Heat Transfer/Fluid Mechanics for a Ten-Slab Nitrogen-Cooled Glass Laser Amplifier

摘要

A parameter study was carried out for a Gas-Cooled Slab (GCS) amplifier with 10 glass slabs, using the 1DFLOW code. The 1DFLOW code was improved by adding graphing capability, automating the nozzle and diffuser design procedure, extending heat transfer correlations, and providing for a variable preheating length to account for ASE heating of the coolant. The three flow geometries investigated are parallel flow through the twenty flow circuits (top to bottom through the channels on both sides of the ten slabs); alternating flow (down one channel, up another, down a third, etc.); series flow in two circuits, one on each side of the amplifier (horizontal flow across a slab, turning in a common slab holder, horizontal flow across the next slab, etc.). The parallel flow geometry was chosen as the best geometry. It has the easiest gas plumbing and the lowest slab temperatures, and the flow rates are reasonable even though they are higher than the other geometries. The alternating geometry was rejected because of relatively high slab temperatures and because of the difficulty of constructing the gas flow connections between the (alternating Brewster angle) slabs. The series geometry was rejected because of its extended nonlinear temperature region and because of the difficulty of constructing the slab holders for continuous flow between slabs. (ERA citation 12:041626)