Cavitation in Machines

Cavitation is a phenomenon in which the formation and collapse of vapor bubbles occur in a liquid flowing through a machine. This can lead to damage to the machine and decrease its efficiency. Let's discuss which machines have the possibility of cavitation.

Reaction Turbines and Centrifugal Pumps

Reaction turbines and centrifugal pumps have the possibility of cavitation. Let's understand why.

Reaction Turbines: These turbines work on Newton's third law of motion and are sensitive to the formation of cavities. As the liquid enters the turbine, it accelerates and passes through the blades. If the pressure at the blade surface drops below the vapor pressure of the liquid, cavities may form. The collapse of these cavities can lead to erosion of the blade surface, decreasing the efficiency of the turbine.

Centrifugal Pumps: These pumps work by converting the kinetic energy of the liquid into pressure energy. As the liquid enters the pump, it enters the impeller, which increases its velocity. If the pressure at the impeller inlet drops below the vapor pressure of the liquid, cavities may form. The collapse of these cavities can lead to erosion of the impeller surface and decrease the efficiency of the pump.

Impulse Turbines and Reciprocating Pumps

Impulse turbines and reciprocating pumps have less possibility of cavitation. Let's understand why.

Impulse Turbines: These turbines work by converting the kinetic energy of the liquid into mechanical energy. As the liquid enters the turbine, it passes through a nozzle, which increases its velocity. The high velocity liquid then passes through the blades, where it loses energy and exits the turbine. The design of these turbines is such that the pressure at the blade surface does not drop below the vapor pressure of the liquid, reducing the possibility of cavitation.

Reciprocating Pumps: These pumps work by using a piston to generate pressure in the liquid. As the piston moves, it creates a pressure difference in the liquid, which forces it to move. The design of these pumps is such that the pressure at the piston surface does not drop below the vapor pressure of the liquid, reducing the possibility of cavitation.

Conclusion

In conclusion, reaction turbines and centrifugal pumps have a higher possibility of cavitation compared to impulse turbines and reciprocating pumps. It is important to take precautions to prevent cavitation, such as maintaining the proper pressure and flow rate of the liquid, to ensure the longevity and efficiency of the machine.

Reaction turbines and centrifugal pumps