ABSTRACT:
Engine testing, ceramic component fabrication and evaluation, component performance rig testing, and producibility experiments at Pontiac comprised AGT 100 activities of this period, January-December 1984. Two experimental engines were available and allowed the evaluation of eight experimental assemblies. Operating time accumulated was 115 hr of burning and 156 hr total. Total cumulative engine operating time is now 225 hr. Build number 11 and 12 of engine S/N l totaled 28 burning hours and constituted a single assembly of the engine core--the compressor, both turbines, and the gearbox. Build number 11 of engine S/N l included a 1:07 hr continuous test at 100% gasifier speed (86,000 rpm). Build number 8 of engine S/N 2 was the first engine test with a ceramic turbine rotor. A mechanical loss test of an engine assembly revealed the actual losses to be near the original design allowance. Component development activity included rig testing of the compressor, combustor, and regenerator. Compressor testing was initiated on a rig modified to control the transfer of heat between flow path, lubricating oiI and structure. Results show successful thermal decoupling of the rig and lubricating/cooling oil. Rig evaluation of a reduced-friction compressor was initiated. Combustor testing covered qualification of ceramic parts for engine use, mapping of operating range limits, and evaluation of a relocated igniter plug. Several seal refinements were tested on the hot regenerator rig. An alternate regenerator disk, extruded MAS, was examined and found to be currently inadequate for the AGT 100 application. Also, a new technique for measuring leakage was explored on the regenerator rig. Ceramic component activity has focused on the development of state-of-the-art material strength characteristics in full- seal e hardware. Injection-molded sintered alpha-SiC rotors were produced at Carborundum in an extensive process and tool optimization study. Correlation of spin-to-burst rotor tests with fracture surface analyses revealed that backface flow and knit-line indications were the frequent cause of rotor bursts at relatively low speeds. A modified fabrication/rework procedure, for both green and sintered rotors, was identified whereby these surface imperfections may be removed. The exploration of injection molded GTE Si3N4 rotors included evaluation of 10 hot isostatically pressed (HIP) rotors. Burst testing demonstrated that HIP processing raised burst speed. Gasifier turbine scroll assemblies, in SiC material, are being fabricated by both Carborundum and Norton. Carborundum units are awaiting hot-rig test; engine test will follow successful rig testing. Fiber reinforced glass-ceramic composite turbine backplates were fabricated by the Corning Glass Works. Different materials were considered, and evaluation was initiated with room temperature bend testing of test bars.