CHAPTER 2 STC DESIGN MODEL
2.5 Conclusions
The study results of this section are summarized as below:
(1) A new STC configuration used with solid force as sealing compliant mechanism has been innovated.
(2) The global analytical model of STC, which includes geometrical definition, thermofluid simulation, dynamics analysis, energy balance and overall efficiency predictions, has all been reviewed and systematized from prior literatures.
(3) A STC design model with parametric algorithm has been constructed. Meanwhile, a practical computer simulation package for STC design has also been built-up which can evaluate overall performance of STC in detail.
(4) According to the market requirement, the COPel has been selected as the basis of STC performance description. Meanwhile, the COPel is defined as the objective function in this study for optimization approach.
Table 2.1 Patents list of radial sealing mechanisms of STC in U.S.A
Types
Assignees Eccentric Link Swing Link Slider Block Driving Bushing Individual Persons US 3,011,694
US 3,560,119
US 3,600,114 US 3,567,348 US 1,906,142
Arthur D. Little US 3,874,827 US 3,884,599 Sanden Corp. US 4,575,319 US 4,435,136 US 4,580,956 US 4,808,094
Sanyo US 4,838,773
American. Standard US 4,934,910 Mitsubishi Denki
Matsushita Co. US 4,764,096
US 5,536,152 US 5,562,436
Carrier Corp. US 5,017,107
US 5,076,772
Hitachi, Ltd. US 5,040,958
MHI US 5,165,879
Nippondenso Co. US 5,575,635
Scroll Technologies
US 6,053,714 US 6,179,592 US 6,352,417 US 6,361,297
Table 2.2 Patents list of axial sealing mechanisms of STC in U.S.A.
Types
Assignees Sealing Means Pressurized gas to the back of Orbiting Scroll
Pressurized gas to the back
of Fixed Scroll Pressing member
Individual Persons US 5,833,442 US 3,874,827
Arthur D. Little US 3,986,799 US 3,994,633 US 3,994,635 US 3,994,636 US 4,199,308 US 4,395,205
US 3,884,599 US 3,994,633
Hitachi, Ltd. US 4,487,560
US 4,216,661 US 4,350,479 US 4,357,132 US 4,365,941 US 4,557,675 US 4,596,520
US 4,861,245
US 5,829,959 US 6,174,150 US 6,589,035 Leybold-Heraeus GmbH
Trane Co. US 4,415,317 US 4,416,597 US 4,462,771
Sanden Corp.
US 4,437,820 US 4,453,899 US 4,460,321 US 4,627,799 US 4,701,115 US 4,722,676 US 4,753,583 US 4,890,987 US 4,968,232 US 5,122,041 US 5,702,241 US 6,126,421
US 5,082,432
American Standard Inc. US 6,126,422 US 6,270,713 US 4,522,575 Mitsubishi Denki Kabushiki
Kaisha
US 4,564,343 US 4,732,550 US 4,740,143 US 4,824,343
US 5,743,720 US 5,800,142
US 5,846,065 US 5,853,288 US 4,846,639
Toshiba US 4,696,630
Copeland
US 4,767,293 US 4,877,382 US 5,102,316 US 5,156,539 US 5,482,450 US RE35216
US 5,580,230 Iwata Air Compressor Co.
(Anest Iwata Corp.) US 4,869,658 US 6,179,590
Tecumseh US 4,884,955 US 5,088,906
US 5,131,828 US 6,139,294 US 6,168,404
US 5,383,772
Carrier Corp. US 5,037,281
US 4,938,669 US 4,992,032 US 4,993,928 US 5,040,956 US 5,085,565 US 5,090,878 US 5,145,345 US 5,256,044 US 5,762,483 US 5,873,711 US 6,149,413 US 6,517,332 Toyoda US 5,076,771 US 5,364,247
US 5,545,020 US 5,547,353
MHI US 6,585,501 US 5,186,616 US 5,257,920
US 5,447,418 General Motor Corp. US 5,226,233
US 6,074,185
Sanyo Electric Co. US 5,242,284
ITRI US 5,252,046 Matsuahita Co. US 5,562,434 US 5,848,883
US 5,630,712
US 5,520,526 US 5,951,272
LG Electronics, Inc. US 5,562,435 US 5,823,757
US 6,299,417 Nippondenso Co. US 5,580,228 US 6,074,141
Bristol Compressors, Inc. US 5,588,820 US 5,593,295 US 6,030,192 Air Squared, Inc. US 5,632,612 US 6,511,308
Scroll Technologies
US 5,989,000 US 6,077,057 US 6,171,008 US 6,224,059 US 6,290,478 US 6,527,528
US 6,554,592
US 6,309,197 US 6,416,301 Varian, Inc. US 6,068,459
Mind Tech Corp. US 6,071,101
Rechi. Precision Co., Ltd. US 6,537,044 US 6,257,852
Fujitsu General,.Ltd. US 6,389,837 US 6,561,776
Daikin Industries, Ltd. US 6,533,561 US 6,514,060
Fig. 2.1 High side and low side configuration of STC
Suction Gas
Discharge Gas
Suction Gas Discharge
Gas Scroll
Pump
Scroll Pump
Motor
High Side Shell Low Side Shell
Pressurized gas flow Suction
Gas
Discharge Gas
Suction Gas Discharge
Gas Scroll
Pump
Scroll Pump
Motor
High Side Shell Low Side Shell
Pressurized gas flow
Fig. 2.2 Major forces acting on the scroll set during compression operation
Fig. 2.3 Internal leakage patterns of STC
Fixed scroll
Orbiting scroll F
tF
θ& F
mFixed scroll
Orbiting scroll F
tF
θ& F
m(a) Eccentric links (Issued by Copeland Co. in US 4,609,334 at Sep.02, 1986)
(b) Swing links (Issued by Trane Co. in US 4,413,959 at Nov. 08, 1983)
(c) Slider block (Issued by Carrier Co. in US 5,017,107 at May 21, 1991)
(d) Driving bushing (Issued by Copeland Co. in US 4,954,057 at Sep. 04, 1990) Fig. 2.4 Major embodiments of radial compliant sealing mechanism of STC
Fig. 2.5 Prior art of driving bushing used in the developed STC of this study
Prior art of Driving Bushing
Prior art of
Driving Bushing
(a) Sealing means
(Issued by Arthur D. Little, Inc. in US 3,994,636 at Nov. 30, 1976)
(b) Pressurized gas to the back of orbiting scroll (Issued by Hitachi, Ltd. in US 4,365,941 at Dec. 28, 1982)
(c) Pressurized gas to the back of fixed scroll
(Issued by Copeland Corp. in US 5,156,539 at Oct. 20, 1992)
(d) Pressing member
(Issued by Tecumseh Co. in US 5,383,772 at Jan. 24, 1995)
Fig. 2.6 Major embodiments of axial compliant sealing mechanism of STC
Fig. 2.7 Prior art of guiding pressured fluid as backpressure on scroll member
Fig. 2.8 The new STC schematic of this study proposed Overturn
Bottom frame Lower journal bearing
Oil pump
Bottom frame Lower journal bearing
Oil pump
(a) Solid force sealing compliant mechanism structure
(b) Solid force sealing compliant mechanism with pin-type
(c) Solid force sealing compliant mechanism with ring-type
Fig. 2.9 STC Solid axial compliant sealing mechanism innovated by this study Overturn
Fig. 2.10 Detailed forces exerted on the orbiting scroll (Ikegawa et al., 1984) Fpa: axial gas force
Fpr: radial gas force Fpt : tangential gas force
Fpo: gas force of the integration of pressure distribution in suction pressure area
Fcm: centrifugal force
Ogm: center of mass of orbiting scroll Rp : reaction force
Ma : moment of force about tangential gas Mr : moment of force about radial gas Mt : moment of force about axial gas
hp : distance between the action line of Fptand Ogm hr : distance between the action line of Rpand Ogm ε : orbit radius
Fpa: axial gas force Fpr: radial gas force Fpt : tangential gas force
Fpo: gas force of the integration of pressure distribution in suction pressure area
Fcm: centrifugal force
Ogm: center of mass of orbiting scroll Rp : reaction force
Ma : moment of force about tangential gas Mr : moment of force about radial gas Mt : moment of force about axial gas
hp : distance between the action line of Fptand Ogm hr : distance between the action line of Rpand Ogm ε : orbit radius
(a) Schematic of vapor compression refrigeration cycle
(b) P-h diagram of the cycle
Fig. 2.11 The simplified refrigeration cycle for defining a real air-conditioner
1
2
3 4
Condenser coils Evaporator coils
Compressor from the refrigerated space 1
2
3 4
Condenser coils Evaporator coils
Compressor from the refrigerated space
1-2 polytropic compression process (in compressor)
2-3 Approximate constant pressure heat rejection process (in condenser unit)
3-4 Throttling process
(in expansion valve or capillary tube)
4-1 Approximate constant pressure heat absorption process (in evaporator unit)
Fig. 2.12 Four major design variables of scroll wrap
Fig. 2.13 The design structure of STC simulation tool
Scroll height (he)
Scroll thickness (t) Scroll pitch (pt)
Roll angle (φr)
Scroll height (he)
Scroll thickness (t) Scroll pitch (pt)
Roll angle (φr)
Fig. 2.14 The flowchart for STC performance simulation in this study
Cooling capacity requirement Boundary conditions &
Constraint definitions
Find scroll wrap dimensions
Design Output
Various chamber areas &
volumes calculation
Radius of base circle
Wrap pitch, thickness, height Orbiting radius
Scroll extending angle
Suction gas mass flow model Heat transfer model
Leakage model Gas heating model Mass & Energy balance Forces & Moments of parts Bearing loads
Dimensions of moving parts Frictional loss Boundary conditions &
Constraint definitions Boundary conditions &
Constraint definitions
Find scroll wrap dimensions
Design Output
Various chamber areas &
volumes calculation
Radius of base circle
Wrap pitch, thickness, height Orbiting radius
Scroll extending angle
Suction gas mass flow model Heat transfer model
Leakage model Gas heating model Mass & Energy balance Forces & Moments of parts Bearing loads
Dimensions of moving parts Frictional loss
CHAPTER 3
THE STC DESIGN MODEL VALIDATION
To bring new STC products to market, the critical issue is to be able to create a practical and validated computer simulation package. In this section, based on the computer simulation package for estimating STC performance that this study developed in Chapter 2, the experimental analysis with R22 refrigerant to validate the results data of which the simulation tool calculated has been carried out. The deviation between predicted and measured data of the verified STC is under 4%. As a result, the validated STC simulation package can be used to guide the STC to practical development.
3.1 Literatures Review
To validate the simulated results with accurate experiments is a very important procedure to put in practice for STC commercial products development. DeBlois and Stoeffler (1988) have taught the detailed techniques used for measuring pressure-crank angle, pressure-volume and suction-compression-discharge processes of scroll compressor. The techniques feature the measurement of shaft speed and instantaneous pressure within the scroll compressor chambers in conjunction with the use of pressure and temperature measuring instrumentations, digital oscilloscope and data acquisition system. Marchese (1992) exhibited an experimental effort to measure the instantaneous pressure acting on an axially compliant orbiting scroll in detail. Therefore, following on the experimental techniques described, a valuable evaluating system to validate the STC simulation tool has been implemented in this
investigation.
3.2 Experimental system description
Figure 3.1 shows the schematic of the laboratory prototype that is semi-hermetic STC with low-side shell structure and applied with R22 refrigerant. Table 3.1 shows the detailed items and functions of each measuring component used in this study that are strategically located in the STC to measure and monitor the temperatures and instantaneous pressures. The developed experimental system include 6 dynamic pressure transducers, 18 K-type thermocouples, one set of proximity probe systems, two pieces of high-pressure feed-through, one set of PC-based monitor systems combined with a digital oscilloscope, power amplifier, and data acquisition system with high-speed.
Figure 3.2 describes the specified 18 temperatures and 6 pressures measuring points that will be observed during experimental validations. The 18 temperatures are used to monitor the thermal status inside of the STC, to ensure the STC in operation is stable and controllable. Table 3.2 lists the detail measuring positions of the 18 located thermocouples.
In particular, the measurement of instantaneous shaft speed and pressure within the scroll elements are useful in understanding the details of the scroll compression process. Six pressure measuring points are located to track continuously from suction to discharge while the STC is in operation. The locations of these pressure transducers should be tuned to precise position with no pressure leakage so as to make sure the detected pressure data is stable and correct. Meanwhile, a magnetic position sensor is used in conjunction with a shaft-mounted single-tooth gear to provide an angular reference position and to trigger the oscilloscope and a second sensor is used is
used in conjunction with a multi-tooth gear to provide instantaneous angular position information. Figure 3.3 depicts the schematic of this pressure acquisition system and Fig. 3.4 shows the photos of this laboratory STC embedded with several sensors and located on the compressor calorimeter to do the validation test. Table 3.3 has described the specifications of compressor calorimeter used in this experimental study.
3.3 Experimental Procedure
1. While setting up the experimental system, every measuring instrument must be calibrated, in the meantime, the laboratory STC prototype for testing ought to be assembled and checked to be running properly. The STC has 18 located thermocouples for measuring temperatures at specified positions, 6 pressure transducers to measure operating pressure inside the compression chambers.
2. The second procedure is to check whether the high-pressure feed through has leakage or not. In this study, a pressurized refrigerant gas with 10kgf/cm2 is given to do this check. Thereafter, readout information from data acquisition system and digital scope, to verify the measuring data from 18 temperatures, 6 pressures and power consumption is reliable and accurate.
3. Install the laboratory STC for testing in the calorimeter. Specified 6 operating conditions as Table 3.4 listed have been carried out as the first stage calibration.
4. While the STC is in operation, the HP3852 data acquisition system acquired the detecting data of temperature and pressure versus crankshaft angle position based on 100kHz catch speed, and the measuring data have been collected into the personal computer, in the meantime, the waveforms of pressure versus crankshaft angle also have been plotted.
5. Analyze these measuring data and check the deviations between real detected and
the calculated results.
6. Revise the experimental system and the developing STC simulation package, to validate experiments continuously until the deviation of results between prediction and measurement can be accepted in practice.
3.4 Experimental Results 3.4.1 First stage calibration
1. At first stage calibration, the STC are working on lower pressure conditions as conditions 1 and 2. Figure 3.5(a) shows the STC has over-compression phenomenon while it is operating at 40Hz. The discharge pressure is raised to 20kgf/cm2 as conditions 3 and 4, and operated at 60Hz. Note that the same results of over-compression status have been shown as Fig. 3.5(b) and also presented that the higher suction pressure of STC will produce higher over-compression pressure.
2. To make sure the over-compression problems, the STC is operated at conditions 5 and 6 with 50Hz and 60Hz, respectively. The over-compression appears as usual even though the STC is driven at different crankshaft speeds. Figure 3.5(c) shows the tested results.
3. Above experimental results depict the discharge port dimension of fixed scroll has some problems because the over-compression is always present in spite of the STC operating at lower pressure ratio or at higher pressure ratio conditions.
4. Furthermore, the results of above experiments also show that the captured pressure from piezoelectric pressure transducers have the interlaced phenomenon during intermediary pressured gas (P2, P3 locations) progress to higher pressure chambers (P4, P5 locations) in the compression process. This phenomenon expresses that the locations of piezoelectric pressure transducers should be tuned so as to prevent
the interference of pressure detection while the pressured gas is progressing.
3.4.2 Second stage validation
1. After modifying the discharge port dimension and tuning the locations of P2~P5 of the piezoelectric pressure transducers, the over-compression and interlaced phenomenon are minimized such as Fig. 3.6 shows.
2. Based on above calibrations, Fig. 3.6 also depicts the comparison of pressure versus crankshaft rotation angle between predicted results and measured results of which the STC is operated at ARI conditions, that condition No. 1 of Table 3.5 shows. The acceptable deviation of results between computer simulation and testing measurement is shown as Table 3.5.
3. From Fig. 3.6 shows, the deviation of pressure versus crankshaft rotation angle between predicted results and measured results is very small. Meanwhile, Fig. 3.7 also shows the 18 temperature measurements data at six different operation conditions, which indicates the laboratory STC prototype has stable thermal distribution within the compressor housing. This measurement data is extremely valuable when used in predicting STC performance with the developed STC simulation package.
4. As Table 3.5 shows the results, the maximum deviations of cooling capacity, power consumption and COPel between calculated results and real measured results are 1.31%, 2.89% and 3.89%, respectively.
3.5 Conclusions
The study results in this section are summarized below:
(1) A practical computer estimation package of STC has been constructed to evaluate
overall performance of STC in detail.
(2) Using an on-line data acquisition system combined with experimental measurement techniques, the pressures and temperatures during the compression process can be captured to understand the details as the scrolls operate during the compression process. Meanwhile, from the detecting data at first stage, the experimental system has been calibrated accurately.
(3) After the calibration of temperature and pressure measurements, the validation between calculated results and real measured data has been carried out. Finally, the deviation of the verified STC’s performance between predicted results and experimental measured results, are under 4%. It means the validated STC simulation package that this study developed, can be used in the STC practical design works.
(4) Based on the research results and technical facilities, the other validations about the temperature distribution on scrolls and the distribution of the thermal deformation on scrolls have been approached continuously by Lin et al. (2005) and given a practical reference for the developed STC simulation tool.
Table 3.1 The items and functions of measuring components and instruments.
Items & Functions Photos
1. T-type thermocouples and connectors:
Max. pressure rating is 400psi,
Operating temp. is – 45 ~ 150ºC
2. PCB 111A20 Dynamic pressure transducers:
Pressure measuring range:
(1) PCB 111A21: ~125psi, (2) PCB 111A26: ~500psi
3. Bently Nevada 7200 proximity transducer system:
(1) High-pressure feed through:
Max. pressure rating is 400psi, Operating temp. is – 45 ~ 121ºC (2) Proximity probe:
Power: -17.5 ~ -26VDC,
calibration range: 2mm (80Mils), Scale factor: 200MV/Mil,
Operating temperature: -34~177ºC (3) Proximitor:
Operating temperature: -51~100ºC, Power: -17.5~-26VDC,
Scale factor: 200MV/Mil 4. PC based monitor system:
Personal computer with 200Hz CPU, PCB 482A10 Amplifying power unit,
HP 54602B digital scope operated at 150MHz, HP 3852A Data acquisition system with 20channels.
HP 82341D HP-IB interface card.
5.Others:
OMEGA Feed through: Max. pressure is 2000psi
Table 3.2 The measuring points of temperatures
Symbols Measuring points Notes
T1 Discharge port of scroll set
T2 Discharge port at isolating member T3 Pressing members of axial sealing
mechanism
To measure the accurate discharge temperature after compression
operation
T4 Back plate of fixed scroll To monitor the fixed scroll temperature variations T5 Orbiting scroll plate To monitor the orbiting scroll
temperature variations T6 Inside hole of motor stator
T7 Upper side of motor stator coils T8 Middle side of motor stator coils T9 Lower side of motor stator coils
To monitor the motor temperature variations
T10 Lower journal bearing
T11 Upper side of isolating member T12 Moddle side of isolating member T13 Lower side of isolating member T14 Suction inlet of scroll set
To measure the accurate suction temperature before inlet to suction port
of scroll set
T15 Driving bushing T16 Main journal bearing T17 Upper side of motor stator T18 Oil sump
To measure each bearing temperature variations and to monitor the oil
supply status
Table 3.3 The specifications of calorimeter used for measuring STC performance.
Items Specifications General description of system According to ISO 917, this equipment is designed
for fully automatic measurements Compressor loop refrigerant R22
Capacity measuring range 1500W~12000W
Measuring method and required accuracy
(1) The equipment is employed for the secondary refrigerant system and liquid flow meter system.
(2) The value of the estimated error for the cooling capacity from the secondary refrigerant system calculated should be lower than liquid flow meter system.
(3) The deviation of cooling capacity and COPel
measuring results between the secondary refrigerant and liquid flow meter system should be within ± 4%.
(4) The accuracy of refrigerant flow-measuring instruments should be within ±1%
(5) The accuracy of speed-measuring instruments should be within ±0.75%
(6) Repeatability ≤ 1%
The background noise of
compressor chamber ≤ 40dBA when Fan is closed
Control items Range Stability
Compressor discharge pressure 10~30 kg/cm2 ± 0.1 kg/cm2 Compressor suction pressure 1.67~9.28 kg/cm2 ± 0.15 kg/cm2
Compressor suction temperature -25~50℃ ±0.5℃
Table 3.4 The operating conditions used for the first stage calibration.
Condition No.
Discharge pressure (kgf/cm2)
Suction pressure (kgf/cm2)
Motor operating frequency (Hz)
1 10 2 40
2 10 2 60
3 20 4 60
4 20 5 60
5 20.86 5.36 50
6 20.86 5.36 60
Table 3.5 The comparisons between simulations and experimental measurements.
Operating Conditions
Cooling Capacity (W)
Power Consumption (W)
COPel
(W/W) No. Evap.
Temp.
Cond.
Temp. Comput. Real Error
(%) Comput. Real Error
(%) Comput. Real Error (%) 1 7.2℃ 54.4℃ 9244.22 9247.59 -0.04 3347.1 3329.4 0.53 2.76 2.78 -0.84 2 5.0℃ 40.0℃ 9890.50 9938.53 -0.48 2493.7 2567.8 -2.89 3.98 3.87 2.70 3 5.0℃ 50.0℃ 9010.92 9007.90 0.03 3008.3 3038.4 -0.99 3.00 2.97 1.18 4 5.0℃ 60.0℃ 7948.99 7846.18 1.31 3659.0 3751.1 -0.02 2.17 2.09 3.89
Fig. 3.1 Experimental apparatus for STC model validation in this study
(a) 18 thermocouple locations for temperature measurements
(b) 6 piezo sensor locations for pressure measurements
Fig. 3.2 Temperatures and pressures measuring locations for experimental validations
T12 T11
Fig, 3.3 Experimental schematic for measuring STC instantaneous pressures
Crankshaft rotation angle 30.0
20.0
10.0
0
360º
Digital oscilloscope Piezoelectric
transducers
Magnetic Proximity transducer
Crankshaft rotation angle 30.0
20.0
10.0
0
360º
Digital oscilloscope Piezoelectric
transducers
Magnetic Proximity transducer
(a) Laboratory STC assembly (b) Laboratory STC located in test bench
(c) Testing feature
Fig. 3.4 Photos of laboratory STC used for validation test in this study
(a) The results of operating conditions 1 and 2
(b) The results of operating conditions 3 and 4
(c) The results of operating conditions 5 and 6 Fig. 3.5 The experimental results at first stage validation
360º
Fig. 3.6 The comparison between calculated results and measuring results Crankshaft rotation angle
(Pd =20.86kgf/cm2, Ps =5.36kgf/cm2, operated at 60Hz) 360º
30.0
(Pressure (kgf/cm2 )
20.0
10.0
0
calculation measurement
Crankshaft rotation angle
(Pd =20.86kgf/cm2, Ps =5.36kgf/cm2, operated at 60Hz) 360º
30.0
(Pressure (kgf/cm2 )
20.0
10.0
0
calculation measurement
1 2 3 4 5 6 ps/pd kgf/cm2 2/10 2/10 4/20 5/20 5.36/20.86 5.36/20.86
fm Hz 40 60 60 60 50 60
T1 ℃ 74.00 75.21 103.20 96.11 104.60 105.56
T2 ℃ 68.11 70.22 92.10 84.33 91.50 92.11
T3 ℃ 58.89 60.12 79.01 72.11 78.09 78.89
T4 ℃ 67.33 72.23 89.20 81.56 89.10 89.78
T5 ℃ 51.72 52.12 58.20 55.72 59.30 60.44
T6 ℃ 63.89 65.41 83.20 72.78 84.00 85.00
T7 ℃ 44.44 45.12 61.01 57.22 61.80 62.78
T8 ℃ 62.78 63.12 80.21 71.11 81.21 82.22
T9 ℃ 44.44 45.12 55.21 50.00 57.22 57.22
T10 ℃ 43.44 43.89 51.20 50.33 51.92 53.94
T11 ℃ 58.89 61.12 79.12 72.11 78.10 78.89
T12 ℃ 53.67 54.18 65.78 60.56 65.01 65.56
T13 ℃ 48.22 49.20 53.12 51.22 54.12 55.39
T14 ℃ 33.67 33.91 35.01 34.44 35.89 36.67
T15 ℃ 55.28 56.10 60.21 59.89 64.21 64.94
T16 ℃ 48.72 49.11 51.50 53.33 56.41 57.44
T17 ℃ 43.39 44.17 51.20 48.78 52.12 53.22
T18 ℃ 42.78 43.12 50.20 49.61 51.91 53.22
Condition No.
Units Symbols
Fig. 3.7 The 18 temperatures measurement data at 6 operating conditions 30.00
40.00 50.00 60.00 70.00 80.00 90.00 100.00 110.00 120.00
T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14 T15 T16 T17 T18
Condiiton No.1 Condition No.2 Condition No.3 Condition No.4 Condition No.5 Condition No.6
18 Thermocouples location symbol of Fig. 3.2 depicted
℃
CHAPTER 4
STC FAMILY DESIGN WITH OPTIMIZATION METHOD
One critical problem in the mass production of commercial STC is that their key components—including fixed scroll, orbiting scroll, Oldham ring, mainframe and crankshaft—all require the use of very high precision machining skills. To help in lowering the complexity, cost and lead-time of product development, a systematic design method with optimization for developing a family of STC is proposed. Such a family design needs to meet two goals: (i) a series of STC with multi-specified cooling capacities should have the same outside shell diameter and use common key parts or casting molds, (ii) the performance of each specified capacity of the developed STC should meet market requirements.
In addition to using the general design optimization model which includes multi-variable, direct search and inequality constraints, both interactive session and discrete
In addition to using the general design optimization model which includes multi-variable, direct search and inequality constraints, both interactive session and discrete