View Factor Orientation (or View factor or shape factor) plays an important role in radiation heat transfer. View factor is defined as, "fraction of radiation leaving surface 'i' and strike 'j' ". Summation Rule (View Factor) If there is are similar surfaces 'i' and 'j' , then: Blackbody Radiation Exchange Radiation Exchange between Opaque, Diffuse, Gray surfaces in an Enclosure 1. Opaque 2. Surfaces 3. Two surface enclosure Radiation Shield It is used to protect surfaces from radiation act like a reflective surface. References: Material from Class Lectures + Book named Fundamentals of Heat and Mass Transfer by Theodore L. Bergman + My knowledge. Photoshoped pics are developed. Some pics and GIF from Google. Videos from YouTube ( Engineering Sights ).
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Introduction To Fluid Mechanics
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Fluid Mechanics:
The science which deals with the behavior of fluids at rest(Fluid Statics) or in motion(Fluid Dynamics) and the interaction of fluids with solids or other fluids at the boundaries.
Fluid Dynamics:
A kind of fluid dynamics in which fluid is at rest or moving with zero velocity.
Hydrodynamics:
The study of motion of fluids that can be approximated as incompressible.
Hydraulics:
A sub-category of hydrodynamics which deals with liquid flows in pipes and open channels.
Gas Dynamics:
It deals with the flow of fluids that undergo significant density change, such as the flow of gases through nozzles at high speed.
Aerodynamics:
Deals with the flow of gases over bodies such as aircraft, rockets and automobiles at high or low speeds.
Another Definition of:
Fluid(Gas + Liquid) ⟾ A matter which continuously deform under the application of applied shear stress. In fluid, stress is proportional to strain rate.
Solid ⟾ A matter which can not deform under shear stress. In solid, stress is proportional to strain.
Application Of Fluid Mechanics:
Power Plant
Natural Flows & Weather
Boats
Aircraft & Spacecraft
Human Body
Cars
Wind Turbines
Piping & Plumbing Systems
Properties Of Fluids:
Property ⟾ Any characteristics of a system.
Intensive Properties ⟾ Properties which is independent of mass of a system.
Extensive Properties ⟾ Properties which depends upon the mass of system that means change with mass changed.
Specific Properties ⟾ Extensive properties per unit mass to change into intensive properties.
Density ⟾ Mass per unit volume is called density.
Specific Volume ⟾ Volume per unit mass or reciprocal of density.
Specific Weight ⟾ It is defined as weight per unit volume.
Specific Gravity ⟾ It is the ratio of density of fluid to the density of water.
Continuum:
The consideration of matter that there are no holes or spaces between molecules is called Continuum.
Viscosity:
Internal resistance to the flow of liquid layers is called Viscosity.
Kinematic Viscosity:
Kinematic viscosity is defined as, dynamic viscosity per unit density.
Drag Force:
The force a flowing fluid exerts on a body in the flow direction. The magnitude of this force depends on viscosity.
Newtonian Equation:
Consider a fluid between two flat parallel plates. The fluid between the plates moves with velocity 'u'. For any fluid between the particles, it is observed:
F ∝ A (Upper Plate Area)
F ∝ U (Upper Plate Velocity)
F ∝ 1/y (Distance from Bottom Plate to the Fluid Layer)
The derivative of velocity profile is given by:
For Newtonian Fluids, the rate of deformation is proportional to the shear stress.
This equation is called Newtonian Equation. Where, น is the Dynamic or Absolute Viscosity.
and; the applied Shear Force is given by,
Types of Fluids:
Depending on the image given above, types of fluid are described ahead:
Newtonian Fluids ⟾ Fluids which follow Newtonian equation in which shear stress is directly proportional to the rate of deformation.
Pseudo-plastics ⟾ Fluids in which viscosity decreases with increasing shear rate and it is shear thinning. For e.g: Milk, cement, clay paint, etc.
Dilatant ⟾ Fluids in which viscosity increases with increasing shear rate and it is shear thickening. For e.g: water-corn starch mixture, water-sand mixture, etc.
Bingham Plastics ⟾ Acts as Newtonian fluid after specific interval.
Surface Tension:
You get each and every information by clicking: here
Cohesive & Adhesive Forces:
Forces between like molecules are called Cohesive Forces. Forces between Unlike molecules are called Adhesive Forces.
Wetting & Non-Wetting Liquids:
Liquids which wet the surface when comes in contact and have acute contact angle are called Wetting Liquids. Liquids which do not wet the surface when comes in contact and have obtuse contact angle are called Non-Wetting Liquids.
Height Of Liquid In Capillary Tube:
Pressure Difference For Bubble & Droplets:
By comparing the horizontal forces on bubble or droplets, we can achieve the following relations:
References:
Materials From Lectures + Own Knowledge + Book named Fundamentals of Fluid Mechanics by Munson, Young and Okiishi's (8th Edition).
TAPING CORRECTIONS There are two types of corrections depending upon the type of errors in tape due to the different conditions. 1. Systematic Errors : Slope Erroneous tape length Temperature Tension Sag 2. Random Errors : Slope Alignment Marking & Plumbing Temperature Tension & Sag 1. Temperature Correction It is necessary to apply this correction, since the length of a tape is increased as its temperature is raised, and consequently, the measured distance is too small. It is given by the formula, C t = 𝛼 (T m – T o )L Where, C t = the correction for temperature, in m. 𝛼 = the coefficient of thermal expansion. T m = the mean temperature during measurement. T o = the tempe...
Projection: The term Projection is defined as: Presentation of an image or an object on a surface. The principles used to graphically represent 3-D objects and structures on 2-D media and it based on two variables: Line of Sight. Plane of Projection. Line of Sight & Plane of Projection: Line of sight is divided into 2 types: Parallel Projection Converging Projection & A plane of projection is an imaginary flat plane upon which the image created by the lines of sight is projected. Orthographic Projection: When the projectors are parallel to each other and perpendicular to the plane of projection. The lines pf sight of the observer create a view on the screen. The screen is referred to as the Plane of Projection (POP). The lines of sight are called Projection lines or projectors. Rules of Orthographic Projection: Edges that are parallel to a plane of projection appear as lines. Edges that are incl...
Diffusion It is defined as, " The transportation of one atom from one state into other state " . Used for hardening of surfaces like die parts, gear, bolt, machine element. Hardening can be done using Temperature-Heat treatment ( diffusion couple ). There are two types of diffusion: Inter-diffusion ↔ in which atoms tend to migrate from region of high concentration to low concentration . Self-diffusion ↔ in which atoms migrate within a solid. Diffusion Mechanism There can be two conditions of moving atoms Empty spaces between adjacent sites. Atoms have sufficient energy to break bond with neighbors atoms which cause lattice distortion during displacement. If we rise temperature, small fractions of atoms is capable of diffusive motion (which cause lattice distortion). Types of Diffusion 1. Vacancy Diffusion It is defined as, " interchange of an atom from a normal lattice position to the adjacent vacant lattice site " . Extent of vacancy diffusion is a function...
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