Differential pressure flowmeters: compared with a venturimeter, the permanent power/pressure loss across an orificemeter is generally

Introduction:Venturimeters and orificemeters are classic differential-pressure flowmeters. While both create a pressure drop to infer flow rate, their hydraulic recoveries differ markedly, impacting pumping cost and energy efficiency.

Given Data / Assumptions:

• Incompressible, steady flow.
• Meters correctly installed and sized.
• Focus is on permanent (unrecovered) pressure loss.

Concept / Approach:A venturimeter accelerates then smoothly decelerates the fluid through a converging–throat–diverging nozzle, enabling high pressure recovery. An orificemeter has a sharp-edged plate causing flow separation and a vena contracta downstream, with large mixing losses and poor pressure recovery, resulting in higher permanent loss.

Step-by-Step Solution:Both devices create a differential pressure ∆p for metering.Venturi: streamlined diffuser recovers much of the kinetic energy → small permanent loss.Orifice: separated flow and turbulence → low recovery → large permanent loss.Therefore, orificemeter loss > venturimeter loss.

Verification / Alternative check:Manufacturer data and handbooks show typical loss coefficients: orifices may lose 50–70% (or more) of ∆p, while venturis often recover most, leaving a small residual loss.

Why Other Options Are Wrong:

• Less than/same as: contradict well-known recovery differences.
• Unpredictable: qualitative ranking is well established.
• Zero: no real meter is lossless.

Common Pitfalls:Confusing differential pressure used for measurement with permanent loss. The two are related but not identical; geometry controls recovery.

Final Answer:More than that in a venturimeter