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Fluid Mechanics and Fluid Power. ENTC 303. Announcements. Course Syllabus Class Webpage http://etidweb.tamu.edu/classes/entc303/ Classnotes in Power Point Homework assignments and solutions eCampus eCampus will be used to post grades, etc. Labs
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Fluid Mechanics and Fluid Power ENTC 303
Announcements • Course Syllabus • Class Webpage • http://etidweb.tamu.edu/classes/entc303/ • Classnotes in Power Point • Homework assignments and solutions • eCampus • eCampus will be used to post grades, etc. • Labs • A lab manual is available for this course • PDF version is available through eCampus • Instructor will also provide notes and questions before and during each lab session • No labs this week
Fluids Mechanics/Fluid Power • Is the study of the behavior of fluids at rest or in motion • Matter: Solids, gas , liquids and plasma • Fluids can be either liquids or gases • Liquids flow freely and conform to their containers • Gases completely fill their containers
Understanding Fluid Mechanics: Why is the study of Fluid Mechanics important? • To be able to predict their behavior in different situations or applications • To be able to size or specify equipment • To estimate the related energy and infrastructure costs • To estimate the system performance under different conditions
Example: Dam http://ga.water.usgs.gov/edu/hyhowworks.html
Example: Hydropower Plant http://www.youtube.com/watch?v=rnPEtwQtmGQ
Example: Airplane http://en.wikipedia.org/wiki/File:Equal_transit-time_NASA_wrong1.gif http://www.youtube.com/watch?v=5ltjFEei3AI
Example: Flood Control http://www.youtube.com/watch?v=EZ5hjNenBcM http://www.nhc.noaa.gov/ 7:00 http://www.youtube.com/watch?v=jtIt7S1bAqg
Buoyancy Example http://www.youtube.com/watch?v =imDFSnklB0k
Example: Oil Extraction https://www.youtube.com/watch?v=3GPU3Zi9J1U
Example: Brake System http://science.howstuffworks.com/ http://www.youtube.com/watch?v=RPgOcQlqPco&feature=related
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 • http://www.youtube.com/watch?v=svdsbL4PLL4
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 => Solution (unknown)
Fluid Properties:Liquid 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
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/4*D2 P Pressure=Force/Area Unit: Psi or Pa (SI)
Example • 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.
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
Key Concepts • Specific Gravity • Is the ratio of density of fluid to the density of reference fluid (usually water) at the same temperature • SG=r/rwater
Specific Weight • Specific Weight = Weight/Volume g = w/V • Examples • 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
Equations for Property Calculations • Circular Area: • Weight: w = m*g • Density: r = m/V • Specific Weight: g = w/V • Specific gravity: SG=r/rwater Area = p/4*D2
Examples • Glycerine at 20° C has a specific gravity of 1.263. Compute its density and specific weight.
Viscosity • Dynamic Viscosity • = Shear Stress/Slope of velocity profile • = n v F Slope = v/y y Units: cP (centipoise), mPa-sec