1. What is Total Dynamic Head (TDH)?

Total Dynamic Head (TDH) is the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe. It's a crucial parameter in pump system design and testing, representing the actual work the pump must perform.

2. How Does the Calculator Work?

The calculator uses the TDH equation:

Where:

• \( Static\ Head \) — Vertical distance from water surface to discharge point (ft)
• \( Friction\ Loss \) — Head loss due to friction in pipes and fittings (ft)
• \( Pressure\ Head \) — Additional pressure at discharge converted to head (ft)

Explanation: The equation sums all components of resistance the pump must overcome to move fluid through the system.

3. Importance of TDH Calculation

Details: Accurate TDH calculation is essential for proper pump selection, system design, and performance testing. It helps ensure the pump can deliver the required flow rate against the system's resistance.

4. Using the Calculator

Tips:

• Measure static head as the vertical distance from the water source to the discharge point
• Calculate friction loss using pipe size, length, flow rate, and material
• Include pressure head if there's additional pressure at discharge (like a pressurized tank)
• All values must be in feet (convert from psi to feet by multiplying by 2.31 for water)

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between static head and TDH?
A: Static head is just the vertical elevation difference, while TDH includes all resistance components the pump must overcome.

Q2: How do I calculate friction loss?
A: Use the Hazen-Williams equation or Darcy-Weisbach equation based on pipe characteristics and flow rate.

Q3: When can I ignore pressure head?
A: When discharging to atmosphere (like an open tank), pressure head is zero.

Q4: Why is TDH important for pump selection?
A: Pumps are rated for flow at specific TDH values. Selecting a pump requires matching your system's TDH curve to the pump's performance curve.

Q5: Does TDH change with flow rate?
A: Yes, friction loss increases with flow rate, so TDH increases as flow rate increases in most systems.