1. Lecture 15 TDH and NPSH
Dr. C. L. Jones
Biosystems and Ag. Engineering

2. Suction Lift
Dr. C. L. Jones
Biosystems and Ag. Engineering

3. Suction Head
Dr. C. L. Jones
Biosystems and Ag. Engineering

4. NPSHR
Dr. C. L. Jones
Biosystems and Ag. Engineering

5. NPSH (net positive suction head)
Dr. C. L. Jones
Biosystems and Ag. Engineering

6. NPSHA
Dr. C. L. Jones
Biosystems and Ag. Engineering

7. NPSHA
Dr. C. L. Jones
Biosystems and Ag. Engineering

8. Static Discharge Head
Static Discharge Head = vertical distance from pump centerline to the point of free discharge or the surface of the liquid in the discharge tank.
Dr. C. L. Jones
Biosystems and Ag. Engineering

9. Total Static Head
Vertical distance between the free level of the source of supply and the point of free discharge or the free surface of the discharge liquid.
Dr. C. L. Jones
Biosystems and Ag. Engineering

10. Total Dynamic Discharge Head
Static discharge head + velocity head at pump discharge flange plus discharge line friction
Total Dynamic Discharge Head (TH or TDH) (this is what we design for!!!)
Total dynamic discharge head – total dynamic suction head (tank above suction)…. Or….
Total dynamic discharge head + total dynamic suction lift (tank below suction)
Dr. C. L. Jones
Biosystems and Ag. Engineering

11. Total Dynamic Suction Lift or Head
(fluid below suction) Static suction lift - velocity head at suction + total friction head in suction line
(fluid above suction) Static suction head + velocity head at pump suction flange – total friction head in suction line
Velocity head = energy of liquid due to motion, Usually insignificant
Dr. C. L. Jones
Biosystems and Ag. Engineering

12. TDH includes friction losses due to piping and velocity
Total Dynamic Discharge Head (TH or TDH) (this is what we design for!!!)
TDH includes friction losses due to piping and velocity
Dr. C. L. Jones
Biosystems and Ag. Engineering

13. Example problems
Dr. C. L. Jones
Biosystems and Ag. Engineering