What is the best method to control flow in a pump system?

Controlling flow in a pump system is crucial for ensuring efficient operation and preventing issues such as cavitation or excessive wear. Throttling the discharge side of the pump is a widely accepted method because it directly influences the flow rate and pressure without altering the pump's physical characteristics. By restricting the flow at the discharge, the pump can still run at its optimal efficiency point, allowing for better control over the system's performance.

This method allows for dynamic adjustments to flow as operational needs change. For instance, if the system requires less flow, throttling can reduce the output while maintaining the pump's operational integrity. Throttling prevents the need for costly modifications to the system and keeps the pump within its designed performance range.

The other methods listed, while they may have their applications, do not provide the same level of control. Increasing suction pressure often leads to increased flow but may not be feasible in all systems and can result in complications such as cavitation. Minimizing fluid temperature can impact viscosity and density but does not directly control flow. Reducing the pump size may change the flow characteristics but involves significant alterations and can increase downtime. Therefore, throttling on the discharge side emerges as the most effective and practical solution for controlling flow in a pump system.