Contents
1 District Heating 1
1.1 District Heating Systems 1
1.1.1 Overview of District Heating Systems 1
1.1.2 Development of District Heating System 2
1.1.3 Industry Standard of District Heating System Pipe Network 8
1.1.4 Problems of District Heating System Pipe Network 13
1.1.5 Future Development of District Heating Systems 25
References 28
2 Basic Characteristics of Heating Pipeline Network System 31
2.1 Heating Pipeline Network 31
2.1.1 Prefabricated Insulation Pipe Structure 31
2.1.2 SoilMass 36
2.2 Long-Distance Transmission and Supply Pipe Network System LayingMethod 40
2.2.1 Laying on the Ground 41
2.2.2 Underground Laying 43
2.3 Installation of Heating Pipeline Network 47
2.3.1 Installation Components of Heating Pipeline Network 47
2.3.2 Layout of Heating Pipeline Network 50
2.3.3 Installation Method of Heating Pipelines 54
References 55
3 Basic Theory of Long Distance Pipeline 57
3.1 Basic Theory of Fluid Solid Thermal Coupling 58
3.1.1 Development of Fluid Structure Thermal Coupling Cooperation 58
3.1.2 Definition and Classification of Fluid Solid Thermal Coupling 60
3.1.3 Fluid–Solid–Thermal Coupling Calculation Theory 66
3.1.4 Research Methods for Fluid Solid Thermal Coupling 74
3.1.5 Theoretical Analysis of Multi Field Coupling 78
References 81
4 Theory of Elastoplasty and Economic Evaluation for Directly Buried Insulated Pipeline Systems 83
4.1 Development of Pipeline Elastoplasticity 83
4.2 Elastoplastic Definition and Classification of Pipeline 85
4.2.1 Elastoplastic Definition and Characteristics of Pipeline 85
4.2.2 Elastoplastic Classification of Pipelines 87
4.3 Pipeline Elastic–Plastic Calculation Theory 89
4.3.1 Calculation Theory of Elasticity 89
4.3.2 Calculation Theory of Plastic Mechanics 92
4.3.3 Definition and Classification of Pipeline Heat Loss 93
4.3.4 Theoretical Calculation of Heat Loss 94
4.4 Economic Evaluation of Pipe Network Operation 102
4.4.1 Economic Evaluation Theory 102
References 104
5 Case Study on Fluid–Solid Thermal Coupling in Heating Pipelines 107
5.1 Effects of the Temperature and Pressure Loads Coupled on Structure Stress of “L”-Type Large-Diameter Buried Pipe Network 108
5.1.1 Overview 108
5.1.2 Numerical Model 109
5.1.3 Results and Analysis 111
5.1.4 Conclusion 119
References 121
6 Effects of End to Side Displacement Load on Structure Stress and Deformation of “L”-Type Large-Diameter Buried Pipe Network 123
6.1 Overview 123
6.2 Numerical Model 124
6.3 Results and Analysis 125
6.3.1 Equivalent Stress and Strain Distribution of Pipeline Network Under Equivalent Displacement Load 126
6.3.2 Effect of Equivalent End Displacement Release on Equivalent Stress and Deformation of Pipelines 127
6.3.3 Equivalent Stress and Deformation Distribution of Pipelines Under Non-Equivalent Displacement Loads 130
6.3.4 Effect of Unequivalent End Side Displacement Release on Equivalent Stress and Deformation of Pipelines 130
6.4 Conclusions 133
References 134
7 Analysis of Fluid–Solid–Thermal Performance of L-Shaped Pipeline System 135
7.1 Overview 135
7.2 Numerical Model 136
7.3 Results and Analysis 139
7.3.1 Comparison of Experimental Parameters 139
7.3.2 Analysis of Pressure and Temperature Fields in the Fluid Region 141
7.3.3 Deformation Distribution Performances of the Pipeline Under Different Loads and Laying Conditions 142
7.3.4 Influences of Different Loads on Maximum Deformation of Elbow 146
7.3.5 Influences of Coupling Action on Maximum Deformation of an Elbow 149
7.4 Conclusions 150
References 151
8 Coupled Validity Analysis of Solid-Heat Multi-Field Model for Straight Tube Flow 153
8.1 Overview 153
8.2 Numerical Model 154
8.3 Results and Analysis 157
8.3.1 Stress and Deformation Distribution of Pressure Pipeline Along Axial Direction and Cross-Section 158
8.3.2 Stress and Deformation Distribution of Pipeline Under Separate Action of Temperature Loading and Pressure Loading 160
8.3.3 Distribution of Stress and Deformation in the Axial Direction at Critical Points of the Pipe Cross-Section Under Coupling Action 165
8.4 Conclusions 166
References 167
9 Influence of Key Structural Parameters on Total Heat Loss and Heat Transfer Between Tubes 169
9.1 Overview 169
9.2 Numerical Model 171
9.3 Results and Analysis 173
9.3.1 Influence ofKey Structural Parameters on the Total Heat Loss of the System 173
9.3.2 Influence of Key Structural Parameters on Heat Transfer Between Tubes 176
9.3.3 Influence of Dimensionless Characteristic Parameters on the Total Heat Loss of the System and Heat Transfer Between Pipes 176
9.3.4 Influence of Dimensionless Characteristic Parameters on Heat Loss Cost and Material Consumption Cost 180
9.4 Conclusions 183
References 184
10 Case Study on External Load Action of Large Diameter Energy Transport Pipeline 187
10.1 Dynamic Response of L-shaped Oil Pipeline Under End-Side Displacement 189
10.1.1 Overview 189
10.1.2 Numerical Model 190
10.1.3 Results and Analysis 192
10.1.4 Conclusions 206
References 207
11 Dynamic Response of Natural Gas Pipeline Under Moving Loads 209
11.1 Overview 209
11.2 Numerical Model 210
11.3 Results and Analysis 212
11.3.1 The Influence of Vehicle Load on the Stress of the Pipeline Section 213
11.3.2 The Influence of Vehicle Position on the Stress of the Pipeline Section 217
11.3.3 Equivalent Model of Moving Load Space–time Conversion 222
11.4 Conclusions 225
References 226
12 Hazardous Area Prediction for Natural Gas Pipelines Under Falling Rocks 229
12.1 Overview 229
12.2 Numerical Model 230
12.3 Results and Analysis 232
12.3.1 Overall Equivalent Stress Distribution of Pipeline 232
12.3.2 Equivalent Force Along the Circumference of the Pipe Section 233
12.3.3 Axial Equivalent Force at Pipe Nodes 236
12.3.4 Evolution and Prediction of Plastic Damage Zone in Pipelines 237
12.4 Conclusions 244
References 245
13 Study on the Plastic Region of Natural Gas Pipeline Under Ground Overload 247
13.1 Overview 247
13.2 Numerical Model 248
13.3 Result and Analysis 252
13.3.1 Overall Stress Distribution and Plastic Zone Development of Pipelines 252
13.3.2 Distribution Characteristics of Hazardous Areas in Pipelines Based on Stress Failure Criteria 255
13.3.3 Distribution Characteristics of Hazardous Areas in Pipelines Based on Strain Failure Criteria 261
13.4 Conclusions 263
References 264
14 Dynamic Response of Hydrogen Transportation Pipeline Under the Action of Oblique Reverse Faults 267
14.1 Overview 267
14.2 Numerical Model 268
14.3 Influencing Factors of Buried Pipeline Under Oblique Reverse Fault 273
14.3.1 Study on the Influence of Internal Pressure on Mechanical Response of Pipeline 273
14.3.2 Study on the Effect of Wall Thickness on the Mechanical Response of Pipes 281
14.3.3 Study of the Effect of Depth of Burial on the Mechanical Response of Pipelines 287
14.3.4 Study of the Effect of Soil Type on theMechanical Response of Pipelines 293
14.4 Plastic Regional Distribution Characteristics of Buried Pipelines Under Oblique Reverse Fault Action 298
14.4.1 Pipeline Plasticity Hazardous Area Analysis 298
14.4.2 Analysis of the Impact of Sensitivities in Pipeline Plasticity Hazardous Areas 303
14.4.3 Equation for Predicting the Length of Pipeline Plasticity Hazardous Areas 308
14.5 Conclusion 310
References 313