2013-2-27 Basic concepts:System Classification 1=Open System(Control volume): 1+2=Closed System(Control mass +2+3Adiabatic closed system 2+3+4 Isolated system Selecting System Boundary Example:compressor and tank Boundary 1:How long will the compressor operate? Boundary 2:What is the electric power input? Boundary 1_ Boundary 2 21 2013-2-27 21 1 2 4 3 Mass, M Work, W heat , Q 1 ⇒ Open System (Control volume)： 1+2 ⇒ Closed System (Control mass) 1+2+3 ⇒ Adiabatic closed system 1+2+3+4 ⇒ Isolated system 41 Basic concepts: System Classification Selecting System Boundary Example: compressor and tank ►Boundary 1: How long will the compressor operate? ►Boundary 2: What is the electric power input? 1-42 Boundary 1 Boundary 2