上游充通大￥ SHANGHAI JIAO TONG UNIVERSITY Engineering Thermodynamics I Lecture 18 Chapter 5 Mass and Energy Analysis of Control Volume Analysis Spring,2017 Prof.,Dr.Yonghua HUANG 强 月是A http://cc.sjtu.edu.cn/G2S/site/thermo.html 1日
Engineering Thermodynamics I Lecture 18 Spring, 2017 Prof., Dr. Yonghua HUANG Chapter 5 Mass and Energy Analysis of Control Volume Analysis http://cc.sjtu.edu.cn/G2S/site/thermo.html
Typical CV system applications/examples © Several devices of interest in engineering ·Nozzle ●Diffuser ●Turbine Compressor Single device 。Pump ●Heat exchanger combination 。Throttling device (system integration) 上游气通大粤 Mar/20,Mon,2017 2 SHANGHAI JLAO TONG UNIVERSITY
Mar/20, Mon, 2017 2 Typical CV system applications/examples Several devices of interest in engineering • Nozzle • Diffuser • Turbine • Compressor • Pump • Heat exchanger • Throttling device Single device (system integration) combination
Nozzle and Diffuser V2>V1 P2<P1 Nozzle:velocity T in the direction of flow 、A↓ Flow-straigftening Nozzle Screens Cross-sectional area (A)varying Acceleration Deceleration Test V2<V1 LNozzle section P2>P1 A↑ Practical application Diffuser:velocity in the direction of flow Diffuser 上游充通大 Mar/20,Mon,2017 3 SHANGHAI JIAO TONG UNIVERSITY
Mar/20, Mon, 2017 3 Nozzle and Diffuser Nozzle: velocity ↑ in the direction of flow Diffuser: velocity ↓ in the direction of flow Cross-sectional area (A) varying A ↓ A ↑ Practical application
Work for nozzles and diffusers (1,1,1: -a-+a+号+)-a(+ dt V2>V1 V2<V1 P2<P1 P2>P1 2 Nozzle Diffuser W W W The only work is flow work at the inlet and outlet of the CV. drops out 上游通大学 Mar/20,Mon,2017 4 SHANGHAI JIAO TONG UNIVERSITY
Mar/20, Mon, 2017 4 Work for nozzles and diffusers W W W The only work is flow work at the inlet and outlet of the CV. Wcv drops out (1,1,1):
Steady state of nozzle or diffuser dt SS 0 m-ri dt d 2 832 inlet exit △PE negligible V2>V1 +-+(心，) Nozzle Relatively much smaller 上游充通大 Mar/20,Mon,2017 5 SHANGHAI JIAO TONG UNIVERSITY
Mar/20, Mon, 2017 5 Steady state of nozzle or diffuser SS inlet exit ∆PE negligible Relatively much smaller Qcv