Radiation Heat Transfer

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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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Center of Gravity and Centroid

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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:

Comments

  1. AnonymousDecember 14, 2019 at 6:23 AM

    Basically there is a small difference between center of mass and center of gravity.
    Center of mass is the geometric center of body whether it is symmetric or not. And center of mass is the the center on which whole body mass is concentrated.

    ReplyDelete

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