Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Radiation cooling of grid
Date: Oct 18, 4:46 pm
Poster: Jim Lux

On Oct 18, 4:46 pm, Jim Lux wrote:

A rough calculation of the radiation cooling of a grid wire. Assume it is .03 cm in diameter (about 10 mil) and 30 cm long and at 2000K (bright orange). Assume the wall of the chamber is at zero (small effect on estimate). If the emissivity is 1, and the power radiates as if it were from one side of the wire's longitudinal cross section (i.e. an area of 1 cm^2), it will lose about 90Watts. As a reasonableness check, compare to an incandescent lightbulb, which runs at 2850K and rejects about 100W from a smaller area (about 1/4 cm^2, by calculation).

If you want to run a bunch of power into a small lab sized fusor, it looks like radiation cooling is where it is at. I'd suggest an working number for max grid dissipation (in watts) of 90*(grid radius in cm).

How does this compare with actual numbers people have measured?