Status and Improved Performance of the Arc-heated Facility L3K.

Abstract

The arc heated facility L3K of DLR has been upgraded in order to test larger TPS components at higher pressure and heat flux rate levels. A segmented arc heater with dual electrodes on both anode and cathode sides allows a low current operation mode on each electrode and keeps the flow contamination level significantly lower compared to Huels arc heaters with comparable power. The calibration phase of the facility is completed. About 70 calibration tests have been performed in different arc heater and test model configurations. Measured radial Pitot pressure profiles behind the exit of a conical nozzle with 29 mm throat and 300 mm exit diameter show a homogeneous flow core of about 280 mm. Long term thermal behaviour of facility components has been tested using different test models. A stagnation point test model with a diameter of 100 mm representing standard test configuration for the qualification of TPS materials was tested for 15 minutes without any operation problems of the facility. Another water cooled cylindrical model with a diameter of 150 mm and length of 200 mm was placed with its main axis perpendicular to the flow axis and tested for 3 minutes to test the flow blockage and thermal behaviour of the facility. Since sophisticated measurement techniques like LIF, IR thermography, pyrometry, heat flux measurements, etc. have already been qualified in the 1 MW L2K facility and are compatible with both facilities, the L3K facility is ready for tests.