《制冷與低溫原理》課件C第三章 蒸氣制冷循環(huán) 3 (3.2.1-3.2.2.1)30

1、3 Vapor refrigeration cycles3.1 One-stage vapor compression systems3.2 Two-stage vapor compression systems3.3 Cascade vapor compression systems3.4 Vapor absorption systems 第三章 蒸汽制冷循環(huán)第一節(jié)單級(jí)蒸氣壓縮制冷循環(huán)第二節(jié)兩級(jí)蒸氣壓縮制冷循環(huán)第三節(jié)復(fù)疊式制冷循環(huán)第四節(jié) 蒸氣吸收制冷循環(huán)3.2 Two-stage vapor compression systems3.2.1 Introduction3.2.2 Design

2、type analysis3.2.3 Operation type analysis第二節(jié)兩級(jí)蒸氣壓縮制冷循環(huán)一、緒論二、設(shè)計(jì)型分析三、操作型分析8/1/202233.2 Two-stage vapor compression systems 第二節(jié) 兩級(jí)蒸氣壓縮制冷循環(huán) 3.2.1 Introduction 一、緒論 Discharge capacity: f（PR） qvsqvt ; Throttle loss: q0 Q0qmq0 qvtq0 /v1 ; Discharge temperature t2.Reasons: （pKp0） and PR ( - 40 ) 1點(diǎn)制冷劑體積流量壓

3、縮機(jī)實(shí)際輸氣量qvsqmv1 qvt qmqvt/v1 輸氣系數(shù)、容積效率qvt理論輸氣量8/1/202243.2 Two-stage vapor compression systems 第二節(jié) 兩級(jí)蒸氣壓縮制冷循環(huán) 3.2.1 Introduction 一、緒論 Cascade compression systems (70140) Multi-stage compression systems (4070)Method 18/1/202253.2 Two-stage vapor compression systems 第二節(jié) 兩級(jí)蒸氣壓縮制冷循環(huán) 3.2.1 Introduction 一、

4、緒論 Cascade compression systems (70140) Multi-stage compression systems (4070)Method 2 8/1/202263.2 Two-stage vapor compression systems 第二節(jié) 兩級(jí)蒸氣壓縮制冷循環(huán) 3.2.2 Design type analysis 二、設(shè)計(jì)型分析Type of cyclesKind of refrigerantsTemperature differenceCompressor efficiencyPs Compressor motorQk CondenserQ0 Evapo

5、ratorqm Compressors, valves and pipesDesignResultsUser specified: TH、TL、Q0Designer chosen: TH、TL、el 、 f3.2 Two-stage vapor compression systems3.2.1 Introduction3.2.2 Design type analysis3.2.2.1 Single-throttle cycles 3.2.2.2 Double-throttle cycles 3.2.3 Operation type analysis第二節(jié)兩級(jí)蒸氣壓縮制冷循環(huán)一、緒論二、設(shè)計(jì)型分

6、析（一）一次節(jié)流循環(huán)（二）二次節(jié)流循環(huán)三、操作型分析8/1/202283.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.1 No interstage cooling 無(wú)中間冷卻ph12 (6)745No interstage cooling Throttle loss: q0 const Q0qmq0 Discharge capacity: f（PR） qvsqvt Discharge temperature t28/1/202293.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.2 With i

7、ncomplete interstage cooling 中間不完全冷卻No interstage coolingWith incomplete interstage cooling8/1/2022103.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.2 With incomplete interstage cooling 中間不完全冷卻With incomplete interstage cooling8/1/2022113.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.3 With comple

8、te interstage cooling 中間完全冷卻10988/1/2022123.2.2 Design type analysis 二、設(shè)計(jì)型分析3.2.2.1 Single-throttle cycles（一）一次節(jié)流循環(huán)User specified: TH、TL、Q0Designer chosen: TH、TL、 Tm iH、iL 、mH 、mLDesign parametersMode of intercoolingNo interstage coolingWith incomplete interstage coolingWith complete interstage cool

9、ing1Tk、T0、tm、t4pk、p0、pmTkTHTkpk ; tm pmT0TL-T0p0 ; t4tmtm（tm5）2t2、t7 h2h1（h2sh1）/id ; h7h6（h7sh6）/igt6t6t2h6h3（h7h6）qmL/qmHt6t310988/1/2022133.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.2 With incomplete interstage cooling 中間不完全冷卻1098qmHh6qmLh2（qmHqmL）h3 h6h3（h2h3）qmL/qmH 8/1/2022143.2.2.1 Singl

10、e-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.2 With incomplete interstage cooling 中間不完全冷卻1098qmHh9qmLh4（qmHqmL）h3 qmHqmL（h3h4）/（h3h9） 8/1/2022153.2.2.1 Single-throttle cycles （一）一次節(jié)流循環(huán) 3.2.2.1.3 With complete interstage cooling 中間完全冷卻qmHh9qmLh2qmLh4qmHh3 qmHqmL（h2h4）/（h3h9） 8/1/2022163.2.2 Design type analys

11、is 二、設(shè)計(jì)型分析3.2.2.1 Single-throttle cycles（一）一次節(jié)流循環(huán)Mode of intercoolingNo interstage coolingWith incomplete interstage coolingWith complete interstage cooling3q0、qkwL、wHq0h1h4 、 wLh2h1qkh7h9 、 wHh7h64qmLqmLQ0 /q0Q0 /（h1h4） （3-43）qmH/qmdL1(h3h4 )/(h3h9 )(h2h4 )/(h3h9 )5qmHqmHqmL qmHqmL (3-47) qmHqmL (3

12、-47)User specified: TH、TL、Q0Designer chosen:iH、iL 、mH 、mL Design parameters10988/1/2022173.2.2 Design type analysis 二、設(shè)計(jì)型分析3.2.2.1 Single-throttle cycles（一）一次節(jié)流循環(huán)User specified: TH、TL、Q0Designer chosen: iH、iL 、mH 、mL Design parametersMode of intercoolingNo interstage coolingWith incomplete interstag

13、e coolingWith complete interstage cooling6PtL PtLqmLwLqmL（h2h1） （3-44）PtH PtHqmHwHqmgH(h7h6 ) （3-48）PtPtPtLPtHqmH/qmdL1(h3h4 )/(h3h9 )(h2h4 )/(h3h9 )7Q0/Pt(h1h4 )/(h2h1 )+(h7h6 ) （3-49）8QkQkqmHqkqmH（h7h9）9QmQmqmL（h9h4）10988/1/2022183.2.2 Design type analysis 二、設(shè)計(jì)型分析 3.2.2.4 Determination of interstage temperature （三）中間溫度的確定1. (MPa)2. (K)3. tm=0.4tk+0.6to+3 () f(Tk、T0、Tm) Tmopt f(max) 8/1/2022193.2.2 Design type analysis 二、設(shè)計(jì)型分析 3.2.2.4 Determination of interstage temperature （