 3832) creates free convection coupling(s) from the top/bottom/both sides of elements N1 on a horizontal plate to a SINK element whose temperature history is described by table or expression N2S. The fluid is assumed to surround, i.e., be both above and below the element. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the characteristic length = area/perimeter of the plate. Alternatively, EXP may be the code SELF, in which case the characteristic length is calculated from the geometry of the group N1.
  • P1 may be TOP, BOTTOM, or BOTH, indicating the side of the plate that convects. If P1 is BOTH, two separate thermal couplings are created, one from each side of the plate.

KODE = RAD

RAD (or 2) creates a radiative conductance parameter R.

If the emissivities of the N1 and N2 elements are table-dependent, the value of R is adjusted at run-time.

where:

  • efirst(N2) is the first emissivity value in the table for element N2.
  • e(N1) is the emissivity value for element N1.
  • e(N2) is the emissivity value for element N2.
  • HN1 is the gray body view factor from N1 to N2.

P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate radiate.

EXP must be zero.

KODE = RAD2

RAD2 (or 36) creates a radiative conductance parameter R.

If the emissivities of the N1 and N2 elements are table-dependent, the value of R is adjusted at run-time.

where:

  • efirst(N1) is the first emissivity value in the table for element N1.
  • efirst(N2) is the first emissivity value in the table for element N2.
  • e(N1) is the emissivity value for element N1.
  • e(N2) is the emissivity value for element N2.
  • HN1 is the (effective emissivity of the N1 elements) * (gray body view factor from N1 to N2).

P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate radiate.

KODE = RAD3

RAD3 (or 50) creates a radiative conductance parameter R.

If the emissivities of the N1 and N2 elements are table-dependent, the value of R is adjusted at run-time.

where:

  • efirst(N1) is the first emissivity value in the table for element N1.
  • efirst(N2) is the first emissivity value in the table for element N2.
  • e(N1) is the emissivity value for element N1.
  • e(N2) is the emissivity value for element N2.
  • HN1 is the gray body view factor from N1 to N2.
  • EXP is the specified emissivity.

P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate radiate.

KODE = RADASN

RADASN (or 24) creates a radiative conductance parameter R between the N1 elements and a SINK element whose temperature history is described by table or expression N2S.

The SINK element number is assigned during run-time.

If the emissivity of element N1 is table-dependent, the value of R is adjusted at run-time.

where:

  • efirst(N1) is the first emissivity value in the table for element N1.
  • e(N1) is the emissivity value for element N1.
  • HN1 is the (effective emissivity of N1) * (gray body view factor from N1 to N2).

KODE = RADASN2

RADASN2 (or 29) creates a radiative conductance parameter R between the N1 elements and a SINK element whose temperature history is described by table or expression N2S.

The SINK element number is assigned during run-time.

where:

  • e(N1) is the emissivity value for element N1, which may be table-dependent.
  • HN1 is the gray body view factor from N1 to N2.

P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate radiate.

EXP must be zero.

KODE = RADASN3

RADASN3 (or 3839) creates a radiative conductance parameter R between the N1 elements and a SINK element whose temperature history is described by table or expression N2S.

The SINK element number is assigned during run-time.

If the emissivity of element N1 is table-dependent, the value of R is adjusted at run-time.

where:

  • efirst(N1) is the first emissivity value in the table for element N1.
  • e(N1) is the interpolated emissivity value for element N1.
  • HN1 is the gray body view factor from N1 to N2.
  • EXP is the specified emissivity.

P1 may be TOP, BOTTOM, or BOTH, depending on whether the top, bottom, or both sides of the plate radiate.

KODE = RADTOT

RADTOT (or 26) creates radiative conductances between the elements of N1 and N2 such that the elements of N1 are coupled to the average temperature of N2 and the elements of N2 are coupled to the average temperature of N1.

For each element pair N1 and N2, two thermal conductance parameters are created, one between N1 and N2AVG, and another between N2 and N1AVG.

where:

  • HN1 is the specified gray body view factor between the N1 and N2 elements, i.e. the fraction of the radiation emitted by the N1 elements and absorbed by the N2 elements.
  • N2AVG is a newly created element whose temperature is the average temperature of the N2 elements.
  • N1AVG is a newly created element whose temperature is the average temperature of the N1 elements.
  • GBVFN2N1 is the gray body view factor between the N2 and N1 elements, i.e. the fraction of the radiation emitted by N1 and absorbed by N2. GBVFN2N1 is computed from the emissivities and areas of the N1 and N2 elements. If the emissivities are table-dependent, the first values of the tables are used to compute GBVFN2N1.
  • e(N1) is the emissivity of element N1.
  • e(N2) is the emissivity of element N2.

If the emissivities are table-dependent, their values are computed at run-time. The value of GBVFN2N1 is not recomputed at run-time.

KODE = RADTOT2

RADTOT2 (or 39) creates radiative conductances between the elements of N1 and N2 such that the elements of N1 are coupled to the average temperature of N2 and the elements of N2 are coupled to the average temperature of N1. HN1 is ignored.

For each element pair N1 and N2, two thermal conductance parameters are created:

where:

  • GBVFN1N2 is the gray body view factor between the N1 and N2 elements, i.e. the fraction of the radiation emitted by the N1 elements and absorbed by the N2 elements. GBVFN1N2 is computed assuming the N1 and N2 elements are located on two opposing very close parallel plates. If the emissivities are table-dependent, the first values of the tables are used.
  • GBVFN2N1 is the gray body view factor between the N2 and N1 elements, i.e. the fraction of the radiation emitted by the N2 elements and absorbed by the N1 elements. GBVFN2N1 is computed assuming the N1 and N2 elements are located on two opposing very close parallel plates. If the emissivities are table-dependent, the first values of the tables are used.
  • N2AVG is a newly created element whose temperature is the average temperature of the N2 elements.
  • N1AVG is a newly created element whose temperature is the average temperature of the N1 elements.
  • e(N1) is the emissivity of element N1.
  • e(N2) is the emissivity of element N2.

If the emissivities are table-dependent, their values are computed at runtime. The values of GBVFN1N2 and GBVFN2N1 are not recomputed at runtime.

KODE = RADTOT3

RADTOT3 (or 41) creates radiative conductances between the N1 and N2 elements such that the elements of N1 are coupled to the average temperature of N2 and the elements of N2 are coupled to the average temperature of N1.

For each element pair N1 and N2, two thermal conductance parameters are created:

where:

  • HN1 is the specified e(N1)*GBVFN1N2 value between the N1 and N2 elements.
  • GBVFN1N2 is the gray body view factor between the N1 and N2 elements, i.e. the fraction of the radiation emitted by the N1 elements and absorbed by the N2 elements.
  • N2AVG is a newly created element whose temperature is the average temperature of the N2 elements.
  • N1AVG is a newly created element whose temperature is the average temperature of the N1 elements.
  • GBVFN2N1 is the gray body view factor between the N2 and N1 elements, i.e. the fraction of the radiation emitted by N1 and absorbed by N2. GBVFN2N1 is computed from the emissivities and areas of the N1 and N2 elements and N1. If the emissivities are table-dependent, the first value of the table is used.
  • e(N2) is the emissivity of element N2.

If the emissivities are table-dependent, their values are computed at runtime. The values of GBVFN2N1 and GBVFN1N2 are not recomputed at runtime.

where:

  • efirst(N1) is the first emissivity value in the table for element N1.
  • efirst(N2) is the first emissivity value in the table for element N2.
  • e(N1) is the interpolated emissivity value for element N1.
  • e(N2) is the interpolated emissivity value for element N2.

KODE = RESISTANCE

RESISTANCE (or 33) creates a linear conductance A(N1)/(HN1*ATOT1).

ATOT1 is the sum of the areas of all the elements N1.

EXP is an optional table or expression number for a conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

KODE = RSERIES

RSERIES (or 7) creates a radiative conductance A(N1)*Emissivity(N1)*HN1 in series with the already existing radiative conductance between N1 and N2, reducing it.

KODE = SOLAR

SOLAR (or 16) writes a solar view factor Card on VUFF with area A(N1), absorptivity(N1), solar view factor HN1, and TIME = EXP.

KODE = SPHEREASN

SPHEREASN (or 3833) creates free convection coupling(s) from element(s) N1 on the surface of a sphere, convecting to a SINK element whose temperature history is described by table or expression N2S. The fluid is assumed to surround, i.e., be both above and below the element. The SINK element ID is assigned during run-time.

  • N1D is the material ID of the fluid, must be present as a Card 9 MAT Card. If it is zero, the fluid properties are obtained from the HYDENV Card.
  • HN1 is the convection coefficient multiplier.
  • EXP is the diameter of the sphere.

KODE = VIEWF

VIEWF (or 3) writes a view factor with area A(N1), emissivity(N1), and view factor HN1 on file VUFF.

KODE = XCOND

XCOND (or 22) creates a linear conductance = HN1.

EXP is an optional table or expression number for a conductance multiplier. The dependent variable on its TABTYPE Card must be COND.

Code examples

AREA 1 5 2 7 4 .36 CONV
$ CONVECTIVE CONDUCTANCES ARE CREATED BETWEEN ELEMENTS
$ 1 AND 7, 3 AND 11, 5 AND 15, WITH MAGNITUDES = AREAS
$ OF 1, 3, AND 5 MULTIPLIED BY .36.

AREA BOXTOP 0 0 AMBIENT 0 .36 CONV
$ CONVECTIVE CONDUCTANCES ARE CREATED BETWEEN THE
$ ELEMENTS OF BOXTOP AND THE SINGLE ELEMENT AMBIENT
AREA GLUE 0 0 0 0 (.03/.001) INTER
$ THE ELEMENTS OF GLUE (CONNECTING TWO SOLID ELEMENTS)
$ ARE INTERFACE RESISTANCE ELEMENTS, WITH THERMAL
$ CONDUCTIVITY OF .03 AND THICKNESS OF .001
AREA PLATE 0 0 AIR 0 FREE .33
$ FREE CONVECTION COND. ARE CREATED BETWEEN THE
$ ELEMENTS OF PLATE & AIR