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.
Rankine Cycle Rankine cycle is an ideal cycle for Vapour Power Cycles and is normally used for Electricity Generation. The Rankine cycle consist of following steps: 1 ↝ 2 : Isentropic Compression in Pump. 2 ↝ 3 : Constant Pressure Heat Addition in Boiler. 3 ↝ 4 : IsentropicExpansion in Turbine. 4 ↝ 1 : Constant Pressure Heat Rejection in Condenser. Energy Balance: Since, all the devices which Rankine Cycle posses are steady flow devices, so the energy balance for Rankine cycle is: 》For Pump ( q = 0 ): 》For Boiler ( w = 0 ): 》For Turbine ( q = 0 ): 》For condenser ( w = 0 ): The thermal efficiency of Rankine Cycle is: How can we Increase the Efficiency of A Rankine Cycle: The efficiency of a Rankine cycle can be increased: Increasing the avg. temperate at which heat is added Decreasing the avg. Temperature at which heat is rejected. The above two objectives can be achieved by following three met...
Advance High Strength Steel Conventional low carbon mild steel has simpler ferritic structure (α-iron) and good ductility. Common type of HSS is High Strength Low Alloy (HSLA) ⇥ has yield strength 550 - 690 N/sq.mm . Manganese ⇥ supporter (stabilizer) of ferrite. Conventional HSS : Is single-phase ferritic steel with a potential for some pearlite in C-Mn steel. Lower strain hardening capacity. Advance HSS : primarily steel with a microstructure containing a phase other than ferrite, pearlite, cementite. Higher strain hardening capacity. Case Study of Automobile There are three different zones in a car: Crumple Zone (Front & Back) Middle Compartment Safety Cage Some important points about these zones are: Crumple Zone ⇥ Made with those materials which absorb maximum amount of energy. Safety Cage ⇥ Multiple areas (like cabins, structural elements). Areas of Safety cage are described ahead: Cabins (Blue Areas) ⇥ Should have high streng...
Air-Standard Cycle Assumptions: The actual cycle is rather more complicated so we deduce it by considering following assumptions: The working fluid is air which continuously flow in a closed loop and act as ideal gas. All process are internally reversible . Combustion process is replaced by Heat addition process. Exhaust process is replaced by Heat rejection process. Here we are discussing 4 main cycles, namely: Otto Cycle or Constant Volume Heat Addition Cycle Diesel Cycle or Constant Pressure Heat Addition Cycle Dual Cycle Brayton Cycle 1. Otto Cycle or Constant Volume Heat Addition Cycle: The information about the diagram is given by: 1 ➤ 2: Isentropic Compression 2 ➤ 3: Constant Volume Heat Addition 3 ➤ 4: Isentropic Expansion 4 ➤ 1: Constant Volume Heat Rejection A. Efficiency of Otto Cycle: The efficiency of Otto Cycle is given by clicking the picture below: B. Work Output of Otto Cycle: The work output of ...
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