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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Tolerance & Fits
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Tolerance
It is defined as, "the magnitude of permissible variation of a dimension or other measured value from the specified value".
Purpose ↠ permit dimensional variations of components, performance, specification and design.
As the permissive tolerance goes on decreasing, the manufacturing cost to achieve it goes on increasing exponentially.
Classification of Tolerance:
Unilateral tolerance ↠ If tolerance distribution is only one side of the basic size.
Bilateral tolerance ↠ When tolerance distribution lies on either side of the basic size.
Compound tolerance ↠ When tolerance is determined by established tolerances on more than one dimensions.
Geometric tolerance ↠ Used to indicate the relationship of one part of an object with another.
Classification of Geometric Tolerance:
Form tolerance ↠ group of geometric tolerance applied to individual features (includes straightness, circularity, flatness, cylindricity).
Orientation tolerance ↠ type of geometric tolerance used to limit the direction/orientation of a feature in relation to other (includes perpendicularity, parallelism, angularity).
Positional tolerance ↠ group of geometric tolerances that controls the extent of derivation of the location of a feature from its true position (includes position, symmetry, concentricity).
Fits
It is defined as, "the relationship between the two mating parts that are to be assembled i.e. the hole and the shaft w.r.t the difference in their dimensions before assembly".
Manufactured parts are required to mate with one another during assembly.
Ideally fits is required for proper functioning of mating parts.
Allowance ↠ intentional difference between the maximum material limits (LLH and HLS) of two mating parts.
Types of Fits:
Clearance Fit ↠ The largest permissible diameter of the shaft is smaller than the diameter of smallest hole.
Interference Fit ↠ The minimum permissible diameter of shaft exceeds the maximum allowable diameter of hole.
Transition Fit ↠ Occurs when two tolerance mating parts are sometimes interference fit and sometimes clearance fit when assembled.
References:
Material from Class Lectures + Book named Fundamentals of Modern Manufacturing Materials, Processes and Systems by Groover + My knowledge.
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