Air Cooling Fan System Vibration Characteristics Of Experimental Research, The Working Conditions

Direct air-cooling fan system is very efficient in water-saving in power station. It is in rapid development and has a wide foreground. But the most urgent problem is how is fan bridge's vibration in engineering designing.The study on vibration of fan bridge including three parts:measurement on dynamic character of fan bridge, measurement on reaction of forced vibration of fan bridge and measurement on disturbing force made by fans. In the three parts mentioned above, the last one is the most important because it is the reason why fan bridge would to vibrate.A 1:1 model of fan system is made. Every equipment of fan system is the same to the one used in the power station and they are fixed at the same precision as in the power station. So the model is very similar to the real fan system in the power station.The measurement use hammer method to study dynamic character of the model structure and get much model characters in detailed statistics, such as natural frequencies, mode and damping ratio, for reference in engineering design.The forced vibration response test use the most advanced vibration testing equipment, named LMS TESTLABE. The test is done as the fan system was working in each exact operation condition in order to know acceleration history and acceleration frequency spectrum. The acceleration values were tested and recoded then were analyzed in order to know the maximum of acceleration on each testing point. The characteristic was known by analyzing to the acceleration frequency spectrum. A conclusion was reached from the analysis of fan bridge's forced vibration to provide a reference for engineering.The measurement use wireless dynamic strain testing skill to test the dynamic strain of the fan spool which is working in each exact operating condition in order to confirm the disturbing force made by the fans. The disturbing force has four components which are created by different reasons. The measurement provide some reference for CHAIN'S self reliant design of Direct Air-cooling system of power station. The four components are:1.force created by eccentric mass of fan rotor 2.force created by fan blades' vibration out of water level surface.3. torque created by air's counterforce 4.force on axial direction created by air's counterforce. The measurement give the exact detailed statistic of every kinds of disturbing force to engineering design of reference.