Area under a curve represents work done by or on the system.
On a P-V diagram the area under the path equals boundary work; cycles enclose net work (clockwise = engine). Isotherms, isobars, adiabats and phase boundaries are drawn. Visualises cycles such as Otto and Brayton.
The area inside an Otto cycle loop equals net work per cycle.
A P-V diagram shows the work of a process as an area, so you can compare cycles and see where work is produced or consumed.
Area under a curve represents work done by or on the system.
A P-V diagram shows the work of a process as an area, so you can compare cycles and see where work is produced or consumed.
Integrate pressure with respect to volume, which is the area under the curve. The direction of the path determines whether work is done by or on the system.
On a clockwise P-V cycle the expansion path lies above the compression path, so the net area represents work done by the system.
Typical applications include comparing the work of two cycles for an engine design, finding the net work of a compressor cycle from its diagram and visualising the expansion of steam in a turbine stage.
Study "Thermodynamic processes" first (topic 12 of 105 in Thermodynamics & Fluids). It covers the groundwork this topic builds on.
Area = work. Direction of cycle. Saturated dome.
The area inside an Otto cycle loop equals net work per cycle.
The next topic is "Phase change", which builds directly on this one.
It is classed as Beginner in Thermodynamics & Fluids (topic 13 of 105). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.