Table of Contents
LINADC
Description
Law for linear heat advection diffusion 1D element (only for HEATX element)
The model
This law is used in combination with the finite element HEATX. The purpose is the modeling of simplified equations of advection-diffusion of heat in a pipe. A lateral heat flow with the surrounding medium is also taken into account. See GEOTHERWAL reports or more information on the formulation.
Files
Prepro: LINADC.F
Availability
| Plane stress state | NO |
| Plane strain state | NO |
| Axisymmetric state | NO |
| 3D state | YES |
| Generalized plane state | NO |
Input file
Parameters defining the type of constitutive law
| Line 1 (2I5, 60A1) | |
|---|---|
| IL | Law number |
| ITYPE | 108 |
| COMMENT | Any comment (up to 60 characters) that will be reproduced on the output listing |
Integer parameters
| Line 1 (3I5) | |
|---|---|
| ITYPE | type of lateral of lateral heat exchange (only one case up to now) |
| IBOUND | type of boundary: = 0 → no boundary = 1 → free flow boundary, the fluid runs out of the pipe (necessary at the end of an open pipe) = 2 → loop boundary, the fluid that runs out of the pipe is injected at the beginning of another segment |
| IDEP | fluid velocity v or heat power $Q_P$ = 1 → depends of DMULT and FMULT respectively = 0 → are constant |
Real parameters
| Line 1 (9G10.0) | |
|---|---|
| RHO | specific mass of the fluid inside the pipe $\left[kg/m^3\right]$ |
| COND | conductivity of the fluid inside the pipe $\left[W/m/K\right]$ |
| CP | specific heat of the fluid inside the pipe $\left[J/kg/K\right]$ |
| v | velocity of the fluid $\left[m/s\right]$ |
| TREF | reference temperature for the computation of advection flux $\left[K\right]$ |
| h | parameter for the lateral heat flux $\left[W/m^2/K\right]$ convective heat coefficient if (ITYPE == 1) such that $q_l = h (t_{ground} - T_{pipe})$ |
| r | radius of the pipe $\left[m\right]$ |
| Qp | heating power if IBOUND=2 $\left[W\right]$ |
| RATIO | ratio of the pipe that is modelled $\in \left[0,1\right]$, $=0.5$ for half a mesh $\left[-\right]$ |
Stresses
Number of stresses
4
Meaning (numerical, not physical)
| SIG(1) | conduction heat flux |
| SIG(2) | advection heat flux (depends on the reference temperature) |
| SIG(3) | lateral heat flux |
| SIG(4) | storage heat flux |
State variables
Number of state variables
1
List of state variables
| Q(1) | 0 |