What is the effect of a higher discharge coefficient C_d on the estimated flow through an orifice?

• A. Increases estimated flow.
• B. Decreases estimated flow.
• C. Has no effect on the estimated flow.
• D. Only affects temperature measurement.

Answer: (A)

Discharge coefficient C_d represents how closely the actual flow through an orifice follows the ideal flow, accounting for losses and the vena contracta. For a fixed orifice area and pressure drop, the flow rate is proportional to C_d (Q ∝ C_d A sqrt(ΔP/ρ)). So increasing C_d makes the estimated flow larger because the flow behaves more like the ideal case, with fewer losses reducing the flow. Decreasing C_d would lower the estimate, and C_d has no direct effect on temperature measurement.