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.
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...
Diffusion It is defined as, " The transportation of one atom from one state into other state " . Used for hardening of surfaces like die parts, gear, bolt, machine element. Hardening can be done using Temperature-Heat treatment ( diffusion couple ). There are two types of diffusion: Inter-diffusion ↔ in which atoms tend to migrate from region of high concentration to low concentration . Self-diffusion ↔ in which atoms migrate within a solid. Diffusion Mechanism There can be two conditions of moving atoms Empty spaces between adjacent sites. Atoms have sufficient energy to break bond with neighbors atoms which cause lattice distortion during displacement. If we rise temperature, small fractions of atoms is capable of diffusive motion (which cause lattice distortion). Types of Diffusion 1. Vacancy Diffusion It is defined as, " interchange of an atom from a normal lattice position to the adjacent vacant lattice site " . Extent of vacancy diffusion is a function...
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