Lecture 1
Hydraulic Machines
(Getting started)
Mahmoud N. Abdelmoez
Assistant Professor, Mechanical Engineering Department
Assiut University, Egypt
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Acknowledgement
• Some of the content of the slides I made for this course is taken, as it is or after
some editing, from the slides made by Prof. Abdelgawad and Dr. Mohammed B.
Effat.
Dr. Mohamed Abdelgawad
Assiut University
American University of Sharjah
• Permission from Professors has been granted.
Dr. Mohammed B. Effat
Assiut University
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An overview of the course|
what are fluids
• Fluids are a phase of matter that includes liquids and gases.
• They deform (flow) continuously under an applied shear stress (or external force).
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An overview of the course|
what is the fluid mechanics
• Fluid mechanics is that discipline within the broad field of
applied mechanics that is concerned with the behavior of liquids
and gases at rest (fluid statics) or in motion (fluid dynamics).
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An overview of the course|
Applications of fluid mechanics-ENERGY
Steam
Turbines
Wind
Turbines
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An overview of the course|
Applications of fluid mechanics-ENERGY
Fuel cells
Redox-flow
batteries
Battery thermal
management
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An overview of the course|
Applications of fluid mechanics-ENVIRONMENT
Dispersion of pollutants in air (urban planning)
Pesticides flow in
porous media
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An overview of the course|
Applications of fluid mechanics-ENVIRONMENT
ventilation in indoor environments
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An overview of the course|
Applications of fluid mechanics-BIOMEDICAL
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An overview of the course|
fluid mechanics, from a control's perspective
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An overview of the course|
fluid mechanics, from a control's perspective
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An overview of the course|
References
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Guidelines & Rules
• Delivering the lecture on time
• Finishing class on time
• Organizing the course carefully
• Setting exams and assignments that are fair and helpful
• Encouraging your questions and comments
• Taking your answers and opinions seriously
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Guidelines & Rules
You can show your interest by:
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Arriving on time
Arriving quietly, if you must be late
Leaving quietly, if you must leave
Listening when I am talking
Silent your mobile phone
Participating in class discussions
Asking questions when the material is not clear to you
Working hard on assignments
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Guidelines & Rules
• You can show respect for your classmates by:
• Keeping quiet when classmates are trying to listen
• Taking classmate’s questions and answers seriously
• Making the class a comfortable experience for everyone
You should demonstrate your academic integrity by:
• NOT copying other student’s work
• NOT letting other students copy your work
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Guidelines & Rules | Office hours
• I welcome your questions and discussions through meetings,
either online or face-to-face (from next week).
• Microsoft Teams: team code (???)
• You can set an appointment by writing an email to me on:
mnady86@aun.edu.eg
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• Any physical quantity can be characterized by dimensions.
• There are seven primary dimensions: length, mass, time, temperature, electric current,
amount of light, and amount of matter.
• In fluid mechanics, we will deal with three of the seven primary dimensions, which are:
• Mass, M
• Length, L
• Time, T
• Other quantities e.g. velocity V, energy E are expressed in terms of the primary
dimensions and are called secondary dimensions, or derived dimensions. For example,
V=LT-1
• Sometimes F (basic dimension of force), L, and T are used, instead of M, L, and T.
As F=mass×accelation, it follows that F=MLT-2. Thus, stress 𝜎 = force/area can be
expressed as FL-2 or ML-1T-2
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Some concepts and definitions|
Dimensions, units, and their homogeneity
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• The magnitudes assigned to the dimensions are called units.
• Two systems of units are commonly used: the SI (international system) and the
English system (United States customary system).
(F-32)*5/9 ℃
The SI units of remaining dimensions are:
electric current: ampere (A)
amount of light: candela (cd)
amount of matter: mole (mol)
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• In engineering,
homogeneous.
all
equations
must
be
dimensionally
• Never mix up two systems of units.
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• Example 1
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Some concepts and definitions|
Dimensions, units, and their homogeneity
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Some concepts and definitions|
Dimensions, units, and their homogeneity
Are the parameters
(constants)
dimensionless?
general vs. restricted homogeneous equations
𝑄 = 2.7𝐴√ℎ
𝑄 = 4.90𝐴√ℎ
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• Example 2
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Some concepts and definitions|
Dimensions, units, and their homogeneity
Prefixes in SI units
Note the UPPER and lower case letters
10/1/2020
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Some concepts and definitions|
Dimensions, units, and their homogeneity
mass (kg) vs. weight (N)
• Weight is a “force” and equals:
mass*gravitational
acceleration,
W=mg (N)
• The mass of a body remains the
same regardless of its location in
the universe. Its weight, however,
changes with a change in
gravitational acceleration
(your weight on moon is different than
that on earth)
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energy (J, kWh) vs. power (W)
The SI units of energy is Joule (J).
The time rate of energy is joule per second (J/s),
which is called a watt (W).
As energy equals power*time, we can express it in
kWh units (as we have in our electricity bills).
Therefore, statements like “the new wind turbine
will generate 50 kW of electricity per year” are
meaningless and incorrect. A correct statement
should be something like “the new wind turbine
with a rated power of 50 kW will generate 120,000
kWh of electricity per year (e.g. ~6.6 hours/day)”
A commonly used unit of power is horsepower (hp),
which is equivalent to 746 W.
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Some concepts and definitions|
Dimensions, units, and their homogeneity
• Example 3
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References
• Content of this lecture is compiled from:
• Sections 1.1, 1.2, 1.3, 1.4, 1.5, 1.8 in the textbook.
• Lec#1&2 of Prof.Abdelgawad slides
• https://iopscience.iop.org/chapter/978-1-6817-4692-0/bk978-1-68174692-0ch4.pdf
• Wikipedia.
• images.google.com
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