Comparative Study On Two Kinds Of Isolation Schemes For The Fan Equipment Considering Mechanical Vibration

Previous earthquakes have demonstrated that the earthquake will cause seriousthreats to the security of nuclear power plants and equipment inside, and bring nuclearsafety problems. With the continuous development of nuclear power plants in China, it’snecessary to carry out research on seismic nuclear power equipment. The isolationtechnology can improve the reliability and safety of nuclear power equipment, and hasgood isolation effect and economic benefit. Nuclear power equipment like nuclear gradefan will produce mechanical vibration during normal operation. When an earthquakecomes, running fan equipment will be affected by both seismic action and mechanicalvibration. Therefore, the isolation device for nuclear fan equipment needs to achieve thepurpose of seismic isolation under seismic action and mechanical vibration.This paper uses two kinds of isolation schemes for nuclear grade fan equipmentconsidering mechanical vibration, which are the wire rope isolator scheme and thelaminated rubber bearing scheme. Through the finite element analysis, compare andstudy isolation effect of two kinds of isolation schemes. This paper firstly introducesequipment damage, isolation principle, the development and application of seismicisolation technology, and the related standard requirements of equipment isolation;secondly introduces the structure, principle and mechanical properties of two kinds ofisolation devices, to provide the theoretical basis for the following finite elementanalysis of fan equipment isolation system. A fan model using the wire rope isolator isestablished and parameters of the isolator are optimized through the finite elementsoftware ANSYS-LSDYNA. Based on the optimization parameters, fan models usingthe wire rope isolator and the laminated rubber bearing are established respectively. Fansystems of two kinds of isolation schemes and their improved schemes are comparedand studied through the finite element analysis.Research results show that: for the fan isolation system considering mechanicalvibration, the wire rope isolator scheme has isolation effect in three directions, but theeffect is not obvious. The laminated rubber bearing scheme has better horizontalisolation effect than that of the former one. But it has almost no vertical isolation effect,sometimes even increase the vertical earthquake action. The improved isolationschemes have better effect than the original ones. Therefore, to achieve the improvedschemes, it’s necessary to study a new kind of wire rope isolator with lower horizontaland higher vertical stiffness, or a new kind of laminated rubber bearing with lowerstiffness. It’s better to develop a new three-dimensional isolation device combining thetwo improved devices to meet the isolation requirement of nuclear grade fan equipment.