Analysis of Fluid Machines: Pumps and turbines, types, principles of operation, performance characteristics, Performance curve, similarity laws, pumps in series and parallel, selection of pumps and turbines Dr. Muhammad Ashraf Javid Assistant Professor 1 Fluid Engineering Mechanics Chapter 7
48
Embed
Fluid Engineering Mechanics · Analysis of Fluid Machines: Pumps and turbines, types, principles of operation, performance characteristics, Performance curve, similarity laws, pumps
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Analysis of Fluid Machines: Pumps and turbines, types, principles of operation, performance
characteristics, Performance curve, similarity laws, pumps in series
and parallel, selection of pumps and turbines
Dr. Muhammad Ashraf Javid
Assistant Professor
1
Fluid Engineering Mechanics
Chapter 7
Objectives
Understand the role of pumps and turbines as energy-conversion
devices and use, appropriately, the terms head, power and efficiency.
Be aware of the main types of pumps and turbines and the distinction
between impulse and reaction turbines and between radial, axial and
mixed-flow devices.
Match pump characteristics and system characteristics to determine
the duty point (demand point)
Calculate characteristics for pumps in series and parallel
Select the type of pump or turbine on the basis of specific speed.
Understand the mechanics of a centrifugal pump and an impulse turbine.
Recognize the problem of cavitation and how it can be avoided.
2
Energy Conversion
Energy Transfer in Pumps and Turbines
Power
3
Machine Efficiency
4
Pumps
Pumps convert mechanical energy to fluid energy
A pump usually refers to a machine used for incompressible fluids
(water, oil); fans, blowers,
Types of pumps
Positive displacement
Centrifugal pump
Axial flow pumps
Mixed flow pumps
5
Pumps: Types
Positive Displacement Pump
These types of pumps displace fixed
volumes of fluid during each cycle or
revolution of the pump.
No longer used for distribution system
pumping in most water systems, but
portable units may be used for
dewatering excavations during
construction.
6
Pumps: Types
Centrifugal Pump
Frequently used in water distribution systems.
Water enters the pump through the eye of the spinning impeller and outward from the vanes to discharge pipe.
A centrifugal pump consists of: A rotating element (impeller) and housing which encloses the impeller and seals the pressurized liquid.
7
Pumps: Types
Axial Flow pumps
In axial-flow pumps, the flow
enters and leaves the pump
chamber along the axis of the
impeller, as shown in Figure
In mixed flow pumps,
outflows have both radial and
axial components.
8
Pumps: Types
The pumps illustrated in Figure are both single-stage pumps, which means