Modeling Heat Mitigation in Hollow-Core Gas Fiber Lasers With Gas Flow

We carry out a computational study to evaluate the temperature reduction by using gas flow in hollow-core gas fiber lasers. We first use the Navier-Stokes equations to study the gas flow in the hollow-core fibers. We compare the density, pressure, and velocity using both an incompressible and a compressible gas model. We show that an incompressible gas model leads to large errors in the case that we study in this paper. We then present a coupled model to study gas flow and heat transfer simultaneously in hollow-core fibers using a compressible gas model. We found that a temperature reduction of about 20% can be achieved by using a differential pressure of 10 atm between the inlet and outlet of the hollow-core fibers. The results also demonstrate that the relative temperature reduction increases when the heat power decreases, the fiber length decreases, and the heat profile is more localized.