Ball valve permits a full flow through the lines with a minimum of ___________?

Ball valve permits a full flow through the lines with a minimum of ___________?

• A. Friction loss
• B. Pressure drop
• C. Turbulence
• D. Viscosity change

Answer: (A)

The main idea here is that a valve’s resistance to flow drops when it is fully opened. A ball valve in the fully open position presents a straight, unobstructed passage through the bore, so the fluid meets little resistance as it passes. This minimizes energy losses due to friction inside the valve, which is what we call friction loss. Since friction loss is the primary form of loss when fluid flows through a valve, keeping the valve open as much as possible reduces this loss to a minimum. The other options aren’t the focus here: pressure drop across the valve is tied to friction loss, and while a smaller pressure drop goes along with lower friction, the question is specifically about the loss due to flow resistance in the valve itself. Turbulence would be higher if the flow were forced through constrictions, not minimized by an open bore, and viscosity change isn’t affected by the valve opening—viscosity is a property of the fluid, not something the valve changes.

The main idea here is that a valve’s resistance to flow drops when it is fully opened. A ball valve in the fully open position presents a straight, unobstructed passage through the bore, so the fluid meets little resistance as it passes. This minimizes energy losses due to friction inside the valve, which is what we call friction loss. Since friction loss is the primary form of loss when fluid flows through a valve, keeping the valve open as much as possible reduces this loss to a minimum.

The other options aren’t the focus here: pressure drop across the valve is tied to friction loss, and while a smaller pressure drop goes along with lower friction, the question is specifically about the loss due to flow resistance in the valve itself. Turbulence would be higher if the flow were forced through constrictions, not minimized by an open bore, and viscosity change isn’t affected by the valve opening—viscosity is a property of the fluid, not something the valve changes.