Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul...
-
Upload
adam-griffith -
Category
Documents
-
view
218 -
download
0
Transcript of Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul...
![Page 1: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/1.jpg)
Analysis of the effects of different types of loads on a Thermo-Acoustic Engine
Chitta Saha, Paul Riley and Mark Johnson
![Page 2: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/2.jpg)
Presentation Outline
- Construction of the tested Thermo-acoustic Engine (TAE)
- Design issues of the low cost Alternator
- Different electrical loads with the TAE
- Power analysis for different load conditions
- Measured results
- Conclusions
![Page 3: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/3.jpg)
Propane Burner TAE
• TAE consists of - Stainless steel bulge (HHX) - 30 layers stainless steel wire mesh regenerator ( 95 µm, 250 µm) - Car radiator (AHX)
• 5.5 kW propane burner, 4 inch pipe and B & C 6PS38 speaker.
• Each engine could be connected in series/parallel or independently.
Radiator
Hot buffer
tube
BulgeInsulation
![Page 4: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/4.jpg)
Requirements of LA for SCORE project
• Alternator design : low cost ( £4/unit ) high efficiency and resonant frequency operation.
• Ultimate goals - Supply 12 V lead acid battery. - Generate 150 W dc power
• Small magnet constrains : (BL)2/Rc
• Meet the output power and cost : frequency & displacement
![Page 5: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/5.jpg)
Limitations of Commercial low cost loudspeakers
• High suspension loss and limited mechanical stability.
• Operate over a large frequency range, LA needs to operate a fixed frequency.
• Lower efficiency and larger weight.
Cone
Voice Coil
Yoke pole pieces
Front suspension
Rear suspension
Magnet
Vent holes
Schematic of a loudspeaker type alternator
![Page 6: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/6.jpg)
SCORE Alternator : Halbach array
• Alternator can be constructed without back iron material, no yoke piece is required.
• Smaller pumping loss due to large hole.
• High Efficiency and high air-gap reversal flux density.
![Page 7: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/7.jpg)
Load power and efficiency with battery circuit for 1 mm gap between coils
0
130
260
390
520
650
0 0.2 0.4 0.6 0.8 1
Ratio : Vbattery/Vp
Av
era
ge
loa
d p
ow
er
(W)
0
20
40
60
80
100E
lec
tric
al e
ffic
ien
cy
(%
)
Power : 9 mm coilPower: 7.5 mm coilPower : 6.5 mm coilPower : 5 mm coilPower : 2 mm coilEfficiency : 9 mm coil
Performance of Alternator with Battery
M
L
N
W
Double coil case 2 mm height 10 coils case
p
L
p
L
p
L
p
L
c
Leout V
V
V
V
V
V
V
V
R
VP 1
222
, cos12
• Battery with rectifier circuit :
• Electrical efficiency for dual coils : 80 % for 125 W when Vbattery/Vp = 0.73, 76 % for 150 W when Vbattery/Vp=0.7
• Max. power : Vbattery/Vp = 0.39
![Page 8: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/8.jpg)
Tested prototype : Halbach array
0
1
2
3
4
5
6
7
8
0 1 2 3
Displacement (mm)
Op
en C
ircu
it p
eak
volt
age
(V)
Measured
Simulated
0
15
30
45
60
0 7 14 21 28 35Load resistance (ohm)
Eff
icie
ncy
(%
)
Acoustic-electrical efficiency
Calculated acoustic-electrical efficiency
• Measured and simulated voltages agree well.
• Discrepancy between measured and calculated efficiency appears due to cracking in the suspension.
![Page 9: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/9.jpg)
Alternator power analysis
RL
Rc
+
Sin
D1
D4
D3
D2
+
Sin
Rc
+-C RL
rmsrms
T
Lc
pps IVdt
RR
tVtV
TP
)
sin)(sin(
2 2/
0
L
LLrmsL R
VRIP
2
22
- Resistive load, source power and load power :
-Battery load can be considered as a RC load when C becomes very large. - Source power and load power for battery rectifier circuit
avgbatterydcLL IVIVP **
))](sin2
1(2
[1 1
22
p
LL
Lp
cavg V
VV
VV
RI
frmsrms
LpL
p
Lp
cs
IV
VVV
V
VV
RP
])(sin1
2
1([
1 2212
![Page 10: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/10.jpg)
Measured results
• Pressure and temperature has been measured using NI DAQ module.• Voltage and power has been measured using PPA2530.• Electrical power is almost proportionally varied with the square pressure.
![Page 11: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/11.jpg)
Loads effect on a Thermo-Acoustic Engine
Load Condition TAE parameters Alternator
HHX (oC) HHX- AHX (oC) Pressure (mBar)
Ac voltage (Vrms)
Ac power (W)
Total power (VA)
Idc (A)(Into 12V lead acid battery)
Load power* (W)
12 V battery + capacitor +
rectifier
413 347 38 13.12 8.96 11.35 0.43 5.59
Capacitor + 30 Ω resistance +
rectifier
411 346 39 13.57 8.89 11.36 0.49 6.85
20 Ω resistance 403 343 37 13.2 8.65 8.65 - 8.65
• Bridge rectifier required a fixed load resistance to generate the same amount of real power with battery.
• No effect on pressure and temperature when the real power is constant.
• Load power is less than generated power due to losses in the rectifier.
![Page 12: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/12.jpg)
Conclusions
• The construction of dual loop 30 layers stainless steel regenerator SCORE TAE is introduced.
• Design issues of SCORE LA and advantages of double Halbach array are discussed.
• Voltage/power measurement issues of the alternator with linear and non-linear load with the full wave rectifier circuit are discussed.
• Variations of the measured pressure and temperature of the engine as well as electrical power are shown.
• Measured results show, no effect on the pressure and temperature with the changing the load condition.
![Page 13: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/13.jpg)
Acknowledgment
The Score project www.score.uk.com is funded by EPSRC, the UK Engineering and Physical Research Council.
![Page 14: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/14.jpg)
![Page 15: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/15.jpg)
Specification of the regeneratorWire diameter 95 umWire spacing 250 umVolumetric Porosity: σ 0.783Solid fraction: (1-σ) 0.217Hydraulic radius 86 umRegenerator width 155 mmRegenerator length 180 mmRegenerator thickness 9 mm
𝑄𝑡ℎ𝑒𝑟𝑚𝑎𝑙 ℎ𝑒𝑎𝑡 = 𝑄𝑏𝑢𝑟𝑛𝑒𝑟 − 𝑄𝑝𝑎𝑛1+𝑝𝑎𝑛2 − 𝑄𝑐ℎ𝑖𝑚𝑛𝑒𝑦 − 𝑄ℎ𝑜𝑢𝑠𝑖𝑛𝑔 𝑊𝑎𝑐𝑜𝑢𝑠𝑡𝑖𝑐 (ℎ𝑒𝑎𝑡) = 𝑄𝑡ℎ𝑒𝑟𝑚𝑎𝑙 ℎ𝑒𝑎𝑡 − 𝑄𝑟𝑒𝑗𝑒𝑐𝑡𝑒𝑑 ℎ𝑒𝑎𝑡 − 𝑄𝑇𝐵𝑇
𝜂𝑆𝑡𝑜𝑣𝑒 = 𝑄𝑝𝑎𝑛 1+𝑝𝑎𝑛 2𝑄𝑏𝑢𝑟𝑛𝑒𝑟 × 100%
𝜂𝑇𝐴𝐸(𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 ) = 𝑊𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦𝑊𝑎𝑐𝑜𝑢𝑠𝑡𝑖𝑐 (ℎ𝑒𝑎𝑡 ) × 100%
𝜂𝑇𝐴𝐸(ℎ𝑒𝑎𝑡) = 𝑊𝑎𝑐𝑜𝑢𝑠𝑡𝑖𝑐 (ℎ𝑒𝑎𝑡 ) 𝑄𝑡ℎ𝑒𝑟𝑚𝑎𝑙 ℎ𝑒𝑎𝑡 × 100%
![Page 16: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/16.jpg)
General power/losses summary of the system
Burner (net power) 4657.71 W Rejected Heat1807.39
WEngine housing losses
519.24 W Acoustic power (Heat) 460.65 W
Heat to the Pans 1170.69 W Electricity power 15 WChimney losses 430.00 W Stove efficiency 25.13%
Heat to the TAE 2537.78 WTAE Efficiency (Heat to Acoustic power(Heat))
18.15%
TBT losses 269.74 WTAE and Generator Efficiency (Acoustic power (Heat) to Electrical power)
3.2%
![Page 17: Analysis of the effects of different types of loads on a Thermo-Acoustic Engine Chitta Saha, Paul Riley and Mark Johnson.](https://reader036.fdocuments.us/reader036/viewer/2022062409/56649b57550346318e8d566f/html5/thumbnails/17.jpg)