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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Computational Fluid Dynamics

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Computational Fluid Dynamics

It is a kind of analysis of systems involving fluid flow, heat transfer in fluids and associated phenomena such as chemical reactions by means of computer based simulation.
Application of CFD analysis are:
  • Internal Combustion Engine or Gas Turbine (Power Plant)
  • Turbomachinery (Pumps or Turbines)
  • Nozzle Flow
  • Flow over Aircraft (Aerodynamics: Lift and Drag)
  • Hydrodynamics of Ship
  • External and Internal environment of building (Wind Loading and Heat or Ventilation)

Why CFD?

  1. It will help us in prototyping.
  2. Reduce lead times and cost of new design.
  3. Can perform experiments (which are very expensive, time taken, hazardous).

How CFD Works?

  1. Pre-Processor  ↔  define flow problem (geometry, meshing, phenomena, properties, boundary conditions).
  2. Solver  ↔  solve problems and calculation of desired variables at nodes (integral analysis, finite differentiation or element or volume/spectral methods).
  3. Post-Processor  ↔  to visualize the solution of domain (vector, contour, Particle tracking, 2D or 3D plots).
Governing equations (either in Integral or Partial Differential form) are:
  1. Mass 
  2. Momentum
  3. Energy

Classification of PDE's

Each type has a different mathematical behavior which implies a different physical behavior of the flow field. Partial differential equations are classified as:
  1. Hyperbolic  ↔  b2 - 4ac > 0
  2. Parabolic  ↔  b2 - 4ac = 0
  3. Elliptic  ↔  b2 - 4ac < 0

References:

  • Material from Class Lectures + Book named Fundamentals of Fluid Mechanics by Munson, Young & Okiishi's (8th Edition) + my knowledge. 
  • Pics and GIF from Google Images.  
  • Videos from YouTube (Engineering Sights).

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