Heat Boundary Element Free Convection Entry
Description: Specifies a free convection boundary condition for heat transfer analysis through connections to a surface element (CHBDYi entry).
Format:
Example:
| Field | Definition | Type | Default |
|---|---|---|---|
| EID | CHBDYG or CHBDYP surface identification number. | Integer > 0 | Required |
| PID | Convection property identification number of a PCONV entry. | Integer > 0 | Required |
| FLMND | Point for film convection fluid property temperature. | Integer ≥ 0 or blank | 0 |
| CNTRLND | Control point for free convection boundary condition. | Integer ≥ 0 or blank | 0 |
| TAi | Ambient points used for convection. | Integer > 0 for TA1, Integer ≥ 0 for TA2 through TA8 | TA1 |
| CTID1, CTID2, CTID3 | TABLEDi set identification numbers that define control point position dependent scale factors in the x, y, and z directions of the basic coordinate system. See Remark 1. | Integer > 0 or blank | |
| ATID1, ATID2, ATID3 | TABLEDi set identification numbers that define ambient point position dependent scale factors in the x, y, and z directions of the basic coordinate system. See Remark 1. | Integer > 0 or blank |
Remarks:
- The basic exchange relationship can be expressed in one of the following forms:
where c (x, y, z) is defined as the product of scale factors returned by tables defined in fields 6, 7, and 8 on the first continuation entry, and a (x, y, z) is defined as the product of scale factors returned by tables defined in field 9 on the first continuation entry and fields 2 and 3 on the second continuation entry
- CONV is used with a CHBDYi (CHBDYG or CHBDYP) entry having the same EID.
- The temperature of the film convection point must be specified to determine the convection film coefficient. If FLMND = 0, the default temperature is the average of the ambient points (average) and element grid point temperatures (average).
- If only one ambient point is specified then all the ambient points are assumed to have the same temperature. If mid-side ambient points are missing, the temperature of these points is assumed to be the average of the connecting corner points.
- See the PCONV Bulk Data entry for an explanation of the mathematical relationships involved in free convection and the reference temperature for convection film coefficient.
