Maintenance of Hydroelectric Generating Units

Abstract

This paper covers the complete overhaul of a 40,000-hp vertical Francis-type hydraulic turbine, operating under 454 ft head to drive a 35,000-kva generator at 257 rpm. Some of the work done was to repair normal wear due to operation over a 20-year period. Other work was of a corrective nature modifying the original design to include improvements found desirable after prolonged operation. Interesting problems were met and solved in some of the work, which involved the handling of heavy parts, and in the use of materials not originally included in the design of the unit.

Simulation of Coal Mechanical Characteristics with Discrete Element Method

“…Therefore, the simulation of uniaxial compression test should be carried out constantly with different micro-parameters, so as to get the granular media group with the same macroscopic mechanical characteristics as laboratory test. So far many researchers at home and broad have been carried out different compression simulation test in the materials of asphalt mixture, soil and concrete, etc through adopting discrete element method, and the mechanical properties and failure mode of DEM sample obtained in the simulation test are agreement with laboratory tests [2][3][4][5][6][7][8]. Up to now, there is no literatures about simulation of coal mechanical characteristics with discrete element method, however, scientific simulation of coal mechanical characteristics is important and significant to the study on coal cutting and crushing with discrete element method.…”