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What is the meaning of 'heat flux has been reset' in the heat exchanger component?

 

I want to use this example model

 

 

01.jpg

 

 

 

 

In this example,
'heat exchange data' parameter is set like this image

 

02.jpg

 

 

 

But I want to do a test using 'heat flow rate' parameter
so I changed the parameter like this,

 

 

03.jpg

 

1000w is default setting.

 

 

 

 

 

04.jpg

 

But, When I simulate this simulation


'impoesed heat flux has been reset ~ ' warning is occuring

 

what is the meaning of reset heat flux??

 

Is this meant to change the 'heat flow rate' parameter to zero?

 

 

 


I always thank you for your help

 

1 REPLY
Solution
Solution
Accepted by topic author Kuro
‎09-07-2016 02:19 AM

Re: What is the meaning of 'heat flux has been reset' in the heat exchanger component?

[ Edited ]

Hi Kuro,

 

the warning mentions that the "heat flux value has been reset to be coherent with inlet temperatures or with heat exchange effectiveness of 1". This means that the "global heat flow rate (to external flow)" variable won't be equal to the "heat flow rate (to external flow)" parameter:

 

reset_flux.png

In your case this is due to the fact that from 0s to 50s both the "internal flow: volume temperature" and the "external flow: outlet mean temperature" are equal to 20°C:

same_t_in.png

consequently no heat can be exchanged (=> the charge air cooler cannot give 1000W to the air).

 

as the above pictures illustrate, the "reset" is only done when this is necessary. In fact this is more a limitation of the "global heat flow rate (to external flow)" than a reset of the "heat flow rate (to external flow)" parameter value.

 

I hope this answer will help you