《制冷与低温原理》课件C第三章 蒸气制冷循环 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 蒸汽制冷循环第一节单级蒸气压缩制冷循环第二节两级蒸气压缩制冷循环第三节复叠式制冷循环第四节 蒸气吸收制冷循环3.2 Two-stage vapor compression systems3.2.1 Introduction3.2.2 Design

2、type analysis3.2.3 Operation type analysis第二节两级蒸气压缩制冷循环一、绪论二、设计型分析三、操作型分析8/1/202233.2 Two-stage vapor compression systems 第二节 两级蒸气压缩制冷循环 3.2.1 Introduction 一、绪论 Discharge capacity: f（PR） qvsqvt ; Throttle loss: q0 Q0qmq0 qvtq0 /v1 ; Discharge temperature t2.Reasons: （pKp0） and PR ( - 40 ) 1点制冷剂体积流量压

3、缩机实际输气量qvsqmv1 qvt qmqvt/v1 输气系数、容积效率qvt理论输气量8/1/202243.2 Two-stage vapor compression systems 第二节 两级蒸气压缩制冷循环 3.2.1 Introduction 一、绪论 Cascade compression systems (70140) Multi-stage compression systems (4070)Method 18/1/202253.2 Two-stage vapor compression systems 第二节 两级蒸气压缩制冷循环 3.2.1 Introduction 一、

4、绪论 Cascade compression systems (70140) Multi-stage compression systems (4070)Method 2 8/1/202263.2 Two-stage vapor compression systems 第二节 两级蒸气压缩制冷循环 3.2.2 Design type analysis 二、设计型分析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第二节两级蒸气压缩制冷循环一、绪论二、设计型分

6、析（一）一次节流循环（二）二次节流循环三、操作型分析8/1/202283.2.2.1 Single-throttle cycles （一）一次节流循环 3.2.2.1.1 No interstage cooling 无中间冷却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）一次节流循环 3.2.2.1.2 With i

7、ncomplete interstage cooling 中间不完全冷却No interstage coolingWith incomplete interstage cooling8/1/2022103.2.2.1 Single-throttle cycles （一）一次节流循环 3.2.2.1.2 With incomplete interstage cooling 中间不完全冷却With incomplete interstage cooling8/1/2022113.2.2.1 Single-throttle cycles （一）一次节流循环 3.2.2.1.3 With comple

8、te interstage cooling 中间完全冷却10988/1/2022123.2.2 Design type analysis 二、设计型分析3.2.2.1 Single-throttle cycles（一）一次节流循环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）一次节流循环 3.2.2.1.2 With incomplete interstage cooling 中间不完全冷却1098qmHh6qmLh2（qmHqmL）h3 h6h3（h2h3）qmL/qmH 8/1/2022143.2.2.1 Singl

10、e-throttle cycles （一）一次节流循环 3.2.2.1.2 With incomplete interstage cooling 中间不完全冷却1098qmHh9qmLh4（qmHqmL）h3 qmHqmL（h3h4）/（h3h9） 8/1/2022153.2.2.1 Single-throttle cycles （一）一次节流循环 3.2.2.1.3 With complete interstage cooling 中间完全冷却qmHh9qmLh2qmLh4qmHh3 qmHqmL（h2h4）/（h3h9） 8/1/2022163.2.2 Design type analys

11、is 二、设计型分析3.2.2.1 Single-throttle cycles（一）一次节流循环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、设计型分析3.2.2.1 Single-throttle cycles（一）一次节流循环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、设计型分析 3.2.2.4 Determination of interstage temperature （三）中间温度的确定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、设计型分析 3.2.2.4 Determination of interstage temperature （