KevinH673

Thanks for all the help, CaptainPanic. I believe I have solved the problem.

Thank you for the quick reply. I actually have taken courses on heat transfer as well as thermofluids, and have done quite a bit of calculation on this already; however with all the variables that need to be accounted for (convection coefficients for the YAG rod, surface area, flow rate, area of the rod, beginning and end temperatures of both the rod and the water) and it has just gotten a bit overwhelming. I have the Reynolds number, as well as the Nusseult number, but am not sure I'm always using the correct equations (or variables in those equations) to get it. Ontop of this, dealing with power levels that oscillate makes it more complicated. Power can spike up to 12 kW or higher for a millisecond, then be off for another 99 milliseconds. At a constant power of 12 kW, the surface temperature is much too high. The second equation you wrote is helpful, but I worry about it not factoring in surface area. Any suggestions?

Thanks for the help. Would this be a convection problem, though? What about if this was simplified as a flat plate with external flow over it. Taking it as a convection problem, I haven't found helpful equations that would deal with a temperature gradient in the fluid and the plate. My heat transfer books only deal with heat exchangers that have two moving fluids. To model the fluid, could I use an equation such as: Q=m*Cp*(To-Ti) Where "Q" is the power of the Yag rod? I'm not sure if I'm using Q correctly.

I'm analysing a heat transfer problem, but I am a bit rusty as it's been a while since I've taken the course. I have two concentric tubes (annulus), and the outside tube has water flowing through it, to cool the solid rod in the middle. I am interested in the temperature gradiants of both the rod and the water. I have the power of the rod (q), the flow rate (Q), the initial temperature of the water, and the area of both the rods. Can this be solved from this? It seems as though it would be an easy problem, but I have not found the correct equation yet.