Team SupersonicRafael Ramirez

Derek SchellErnest 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/AcousticOur 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 EngineComponents: Our solar device consists of five components: a

dish, heating plate, beta engine, cooling jacket, and a flywheel

Thermodynamic Model Stirling Cycle

1-2: 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 ExpansionIsochoric Heat RemovalIsothermal CompressionIsochoric 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 reflectorAdjusted to achieve optimal focal length

Attached to Solar TrackerWater 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