IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

High-brightness fiber coupled pumps

Abstract: Advanced high volume applications require pumps with high power, high brightness, and high power efficiency. New generation devices meet all of these challenging requirements, while still maintaining the advantages of distributed pumping architecture including high reliability inherent to single emitter sources. Based on new-generation long-cavity diode chips, new pumps are capable of more than 60W CW power ex-fiber output (100 μm core diameter) into NA ~ 0.12. Peak power efficiency stays over 60%. All of the above is provided at room heatsink temperature, maintained by basic air- or water-cooling.

Numerical simulation of thermal plumes in a Herschel–Bulkley fluid

Abstract: We present a three dimensional numerical study of thermal plumes, developing from a localized heat source in a yield stress and shear thinning fluid. We assume that the fluid viscosity follows a Herschel–Bulkley law with a low shear rate viscosity plateau. Comparison of the plume onset time and morphology observed in the numerical study and in laboratory experiments with Carbopol shows good agreement. An extensive parameter study allows us to identify two local non-dimensional parameters that determine whether a plume rises through the fluid. The first parameter is the Bingham number, Bi, which compares the yield stress to the viscous stress. The second parameter, the yield number Ψ, compares the stress induced by the buoyancy of an equivalent hot sphere to the yield stress. We find that a plume develops only if Ψ > Ψc = 5 ± 1.2 and Bi 1. Hot fluid continues to rise from the bottom of the tank but spreads under an unyielded, high viscosity region at the top of the box.