Water Hammer in Pipe-Line Systems (eBook)

Front Cover 1
Water Hammer in Pipe - Line Systems 4
Copyright Page 5
Contents 8
Preface 12
List of symbols 14
Chapter 1. Water hammer 22
1.1 The origin of water hammer 22
1.2 Physical principles 23
1.3 Actual cases 29
1.4 Causes of water hammer 31
1.5 Examples of water hammer 33
Chapter 2. Basic equations 38
2.1 Derivation 38
2.2 Scope of application 41
Chapter 3. Solution of the basic equations 44
3.1 Methods of solution 44
3.2 Application of the method of characteristics 46
3.3 Schematization of the pipe-line system 48
Chapter 4. Parameters of the basic equations 50
4.1 Velocity of propagation of the pressure wave 50
4.2 Pipe-line diameter 55
4.3 Density of the liquid 56
4.4 Pressure losses due to friction 56
4.5 Velocity of the liquid 58
4.6 Solid particles in the pipe-line 58
4.7 Gas in the pipe-line 63
4.8 Pressure in the pipe-line 66
4.9 Cavitation 67
Chapter 5. Damping devices 69
5.1 Junction without a damping device 69
5.2 Constant pressure 69
5.3 Reservoir 70
5.4 Air chamber 71
5.5 Surge tank 73
5.6 Overflow 74
5.7 Air inlet valve 76
5.8 Cavitation 78
5.9 Integrated damping device 80
5.10 Pressure 85
5.11 Discharge 87
Chapter 6. Pressure devices 90
6.1 Attachment without a pressure device 90
6.2 Closed pipe-line 90
6.3 Local loss 91
6.4 Control valve 92
6.5 Non-return flap valve 94
6.6 Butterfly valve 94
6.7 Condenser 99
6.8 Pump 103
6.9 Turbine with fixed characteristics 107
6.10 Turbine with variable characteristics 109
6.11 Turbine controlled by a governor 114
Chapter 7. Calculation of water hammer 121
7.1 Computer application 121
7.2 Preparation 121
7.3 Input data 122
7.4 Data input and output of the results 126
7.5 Solution for the sections 128
7.6 Solution for the junctions 130
7.7 The initial state 134
7.8 Calculations for the damping devices 136
7.9 Calculations for the pressure devices 142
7.10 Calculation procedure 150
7.11 Iterative solution for the junctions 151
7.12 Checking whether a steady state was attained 152
7.13 Maximum and minimum values 152
7.14 Submission for several calculations 153
Chapter 8. Calculation of the steady state 155
8.1 Abridged calculation of the steady state 155
8.2 Modification of the pipe-line sections 156
8.3 Modification of the damping devices 157
8.4 Modification of the pressure devices 158
8.5 Submitting the calculation 160
Chapter 9. Input data file 164
9.1 Name of the calculation 164
9.2 Sections 166
9.3 Junctions 166
9.4 Parameters 167
9.5 Type of calculation 209
9.6 Graphical and numerical outputs 211
9.7 Subtitle of the calculation 216
Chapter 10. WTHD program for creating the input data file 217
10.1 Starting work with the WTHD program 217
10.2 Adding a data line to the end of the file 218
10.3 Inserting a data line into the file 218
10.4 Deleting a data line from the file 219
10.5 Modifying a data line 219
10.6 Adding a further data file 220
10.7 Formal checking of the file 220
10.8 Listing of a data file 220
10.9 Plotting of functions 221
10.10 Terminating the WTHD program 223
Chapter 11. Output of the results 224
11.1 Main output 224
11.2 Graphical output 226
11.3 Numerical output 227
11.4 WTHG program for plotting the numerical output 227
Chapter 12. Reduction of water hammer 230
12.1 Adjustment régime of a valve 230
12.2 Pump 231
12.3 Surge tank 232
12.4 Air chamber 233
12.5 Other methods of protection 233
Chapter 13. WTHM program for the calculation of water hammer 235
13.1 Basic layout of the program 235
13.2 The main program 235
13.3 Subprograms 239
13.4 Errors in the calculation 241
13.5 Denotation of the variables 244
Chapter 14. Examples of the calculation of water hammer 248
14.1 Abrupt closing of a pipe-line without considering the effect of pressure losses due to friction 251
14.2 Abrupt closing of a pipe-line with the effect of pressure losses taken into account 259
14.3 Control valves in the delivery pipe-line of a pump 272
14.4 Calculation of the characteristics of a valve from pressure measurements 280
14.5 Calculation of the valve control régime producing a required pressure or discharge curve 284
14.6 Calculation of the steady state of flow in a pipe-line network 291
14.7 Periodic variations in pressure 295
14.8 Protection of a delivery pipe of a pump by an air chamber 302
14.9 Water hammer induced by cavitation after disconnection of a pump 307
14.10 Calculation of discharge from pressure measurements 311
14.1 I Calculation of the characteristics of a pump from the measured pressures and speed 314
14.12 Starting-up of a pump with an electric motor, a butterfly valve and a condenser 317
14.13 Turbine with variable characteristics 322
14.14 Governor-controlled turbine 328
Appendix A: Subprograms for the damping and pressure devices 334
Appendix B: List of files on WTHM diskette 353
References 354
Appendix of references 357
Index 360