What type of pressure is referenced in closed conduit problems?

• A. Absolute pressure
• B. Gauge pressure
• C. Atmospheric pressure
• D. Vacuum pressure

Answer: (B)

In closed conduit problems, gauge pressure is the type of pressure that is typically referenced. Gauge pressure is measured relative to atmospheric pressure, meaning it indicates the pressure above the current atmospheric conditions. This is particularly relevant in fluid mechanics and hydraulic studies, where the behavior of fluids within closed systems, such as pipelines or conduits, is assessed.

When analyzing closed conduits, engineers often focus on the pressure available for the flow and the calculations involving head losses or energy changes in the system, which require a pressure measurement that excludes atmospheric effects. Gauge pressure readings are more useful in practical applications, as they provide a clearer understanding of the actual pressure forces acting on fluids within the system.

Using absolute pressure would incorporate atmospheric pressure into calculations, which can unnecessarily complicate analyses, especially in closed systems where the focus is on the relative pressure exerted by the fluid itself. Atmospheric pressure and vacuum pressure refer to conditions related to the air pressure outside the system, but they are not the primary concern in assessing flow within a closed conduit. Hence, gauge pressure is the most relevant and applicable measure in this context.