Heat Exchanger: +40C rise at 16 liters/minute flow rate

[Edwardminett]

Summary:: How to calculate the rate of heat transfer between hot external water and cold internal water in a pipe.

The image attached is my attempt at the question however, I find myself stuck trying to work out internal and external heat transfer coefficient.

 

[Chestermiller]

What are your thoughts on how to proceed so far, say, first for the case of the internal heat transfer coefficient?

 

[Edwardminett]

What are your thoughts on how to proceed so far, say, first for the case of the internal heat transfer coefficient?

I'm not to sure, most places I searched said use the Nusselt number equation but I'm not sure if this is correct or how to calculate this?

 

[Chestermiller]

I'm not to sure, most places I searched said use the Nusselt number equation but I'm not sure if this is correct or how to calculate this?

Tell me your understanding of how the Nusselt number is estimated. Where have you researched so far?