Combining high power laser modules with compound parabolic concentrators to test components at high heat fluxes

Abstract

Assessing the performance and lifetime of components is a key step towards deploying new technologies in the aerospace and fusion sectors. Experimental testing at representative thermal conditions is particularly important when investigating novel materials that have yet to be fully characterized. This paper presents the key features of a new high-power laser facility developed to test components destined for extreme environments.This facility, OLAHF (Oxford LAser Heating Facility), provides a maximum power of 24 kW over an area of 200 mm by 104 mm for a base intensity of 1.15 MW/m2 via a combination of laser modules. A bespoke control system manages the laser and instrumentation systems as well as supporting cooling air and water infrastructure. A numerical model of the lasers is validated against supplier data, enabling high fidelity computational representation of experimental setups.Compound parabolic concentrators (CPCs) are investigated to increase applied laser power over smaller testing surfaces. A laser module-CPC system assessed the performance of gold and aluminum coatings at a range of surfaces roughnesses. High transmission efficiencies were demonstrated when surfaces are gold coated and below 0.1μm average roughness. Future plans for OLAHF are additionally presented, including additional test campaigns using higher power CPC systems.