Flow-Induced Instabilities of Reversible Pump Turbines (SpringerBriefs in Energy)

Preface
Contents
Abbreviations
1 Introduction
	1.1 Background
	1.2 Research Status
	1.3 Description of the Book
	References
2 Generation Mechanisms of Typical Unstable Flows
	2.1 Rotor–Stator Interaction
	2.2 Vortex Rope
	2.3 Rotating Stall
	2.4 Karman Vortex
	2.5 Cavitation
	References
3 Flow-Induced Pressure Fluctuations and Vibrations in Generating Mode
	3.1 General Description
	3.2 Experimental Setup
		3.2.1 Structural Sketch and Essential Parameters of the RPT
		3.2.2 Definitions of Dimensionless Parameters
		3.2.3 Experimental Instruments and Procedures
	3.3 Signal Analysis Methods
		3.3.1 Peak-to-Peak Value
		3.3.2 FFT Spectrum
	3.4 Influences of Load Variations
	3.5 Influences of Water Head Variations
	References
4 Flow-Induced Transient Pressure Fluctuations During Start-up Process of Pumping Mode
	4.1 General Description
	4.2 Experimental Setup
		4.2.1 Structural Sketch and Essential Parameters of the RPT
		4.2.2 Monitoring Points and Experimental Sensors
		4.2.3 Description of Start-up Process of Pumping Mode
		4.2.4 Definitions of Dimensionless Parameters
	4.3 Signal Analysis Methods
		4.3.1 Savitzky-Golay Filter
		4.3.2 Peak-to-Peak Value
		4.3.3 STFT Spectrogram
	4.4 Transient Pressure Fluctuations in First Stage
		4.4.1 Operational Details
		4.4.2 Time-Domain Analysis
		4.4.3 Time–Frequency Analysis
	4.5 Transient Pressure Fluctuations in Second Stage
		4.5.1 Operational Details
		4.5.2 Time-Domain Analysis
		4.5.3 Time–Frequency Analysis
	References
5 Evaluation of Operational Stability of Main Shaft
	5.1 General Description
	5.2 Signal Analysis Methods
		5.2.1 Wavelet Threshold De-noising Method
		5.2.2 Empirical Mode Decomposition
		5.2.3 Ensemble Empirical Mode Decomposition
		5.2.4 Variational Mode Decomposition
		5.2.5 Cross-Correlation Coefficient
		5.2.6 Permutation Entropy
		5.2.7 Flowchart of Proposed Signal Analysis Procedure
	5.3 Extraction of Simulated Shaft Displacement Signal
		5.3.1 Description of Simulated Shaft Displacement Signal
		5.3.2 Signal Analysis Results
	5.4 Extraction of Measured Shaft Displacement Signal
		5.4.1 Description of Measured Shaft Displacement Signal
		5.4.2 Signal Analysis Results
	5.5 Recognition of Shaft Orbit
		5.5.1 Pressure Fluctuations in Draft Tube
		5.5.2 Shape Evolution of Shaft Orbit
		5.5.3 Permutation Entropy of Shaft Orbit
	References
6 Intelligent Recognition of Flow-Induced Vibration Faults
	6.1 General Description
	6.2 Feature Extraction
		6.2.1 Time-Domain and Frequency-Domain Indexes
		6.2.2 Energy Indexes Based on VMD
		6.2.3 Permutation Entropies Based on VMD
		6.2.4 Multidimensional Eigenvector
	6.3 Intelligent Recognition Algorithms
		6.3.1 Extreme Learning Machine
		6.3.2 Restricted Boltzmann Machine
		6.3.3 Deep Belief Network
	6.4 ME-VMD-DBN Fault Diagnostic Model
	6.5 Recognition of Flow-Induced Vibration Faults of Top Cover
		6.5.1 Description of Samples
		6.5.2 Recognition Results
	References
7 Conclusion
Index