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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Cogeneration
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Cogeneration
It is defined as, "Sequential generation of two different forms of energy from a single source (generally mechanical and thermal energy, Combined Heat & Power Generation)".
For E.g.: Warm pool water with Lower Costs and Lower Emissions of Conventional powerplant.
Technical Options for Cogeneration
Cogeneration is not used by large industries.
For constant temperature heating or drying, steam is very good (since isothermal conditions can be maintained allowing saturated steam to condensed (at that temp) utilizing latent heat.
Reduction of Carbon Emissions
1. Reciprocating Engine Cogeneration Systems
It is defined as, "Utilizing one source (diesel/gas engine) to produce electricity energy converted into heat water (process heat)".
Steps:
Burning of Fuel in engine ↦ Produce heat ↦ Produce electricity ↦ engine is cooled by coolants ↦ which transfer heat contents into circulating water ↦ which is further heated in boiler.
2. Gas Turbine Cogeneration Systems
Steps:
Fuel + air ↦ Compressed + Burn in compressor ↦ hit to turbine blades (expands) ↦ which make shaft to rotate, which produce electricity ↦ remaining heat is used to heat water.
3. Steam Turbine Cogeneration Systems
It is similar to Rankine Cycle but Condenser is replaced by Process Heater (which gives process heat as per our requirement).
Additional Components ↦ process heater + pump.
Continuously bled steam in process heater.
Steps:
Fuel burn in boiler ↦ Steam produced ↦ hit turbine blades ↦ Electricity generated ↦ Steam enter process heater ↦ Exchange heat with cold chemicals.
There are two types of Steam Turbine, namely:
Back Pressure Turbine
Pass Out Turbine
Back Pressure Turbine
It is defined as, "When the exhaust steam from cogeneration of the turbine is utilized for process work".
We can modify initial steam pressure or exhaust pressure to get required steam of desired pressure and temp.
Process heater is running Above or At atmospheric pressure.
Ideally, we want 100% of heat extracted to transform steam into liquid .
Pump cannot work with 2 phase.
Pass Out Turbine
It is defined as, "The back pressure turbine through which a certain quantity of steam is continuously exhausted for the process heating at desired pressure and temp".
Process Heater ↦ has Higher Power-to-Heat ratio.
Feasibility Criteria ↦ Cost of generation, No utility present.
References:
Material from Class Lectures + Book named Power plant Engineering by P.K Nag (4th Edition) + My knowledge.
Angles & Directions Angles are also called bearings. Bearings are the acute angles between lines and meridians. They are divided into following types. Related Terms : Meridian : Imaginary line joining North and South poles. Declination : Difference between magnetic and true meridians. Azimuth : Clockwise angle taken from Geodatic North. * If area is greater ➤ use Geodatic North * If area is smaller ➤ use Magnetic North Magnetic Declination maybe towards East or West. For east ➤ Magnetic bearing=true bearing - Declination For west ➤ Magnetic bearing=true bearing + Declination Forward Bearing : Bearing taken in the direction of traverse. Backward Bearing : Bearing taken in opposite direction of traverse. Forward bearing - Backward bearing=180 For anti-clockwise : FB of line = BB of previous line + angle Example: In an anti-clockwise traverse <A=102'30',...
Center of Gravity: It is defined as; The resultant weight of a system which passes through a single point is called Center of Gravity ( G ). Center of Mass: It is defined as; The point at which the whole mass of the system acts. The concept of center of mass is cleared from the video given below: Centroid of a Volume: Objects having three dimensions have the centroid which is its geometric centre. Centroid of an Area: Objects having two dimensions have the centroid which is its geometric centre. Centroid of a Line: Objects having linear dimensions have the centroid which is its geometric centre. Composite Bodies: A composite body consists of a series of connected simpler shaped Bodies which may be rectangular, triangular, semicircular, etc. References: www.youtube.com www.wikipedia.com http://web.aeromech.usyd.edu.au/statics/doc/friction/Friction1.htm From Book Engineering Mechanics sta...
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...
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