A LASER plateau size optimization strategy for TMF tests

Kurzfassung

The key component of the Thermo-Mechanical Fatigue (TMF) - test bench at DLR Lampoldshausen is a diode LASER with an optical output power of 11 kW. With the currently built-in LASER optics, heat flux values up to 8 MW/m2 can be obtained on a LASER beam plateau area of 51 mm x 19 mm. This LASER power density is sufficient to assess the life expectation of nozzle structures and to serve as a validation experiment for nozzle life prediction models. However, for the thermo-mechanical fatigue testing and validation of chamber wall structures, higher LASER power densities are needed. The cost-saving alternative to an increase of the LASER power is to replace the currently available LASER optics by a new LASER optics, leading to a smaller LASER beam plateau size and therefore, resulting in a larger LASER power density. In the current publication, an optimization strategy for the size of the LASER beam plateau area of the new optics module is shown.