Bug 4560 describes an error where a heat transfer grading factor greater than one causes the fluid exit temperature in convection heat transfer to exceed the wall temperature, a non-physical result. The issue arises because the grading factor is applied after limiting the convection coefficient using the Stanton number. It first appeared in version 8.0.11 rev 4573 (March 2008) and was corrected in version 8.15.0.5062. The workaround is to limit grading factors to 1 or carefully monitor solver warnings when using higher values.
ERROR INFORMATION
Bugzilla Error Number | BUG 4560 |
Description of Error | When a heat transfer grading factor larger than one (1) is specified for convection heat transfer, the component fluid exit temperature can exceed the wall temperature that heat is convected to or from. |
Comments | The convection heat transfer coefficient is constraint, to avoid the non-physical situation where the component fluid exit temperature exceeds the solid wall temperature, using the Stanton-number limit. The heat transfer grading factor was applied to the convection heat transfer coefficient after the adjustment to enforce the Stanton-number limit, thus situation could arise where the fluid temperature exceeds the wall temperature. |
First Incorrect Version | 8.0.11 rev 4573 March 2008 | Corrected Version: | 8.15.0.5062 |
Workaround Description: Limit heat transfer grading factors to 1, OR when using a value greater than 1 pay careful attention to the solver warning regarding the fluid temperature exceeding the wall temperature and adjust the grading factor accordingly. A resolution to the problem will be available in the next official release. |