Inlet diameter to a pump is larger than outlet diameter. Pump inlet is usually running at slightly negative pressure and its diameter is larger to slow down fluid flow velocity in order to prevent cavitation which is very destructive to the pump casing and internal parts. Pump outlet is always under pressure so there is no fear of cavitation thus its diameter can be smaller. Pump inlet diameter is larger as the inlet flow comes with lower velocity in that case if we reduce the inlet diameter then the flow will face more fictional losses which will reduce the velocity more which in turn lowers the net positive suction head available for the pump and it will start cavitating. Velocity considerations for pump design are generally 1 m/s for inlet and 2-2.5 m/s for outlet.
Pump inlet causes suction thus the negative pressure and thus we need greater volume with less velocity to avoid cavitation, the outlet as it pushes the flow forward to the desired destination a greater pressure and velocity is required thus the smaller the diameter the better. and yes the greater the diameter the bigger the cross sectional area also depending more on the thickness of the pipe because when dealing with fluid flow within a pipe we take into account the pipe diameter which affects the internal diameter which is the main one where the fluid will be flowing and it impacts the fluid flow greatly. So in simple words the thicker the pipe the smaller the internal diameter thus the smaller the area where the fluid will flow.
No comments:
Post a Comment