Ower / Pankhurst The Measurement of Air Flow

5. Auflage 2014
ISBN: 978-1-4831-8804-1
Verlag: Elsevier Science & Techn.
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 376 Seiten, Web PDF

The Measurement of Air Flow: 5th Edition (in SI Units) deals primarily with the measurement (expressed in SI units) of the speed of air in motion relative to solid boundaries or surfaces. The methods described apply not only to air flow but also to the flow of other gases with little, if any, modification, except as regards the numerical values of the various physical properties occurring in the equations. Furthermore, much of the theory applies to the flow of both liquids and gases. Comprised of 13 chapters, this volume begins with an overview of the general principles of the pressure-tube anemometer used in measuring pressure difference from which the speed of flow can be deduced. The reader is then introduced to the characteristics of pitot and static tubes in incompressible flow; pitot and static observations in compressible flow; and the flow of air in pipes of circular cross-section. Subsequent chapters focus on the measurement of incompressible flow in pipes by pitot and static traverse methods; methods of flow measurement based upon the rates of cooling of hot bodies; and the measurement of pulsating flow. This book is intended for students and engineers and for other practitioners concerned with the measurement of the speed of air flow.

Autoren/Hrsg.

Ower, E.

Pankhurst, R. C.

Inhaltsverzeichnis

1;Front Cover;1
2;The Measurement of Air Flow;4
3;Copyright Page;5
4;Table of Contents;6
5;PREFACE;8
6;ACKNOWLEDGEMENTS;10
7;ABBREVIATIONS USED IN LISTES OF REFERENCES;12
8;CHAPTER I. INTRODUCTION;14
8.1;References;18
9;CHAPTER II. GENERAL PRINCIPLES OF THE PRESSURE-TUBE ANEMOMETER;19
9.1;Static and Velocity Pressures;20
9.2;Pressure-tube Anemometers;21
9.3;Bernoulli's Theorem and its Application to the Measurement of Fluid Velocity;23
9.4;Bernoulli's Equation in Compressible Flow;27
9.5;Viscosity;29
9.6;The Boundary Layer;30
9.7;Dimensional Homogeneity; Reynolds Number and Mach Number;31
9.8;References;34
10;CHAPTER III. THE CHARACTERISTICS OF PITOT AND STATIC TUBES IN INCOMPRESSIBLE FLOW;35
10.1;General Principles of Design; Pressure Distribution Along Surface;36
10.2;The Pitot–Static Tube;37
10.3;The Characteristics of Pitot–Static Tubes;38
10.4;The Calibration Factors of Pitot–Static Tubes;41
10.5;The Values of the Pitot–Static Factor to be Used in Practice;45
10.6;Limitations of the Pitot–Static Tube for the Measurement of Low Speeds Under Industrial Conditions;47
10.7;Pressure-tube Anemometers with Factors Greater than Unity;48
10.8;The Pitot Cylinder;50
10.9;Disk Static Heads;52
10.10;The Effect of Turbulence on Pitot and Static Tubes;54
10.11;The Effect of a Velocity Gradient on the Reading of a Pitot Tube;56
10.12;Effects of Viscosity and Wall Proximity;57
10.13;The Effect of Misalignment;59
10.14;Checking the Calibration of a Pitot–Static Tube;63
10.15;Effect of Vibration on the Readings of a Pitot–Static Tube;64
10.16;Determination of Flow Direction;65
10.17;References;68
11;CHAPTER IV. PITOT AND STATIC OBSERVATIONS IN COMPRESSIBLE FLOW;70
11.1;Readings of Pitot Tubes in Compressible Flow;70
11.2;Pitot Tubes in Supersonic Shear Flow;75
11.3;Readings of Static Tubes in Compressible Flow;76
11.4;Pitot–Static Tubes;81
11.5;A Supersonic-flow Total-pressure Probe;83
11.6;Determination of Velocity and Mass Velocity: Measurement of Temperature;83
11.7;Error Equations in Compressible Flow;85
11.8;References;86
12;CHAPTER V. THE FLOW OF AIR IN PIPES OF CIRCULAR CROSS-SECTION;88
12.1;The Resistance of a Pipe to the Motion of a Fluid Along it;91
12.2;The Resistance of Smooth, Straight, Cylindrical Pipes;93
12.3;Rough Pipes;96
12.4;Velocity Distribution Across a Section of a Smooth Circular Pipe;98
12.5;Ratio of Mean to Axial Velocity;101
12.6;Velocity Distribution in Rough Pipes;101
12.7;Streamline or Laminar Flow in Pipes;102
12.8;The Resistance of a Pipe of Varying Cross-section;105
12.9;The Resistance of Bends and Sharp Corners in Incompressible Flow;108
12.10;Reduction of the Resistance of Mitre Bends;114
12.11;Diffusers and Sudden Expansions;120
12.12;The Turbulent-velocity Components in Fully Developed Pipe Flow;124
12.13;References;125
13;CHAPTER VI. THE MEASUREMENT OF INCOMPRESSIBLE FLOW IN PIPES BY PITOT AND STATIC TRAVERSE METHODS;127
13.1;Determination of the Mean Velocity;128
13.2;Evaluation of Pitot–Static Observations;135
13.3;Measurement of the Mean Total Pressure at a Section of a Pipe;139
13.4;Practical Notes on the Use of Pitot–Static Tubes in Pipes;140
13.5;Effects of Turbulence in Pipe-Flow Measurements;143
13.6;Influence of Displacement of Effective Centre of Pitot-tube in Pipe-flow Measurements;145
13.7;Stem-retraction Effect;147
13.8;Stem-blockage Effect;148
13.9;Measurement of Wall Static Pressure;151
13.10;Minimum Pipe Diameter in Which the Standard Pitot or Pitot–Static Tube can be Used;153
13.11;The Relative Merits of Measuring Static Pressure at a Side Hole or by Static-tube Traverse;155
13.12;Measurement of Flow in Small Pipes;157
13.13;References;162
14;CHAPTER VII. THE PLATE ORIFICE, SHAPED NOZZLE, AND VENTURI TUBE;163
14.1;Equations for the Theoretical Flow Through a Constriction;163
14.2;The Practical Use of Constrictions;166
14.3;Equations for the Flow Through a Thin Plate Orifice;168
14.4;Note on Definition Discharge Coefficient;171
14.5;Variables Affecting the Discharge Coefficient;171
14.6;The Plate Orifice;173
14.7;Standard Orifices;175
14.8;The Shaped Nozzle;189
14.9;The Standard Nozzle;190
14.10;The Venturi Tube;195
14.11;The Use of Orifices and Nozzles Other than in Pipelines;201
14.12;Special Forms of Orifice;203
14.13;Critical-flow Metering;204
14.14;Flow Straighteners;205
14.15;References;209
15;CHAPTER VIII. THE VANE ANEMOMETER;212
15.1;Low-speed Anemometers;213
15.2;Calibration Curves;215
15.3;Readings in an Inclined Stream;215
15.4;Characteristics Indicated by Theory;218
15.5;Measurement of the Rate of Flow in Pipes with Vane Anemometers;219
15.6;The Theory of the Vane Anemometer;220
15.7;References;244
16;CHAPTER IX. METHODS OF FLOW MEASUREMENT BASED UPON THE RATES OF COOLING OF HOT BODIES;245
16.1;The Cooling of Heated Wires;246
16.2;Hot-wire Anemometers;247
16.3;Electric Flowmeters;260
16.4;The Kata-Thermometer;261
16.5;References;263
17;CHAPTER X. MANOMETERS;265
17.1;The Simple U-tube;266
17.2;Single-limb Inclined-tube Manometer;267
17.3;Multi-tube and Curved-tube Manometers;269
17.4;Tilting Micromanometers;273
17.5;Long-range Micromanometers;278
17.6;Micromanometers with Small Time-lag;281
17.7;Very Sensitive Manometers;286
17.8;Betz Gauge;287
17.9;Ring-balance Manometer;289
17.10;The Two-Liquid Differential Manometer;289
17.11;Calibration of Manometers;291
17.12;Manometer Connexions;294
17.13;Lag in Leads;296
17.14;Pressure Transducers;297
17.15;References;298
18;CHAPTER XI. MISCELLANEOUS METHODS OF FLOW MEASUREMENT;300
18.1;Mean Rate of Flow in a Pipe from a Single Observation;300
18.2;The Conical Inlet Nozzle;306
18.3;The Measurement of Velocity by Observation of the Frequency of Eddies Shed by a Circular Cylinder;307
18.4;The Kent Vortex Meter;310
18.5;The Fluid-jet Anemometer;310
18.6;The Laser Doppier Anemometer;311
18.7;The Soap-film Method;314
18.8;The Quartz-fibre Anemometer;315
18.9;Direct-reading Velocity and Quantity Meters;315
18.10;References;331
19;CHAPTER XII. THE MEASUREMENT OF PULSATING FLOW;333
19.1;Measurements with Orifice Plates;335
19.2;Effects of Pulsations on Manometers;341
19.3;The Viscous Flowmeter;342
19.4;Turbine Meters;343
19.5;Mass Flowmeters;344
19.6;Hot-wire anemometers;344
19.7;Reduction of Pulsations by Contraction of the Stream;345
19.8;References;345
20;CHAPTER XIII. EXAMPLES FROM PRACTICE;347
20.1;Measurement with a Pitot–static Tube of the Quantity of Air Flowing Along a Pipe;347
20.2;Calibration of a Small Plate Orifice;348
20.3;Note on Determination of Flowrate in Peripheral Zone;360
20.4;Effect of Humidity on Air-speed Measurement;360
20.5;Note on the Changes of Static and Total Pressure Along a Pipe System and on the Measurement of Resistance;363
20.6;References;364
21;APPENDIX I: METRIC UNITS;366
22;APPENDIX II: NUMERICAL EVALUATION OF NON-DIMENSIONAL QUANTITIES;370
23;APPENDIX III: STANDARD ATMOSPHERIC PROPERTIES AT SEA-LEVEL;372
24;NAME INDEX;374
25;SUBJECT INDEX;378