The question is about flow work in open-system thermodynamics and presents two statements to evaluate. Option a: 'Wflow = pV' This expresses flow work as the product of pressure and volume for the fluid mass being pushed into or out of a control volume. In many treatments of flow (open-system) analysis, the flow work required to bring in (or push out) mass is indeed p times the volume associated with that mass (w_flow = pV) when pressure is approximately uniform at the boundary. The idea captures the basic mechanical work needed to create space for the entering fluid, so this statement aligns with the standard definition of flow work in a simple form. Option b: 'is work done by a pressure, to translate matter into the system' This is describing the physical mechanism behind flow work: the surrounding (upstream) pressure performs work on the fluid to push it into the control volume, i.e., to translate matter into the system. Conceptually, this is accurate: flow work is the work done by pressure to move matter across the system boundary and into the control volume. The wording 'translate matter into the system' is a bit unusual, but the core idea—that pressure does the work to press matter into the system—is correct. Potential subtle pitfalls to consider: If pressure is not uniform, the exact expression for w_flow would involve an integral of p dV over the entering fluid mass, but the simplified pV form is a common and useful approximation for constant boundary pressure. Also, in some texts, flow work is discussed as pV for the entering (or leaving) mass, not the entire system, so care is needed about what V represents (the specific volume of the entering stream versus the system’s own volume). Nevertheless, both statements capture the essential concepts: Wflow = pV expresses the pressure–volume work involved, and the second statement describes that the work is performed by the surrounding pressure to bring matter into the system. In summary, neither option appears to be incorrect on the core thermodynamic interpretation, and together they reflect the standard understanding of flow work in open-system analysis.

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BH20A0720 Engineering Thermodynamics - Blended teaching 2.9.2024-15.12.2024 Quiz 9

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The question is about flow work in open-system thermodynamics and presents two statements to evaluate. Option a: 'Wflow = pV' This expresses flow work as the product of pressure and volume for the fluid mass being pushed into or out of a control volume. In many treatments of flow (open-system) analysis, the flow work required to bring in (or push out) mass is indeed p times the volume associated with that mass (w_flow = pV) wh......Login to view full explanation

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BH20A0720 Engineering Thermodynamics - Blended teaching 2.9.2024-15.12.2024 Quiz 9

Flow work...

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类似问题

Which of the following equations describes the work done by environment, as it pushes mass elements through the boundary? (qm is mass flow rate, p is pressure, v is specific volume, w is velocity)

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