Water is pumped with a centrifugal pump, and measurements made on the pump indicate that for a flowrate of 240 gpm the required input power is 6 hp. For a pump efficiency of 62%, what is the actual head rise of the water being pumped?
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1
Introduction
1.2
Dimensions, Dimensional Homogeneity and Units
1.4
Measures of Fluid Mass and Weight
1.5
Ideal Gas Law
1.6
Viscosity
1.7
Compressibility of Fluids
1.8
Vapor Pressure
1.9
Surface Tension
2
Fluid Statics
2.10
Hydrostatic Force on a Curved Surface
2.11
Buoyancy, Flotation, and Stability
2.12
Pressure Variation in a Fluid with Rigid-Body Motion
2.3
Pressure Variation in a Fluid at Rest
2.4
Standard Atmosphere
2.5
Measurement of Pressure
2.6
Manometry
2.8
Hydrostatic Force on a Plane Surface
3
Elementary Fluid Dynamics- The Bernoulli Equation
3.2
F= ma along a Streamline
3.3
F= ma Normal to a Streamline
3.5
Static, Stagnation, Dynamic, and Total Pressure
3.6
Examples of Use of the Bernoulli Equation
3.6.2
Confined Flows
3.6.3
Flowrate Measurement
3.7
The Energy Line and the Hydraulic Grade Line
3.8
Restrictions on Use of the Bernoulli Equation
4
Fluid Kinematics
4.1
The Velocity Field
4.2
The Acceleration Field
4.2.1
The Material Derivative
4.4
The Reynolds Transport Theorem
5
Finite Control Volume Analysis
5.1
Conservation of Mass- The Continuity Equation
5.1.2
Fixed, Nondeforming Control Volume
Uniform Velocity Profile or Average Velocity
5.1.3
Moving, Nondeforming Control Volume
5.1.4
Deforming Control Volume
5.2
Newton's Second Law- The Linear Momentum and Moment-of-Momentum Equations
5.2.2
Application of the Linear Momentum Equation
(also see Lab Problems 5.1LP, 5.2LP, 5.3LP, and 5.4LP)
5.2.3
Derivation of the Moment-of-Momentum
Equation
5.2.4
Application of the Moment-of-Momentum
Equation
5.3
First Law of Thermodynamics- The Energy Equation
5.3.2
Application of the Energy EquationNo Shaft
Work and Section 5.3.3 The Mechanical Energy Equation
and the Bernoulli Equation
5.3.3
Application of the Energy Equation and the
Bernoulli EquationCombined with Linear Momentum
5.3.4
Application of the Energy Equation to
Nonuniform Flows
5.3.5
Combination of the Energy Equation
and the Moment-of-Momentum Equation
6
Differential Analysis of Fluid Flow
6.1
Fluid Element Kinematics
6.10
Other Aspects of Differential Analysis
6.2
Conservation of Mass
6.3
The Linear Momentum Equation
6.4
Inviscid Flow
6.5
Some Basic, Plane Potential Flows
6.6
Superposition of Basic, Plane Potential Flows
6.8
Viscous Flow
6.9
Some Simple Solutions for Laminar, Viscous, Incompressible Flows
6.9.2
Couette Flow
6.9.3
Steady, Laminar Flow in Circular Tubes
6.9.4
Steady, Axial, Laminar Flow in an Annulus
7
Dimensional Analysis, Similitude, and Modeling
7.1
The Need for Dimensional Analysis
7.10
Similitude Based on Governing Differential Equations
7.3
Determination of Pi Terms
7.5
Determination of Pi Terms by Inspection
7.6
Common Dimensionless Groups in Fluid Mechanics
7.7
Correlation of Experimental Data
7.8
Modeling and Similitude
7.9
Some Typical Model Studies
8
Viscous Flow in Pipes
8.1
General Characteristics of Pipe Flow
8.2
Fully Developed Laminar Flow
8.3
Fully Developed Turbulent Flow
8.4
Dimensional Analysis of Pipe Flow
8.4.2
Minor Losses
8.4.3
Noncircular Conduits
8.5
Pipe Flow Examples
8.5.2
Multiple Pipe Systems
8.6
Pipe Flowrate Measurement
9
Flow Over Immersed Bodies
9.1
General External Flow Characteristics
9.2
Boundary Layer Characteristics
9.3
Drag
9.4
Lift
10
Open-Channel Flow
10.2
Surface Waves
10.3
Energy Considerations
10.4
Uniform Flow
10.4.3
Uniform FlowDetermine Flowrate
10.5
Gradually Varied Flow
10.6
Rapidly Varied Flow
10.6.2, 3
Sharp-Crested and Broad-Crested Weirs
10.6.4
Underflow (Sluice) Gates
11
Compressible Flow
11.1
Ideal Gas Thermodynamics
11.2
Stagnation Properties
11.3
Mach Number and Speed of Sound
11.4
Compressible Flow Regimes
11.5
Shock Waves
11.6
Isentropic Flow
11.7
One-Dimensional Flow in a Variable Area Duct
11.8
Constant-Area Duct Flow With Friction
11.9
Frictionless Flow in a Constant-Area Duct with Heating or Cooling
12
Turbomachines
12.1
Introduction
12.4
The Centrifugal Pump and Section 12.4.1
Theoretical Considerations
12.4.2
Pump Performance Characteristics
12.4.3
Net Positive Suction Head (NPSH)
12.4.4
System Characteristics and Pump Selection
12.5
Dimensionless Parameters and Similarity Laws
12.6
Axial-Flow and Mixed-Flow Pumps
12.7
Fans
12.8
Turbines
12.9
Compressible Flow Turbomachines
Textbook Solutions for Fundamentals of Fluid Mechanics
Chapter 12.4.2 Problem 12.11
Question
Water is pumped with a centrifugal pump, and measurementsmade on the pump indicate that for a flowrate of 240 gpm therequired input power is 6 hp. For a pump efficiency of 62%, whatis the actual head rise of the water being pumped?
Solution
The first step in solving 12.4.2 problem number 1 trying to solve the problem we have to refer to the textbook question: Water is pumped with a centrifugal pump, and measurementsmade on the pump indicate that for a flowrate of 240 gpm therequired input power is 6 hp. For a pump efficiency of 62%, whatis the actual head rise of the water being pumped?
From the textbook chapter Pump Performance Characteristics you will find a few key concepts needed to solve this.
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Title
Fundamentals of Fluid Mechanics 8
Author
Philip M. Gerhart, Andrew L. Gerhart, John I. Hochstein
ISBN
9781119080701
Water is pumped with a centrifugal pump, and measurementsmade on the pump indicate that
Chapter 12.4.2 textbook questions
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Chapter 12: Problem 12 Fundamentals of Fluid Mechanics 8
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Chapter 12: Problem 12 Fundamentals of Fluid Mechanics 8
The performance characteristics of a certain centrifugal pump are determined from an experimental setup similar to that shown in Fig. 12.10. When the flowrate of a liquid (SG = 0.9) through the pump is 120 gpm, the pressure gage at (1) indicates a vacuum of 95 mm of mercury and the pressure gage at (2) indicates a pressure of 80 kPa. The diameter of the pipe at the inlet is 110 mm and at the exit it is 55 mm. If z2 z1 = 0.5 m, what is the actual head rise across the pump? Explain how you would estimate the pump motor power requirement.
Read more -
Chapter 12: Problem 12 Fundamentals of Fluid Mechanics 8
The performance characteristics of a certain centrifugal pump having a 9-in.-diameter impeller and operating at 1750 rpm are determined using an experimental setup similar to that shown in Fig. 12.10. The following data were obtained during a series of tests in which z2 z1 = 0, V2 = V1, and the fluid was water. Q (gpm) 20 40 60 80 100 120 140 p2 p1 (psi) 40.2 40.1 38.1 36.2 33.5 30.1 25.8 Power input (hp) 1.58 2.27 2.67 2.95 3.19 3.49 4.00 Based on these data, show or plot how the actual head rise, ha, and the pump efficiency, , vary with the flowrate. What is the design flowrate for this pump?
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Chapter 12: Problem 12 Fundamentals of Fluid Mechanics 8
Determine algebraic equations for the pump head rise, power, and efficiency as functions of flow rate based on the data from Problem 12.18. Analytically determine the Best Efficiency Point and the BEP flow, head rise, and power. How do these values compare with those from Problem 12.18?
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