Adding a Process Plot (in Visualisation of Air Standard Cycles)
Definition
Each of the simulated air standard cycles comprises four processes. You can compare these
against your own individual plots of processes.
Where it occurs.
Isochoric (constant volume) processes are part of the air standard Otto, Diesel and Stirling cycles.
An isobaric (constant pressure) expansion is part of the air standard Diesel cycle.
Isothermal (constant temperature) processes are part of air standard Carnot and Stirling cycles.
Isentropic (constant entropy) processes are part of air standard Carnot, Otto, Diesel and Stirling cycles.
Special features
All processes plotted concern an ideal gas, with the thermophysical properties of dry air.
How to draw it
Left click on the pV or Ts to create a point of interest. Choose a process from the drop down box. To delete this process, highlight the curve by left clicking inside the circular handle (the curve will turn red). Press the "delete added process" button.
The theory
For an ideal gas at constant temperature pressure and volume are in inverse proportion to each other. Or, from the Ideal Gas Law,
$$ p = mRT \times \frac{1}{V} $$
For an isentropic expansion
$$ p V^{\gamma} = const $$
The calculations of ideal gas internal energy, enthalpy and entropy are explained in conjunction with
the point of interest.
Exercises
(1) Click on the graph to get a POI and plot an isotherm through it. Click along the isotherm to set new POIs and note how - within the constraints of setting POIs by eye - temperature and internal energy are constant.
(2) Using the pV chart, plot an Otto cycle. Place matching isochoric lines and isentropic curves close to the cycle or on it. Repeat with the Ts char.
Links
... to follow.