Temperature profiles
 

hey guys.

I need some help. i have some problems with simulating 2 flat plate solar air heaters in a row. When i get results of first one, i write velocity and temperature profile of the air flow at outflow (and others temperature profiles at the end of panel (temperature of glass, insulation,..) and use this at inlet boundary condition in the next one. But when i look the results of the second panel are not ok. Temperature of air is looking fine ( rise with distance), but the temperature on others solid material at beginning is dropping from inlet parameters (prescribed temperatures) and after awhile it begin to rise again (this does not make sense).
When I'm doing wrong, can someone give me any advise?

Thanks and best regards

[QUOTE=mare910;435671]hey guys.

I need some help. i have some problems with simulating 2 flat plate solar air heaters in a row. When i get results of first one, i write velocity and temperature profile of the air flow at outflow (and others temperature profiles at the end of panel (temperature of glass, insulation,..) and use this at inlet boundary condition in the next one. But when i look the results of the second panel are not ok. Temperature of air is looking fine ( rise with distance), but the temperature on others solid material at beginning is dropping from inlet parameters (prescribed temperatures) and after awhile it begin to rise again (this does not make sense).
When I'm doing wrong, can someone give me any advise?

Thanks and best regards
Attachment 23134

Attachment 23135

Hi mare910,

A question: are you using a shell conduction boundary condition for the plates or constant heat flux? Also, have you given a thickness the walls?

Also, try looking at a temperature plot along the direction of heating to get a better idea - contours are sometimes deceptive :D

thanks for your replay.
I define constant temperature and for wall tickness i prescribed length of modul.