Total manometric height is the energy per unit of weight that the system requires to transport the fluid from the suction reservoir to the discharge reservoir, with a certain flow.
This energy will be furnished by a pump, and will be the fundamental parameter for its selection.
It is important to note that in a pumping system, the required condition is the flow, while the total manometric height is a consequence of the installation.
The Total Manometric Height of the system (H) can be calculated by:
 
Where:
-
Pd [kgf/cm²] - Pressure in the discharge reservoir
-
Ps [kgf/cm²] - Pressure in the suction reservoir
-
g [kgf/dm³] - Specific weight of the fluid
-
Vd [m/s] - Speed in the discharge reservoir
-
Vs [m/s] - Speed in the suction reservoir
-
g [m/s²] - Acceleration of gravity
-
Hgeo [m] - Geometric height
-
Hp [m] - Load losses
The constant 10 is to adjust the system of units used
The previous formula is used to determine the total manometric height of the system in design terms, that is, used to determine load losses, etc.
For an already operating system, some of the values can be obtained directly from measurements made at the facility itself. In this case, the total manometric height can be obtained in the following manner:
Where:
-
pd [kgf/cm²] - Pressure at the discharge
-
ps [kgf/cm²] - Pressure at the suction
-
g [kgf/dm³] - Specific weight of the fluid
-
vd [m/s] - Speed at the discharge
-
vs [m/s] - Speed at the suction
-
g [m/s²] - Acceleration of gravity
-
Z [m] - Difference of elevation between the centerlines of the rotors and the pressure gages (suction and discharge)
The constant 10 is to adjust the system of units used.
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