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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Frames and Machines
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Truss and it's Types:
Truss is a structure of connected elements forming triangular units, and a bridge whose load-bearing superstructure is composed of a truss.
There are three types of truss and they are:
1. Simple Truss:
A truss is a structure composed of slender members joined together at their end points.
2. Planar Truss:
Planar truss lies in single plane and typically used in parallel to form roofs and bridges.
3. Space Truss:
A space Truss consists of members joined together at their ends to form a stable three-dimensional structure.
Assumptions for Designing Truss:
To design the truss, we have two assumptions:
All loadings are applied at the joints.
The members are joined by smooth pins.
The Method of Joints:
In order to analyze or design a truss, it is necessary to determine the forces in each of its members. Method of joints consists of fool owing steps:
Truss is in equilibrium so does its joints.
Draw Free-body diagrams for each joint.
Apply the force equilibrium equations and obtain the required ones.
ΣFx = 0
ΣFy = 0
The Method of Sections:
By using the method of sections, you need to follow the instructions below:
Truss is in equilibrium so does the segments of truss.
Draw free Body diagram indicating all forces.
Cut the free Body diagram into its simple parts.
Apply the equilibrium equations to find the required forces and moments.
ΣFx = 0
ΣFy = 0
ΣMo = 0
Zero Force Members:
Zero-force members in a truss members which do not have any force in them. Zero-force members are used to increase the stability of the truss during construction and to provide added support of the loading is changed.
Frames:
Frames used to support loads which are often composed of pin-connected multi-force members that are subjected to more than two forces.
Machines:
Machines contain moving parts which are often composed of pin-connected multi-force members that are subjected to more than two forces.
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...
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...
Lubrication: It is defined as the admittance of oil between two surfaces having relative motion. Why do we need Lubrication? The functions of lubrication are described ahead: Reduce friction between moving parts. Reduce wear and tear of parts. Shock absorbing. To cool the surfaces in contact. Properties of Lubricants: Following are the properties of Lubricants: Viscosity ➸ Internal resistance to flow of liquid. It is the ability of oil to resists internal deformation due to load and mechanical stresses. Viscosity Index ➸ It represents the change in viscosity of oil with temperature. The greater the viscosity index, the smaller the change in viscosity with temperature. Flash Point Temperature ➸ The lowest temperature at which vapor of lubricating oil will ignite when given an ignition source. Fire Point Temperature ➸ It is the minimum temperature at which vapor of fluid will keep burning after the i...
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