team supersonic rafael ramirez derek schell ernest tom christopher walker
TRANSCRIPT
Team SupersonicRafael Ramirez
Derek Schell
Ernest Tom
Christopher Walker
STIRLING ENGINE
OVERVIEW Initial Customer Design/Acoustic-Rafael Thermodynamic Model-Chris Construction of Artifact-Derek Testing-Tom Improvements-Tom Reflection-Derek
Initial Customer Design/Acoustic
Our initial customer design was Thermo Acoustics which is the science of generating or amplifying sound waves using heat. Our team has reconsidered the Thermo Acoustic Project due to limited time and resources .We decided on moving forth a different direction with a Beta Stirling Engine.
Reasons: A Beta Stirling engine seemed to be more feasible than a thermo acoustic
engine when it came down to our constraints. A beta stirling engine modeling and design were fairly similar to thermo
acoustics, so all of our progress wasn’t lost. Out of the major types of stirling engines we chose a beta due to single
power piston arranged within the same cylinder on the same shaft as a displacer piston simplifying our design and making us meet our constraints.
Since a beta stirling engine follows a stirling cyclic compression and expansion of air, our modeling followed four processes discussed in Thermo Fluids class
Stirling Engine
Components: Our solar device consists of five components: a
dish, heating plate, beta engine, cooling jacket, and a flywheel
Thermodynamic Model
Stirling Cycle1-2: Isothermal Expansion2-3: Isochoric Heat Removal 3-4: Isothermal Compression4-1: Isochoric Heat Addition
Initial Condition4-1: Isochoric Heat AdditionSTP -> 1-2 of the cycle
Thermodynamic Model Beta-type Stirling Engine/Cycle
1-2: Isothermal Expansion
2-3: Isochoric Heat Removal
3-4: Isothermal Compression
4-1: Isochoric Heat Addition
Thermodynamic Model Initial State
Initial Start-up
Process D
Isochoric Heat Addition
State 4 State 1 (=)
Pressure [Pa] 101325 289485.9901
Volume [m^3] 0.000260625 0.000260625
Temp [K] 294.26 841.1353103
Sp. Vol. [m^3/kg] 0.83392 0.83392
Enthalpy [J/kg] 420760 1266100
Int. Energy [J/kg] 336270 955370
Mass [kg] 0.00031253 0.00031253
Density [kg/m^3] 1.199155794 1.199155794
Thermodynamic Model Cycle States
Beta Stirling Cyle
Process A Process C Isothermal Expansion Isothermal Compression
Process B Process D Initial Process D
Isochoric Heat Removal Isochoric Heat Addition Isochoric Heat Addition
State 1 State 2 State 3 State 4 State 1 (=) State 4 State 1 (=)
Pressure [Pa] 289485.9901 144742.995 108139.5267 216279.0534 289485.9901 101325 289485.9901
Volume [m^3] 0.000260625 0.00052125 0.00052125 0.000260625 0.000260625 0.000260625 0.000260625
Temp [K] 841.1353103 841.1353103 628.4240167 628.4240167 841.1353103 294.26 841.1353103
Sp. Vol. [m^3/kg] 0.83392 1.66784 1.66784 0.83392 0.83392 0.83392 0.83392
Mass [kg] 0.00031253 0.00031253 0.00031253 0.00031253 0.00031253 0.00031253 0.00031253
Density [kg/m^3] 1.199155794 0.599577897 0.599577897 1.199155794 1.199155794 1.199155794 1.199155794
Thermodynamic Model P-v Diagram
0.0002 0.00025 0.0003 0.00035 0.0004 0.00045 0.0005 0.000550
50000
100000
150000
200000
250000
300000
350000
Isothermal Expansion
Isochoric Heat Removal
Isothermal Compression
Isochoric Heat Addition
Specific Volume [m^3/kg]
Pressure [kPa]
13 W
Thermodynamic Model Flywheel
KE = ½ I ω²I = mr²From work output, and size limit of flywheel due
to material on hand and solving for ω○ ~22,000 rev/min
Designed for 250 rev/minSystem will require a matched load or a brake to
operate continuously
Thermodynamic Model Output
Win Wout Wnet
52.29607205 -39.0711307 13.22494134
Qtot [W]= 13.22494134
Tmax Tmin ΔT [K]
841.1353103 628.4240167 212.7112936
η (calculated) η (theoretical)
0.132256072 0.220680892
Construction of Artifact Solidworks Model Developed Tweaked Model due to materials available All 6061 Aluminum
Machined most of the parts on a lathe and mill on our own
Assembled using small ball bearings to reduce friction
Attached to purchased parabolic reflector
Adjusted to achieve optimal focal length
Attached to Solar Tracker
Water Flow Attached
Testing
Ernest What do you have working? How do you
know it works? How have you documented that it works?
How we ran out of time – final assembly issues
Improvements
Ernest A plan for any future actions necessary
to complete the project successfully
Reflection Much less structured than other projects More freedom in design and creation of the
prototype More time to model prior to construction More instruction on the topic of the semester
prior to starting the design More specific constraints Teams based on scheduling Required more individual team organization