Heating from laser (q) on copper beam dump

[KevinH673]

I'm attempting to analyze the heat on a 'bump dump' and could use your help in modeling the equation correctly.

I have a laser beam coming through an optic and hitting a copper beam dump of certain surface area, A. The laser is emitting a power, q, in Watts. The copper beam dump is surrounded by water flowing about it at a rate of Q. The water is at temperature Tw. How would I calculate the surface temperature of the copper beam dump

 

[KevinH673]

Im guessing I can just use convection

q=h*A*Delta T

 

[IRstuff]

Well, at the surface, it's mostly conduction to the back, and radiation and convection to the front. However, the equation for convection and conduction hasthe same basic form. Only the radiation is drastically different.

TTFN

FAQ731-376

 

[racookpe1978]

Unless your laser is one of those (very few!!!!) ultra high power anti-missile Dept of Defense 6-inch diameter multi-megawatt chemical laser beams, you won't get "any" heating from the laser going through water (?) and hitting the copper.

Under NO circumstances will you get more energy per unit time depositied in the surface area of the laser beam than what you add INTO the laser from its power source. So start there.

Energy out = Energy in - stimulation energy - efficiency of laser source.

You lose additional energy going through air between the laser ans the target (how far ?), going through your "lens (or glass pipe holding the water around the copper) holding the copper, and in hitting the copper and reflecting off of the surface of the copper. (To improve absorption of energy, darken the copper, roughen the surface. Or just let it corrode for a while.)

My frank opinion? A few hundredths of one degree. Your water will control the copper temperature more than any laser. Other than laser cutting tools, weapons, or star wars inventions.

Measure outlet water temp - inlet water temperature and find out.