外文翻譯---旋轉(zhuǎn)機(jī)械葉片振動時軸的瞬時角速度（英文）

1、Shaft instantaneous angular speed for blade vibration in rotating machineAhmed A. Gubran, Jyoti K. Sinha nSchool of Mechanical, Aerospace and Civil Engineering (MACE), The University of Manchester, Sackville Street, Manc

2、hester M13 9PL, UKa r t i c l e i n f oArticle history:Received 29 June 2012Received in revised form19 December 2012Accepted 3 February 2013 Available online 26 March 2013Keywords:Instantaneous angular speed (IAS)Blade v

3、ibrationBlade health monitoring (BHM)Blade faultsShaft torsional vibrationOrder trackinga b s t r a c tReliable blade health monitoring (BHM) in rotating machines like steam turbines and gasturbines, is a topic of resear

4、ch since decades to reduce machine down time, maintenancecosts and to maintain the overall safety. Transverse blade vibration is often transmittedto the shaft as torsional vibration. The shaft instantaneous angular speed

5、 (IAS) is nothingbut the representing the shaft torsional vibration. Hence the shaft IAS has been extractedfrom the measured encoder data during machine run-up to understand the bladevibration and to explore the possibil

6、ity of reliable assessment of blade health. A numberof experiments on an experimental rig with a bladed disk were conducted with healthybut mistuned blades and with different faults simulation in the blades. The measured

7、shaft torsional vibration shows a distinct difference between the healthy and the faultyblade conditions. Hence, the observations are useful for the BHM in future. The paperpresents the experimental setup, simulation of

8、blade faults, experiments conducted,observations and results.fax: þ44 161 3064601.E-mail addresses: ahmed.gubran@postgrad.manchester.ac.uk, ahmed.gurban1@gmail.com (A.A. Gubran), jyoti.sinha@manchester.ac.uk (J.K. S

9、inha).Mechanical Systems and Signal Processing 44 (2014) 47–59It is also assumed that the time interval for nth tooth is measured at the time, Tn asTn ¼ tn þtn þ1 2 ð2Þwhere n¼1, 2, 3, 4, 5,

10、y, N number of teeth in the gear of the encoder. (ii) The angular displacement Dy for the each equally spaced tooth in the gear wheel of the encoder can be written asDy ¼ 3601=N ¼ 2pN ð3Þ(iii) Hence t

11、he instantaneous angular speed (IAS) at time, Tn in terms of revolution per second (RPS) can be calculated asInstantaneous angular speed ðIASÞ ðf snÞ at ðTnÞ ¼ DyðDtn2pÞ ð

12、;4ÞThe extracted IAS signal from the measured pulse train from an encoder may look as shown in Fig. 2 if the shaft is rotating at a constant speed. It is expected to be the ideal case when there is no fluctuation in

13、 the speed during the shaft rotation and/or no shaft torisonal vibration i.e., Dt1 ¼ Dt2 ¼ Dt3 ¼ ? ? ? ¼ DtN. However in reality these time intervals, Dtn, may not be always constant due to the speed

14、fluctuation and/or due to the presence of shaft torsional vibration and can be presented as Fig. 3. The time vectors, Tn and corresponding IAS, f ns may not be at the equal time interval, hence the data are re-sampled wi

15、th a uniform time interval before further signal processing.3. Experimental setupIn order to investigate the feasibility of torsional vibration measurement technology for incipient blade deterioration, an experimental te

16、st rig was built in the dynamics Lab at the school of MACE at the University of Manchester for this study. The test rig mainly consists of: (a) 1 hp 3-phase motor, (b) two SKF type YS 20 TF, ball bearings, (c) a steel sh

17、aft of diameter 20 mm, (d) a bladed disc with eight rectangular blades, and (e) a flexible coupling between the motor shaft and the rotating rig shaft. The schematic of rig with the instruments is shown in Fig. 4. A phot

18、ograph of the test rig including the measurement system is also shown in Fig. 5. The dimensions and material properties for the shaft–disc–blade system are listed in Table 1. The photographs for a blade and a bladed disc

19、 are also shown in Fig. 6.3.1. InstrumentationsFigs. 4 and 5 also show the mounting of the encoder at the end of the rotor shaft and the accelerometers on the bearing housing. The measuring system composed of one rotary

20、shaft encoder, Kubler-2400, which generate 360 pulses per revolution. A tacho sensor (Model S51-PA-2-A00-NK) retro-reflective optical sensor was used to monitor rotating speed.Fig. 2. Idealised shaft IAS showing constant