Blade Design and Analysis for Steam Turbines

by Singh, Murari; Lucas, George

• ISBN13: 9780071635745
• ISBN10: 0071635742
• Edition: 1st
• Format: Hardcover
• Copyright: 2011-04-14
• Publisher: McGraw-Hill Education

Summary

Proven methods for evaluating existing steam turbine design to select proper blade for failure-free steam turbine operationBlade Design and Analysis for Steam Turbinesdetails blade functionality and how it fits in relation to the complete steam turbine system as well as construction materials and methods, manufacturing processes, and design methods to estimate reliability of blades under fatigue and vibration. Blades are at the heart of process steam turbines used to generate electricity from wind, steam, gas, and solar hydrogen. The information in this book helps turbine designers, mechanical engineers, process equipment design/maintenance engineers, and buyers of turbines estimate the reliability of blades.Blade Design and Analysis for Steam Turbines Contains abbreviations and symbol interpretations Presents a blade life assessment methodology Includes 150 illustrations Covers practical aspects of designing and assessing tools Equips you with the knowledge base to select appropriate blade designsIn-depth, practical coverage: Performance Fundamentals & Blade Loading Determination; Construction of Blades and Attachments; Relevant Strength of Materials; Fundamentals of Vibration; Damping Concepts as Applicable to Turbine Blades; Vibration Behavior of Bladed Disk System; Evaluation Concepts for Vibration of Blades; Reliability Evaluation for Blade Design; Advanced Topics

Table of Contents

Preface	p. xiii
Acknowledgments	p. xv
Introduction	p. 1
Importance of Blades in Steam Turbines	p. 1
Brief Historical Perspective of Technological Development	p. 2
Steam Turbine Design Process, Performance Estimation, and Determination of Blade Loads	p. 11
Turbine Design Process	p. 12
Introduction to Steam Turbine Thermodynamics	p. 13
Velocity Diagrams	p. 17
Euler's Equation	p. 17
Impulse Turbine	p. 19
Reaction Turbine	p. 22
Application Requirements and Conditions of Service	p. 25
Preliminary Turbine Design	p. 27
Number of Stages	p. 27
Airfoil Section Shape	p. 29
Number of Blades	p. 32
Blade Loading	p. 34
Steady Loads	p. 34
Unsteady Blade Loads	p. 37
Turbine Blade Construction, Materials, and Manufacture	p. 47
Airfoils	p. 49
Impulse and Reaction Blades	p. 50
Impulse	p. 50
Reaction	p. 51
Twisted-Tapered Airfoils	p. 52
Roots	p. 53
Circumferential or Tangential Dovetail Roots	p. 53
Axial Roots	p. 57
Pinned Roots	p. 59
Shrouds and Auxiliary Dampers	p. 62
Riveted Shrouds	p. 62
Integral Shrouds	p. 63
Z-Lock Shrouds	p. 64
Auxiliary Shroud Dampers	p. 65
Blade Materials	p. 67
Stainless Steel	p. 68
Titanium	p. 69
Other Blade Materials	p. 70
Material Forms	p. 71
Manufacturing Processes	p. 73
Erosion Protection-Condensing Stages	p. 76
Bladed Disk Assembly Processes	p. 79
Assembly of Bladed Disks with Circumferential Dovetail Roots	p. 79
Bladed Disk Assembly-Axial Fir Tree Roots	p. 83
Bladed Disk Assembly-Pinned Roots	p. 84
Riveted Shroud Installation	p. 86
Integral Shroud Installation	p. 93
Inspection, Testing, and Quality Assurance	p. 96
System of Stress and Damage Mechanisms	p. 99
Stress-Strain Behavior of Metals	p. 100
Engineering Stress-Strain Properties	p. 105
True Stress-Strain Properties	p. 106
Measure of Material's Engineering Energy Capacity	p. 108
Stress Tensor and Strain Tensor	p. 109
Stress at a Point and Stress Concentration	p. 110
Three-Dimensional Expression for Stress at a Point	p. 115
Principal Stresses and Direction Cosines	p. 116
Deformation and Fracture Damage	p. 120
Theories of Failure under Static Loads	p. 121
Creep	p. 125
Damage due to Cyclic Loading	p. 137
Review of Fundamentals of Vibration	p. 157
Discrete Systems	p. 158
Single-Degree-of-Freedom (SDOF) System	p. 158
Multiple-Degree-of-Freedom (MDOF) System	p. 161
System with Equal Frequencies	p. 164
Continuous Systems	p. 166
Cantilever Beam	p. 166
Circular Plate	p. 169
Damping Concepts	p. 171
Rheological Model	p. 171
Factors Affecting Damping	p. 172
Viscous Damping	p. 173
Critical Damping	p. 173
Proportional Damping	p. 173
Frictional Damping and Z-Lock Shroud	p. 174
Simple Estimation Method-Macromodel	p. 177
Dynamic Consideration	p. 181
Equivalent Viscous Damping	p. 184
Macroslip and Microslip	p. 186
Summary of Simple Analysis	p. 188
Vibration Behavior of Bladed Disk System	p. 191
Single Cantilevered Blade	p. 191
Packet of Blades	p. 192
Individual Disks	p. 193
Analysis of a Bladed Disk System	p. 194
Freestanding (Blades with or without a Shroud But Not Connected to One Another)	p. 194
Packeted Bladed Disk	p. 196
Completely Shrouded Design	p. 200
Evaluation Concepts for Blade Resonant Vibration	p. 201
Campbell Diagram	p. 201
Interference Diagram (SAFE Diagram)	p. 202
Work Done by an Applied Force	p. 203
Interference Diagram When Harmonics of Excitation Are Larger Than One-Half of the Number of Blades	p. 217
Effect of Temperature and Speed on Natural Frequencies	p. 221
Effect on Natural Frequency due to Centrifugal Stiffening	p. 221
Lacing Wire Construction	p. 222
Determination of Effects of Number of Blades in a Packet	p. 225
Quick Check for Requirement of a Lacing Wire Construction	p. 225
Sizing and Positioning of a Lacing Wire	p. 227
Check of Stress in the Hole in the Blade	p. 229
Partial Admission Stage	p. 232
Damped Free Vibration	p. 238
Damped Forced Vibration	p. 238
Effect of Mistuning of a Bladed Disk System on Vibration Response	p. 243
Impure Mode Shapes (Packeted Bladed Disk)	p. 245
Graphical Method	p. 250
Mathematical Expression	p. 253
Effect on Response	p. 254
Reliability Evaluation for Blade Design	p. 257
Loads, Stress, and Evaluation	p. 257
Stress due to Centrifugal Load	p. 258
Stress due to Steam Forces	p. 259
Resonant Vibration	p. 262
Blade Frequency Evaluation	p. 263
Exciting Forces	p. 264
Running Speed Harmonic Excitation	p. 264
Nozzle Passing Frequency (NPF) Excitation	p. 265
Partial Admission Excitation	p. 267
Factor of Safety Calculation	p. 268
Influence of Tolerance Stack Up in Root-Disk Attachment	p. 272
Summary of Design Criteria	p. 277
Checklist for Auditing a Blade Design	p. 278
Life Assessment Aspects for Blade	p. 283
Assessment of Useful Life of Blade in Presence of High Cycle Fatigue	p. 283
Factor of Safety Concept for High Cycle Fatigue	p. 289
Life Estimation	p. 289
Process of Shot Peen and Laser Peen to Improve Fatigue Life	p. 294
Basic Explanation for Increase in Fatigue Life	p. 294
Residual Stress due to Shot Peen	p. 296
Linear Approximation of Compressive Layer Profile	p. 296
Exponential Approximation of Compressive Layer Profile	p. 299
Combination of Applied and Residual Compressive Stress	p. 302
Linear Approximation of Combined Stress	p. 303
Exponential Approximation of Combined Stress	p. 304
Mechanistic View of Improvement in Fatigue Life due to Shot Peen	p. 306
Improvement during High Cycle Fatigue	p. 306
Improvement during Low Cycle Fatigue-Zero Mean Stress	p. 308
Process of Laser Peen	p. 308
Estimation of Risk	p. 313
Probabilistic Concept to Quantify Risk of a Proposed Design	p. 313
Probabilistic Treatment of Factor of Safety Based on Goodman Equation	p. 320
Transformation of Random Variables	p. 324
Single Cantilever Beam	p. 325
Probabilistic Low Cycle Fatigue Concept	p. 330
Summary	p. 333
Deterministic Reliability Estimation	p. 333
Stress and Fatigue Analysis	p. 333
Creep Analysis	p. 334
Modal Analysis	p. 334
Response Analysis	p. 335
Goodman Factor of Safety Based on Above Analysis	p. 335
Deterministic Life Estimation	p. 335
Probabilistic Reliability Analysis	p. 338
Probabilistic Goodman Analysis	p. 338
Probabilistic Frequency Analysis	p. 340
Probabilistic Life Estimation	p. 340
Appendix: Fourier Series	p. 343
Bibliography	p. 347
Index	p. 351
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