Graphic courtesy of Dr. Israel Urieli of Ohio University.
The results obtained suggest an initial configuration of a two cylinder
alpha engine of 185 cubic centimeters swept volume operating at 1000 RPM
with an average internal pressure of 147 psi. The cylinder diameter
is approximately 5.7 cm and the stroke is 5.7 cm. At this point the
mechanical transmission and the gas used as the working fluid has not been
selected. Note that the gas selected will have no real impact on
the parameters described above but will greatly impact the number of channels
and tubes of the heat exchangers as well as the parameters of the regenerator.
At this point we will invoke the principles of scaling and similarity to
go forward with this engine.
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From CH.
5 & 6 of 'The Regenerator and the Stirling Engine' by Dr. Allan J.
Organ, ISBN1860580106 |
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Instructions
for use: Enter Data Values in the area under 'Enter Values'. The values
to be entered are three of the four values of Power, rpm, pref and Vsw
of the machine you want to create. This is called the Derivative Machine.
You must also enter the values of the gas which you are using as the working
fluid. The values for the three most popular are listed. You may use other
gases by determining the values for the specific gas you want to use and
entering it |
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2/1/03
22:14 |
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Enter |
Results |
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Values |
Here |
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| P |
Power
in Watts |
350.00 |
350.00 |
Watts |
| rpm |
Revolutions
per Minute |
1000 |
1000 |
rpm |
| pref |
Reference
Pressure (Mpa) 1 ATM=0.101325 Mpa |
1.000 |
1.00 |
Mpa |
| Vsw |
Swept
Volume in CC (cm3) |
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187.67 |
cm3 |
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Values
of Gas Parameters Hydrogen=1, Helium=2, Nitrogen (Air)=3 |
3 |
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| R |
Gas
Constant =(J/kg °K) 4120, 2080, 287 |
287 |
287 |
(J/kg-°K) |
| g |
Specific
Heat Ratio (Cp/Cv) 1.41 1.66 1.41 |
1.41 |
1.41 |
(Cp/Cv) |
| mref |
Gas
Viscosity (Pa-s) 8.4E-06 1.69E-05 1.70E-05 |
1.69E-05 |
0.0000169 |
Pa-sec |
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Inches |
mm |
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| Lref, Sth |
Reference
Length or Thermodynamic Stroke =(Vsw)1/3 |
2.2540 |
57.253 |
mm |
| Lrd |
Length of Regenerator '=(lrd
)*
(Sthd) |
0.9278 |
24 |
mm |
| Dh |
Diameter of the Regenerator
Housing |
4.517 |
114.723 |
mm |
| Affrd |
Free Flow Area of Regenerator
= (affrd)*(Sthd)2 |
16.022 |
10337 |
mm2 |
| dw |
Diameter
of Regenerator Wire = 4*(rhrd)* (1- ¶v)/(¶v) |
0.0026 |
0.0664 |
mm |
| mw |
Mesh Number
of Regenerator Wire Mesh =4*(1- ¶v)/(3.14159*dw) |
153 |
6.0379 |
wires/mm |
| nr |
Number of Gauzes in the
Regenerator 'Stack' |
177 |
177 |
gauzes |
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| Ntcr |
Thermal Capacity Ratio
of the Regenerator NTCR=(Tref)(rw)(cw)/Pref |
1315 |
1315 |
ratio |
| Nf |
Fourier Modulous
of Regenerator Nf=a/(ns)(dw)2 |
8.657 |
8.657 |
ratio |
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| Tnxed |
Number of
Tubes in the Expansion Exchanger =Affxed/((0.25*3.14159)*(dxed)2) |
71 |
71 |
tubes |
| Lxed |
Length of Expansion Exchanger
Tubes '=(lxed
)*
(Sthd) |
5.3610 |
136 |
mm |
| dxe |
Diameter of Expansion Exchanger
Tubes = 4 * rhxed |
0.0972 |
2.469 |
mm |
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| Tnxcd |
Number of
Tubes in the Compression Exchanger =Affxcd/((0.25*3.14159)*(dxed)2) |
1622 |
1622 |
tubes |
| Lxcd |
Length of Compression Exchanger
Tubes '=(lxcd
)*
(Sthd) |
1.8340 |
47 |
mm |
| dxc |
Diameter of Compression
Exchanger Tubes = 4 * rhxcd |
0.0320 |
0.813 |
mm |
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