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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Energy, Energy Transfer and Energy Analysis
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Forms of Energy
Macroscopic Form of Energy:
The energy which a body posses by its whole that it is measured with respect to some outside reference frame.
Microscopic Form of Energy:
The energy which is related to the molecular structure of a system and a degree of molecular activity. These energies are independent of the outside reference frame.
kinetic and Potential Energies:
Kinetic energy is defined as the energy related to motion of the body.
Potential energy is defined as the energy associated with the position of the body.
Total Energy of a System:
In the absence of magnetic, electric and surface tension effects, the total energy of a system consist of sum of internal, potential and kinetic energies.
Volume, Mass and Energy Flow Rate:
Volume flowing through area per unit time is called Volume Flow Rate.
Amount of mass flowing through a cross section per unit time is called Mass Flow Rate.
Energy associated with a fluid at mass flow rate is called Energy Flow Rate.
Mechanical Energy:
The form of energy that can be converted to mechanical work completely and directly by a device. Like kinetic energy, potential energy, pressure, e.t.c.
Energy Transfer by Heat:
It is a boundary phenomena in which energy transfer take place due to the difference in temperature of bodied.
Energy Transfer by Work:
Energy transfer take place due to the force acting a distance.
Shaft Work or Mechanical Work:
Spring Work:
It is a mechanical work in which work is done due to spring.
First Law of Thermodynamics:
Law of Conservation of Energy states that;
Energy can neither be created nor be destroyed but it can be transfered from one form to another.
Angles & Directions Angles are also called bearings. Bearings are the acute angles between lines and meridians. They are divided into following types. Related Terms : Meridian : Imaginary line joining North and South poles. Declination : Difference between magnetic and true meridians. Azimuth : Clockwise angle taken from Geodatic North. * If area is greater ➤ use Geodatic North * If area is smaller ➤ use Magnetic North Magnetic Declination maybe towards East or West. For east ➤ Magnetic bearing=true bearing - Declination For west ➤ Magnetic bearing=true bearing + Declination Forward Bearing : Bearing taken in the direction of traverse. Backward Bearing : Bearing taken in opposite direction of traverse. Forward bearing - Backward bearing=180 For anti-clockwise : FB of line = BB of previous line + angle Example: In an anti-clockwise traverse <A=102'30',...
Center of Gravity: It is defined as; The resultant weight of a system which passes through a single point is called Center of Gravity ( G ). Center of Mass: It is defined as; The point at which the whole mass of the system acts. The concept of center of mass is cleared from the video given below: Centroid of a Volume: Objects having three dimensions have the centroid which is its geometric centre. Centroid of an Area: Objects having two dimensions have the centroid which is its geometric centre. Centroid of a Line: Objects having linear dimensions have the centroid which is its geometric centre. Composite Bodies: A composite body consists of a series of connected simpler shaped Bodies which may be rectangular, triangular, semicircular, etc. References: www.youtube.com www.wikipedia.com http://web.aeromech.usyd.edu.au/statics/doc/friction/Friction1.htm From Book Engineering Mechanics sta...
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...
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