Failure Analysis And Monitoring Method Research Of Large Cooling Tower Fan Blade Based On Finite Element Modal Analysis

Large cooling tower fan is widely used in industrial circulating water system of the petroleum, electric power, metallurgy, chemical, and textile. When it runs, it can forcedly cooling higher temperature industrial water to make the water reused. Its key position makes enterprise to require that it should have relatively high safety stability. So enterprise can master the situation of the fan at real time and avoids serious accident if failure happens and the machine shut down. So all this makes the paper have very strong practical significance.The paper took fan blade modal analysis as main method and detailed researched the fracture part and way of damaged blade. Combining theoretical modal analyzing conclusion, the paper analyzed fragile part of blade and proposed improving scheme. Studying the existing fan failure diagnosis document, the paper proposed a new, easy and effective monitoring manner and designed a scientific and effective real time monitoring and alarming system of cooling tower fan. The researching achievement has been used in Sinopec production practice and shown that it has very good practical value.The main research achievements include:(1) extensively surveying the application of modal analysis in cooling tower fan blade analysis and deeply researching fan structure and detailed analyzing common failure mode of cooling tower fan and analyzing failure reason form mechanism and selectively analyzing the element caused blade fracture.(2) expounding theoretical basis of fan blade static modal analysis and establishing 3D solid model of fan blade and utilizing professional grid software Hypermesh to make blade meshing and using finite element software ANSYS to carry out modal analysis and comparing each modal to find out fragile part of fan blade and analyzing the solution.(3) analyzing modal when the blades of fan run and comparing static modal analyzing result and detailed describing modal result effect from power stiffening and analyzing the fan blade life effect caused by vibration through blade vibration analysis.(4) designing real time monitoring system based on blade tip pulse timing monitoring theory, and realizing blade real time monitoring, and designing fan remote automatic alarming system and text message monitoring and blue tooth monitoring system, and realizing fan blade failure on-time alarming and shut-down of fan blades.