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HARDWARE PROJECT REPORT ON TOPIC : FABRICATION OF STERLING ENGINE
SUBMITTED BY :Nikhil Agrawal
Contents Abstract
Introduction
Literature
Materials and tools required
Calculations
Applications
AbstractWorldwide attempts are being made to increase the use of renewable energy sources as well as to use our current fossil fuel energy sources more efficiently.
The aim of this project was to build a prototype of a Stirling engine and analyse its performance. This project provided a great opportunity to gain experience with mechanical design, manufacturing, and the fundamentals of Stirling engines.
We applied our knowledge of thermodynamics to the design of the engine, and developed formulas to predict its power output at different temperature differentials
IntroductionHistoryThe Stirling Engine is one of the hot air engines. It was invented by Robert Stirling (1790-1878) and his brother James. His father was interesting in engine and he inherited it. He became a minister of the church at Scotland in 1816. At this period, he found the steam engines are dangerous for the workers. He decided to improve the design of an existing air engine. He hope it wound be safer alternative. Earlier Sterling Engine
DIFFERENT TYPES
Alpha Stirling Engine Gamma Stirling EngineBeta Stirling Engine
Literature Stirling engines are external combustion engines, which means no
combustion takes place inside the engine and there’s no need for intake or exhaust valves. As a result, Stirling engines are smooth-running and exceptionally quiet.
Because the Stirling cycle uses an external heat source, it can be run on whatever is available that makes heat — anything from hydrogen to solar energy to gasoline.
Sterling engine is a device that converts heat energy to mechanical power by alternately compressing and expanding a fixed quantity of working fluid at different temperatures.
Working PrincipleI. One side of the engine is continuously heated while the other side is
continuously cooled.
II. First, the air moves to the hot side, where it is heated and it expands pushing up on a piston.
III. Then the air moves through the regenerator to the cold side, where it cools off and contracts pulling down on the piston.
IV. Temperature change inside the engine produces the pressure change needed to push on the piston and make the engine run.
STIRLING CYCLE
1-2: constant volume process
2-3: isothermal expansion process
3-4: constant volume process
4-1: isothermal compression
process. P- V Di agr am
CYCLEEFFICIENCYNet work, Wnet= Wexp+ Wcomp
Net heat, Qtotal = Qheat+ Qexp
Recovered mechanical energy:Wnet = Wexp+ Wcomp
Wnet = ∫exp PdV + ∫comp PdV (P = nRT / V)Wnet = ∫exp (nRTmax/ V) dV+ ∫comp (nRTmin/ V) dV Wnet= nR (Tmax-Tmin) ln (Vmax/ Vmin)
Provided heat :Qexp= ∫exp PdV Qexp= nR Tmax ln(Vmax/ Vmin )Qheat= nCv (Tmax-Tmin)Qtotal = nCv (Tmax-Tmin) + nR Tmax ln (Vmax/ Vmin)
Cycle efficiency : η = [R (Tmax-Tmin) ln (Vmax/ Vmin)] [Cv (Tmax-Tmin) + R Tmax ln (Vmax/ Vmin)]
Efficiency Theoreticallyo Stirling engine efficiency = Carnot efficiency.o Unfortunately working fluid or gas is not ideal,this causes the
efficiency to be lower than Carnot efficiency.
In fact, Stirling engine efficiency depends ono Temperature ratio (proportionally).o Pressure ratio (inversely proportional).o Specific heat ratio (inversely proportional)
Materials Required 2 cylindrical tin cans 22 mm PVC pipe elbow Double sided foam tape Fishing line or thick string/line Sandpaper (80-120 grit) 18 gauge steel wire(1.5 mm) 24 gauge steel wire(0.6 mm) CD Bottle cap Balloon 8-12 bolt,nut,and 2 washers
Tools Required Exacto knife Scissors(Tin snips) Thumb Tack Plyers Wire cutters Alcohol lamp or Tea light/candle Magnet An iron
Output prototype
Applications Water pump stations. Combined heat and power plant. Solar power generation. Stirling cyrocoolers. Heat pump. Marine engines. Nuclear power. Aircraft engines. Micro CHP .
Conclusion The Stirling engine is noted for its high efficiency compared to
steam engines, quiet operation, and the ease with which it can use almost any heat source.
This engine is currently exciting interest as the core component of micro combined heat and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.
REFERENCES https://en.wikipedia.org/wiki/Stirling_engine THERMAL ENGINEERING by Er.R.K.RAJPUT Engineering Thermodynamics by PK Nag
THANK YOU