In pump head terminology, Hd represents which head?

• A. Discharge Head
• B. Suction Head
• C. Elevation Head
• D. Head Loss

Answer: (A)

In pump head terminology, head is the energy per unit weight of the fluid, and each measured point has its own energy level described by components like elevation, pressure, and velocity. Hd is the discharge head—the energy level of the fluid as it leaves the pump into the discharge pipe. It can be written as Hd = z_d + p_d/γ + v_d^2/(2g), incorporating the elevation, pressure, and velocity at the discharge.

The pump raises the fluid from suction to discharge, so the pump head produced is the difference Hd − Hs (the suction head), with losses sometimes accounted for separately. Head loss represents energy lost to friction and fittings, usually denoted Hl, not Hd. Elevation head is simply the elevation term z, not the combined discharge energy. So the term Hd specifically identifies the discharge side energy, making it the correct interpretation.