Upgrading of the Arc Heated Facility L3K.

Abstract

Since 1992 the arc heated facility L3K has been upgraded in order to perform material qualification tests for re-entry trajectories. A segmented arc heater with an input power of 5 MW has been installed which is powered by a multiply configurable rectifier. Additionally, the facility has been provided with a new diffuser and hot gas heat exchanger. The existing test chamber, vacuum pumping system and exhaust gas cleaning system were modified in order to run air mass flow rates up to 300 g/s. A second gas supply system was installed for argon which is used for the ignition of the arc heater and electrode protection. Two separate water cooling circuits are needed to protect the individual facility components from over-heating. Operation is controlled by an automatic control system which in case of a malfunction either generates an alarm or cuts off the facility. The individual facility components and the supply and control systems are described in detail. During the arc heater commissioning phase a large number of tests were performed which showed that the facility meets the technical requirements for material qualification tests. The results of two selected tests are discussed in detail.