thermal rejection limit of fluid
 

Dear all,

in thermal-fluid analysis, is there a limit on the heat rejection by the fluid it can achieve please?

what theory, or parameter should i read on? conservation of energy?

i believe that, for a given amount of heat source, the fluid which has a fix flowrate and temperature flowing through cooling channel of fix dimensions is only able to reject a certain amount of heat from the heat source. As the heat source increases, the fluid can only reject a max. limit from the heat source and stay constant.

Look forward to hear of any comments/ideas.

Yes, there is a maxiumum, which is the amount of heat that a heat pump working in a Carnot cycle can transmit between the high temperature reservoir (the wall temp) and your sink, check your thermodynamics book for the definition
For the real amount of heat, it is a function of the Nusselt number, write down the definition and see what you can achieve.
Good luck