How does nozzle orifice size affect flow rate?

How does nozzle orifice size affect flow rate?

• A. Larger opening increases flow rate
• B. Larger opening decreases flow rate
• C. No effect on flow rate
• D. Smaller opening increases flow rate

Answer: (A)

Flow rate through a nozzle depends on how much cross-sectional area there is for fluid to pass. For a given pressure difference driving the flow, the velocity of the fluid exiting the nozzle is largely set by that pressure (and associated losses), while the amount that can pass per unit time scales with the opening area. So when the orifice is larger, more fluid can flow each second, increasing the flow rate. The relationship can be summarized by Q ≈ C_d × A × sqrt(2ΔP/ρ), showing that flow rate is proportional to the opening area. A smaller opening restricts flow, lowering the rate.

Flow rate through a nozzle depends on how much cross-sectional area there is for fluid to pass. For a given pressure difference driving the flow, the velocity of the fluid exiting the nozzle is largely set by that pressure (and associated losses), while the amount that can pass per unit time scales with the opening area. So when the orifice is larger, more fluid can flow each second, increasing the flow rate. The relationship can be summarized by Q ≈ C_d × A × sqrt(2ΔP/ρ), showing that flow rate is proportional to the opening area. A smaller opening restricts flow, lowering the rate.