1. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 1 Open System Analysis-1. Conservation of Mass Spring Work Where x is displacement of spring from rest

2. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 2 Open System Analysis-1. Conservation of Mass Work from expansion of solid bars Where σ n is the normal stress, N/m 2

3. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 3 Open System Analysis-1. Conservation of Mass Stretching a liquid film Where σ s is surface tension in N/m

4. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 4 Open System Analysis-1. Conservation of Mass Raising or accelerating a body

5. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 5 Open System Analysis-1. Conservation of Mass Nonmechanical work Electrical –force is voltage and displacement is electrical charge Magnetic –magnetic field strength is force –total magnetic dipole moment is the displac. etc.

6. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 6 Open System Analysis-1. Conservation of Mass OPEN SYSTEMS ANALYSIS - 1 Conservation of Mass

7. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 7 Open System Analysis-1. Conservation of Mass What are open systems? System

8. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 8 Open System Analysis-1. Conservation of Mass Steady and unsteady mass flow in a control volume...

9. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 9 Open System Analysis-1. Conservation of Mass An unsteady situation: dm C.V. /dt >0 Mass flow into control surface, kg/s Mass in system,m(t) Control surface Control Volume

10. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 10 Open System Analysis-1. Conservation of Mass A steady situation: dm C.V. /dt =0 Massoutflow Massinflow Control surface Control Volume

11. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 11 Open System Analysis-1. Conservation of Mass An unsteady situation: dm C.V. /dt >0 Massoutflow Massinflow Control surface Control Volume

12. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 12 Open System Analysis-1. Conservation of Mass The general balance principle for the lumped system: A rate equation Rate of change of mass in system = Rate of all mass inflow Rate of all mass outflow - Net rate of mass creation +

13. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 13 Open System Analysis-1. Conservation of Mass Rate of change of mass in the control volume = Rate of all mass inflow =

14. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 14 Open System Analysis-1. Conservation of Mass Rate of all mass outflow = Net rate of mass creation =

15. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 15 Open System Analysis-1. Conservation of Mass General lumped form

16. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 16 Open System Analysis-1. Conservation of Mass Steady state lumped form

17. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 17 Open System Analysis-1. Conservation of Mass Average velocities...

18. Instructor’s Visual Aids Heat Work and Energy. A First Course in Thermodynamics © 2002, F. A. Kulacki Chapter 3 Module 3 Slide 18 Open System Analysis-1. Conservation of Mass Mass flow Average velocity or mass average velocity