Fluid Mechanics and Fluid Power

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Fluid Mechanics and Fluid Power

• ENTC 303

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Announcements

• Course Syllabus
• Class Webpage
• http//etidweb.tamu.edu/classes/entc303/
• Classnotes in Power Point
• Homework assignments and solutions
• WebCT
• Grades
• Labs
• A lab manual is available for this course
• PDF version will be available on line soon, just
  go to E-Learning
• Instructor will also provide notes and questions
  before and during each lab session
• No labs this week

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Fluids Mechanics/Fluid Power

• Is the study of the behavior of fluids at rest or
  in motion
• Fluids can be either liquids or gases
• Liquids flow freely and conform to their
  containers
• Gases completely fill their containers

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Understanding Fluid Mechanics Why is the study
of Fluid Mechanics important?

• To be able to predict their behavior
• To be able to size specify equipment
• To estimate the related energy and infrastructure
  costs
• To estimate the system performance under
  different conditions

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Examples of Fluid Mechanics System
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Example Dam
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Example Hydropower Plant
http//science.howstuffworks.com/
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Example Flood Control
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Example Oil Extraction
http//science.howstuffworks.com/
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Example Brake System
http//science.howstuffworks.com/
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Fluid Power Examples

• Hydraulic elevator
• http//science.howstuffworks.com/elevator1.htm
• Hydraulic Machines
• http//science.howstuffworks.com/hydraulic1.htm
• http//science.howstuffworks.com/hydraulic2.htm

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Purpose and Objectives

• Understand the key concepts in fluid mechanics
  (i.e. laws of physics, etc.)
• Use of the laws of physics, system conditions and
  fluid properties to solve real problems
• Learn how to logically and methodically solve
  fluid mechanics problems
• Lifelong skills
• known methodology gt Solution (unknown)

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Fluid PropertiesLiquid or Gas

• Liquids are
• Slightly compressible, DV ? f(DP)
• Viscous (high viscosity)
• Viscosity decreases with temperature
• Gases are
• Compressible, DV f(DP)
• Low viscosity
• Viscosity increases with temperature

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Key Concepts/Properties

• Pressure
• Amount of Force exerted on a unit area
• P Force/Area
• Pressure acts uniformly in all directions and
  perpendicular to the boundaries in the container
• Example Piston

Force
Area p/4D2
P
PressureForce/Area
Unit Psi or Pa (SI)
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Example 1

• A container holding a liquid supports a loaded
  movable piston. Determine the magnitude of the
  pressure in the liquid under the piston if the
  total weight of the piston and load is 500 N, and
  the area of the piston is 2500 mm2.

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Key Concepts

• Density
• Amount of mass per unit volume
• r mass/volume
• Density is a fluid property and slightly
  dependent on temperature
• Units kg/m3, g/cm3, lb/ft3
• Specific Volume
• Inverse of density
• n 1/r, m3/kg

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Key Concepts

• Specific Gravity
• Is the ratio of density of fluid to the density
  of a reference fluid (usually water at a
  reference temperature)
• SGr/rwater

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Specific Weight

• Specific Weight Weight/Volume
• g w/V
• Example 2
• Calculate the weight of a reservoir of oil if it
  has a mass of 825 kg
• If the volume is 0.917 m3, compute density,
  specific weight, specific gravity

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Equations for Property Calculations

• Circular Area
• Weight w mg
• Density r m/V
• Specific Weight g w/V
• Specific gravity SGr/rwater

Area p/4D2
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Example 3

• Glycerine at 20 C has a specific gravity of
  1.263. Compute its density and specific weight.