Dissertation > Excellent graduate degree dissertation topics show

Study of Pressure Fluctuations on the Cold Test Fluidized Bed

Author: XiaBao
Tutor: GaoJianQiang
School: North China Electric Power University
Course: Thermal Power Engineering
Keywords: fault analysis bubbling fluidized bed pressure signal spectrum analysis wavelet packet analysis
CLC: TK229.6
Type: Master's thesis
Year: 2011
Downloads: 94
Quote: 0
Read: Download Dissertation

Abstract


Currently the boiler pressure measuring points of the circulating fluidized bed are all installed in the furnace walls. Extensive recycling of materials, and frequent frication and clash of measuring points make the plug wear problem at the measuring points very serious, resulting in inaccurate measurements or damage of the measuring points. To solve the problem, in this thesis I arrange pressure measuring points on the walls at the entrance of the wind chamber hood when setting up cold bubbling fluidized bed test rig, then the collected pressure signals are transformed into digital signals with pressure signal acquisition system,and the digital signals are stored in the computer. During the test, I collect pressure fluctuation signals in normal operating conditions and disturbance conditions by adjusting and changing the test’s control conditions and carry out in-depth analysis and research of the signals to probe pressure fluctuation conditions in fluidized bed.Based on Matlab programming and using autocorrelation function of the Fourier transform method, the time domain signals are transformed into frequency domain signals. From the received signal spectrum we can clearly see that the pressure fluctuation at the hood inlet is closely related to some parameters such as static bed height of fluidized bed and superficial gas velocity, in addition pressure wave energy is mainly manifested by low-frequency pressure fluctuations, which show that monitoring signals collected at hood entrance can reflect the status of pressure fluctuation in fluidized bed. Then I denoise the signals,by comparative analysis of project filter method and wavelet denoising method,wavelet denoising method is proved better than project filter method. Further by selective comparison of different wavelet bases for denoising, it is concluded that db2 wavelet three-layer decomposition denosing method can be used to achieve the best denosing effects.During the test, I stimulate some disturbance conditions such as failure of monitoring pressure signals in fluidized bed scene, disturbance generated by placing materials and hood blocking. By using time domain analysis, frequency domain analysis and wavelet packet analysis, I reach different results in normal conditions and disturbance conditions and establish the fault signals’diagnosis and recognition method. I use time domain analysis, by using method of setting confidence interval, to determine whether pressure signals go wrong. I use frequency domain analysis, by comparing different spectrums in normal conditions and placing materials disturbance conditions, to serve spectrum as feature vector and achieve fault diagnosis recognition. By using wavelet packet analysis, carrying out three-layer decomposition of the pressure signals and reconstructing them, and comparing different node powers at each node in normal and disturbance conditions, it is concluded that the signal power spectrum at p30 can serve as feature vector to determine whether hood block arise in circulating fluidized bed, achieve fault diagnosis and provide a theoretical reference and basis for field application.

Related Dissertations

  1. The Research on the Experimental Technique of the Testing of the Large Scale Model in Real Waves,U661.7
  2. The Study of Palmprint Image Identification Based on Wavelet Analysis,TP391.41
  3. Three parameters of human stress detection system,R318.0
  4. FPGA DSP for GPS -based digital IF signal source design,TN741
  5. The overloaded train bearing failure audio signal integrated diagnostic program research,U279
  6. Research of Fault Diagnosis Instrument for Gearbox Based on Vibration Signal Analysis,TH165.3
  7. Study of Sea Wave and Tide Measurements Based on GPS Velocity Estimation,P228.4
  8. Factor Analysis and Feature Extraction on Rolling Mill Chatter,TG333
  9. Study on the Fault Diagnosis of Variable Frequency Speed Regulation System Based on Wavelet Packet Neural Network,TM921.51
  10. Research on the Impact of the Velocity Inlet Boundary Condition to the Bubbling Fluidized Bed,TK124
  11. Blasting vibration characteristics and impact of the building structure,TU311.3
  12. Intelligent Diagnosis of Epilepsy Based on the Wavelet Transform and Genetic Neural Network,TP183
  13. The Design of EEG Signals Acquisition and Analysis System,R318.6
  14. Fault Diagnosis of the Key Components of CNC Machine Based on Wavelet Neural Network,TP183
  15. Research on the Pipeline Leak Location Based on Wavelet Packet Analysis and Neural Networks.,TP183
  16. Seismic Response Analysis of Continuous Rigid Frame Bridge with Bottom Cable Level Layout,U442.55
  17. The Control Circuit Design of Mine Roof Pressure Signal Acquisition,TD326
  18. The Experimental Study of Renal Capsular Block on Gastric Electrophysiologic Contribution,R614
  19. Railway steel box girder single cable plane cable - stayed bridge design and structure of the static and dynamic analysis of,U448.27
  20. VSR ARM-based system design,TG156.92
  21. Design and Implementation of Radar Signal Simulator Based on DDS,TN955

CLC: > Industrial Technology > Energy and Power Engineering > Steam Power Engineering > Steam boiler > Various types of boilers > Coal-fired boilers
© 2012 www.DissertationTopic.Net  Mobile