Definitions check: “Mean effective pressure” (MEP) for a compressor is the hypothetical constant pressure that, acting on the swept volume, would produce the same work per cycle; it is not a volumetric quantity.
Correct Answer: none of the above
Introduction / Context:Terminology matters: volumetric performance and work indicators are different concepts in compressor engineering. Mean effective pressure (MEP) is a work proxy, not a flow definition.
Given Data / Assumptions:
- Compressor cycle on a p–v diagram.
- Swept (displacement) volume V_s and indicated work per cycle W_ind.
Concept / Approach:MEP is defined so that W_ind = MEP * V_s. It allows comparison of different machines independent of size. Volumetric quantities like “actual volume delivered at standard conditions” are instead Free Air Delivery (FAD) or relate to volumetric efficiency—not MEP.
Step-by-Step Solution:
Define MEP: MEP = W_ind / V_s.Observe that none of the listed options describe a pressure or work-based metric.Therefore, the correct choice is “none of the above.”Verification / Alternative check:Handbooks present MEP as a notional constant pressure creating the same area (work) under the indicator diagram over the stroke volume.
Why Other Options Are Wrong:
- Actual volume delivered at STP: This is FAD.
- Volume delivered or sucked: Raw volumetric measures; neither is a pressure nor work term.
Common Pitfalls:Equating volumetric efficiency or FAD with MEP; they measure different aspects—flow vs. work.
Final Answer:none of the above