Author(s): Hermod Brekke
Linked Author(s): Hermod Brekke
Keywords: No Keywords
Abstract: The paper gives a brief discussion on safety and risk factors in hydraulic turbines and pumps in operation. The safety and lifetime based upon development of materials and design of stress carrying rotating and stationary parts in hydraulic turbines are discussed. Acceptance criteria for defects in base materials and welds for safe operation during life time are given based on fracture mechanics. The possibility of a brittle heat affected zone (HAZ) in fine grain high tensile strength steel is briefly described. A limitation of the working stresses to allow for "leakage before rupture" of pressurized spiral cases and pipes in general is discussed. Fatigue life time problems on runners are discussed. The possibility of extreme pressure peaks caused by governor failure or self exitating pressure oscillations caused by small gate openings or leaking seals in valves are discussed in the end of the paper.
Year: 1993