1. ©1997 by M. Kostic Ch.9: Pressure & Velocity Measurements Pressure Concept:Pressure Concept: …it is an inward-normal force per unit (contact) area [N/m 2, psi, atm, inHg, …] …it is net-effect of change of momentum of a fluid’s molecules collision with real (or imaginary) surface …absolute lack of molecular activity is the zero absolute pressure …it is a material property…it is a material property

2. ©1997 by M. Kostic Pressure Scales Vacuum pressure Gauge pressure Absolute pressure Standard atm. pressure 101.325 kPa(abs) 14.696 psi(a) 760 mmHg(a) 29.92 inHg(a) Local atm. pressure Local atm. pressure

3. ©1997 by M. Kostic Reference pressure instruments

4. ©1997 by M. Kostic U-tube Manometer PAPA PBPB

5. ©1997 by M. Kostic Inclined tube manometer

6. ©1997 by M. Kostic Elastic-element pressure sensors

7. ©1997 by M. Kostic Bourdon tube pressure gauge

8. ©1997 by M. Kostic Diaphragm pressure transducer

9. ©1997 by M. Kostic Piezoelectric pressure transducer

10. ©1997 by M. Kostic Design and errors of Pitot/Prandtl probe