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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Orthographic Projections
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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 inclined to a plane of projection appear as foreshortened lines.
Curved edges project as straight lines on the plane of projection to which they are perpendicular.
Curved edges project as curved lines on the planes to which they are parallel or inclined.
Normal surfaces appear as an edge in two opposite principal views, and appear as surface in all other principal views.
Inclined surfaces appear as an edge in two opposite principal views, and appear foreshortened in all other principal views.
Six Principal Views of Orthographic Projection:
Six principal view of orthographic projection are:
How We Draw Views Of Orthographic Projection:
The figure shows how we draw views of orthographic projection and co-relate them with each other.
How We Choose The Front View:
It is the most important step taken when you start to draw views of Orthographic Projections. You should follow guidelines to get your path correct.
Front view should have minimum hidden lines.
The view should be stable.
Most basic profile should be used.
Types Of Projections:
There are two types of projections, namely:
First Angle Projection
Third Angle Projection
1. First Angle Projection:
2. Third Angle Projection:
Symbols Of Angles of Projections:
You should draw these symbols if you are going to draw views of Orthographic Projection.
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...
Types Of Lines And Its Uses: There are three types of types on the basis of thickness and they are: Visible Lines ↝ It represents features that can be seen in the current view. Hidden Lines ↝ It represents features that cannot be seen in the current view. Center Line ↝ It represents symmetry, path of motion, centers of circles,, axis of asymmetrical parts. Dimension and Extension Lines ↝ It indicates the sizes and location of features on a drawing. Placement Of Dimension Lines: Dimension should be outside the view. Dimension should be applied to one view. Dimension should be placed in a view that shows the distance in its true length. Dimension lines should be placed, in general 10 mm (1/2 in) away from the outlines from the view. Parallel lines should be placed uniformly. Values should be midway (auto centered) between the arrow heads, except when a center-line interferes. Dime...
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