Ramos fluid mechanics


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A look a fluid mechanics in lifting devices.
http://www.advancedhandling.com/overhead_lifting_equipment/overhead_handling_equipment.ht http://www.bristol-business.net/bristols-sharklets-make-their-first-flight/m

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Learning Materials Production Open Training and Education Network-Distance Education
NSW Department of Education and Training 2000. 51 Wentworth Rd. Strathfield NSW 2135.
Revised 2003.

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Ramos fluid mechanics

  1. 1. FLUID MECHANICSBraking systems & Lifting Devices.
  2. 2. CASE STUDIES RELEVANT TO THEENGINEERING STUDIES STAGE 6 SYLLABUSBOARD OF STUDIES NSW• Note to teachers.• – Case Studies relate to two separate modules found in the current Engineering Studies syllabus. One engineering application module (3) – Braking systems, can be found on the preliminary course 30 hours indicative. The second can be found as a focus module (3) – Aeronautical engineering, found in the HSC course 30 hours indicative.• Other parts of the syllabus can be linked to this digital teacher resource.• Fluid mechanics :The scientific study of static and dynamic actions of liquids andgasses in motion (fluid dynamics) and at rest (Hydrostatic). Fluidmechanics as a topic also investigates internal and external forcesand how these forces affect the flow properties of fluids.
  3. 3. LIQUID AND GAS• Liquid is a fluid that will spread out but remain in pools if poured onto a flat surface. Liquid poured into a container will fill the container in any shape starting from base.• Gas will disperse in all directions if released. If forced into a container gas will fill the shape making contact with all surfaces.
  4. 4. SECTION ONE – BRAKING SYSTEMS.• Syllabus outcomes: P2.1,P3.1,P4.1• If all the systems of a vehicle were to be broken down and prioritised the braking system would have to be one the most important.• Fluid Mechanics- are linked with basic hydraulics found in braking systems. Early mechanical braking systems such as levers and cables, were not only unreliable and unsafe, they also inadequate in providing equal braking pressure to the braking system.
  5. 5. BLAISE PASCALHydraulic systems work on the principle that confined fluid under pressure, will be transmittedundiminished and equally in all directions.
  7. 7. Here we can see the weight putting force on theliquid; this force is acting in all directions thusincreasing the pressure on all sides of the container.The pressure being the same at all points.
  8. 8. This image shows that liquid takes the shape of anycontainer; the whole area is occupied filling it inbetween two weights.
  9. 9. Applying force to the left cylinder or weightdemonstrates that the liquid is not compressible soits volume stays the same.
  10. 10. The effect is that the force gets transferred to theopposite cylinder.Where only the weight is free to move, due to theshape of the container. What we can also see is thatboth cylinders are equal thus the pressure exerted ineach force is the same.
  11. 11. Pascals theory – mathematically F2 F1 A1 A2 F1 F2 = A1 A2
  12. 12. A similar or relevant principle can be explained bythis man, Archimedes investigated density andbuoyancy over 2000 years ago.
  13. 13. Archimedes Principle states that the buoyant force on a submerged object is equalto the weight of the fluid that is displaced by the object. Or………..The weight of the displaced liquid is equal to the weight of the floating object click on the link to watch a short clip.
  14. 14. THE USE OF HYDRAULIC PRINCIPLES IN PERSONAL ANDPUBLIC TRANSPORT- BRAKING SYSTEMS• Syllabus outcomes: P1.1,P2.1,P3.1,P4.1,P4.2P4.3.PASSENGER CARHere’s an example of a discbraking system, commonly foundin passenger cars, motorcyclesand light duty trucks.
  15. 15. Hydraulic drum brakes using Pascalsprinciple.
  16. 16. MOTORCYCLE Hydraulic disc brakesAn attempt to slow or stop the rotation of a wheel by friction,brake pads are used to clamp to a disc connected to the wheel.
  17. 17. DIFFERENCE BETWEEN HYDRAULIC AND AIRBRAKES IS THAT AIR CAN BE COMPRESSED. From a scientific point of view liquid cannot be compressed.
  18. 18. INNOVATIONS IN BRAKING SYSTEMS.• Syllabus outcomes:P1.1,P2.1,P3.1,P3.3,P4.1,P4.2,P4.3• One of the most common innovations in braking systems would have to be ABS- Antilock Braking System.In 1988 BMW introduced the first ABS system for amotorcycle. An electro-hydraulic brake servo and adaptivebrake-power distribution system which was the first of itskind in the world.
  19. 19. How is the BMW Integral ABS innovative?• The hand-brake lever and pedal- operated brake act simultaneously on both wheels• To ensure optimum decaccellartion• When reaching the wheel lock limit, the brake power is distributed and regulated electronically• Two seperate brake servos relieve pressure build up on both wheels.
  20. 20. WHY HYDRAULIC DISC BRAKES SUPERCEED DRUM BRAKES Motorcycle disc brakes : • Usually made from different materials such as stainless steel , to prevent rust • They are drilled and slotted to dissipate water from the road or rain • The drilled brake or slotted wholes also act as a heat sink under heavy braking • can be electronically controlled to include ABS Bicycle disc breaks: • Range from simple cable systems to expensive six-piston hydraulic systems • Can be manufactured from aluminium and titanium for weight reduction and durability Large lightweight trucks, passenger rail cars, some aeroplanes • Replacing drum brakes • Less wear and maintenance • Commonly manufactured out of grey iron due to hardness, chemical composition, tensile strength
  21. 21. SECTION TWO – LIFTING DEVICES• Syllabus outcomes:P2.1,P4.3,H2.2,H4.1,Lifting devices can range from simple to computercontrolled machines that are part of our daily lives.
  22. 22. EXAMPLES OF COMMON LIFTING DEVICES.If it’s too heavy or awkward to carry or move a lifting device either simple or complex will make it easier for you.
  23. 23. HOW THREE SIMPLE MACHINES WORKDIFFERENTLY TO COMPLETE THE SAME TASK• They all have a screw mechanism two of these designs are force magnifiers.
  24. 24. HYDRAULICS & PNEUMATICS & COMPRESSIBILITY• Fluid volume can be reduced by an increase of pressure if we are working with a gas. Due to the molecules being close together or cohesive (attracted to each other) liquid cannot compress even if a lot of pressure is applied.• Gases have molecules that are far apart thus allowing it to either compress under pressure or compress reducing the volume of the gas.• Syllabus outcomes: H4.3,H6.1,
  25. 25. THE IMPACT OF LIFTING DEVICES THROUGH THE DEVELOPMENT OF A SAFER SYSTEM.• Without hydraulic lifting devices that range from car jacks to construction cranes it can be said the effort it would take to move or lift objects heavier than humans would be near impossible.• One innovation available that makes lifting a car safer and more convenient must be the Safe T Jack system. The bottle jack system if not supported correctly in the recommended lift area may be unstable and dangerous.
  26. 26. The hydraulic floor jack may hold more weightthan the bottle jack however is heavy and takesup a lot of floor space especially working on asmall car or cramped area. Features of the Safe T Jack • Available in 2 and 3 tonne capacities • A removable power/lifting unit leaving the jack stand in place • Transfer between a hydraulic jack to a mechanical stand • All components can be assembled to produce a conventional jack stand. • Click on the link to learn more.
  27. 27. PNEUMATICS & HYDRAULICS IN AN AERONAUTICAL APPLICATION.• Syllabus outcomes: H4.1,H4.3,H6.1,H3.2,H3.3• So far we have understood that a hydraulic system uses the pressure of a liquid to preform a mechanical function.• The hydraulic system can also be a force multiplier if one piston is smaller than the other despite travelling a longer distance a greater load can be lifted.
  28. 28. THE PNEUMATIC SYSTEM• Create more noise when at work in comparison to hydraulic systems that use oil.• At first an effort is applied to a piston• The piston compresses the air in a tank that is connected to a pipe or hose.• The pipe or hose is fitted with a relief valve that allows the control of air to be turned off or on the pressure of the controlled air powers gears connected to fans• Several tools are use available for work in several different applications,ranging from dentists’ drills to jack hammers.
  29. 29. Compressed air is directed through the air inlet.The system moves the piston in the intendeddirection forcing it move in a reciprocatingaction.
  31. 31. The use of hydraulics in the aero industry start from the actual production of theaircraft to the take off and landing .• Elevators• Ailerons• Rudders• Flaps• Electronic hydraulic controllers• computational fluid dynamics CFD
  32. 32. AN AERONAUTICAL INNOVATION• Wing tip devices known as SHARKLETS. Aerodynamic improvements such as • 15% reduction in fuel consumption • Lower operating costs • Reductions in engine noise & emissions • Assists with the wing tip vortex creating safer flights for passengers and crew.