Hướng dẫn dòng chảy thủy lực
OPERATIONS TRAINING PROGRAM STUDENT TEXT Rev. 0 FLUID FLOW OPERATIONS TRAINING PROGRAM Contents: Table of Contents: NOTICE: If you plan to use this material in a classroom setting, then please purchase the exam bank and answer key from the Scribd store for $4.99 or visit marathonjohnb at Scribd. The exam is given at the end of the course and has specific questions for each chapter ii Contents: iii Chapter 1 INTRODUCTION TO FLUIDS 12 Introduction 12 Description of Fluids 13 Humidity 14 Relative Humidity 14 Density () and Specific Volume () 14 Density Differences for Non-Mixable (Non-Miscible) Fluids 15 Specific Gravity 18 Pressure (p) 21 Pressure Measurements 23 Absolute, Gage, and Vacuum Pressure Relations 30 Buoyancy 32 Hydrostatic Pressure 34 Pascal's Law (the law of hydraulics) 39 Pressure Difference for Fluid Flow 41 Chapter 1 Summary 43 Chapter 2 Compression of Fluids 45 Compressibility 45 The Combined Gas Law 45 Effects of Pressure Changes on Confined Fluids 47 Effects of Temperature Changes on Confined Fluids 48 Filling and Venting 48 iii of xii Rev. 0 OPERATIONS TRAINING PROGRAM Chapter 2 Summary 51 Chapter 3 NATURAL CIRCULATION FLOW 53 Natural Circulation 53 Conditions Required For Natural Circulation 54 Chapter 3 Summary 56 Chapter 4 VOLUMETRIC AND MASS FLOW RATE 57 Volume (V) 57 Volumetric Flow Rate () 59 Mass, Density, and Specific Volume 64 Mass Flow Rate () 66 The Steady Flow Condition 68 Continuity of Flow 68 Chapter 4 Summary 75 Chapter 5 TYPES OF FLOW 77 Laminar Flow 77 Turbulent Flow 77 Factors Influencing Type of Flow 78 Ideal Fluid 79 Noise Level and Flow Rate 79 Chapter 5 Summary 80 Chapter 6 FORMS OF ENERGY &THE GENERAL ENERGY EQUATION 81 General Energy Equation 81 Potential Energy (PE) 83 Kinetic Energy (KE) 84 Flow Energy (FE) 84 Internal Energy (U) 87 Heat, as an operator controlled input or output (Q) 88 Work, as an operator controlled input or output (W) 89 General Energy Equation 89 A Special Case of the General Energy Equation: Bernoulli's Principle 92 Simplified Bernoulli's Equation 94 Specific Energies 96 Chapter 6 Summary: 98 ENERGY CONVERSIONS IN IDEAL FLUID SYSTEMS 99 iv of xii Rev. 0 OPERATIONS TRAINING PROGRAM Energy Conversions in Ideal Fluid Systems 99 Energy Conversions for Changes in Cross-Sectional Area (Flow Area) 99 Energy Conversions for Changes in Elevation 102 Chapter 7 Summary: 105 Chapter 7 Energy Conversions in Real Fluid Systems 107 Friction 107 Fluid Friction 107 Viscosity 108 Energy Conversion by Fluid Friction in Real Fluids 108 Energy Conversion by Fluid Friction 110 Open versus Closed Fluid Flow Systems 116 Energy Conversions in Closed Systems 116 _Head_ 120 Head Loss due to Friction 125 Throttling 126 Overcoming Head Losses 127 Centrifugal Pump Operation 128 Positive Displacement Pump Operation 129 Using the General Energy Equation to Analyse Real Fluids 130 Specific Rules Using Arrow Analysis 135 The General Energy Equation and Diagnosis using Arrow Analysis 137 Chapter 8 Summary: 149 Chapter 8 Fluid Flow Measurement 151 Flow Measuring Devices 151 Differential Pressure Meters 151 Orifice Plates 151 Flow Nozzles 153 Venturi Tubes 153 Other Applications of the Venturi Principle 154 Chapter 9 Summary: 157 Water Hammer and Pipe Whip 159 Mechanisms of Water Hammer 159 Occurrence of Water Hammer (and Steam Hammer) 159 Cavitation 165 Cavitation in Centrifugal Pumps 165 v of xii Rev. 0 OPERATIONS TRAINING PROGRAM Net Positive Suction Head (NPSH) 167 Conditions Causing Cavitation 168 Minimizing Gas Formation in Liquid Piping Systems 170 Other Pump Problems 170 Possible Results of Water Hammer 171 Methods of Water (and Steam) Hammer/ Pipe Jet & Pipe Whip Prevention 174 Chapter 10 Summary 176 Chapter 9 Unintended Siphoning 177 Introduction 177 Siphoning 177 Chapter 11 Summary 180 List of Figures: Figure 1-1 Example of non-miscible fluids 15 Figure 1-2 Pressure caused by Molecules 22 Figure 1-3 Force versus Pressure 22 Figure 1-4 Pressure Scales 24 Figure 1-5 Typical Pressure Gage 24 Figure 1-6 Liquid Supported by Atmospheric Pressure 25 Figure 1-7 Buoyancy Forces on an Object 33 Figure 1-8 Relationship between Liquid Level and Pressure 34 Figure 1-9 Pressure Versus Height 35 Figure 1-10 Static Head versus Pressure 36 Figure 1-11 Head and Pressure Illustration 38 Figure 1-12 Pressurizing a 40 Figure 1-13 Hydraulic System Forces 40 Figure 1-14 A Simple Hydraulic System 41 Figure 3-15 Air Baloon Buoyancy 53 Figure 3-16 Heat Source / Heat Sink 54 Figure 4-17 Volume of an Object 57 Figure 4-18 Volume of Pipe Section A 58 vi of xii Rev. 0 OPERATIONS TRAINING PROGRAM Figure 4-19 Volume of Pipe Section B 58 Figure 4-20 Volumetric flow Rate Visual 59 Figure 4-21 Volumetric Flow rate Between Two Points 60 Figure 4-22 Volumetric Flow Rate Example 1 61 Figure 4-23 Volumetric Flow Rate Example 2 63 Figure 4-24 Mass Flow Rate Example 67 Figure 4-25 Continuity of Flow 68 Figure 4-26 Continuity Example 2 71 Figure 5-27 The Two Basic Types of Fluid Flow 78 Figure 6-28 A Visual of Potential Energy 83 Figure 6-29 Visual of Kinetic Energy 84 Figure 6-30 Flow Energy in Compressing Piston 85 Figure 6-31 Flow Energy in Fluid Flow through a Pipe 85 Figure 6-32 Visual of Flow Energy 86 Figure 6-33 Visual of Internal Energy 87 Figure 6-34 Visual of Heat Energy 88 Figure 6-35 Visual of Work Energy 89 Figure 6-36 Fluid Energies 'IN' versus 'OUT' 90 Figure 6-37 Energies Added versus Energies Removed 90 Figure 6-38 Visual of the General Energy Equation 91 Figure 6-39 Bernoulli's Principle 92 Figure 6-40 Ping Pong Ball Floating in Air Stream 93 Figure 6-41 Air Passing Above and Below Airplane Wing 93 Figure 6-42 Air Passing by a Thrown Baseball 94 Figure 7-43 Pipe Section with a Reduction in Area 101 Figure 7-44 Pipe Section With Increase in Area 101 Figure 7-45 Pipe Section with Increasing Elevation 103 Figure 7-46 Pipe Section with Decreasing Elevation 103 Figure 8-47 Straight Pipe Section 109 Figure 8-48 Pipe Section with Changes in size and Elevation 109 Figure 8-49 The Pressure Drop from a 1°F Temperature Rise 111 vii of xii Rev. 0 OPERATIONS TRAINING PROGRAM Figure 8-50 Pressure Drop and Fluid Friction 114 Figure 8-51 Energy Conversions in a Closed System 117 Figure 8-52 A Simple Closed Loop System 119 Figure 8-53 Closed Loop Example 119 Figure 8-54 Pressure is Proportional to Column Height 120 Figure 8-55 Pressures Within a Fluid Flow System (exaggerated) 123 Figure 8-56 Total Static Head Examples 125 Figure 8-57 Typical Valve 127 Figure 8-58 A Centrifugal Pump 128 Figure 8-59 Pressures Within a Centrifugal Pump 129 Figure 8-60 Positive Displacement Pump 130 Figure 8-61 General Energy Equation in Mental Form 130 Figure 9-62 A Simple Orifice Plate 152 Figure 9-63 A Simple Flow Nozzle 153 Figure 9-64 Simple Venturi Tube 154 Figure 9-65 Auto Carburetor Uses Venturi Principle 154 Figure 9-66 A Typical Steam Jet 155 Figure 9-67 A Simple Eductor 156 Figure 10-68 Case 1 Valve Quickly Closed 162 Figure 10-69 Case 2 Valve Quickly Opened 162 Figure 10-70 Case 3: Cold Condensate in Steam Line 163 Figure 10-71 Case 4: Hot Condensate in Steam Line 163 Figure 10-72 Case 5: Boiling 164 Figure 10-73 Cavitation in a Centrifugal Pump 166 Figure 10-74 Cavitation and the Collapsing Bubble 167 Figure 10-75 Pump Runout 168 Figure 10-76 Low Suction Pressure 169 Figure 10-77 Pipe Rocket / Pipe Jet 172 Figure 10-78 Pipe Whip 173 Figure 11-79 Example of a Siphon 178 viii of xii Rev. 0 OPERATIONS TRAINING PROGRAM List of Tables: Table 1-1 Densities of Common Materials 15 Table 1-2 Densities of Common Fluids 21 Table 1-3 Common Pressure Units 26 Table 1-4 Absolute, Gage and Vacuum Pressure 30 List of Terminal Objectives: TO 1.0Given the necessary fluid system parameters, SOLVE for unknown fluid parameter values as system conditions are varied 12 TO 2.0Given the necessary fluid system parameters and using the Combined Ideal Gas Law, DESCRIBE the compressibility or incompressibility of a fluid when a pressure is exerted 45 TO 3.0For any natural circulation fluid system, DESCRIBE the mechanism that allows for fluid flow 53 TO 4.0Using fluid system volumetric and mass flow rates, SOLVE for unknown fluid parameters values to predict fluid system characteristics 57 TO 5.0Given the necessary fluid system parameters, DETERMINE the fluid flow type and the flow characteristics of that fluid system 77 TO 6.0Given a fluid system, IDENTIFY the forms of energy using the General Energy Equation 81 TO 7.0GIVEN an Ideal fluid system where no heat is transferred in or out, and no work is performed on or by the fluid, EXPLAIN the energy conversions that occur 99 TO 8.0GIVEN a Real fluid system, DESCRIBE the effects of fluid friction to predict energy conversions 107 TO 9.0EXPLAIN the energy conversions that occur as fluid flows through the Venturi tube, flow nozzle, and orifice plate flow measuring devices 151 TO 10.0IDENTIFY the conditions and prevention methods for both "water hammer" and "pipe whip" in fluid systems 159 TO 11.0IDENTIFY the conditions and prevention methods of a fluid siphon for a fluid system 177 ix of xii Rev. 0 OPERATIONS TRAINING PROGRAM References: ARITHMETIC: Student Text, TTFGMAPA.H0102, rev. 2 / Westinghouse Savannah River Company, Aiken, SC MATHEMATICS: Student Text, TTFGMA1A.H0104, rev. 4 / Westinghouse Savannah River Company, Aiken, SC Bay, Denise and Horton, Robert B., Macmillan Physical Science, Teacher's Edition, Macmillan Publishing Co., New York, (1988). Cline, John W., Thermodynamics, Heat Transfer, and Fluid Flow, Westinghouse Savannah River Company HLW Fundamentals Training Program, (1993). Driskell, Les., Control Valve Selection and Sizing, Instrument Society of America, North Carolina, (1983). Driskell, Les, Control-Valve Selection and Sizing, Independent Learning Module, Instrument Society of America, Publishers Creative Services Inc., Research Triangle Park, North Carolina, (1983). Durham, Franklin P., Thermodynamics, 2nd ed., Prentice-Hall, Inc., New Jersey, (1959). Freeman, Ira M., Physics Made Simple, Revised Edition, Bantan Doubleday Dell Publishing Group, Inc., New York, (1990). Giancoli, Douglas C., Physics, 3rd ed, Prentice Hall, New Jersey, (1991). Glasstone, Samuel and Sesonske, Alexander, Nuclear Reactor Engineering, 3rd ed., Van Nostrand Reinhold Co., New York, (1981). Heimler, Charles H. and Price, Jack S., Focus on Physical Science, Teacher's Edition, Charles E. Merrill Publishing Co., Ohio (1984). Hewitt, Paul G., Conceptual Physics a new introduction to your environment, 3rd ed., Little Brown and Company, Inc., Boston, (1977). Holman, J. P., Thermodynamics, 4th ed., McGraw Hill, Inc., New York, (1988). Julty, Sam, How Your Car Works, Book Division, Times Mirror Magazines, Inc., New York (1974). Murphy, James T., Zizewitz, Paul W., and Hollon, James Max, Physics Principles & Problems, Charles E. Merrill Publishing Co., Ohio, (1986). Serway, Raymond A. and Faughn, Jerry S., College Physics, 2nd ed., Saunders College Publishing, Philadelphia, (1989). U.S. Department of Energy, DOE Fundamentals Handbook, Thermodynamics, Heat Transfer, and Fluid Flow, Vols. 1 through 3, U.S. Department of Energy, (1992). Wiedner, Richard T. and Sells, Robert L., Elementary Classical Physics, College Physics Series, Vol. 1, Allyn and Bacon, Inc, Boston, (1965). x of xii Rev. 0 OPERATIONS TRAINING PROGRAM This page was intentionally left blank xi of xii Rev. 0 [...]... subjected to different accelerations Page 12 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids Even though a detailed analysis of fluid flow can be extremely difficult, the basic concepts involved in fluid flow problems are fairly straightforward These basic concepts can be applied in solving fluid flow problems through the use of simplifying assumptions.. .OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids Chapter 1 INTRODUCTION TO FLUIDS This chapter introduces various terms used to describe the characteristics of a fluid and some basic flow characteristics of given fluids in a typical application It also presents the relationship between various parameters within a given fluid system under various... υ SG = 57 4 62 4 SG = 0.92 1 ft 3 00174 lbm Since this is less than 1 it will float Page 19 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids Page 20 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids *Note: Gases are compared to the density of air and not to the density of water The standard of comparison... atm 1 atm 408 in of H 2 O 29.92 in Hg 1 atm 760 mm Hg Page 25 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids 1 atm 760 torr 1 atm 101 × 105 Pa Table 1-3 Common Pressure Units Page 26 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids The following examples utilize common pressure units: a Convert 14.0... to the continuity equation) which will be explained in this module Description of Fluids A fluid is any substance that flows The molecules of fluids are not rigidly attached to each other Essentially, fluids are materials which have no repeating crystalline structure Fluids include both liquids and gases Liquids are fluids which have a definite volume and take the shape of their container Gases also... Non-Mixable (Non-Miscible) Fluids Miscibility is the property of two substances, which makes them "mixable" Salt and water are miscible so when they are mixed together they make salt water and stay mixed until separated by evaporation But when Page 15 Figure 1-1 Example of non-miscible fluids of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids two substances... unknown material has a specific volume of ρ= 1 υ ρ= 1 00200 ρ = 50 ft 3 lbm lb m ft 3 Page 17 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids Specific Gravity Specific gravity is the ratio of the density of a fluid or solid to the density of a standard fluid Water is the standard of comparison for liquids and solids, and air is the standard of comparison... circulated through a gasoline or diesel engine, the air flow past the windings of a motor, and the flow of water through the core of a nuclear reactor Fluid flow systems are also commonly used to provide lubrication Fluid flow in the nuclear field can be complex and is not always subject to rigorous mathematical analysis Unlike solids, the particles of fluids move through piping and components at different... other molecule Page 21 of 170 Rev 0 OPERATIONS TRAINING PROGRAM Student Guide: Fluid Flow Chapter 1: Introduction to Fluids These key characteristics either alone or taken together explain all of the other characteristic of fluids of interest in this course Stated another way; these three characteristics are the major source of the other general characteristics of every fluid! Therefore, knowing the mass,... the Fluid Flow term “Pressure” to include units EO 1.5 Given the necessary fluid parameters, CALCULATE/CONVERT absolute pressure, gage pressure, feet of head, or vacuum pressure for a fluid system EO 1.6 EXPLAIN Archimede’s Principle and relate it to the term “Buoyancy” EO 1.7 DESCRIBE the relationship between the pressure in a fluid column and the density and depth of the fluid EO 1.8 DEFINE the Fluid . Figures: Figure 1-1 Example of non-miscible fluids 15 Figure 1-2 Pressure caused by Molecules 22 Figure 1-3 Force versus Pressure 22 Figure 1-4 Pressure Scales. Sink 54 Figure 4-1 7 Volume of an Object 57 Figure 4-1 8 Volume of Pipe Section A 58 vi of xii Rev. 0 OPERATIONS TRAINING PROGRAM Figure 4-1 9 Volume of Pipe