Which of the following is a principal function of valves?

The principal function of valves is to regulate flow within a piping system. Valves control the passage of fluids—whether liquids or gases—by opening, closing, or partially obstructing various passageways. This regulation is crucial in maintaining the desired pressure and flow rates within a system, ensuring it operates efficiently and safely.

When it comes to fluid dynamics, the ability of a valve to control flow directly impacts the performance of the entire system. They can be used to start or stop the flow, throttle the flow rate, or redirect fluid to different parts of the system. By providing precise control, valves help in maintaining optimal operating conditions, which is essential in various applications ranging from residential plumbing to complex industrial systems.

Options related to regulating voltage, generating pressure, or storing energy do not accurately represent the primary function of valves in piping systems. Instead, these functions pertain to electrical systems or mechanical components such as pumps and accumulators.