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Thermal Solver
Contains thermal solver related guides, such as the TMG reference manual, thermal API guide, and error message list.
Thermal solver API guide
Allows you to create or add functionality to enhance the thermal solver capabilities.
User written subroutines
This section describes two types of user-written subroutines.
Subroutine and function definitions
Subroutine definitions
Subroutine GRP2GRP
Calculates the heat flow through all the conductances from element groupa to element groupb.

Thermal Solver
Contains thermal solver related guides, such as the TMG reference manual, thermal API guide, and error message list.
- Thermal solver guides
  Maya HTT's thermal solver is included in Simcenter 3D and in Simcenter Femap. This page contains links to thermal solver guides, which help you understand how the thermal solver works.
- Thermal solver theory
  Describes the theory and methods of the thermal solver.
- Thermal solver API guide
  Allows you to create or add functionality to enhance the thermal solver capabilities.
  - Introduction
  - Supported compilers
  - User written subroutines
    This section describes two types of user-written subroutines.
    - USER1 subroutine
    - Interacting with the thermal solver
    - USERF subroutine
    - Specific examples
    - Subroutine and function definitions
      - Function definitions
      - Subroutine definitions
        Subroutine ADDCOND
        Adds conductances to the model. You call this routine once when KODE = 5.
        Subroutine CHANGENODECOORDS
        Changes the coordinates of a node by adding a displacement. The solver recalculates the conductive conductances of elements containing this node.
        Subroutine CMA_DEF
        Defines a set of elements that are affected by a change in attitude.
        Subroutine CMA_Orient
        Implements a change in model attitude with respect to Sun and planet.
        Subroutine CONDNOS
        Generates a list of conductances associated with an element.
        Subroutine CONDNOS2
        Returns all the conductive conductances associated with the elements of the group, including the conductances connecting the boundary elements. This routine is used only with the element CG method.
        Subroutine CREDIST2
        Returns the redistribution factors for capacitance and heat loads for element iel.
        Subroutine DESCRIP
        Accesses all the parameters associated with a Card 9 - DESCRIP Character String Descriptor Cards - Optional.
        Subroutine FAN
        Imposes a mass flow on a fan in a fluid network.
        Subroutine FASTSOLVE2
        Solves the matrix equation AX = B using the iterative biconjugate gradient method, where X is the output vector. The matrix A is created from the contents of arrays icd and cond.
        Subroutine FORMOUT
        Prints the contents of an array in TMG TEMPF file format or I-DEAS element data set type 56 universal file format. Use this routine to generate I-DEAS results from any model parameter.
        Subroutine FREE_MEMORY
        Frees the memory for array number iarr.
        Subroutine GENERIC
        Returns the parameters associated with the Card 9 - GENERIC Generic Entity Cards.
        Subroutine GENERICINDEX
        Returns the external index of a generic entity for the given internal index and the number of generic entities present in variable numgenerics. If a given internalid input value does correspond to any existing generic entity then a zeroexternalid value is returned.
        Subroutine GETLAYERS
        Returns the number of layers and a list of elements associated with a multilayer shell elements.
        Subroutine GET_MEMORY
        Allocates iel memory locations into array number iarr.
        Subroutine GET_POINTER
        Returns the pointer pntr for array number iarr.
        Subroutine GETTEMPCONDUCTIVITY
        Returns the interpolated value of the thermal conductivity at specified temperature.
        Subroutine GRP2GRP
        Calculates the heat flow through all the conductances from element groupa to element groupb.
        Subroutine HYDPROPPUT
        Sets the hydraulic property values for an element in a flow network.
        Subroutine LONGNAME
        Maps between external (user defined) and internal group names. Internal group names are limited to seven characters and may not contain spaces. To meet these requirements while avoiding group name duplication requires the change of some group names significantly.
        Subroutine NAMAR
        Returns a list of elements in a group. It uses thermal solver internal group name conventions. The group name is determined with a call to the routine LONGNAME.
        Subroutine NAMARG
        Returns internal numbers of elements in array that are associated with the group number. This subroutine is the same as subroutine NAMAR, except that it uses the group number instead of its name.
        Subroutine PELTIER
        Calculates the heat inputs to the hot and cold sides of a Peltier device.
        Subroutine ProcessMotion
        Recalculates orbital fluxes and radiation conductances for the current model configuration and attitude. The user is responsible for determining what needs to be recalculated.
        Subroutine PUT_DOUBLE
        Stores values into array.
        Subroutine PUT_INTEGER
        Stores values into array number iarr at location iel.
        Subroutine PUT_REAL
        Stores real values into array number iarr at location iel.
        Subroutine READPROP2
        Loads element properties into arrays.
        Subroutine Set_Orbital_Fluxes
        Sets new values for solar flux, planet IR and albedo.
        Subroutine SRBM_DEF
        Defines Simple Rigid Body Motion (SRBM).
        Subroutine SRBM_ MOVE
        Defines motion for an SRBM.
        Subroutine TCNAME
        Generates a list of conductances that directly join the elements in two groups, or join one group to the rest of the model.
        Subroutine TCNAMEG
        Returns the conductance array in the same format as in subroutine TCNAME, which is between two groups of elements with group numbers IGRP1 and IGRP2. This subroutine is the same as subroutine TCNAME,except that it uses the group numbers instead of their names.
        Subroutine THERMOSTAT
        Checks or sets the state of a thermostat.
        Subroutine TINT
        Returns an interpolated value from a thermal solver table. The table is defined in both cards: Card 9 - TABDATA Analyzer Table Data Cards - Optional and Card 9 - TABTYPE Table Variable Type Definition Card - Optional.
        Subroutine TMGN12
        Returns the conductance type code and the internal element numbers for a conductance.
        Subroutine TUNITS
        Returns parameters defining the units set of the model.
        Subroutine USER_QUANTITY
        Gives an access to data in named user quantities.
        Subroutine USER_TINTERP
        Calculates an interpolated temperature at the array of points contained in coords, where coords(3,numpoints) contains the X,Y,Z coordinates of a set of points. It returns the corresponding interpolated temperature values in tintp(numpoints) array.
        Subroutine USER_TINTERP2
        Calculates an interpolated temperature at the array of points contained in coords, where coords (3,numpoints) contains the X,Y,Z coordinates of a set of points.
        Subroutine USER_TINTERPINIT
        Initializes the nodal temperature interpolator on the subset of elements in the model, which is defined by the group name. It is called before using the USER_TINTERP and the USER_TINTERP2 subroutines.
        Subroutine USERARRAY
        Places or gets a value into user-defined array. The array is identified by number.
        Subroutine VARVAL
        Returns the value of the symbolic variable defined on a Card 9 - VARIABLE Variable Definition Card - Optional in the Thermal Solver Reference Manual.
    - Compiling, linking, and debugging
  - Plugin functions in expressions

Subroutine GRP2GRP

Calculates the heat flow through all the conductances from element groupa to element groupb.

Calling convention:

call grp2grp(groupa,groupb,t,gg,r,c,htflow,maxno,nocon,par)


Arguments	Data type	Input/Output	Description
`groupa`	Character*7	Call	The name of the first group. Positive heat flow is from `groupa` to `groupb`. The name is 7 characters long, pad with spaces if required.
`groupb`	Character*7	Call	The name of the second group. Positive heat flow is from `groupa` to `groupb`. The name is 7 characters long, pad with spaces if required.
`htflow`	Real(10)	Return	Heat flow description. `htflow(1)` - The heat flow through conductive conductances. `htflow(2)` - The heat flow through radiative conductances. `htflow(3)` - The heat flow through forced convection conductances. `htflow(4)` - The heat flow through free convection conductances. `htflow(5)` - The heat flow through 1-way radiative conductances. `htflow(6)` - The heat flow through 1-way conductive conductances. `htflow(7)` - The heat flow through linear convective conductances. `htflow(8)` - The heat flow through CFD related conductances.
`par`	Real(4)	Call	Control of results printing to the report log file. `par(1)` - If `par(1)=1` then heat flows are printed. `par(2)` - If `par(2)=1` then heat flows through individual conductances are printed. `par(3)` set to 0. `par(4)` set to 0.
`t`	Real	Call	`t(j)` is the temperature of the internal element `j`, for internal element numbers ≤`maxn1`+`maxn2`.
`gg`	Real	Call	`gg(j)` is the current value of the resistance `j`, that is, the inverse of the conductance `J`. If `J` is a radiative conductance, then `gg(j)` is the inverse of its current linearized value, that is, the temperature difference between its elements divided by the heat flow through it.
`r`	Real	Call	The conductance parameter of conductance `J.`
`c`	Real	Call	`c(i)` is the capacitance of internal element `i`. Temperatures of elements with `c(i`) < `0` are not computed with the normal heat balance equations. `MCV` elements and sink elements are assigned `c(i`) < `0`.
`maxno`	Real	Call	The number of elements (`maxn0` = `maxn1` + maxn2).
`nocon`	Real	Call	The number of conductances (cannot be changed).