Solution Absolute pressure: System boundary. H2O Pabs Pgage Patm =75+100 =175 kPa m=I kg V=6L p=75 kPa (gage) Sat.steam leaving Vapor Liquid T=Tat@175kPa=116.04C Cin =500 W Mass energy balance: 0 U(④-U.O=Qv-W+∑ih:-∑m,h uniform =(m2u2-muj)cv -h.=么en5n=270.2Kkg Qin (m -m2)he (muz mu)cv =Qn△t=(0.5kJ/s)(30×60s)=900kJ 上泽通大学 April 8,2018 8 SHANGHAI JIAO TONG UNIVERSITYApril 8, 2018 8 Solution Absolute pressure: Sat. steam leaving Mass & energy balance: 0 0 =(m2u2 - m1u1 )cv uniform 1