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A process during which the entropy remains constant is called an isentropic process, written = or =. [12] Some examples of theoretically isentropic thermodynamic devices are pumps , gas compressors , turbines , nozzles , and diffusers .
[2] In an isenthalpic process, the enthalpy is constant. [2] A horizontal line in the diagram represents an isenthalpic process. A vertical line in the h–s chart represents an isentropic process. The process 3–4 in a Rankine cycle is isentropic when the steam turbine is said to be an ideal one. So the expansion process in a turbine can be ...
For reversible (ideal) processes, the area under the T–s curve of a process is the heat transferred to the system during that process. [1] Working fluids are often categorized on the basis of the shape of their T–s diagram. An isentropic process is depicted as a vertical line on a T–s diagram, whereas an isothermal process is a horizontal ...
Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension General heat/thermal capacity C = / J⋅K −1: ML 2 T −2 Θ −1: Heat capacity (isobaric)
Compression, 1→2 Heat addition, 2→3 Expansion, 3→4 Heat rejection, 4→1 Notes Power cycles normally with external combustion - or heat pump cycles: Bell Coleman: adiabatic: isobaric: adiabatic: isobaric A reversed Brayton cycle Carnot: isentropic: isothermal: isentropic: isothermal Carnot heat engine: Ericsson: isothermal: isobaric ...
An isentropic process is customarily defined as an idealized quasi-static reversible adiabatic process, of transfer of energy as work. Otherwise, for a constant-entropy process, if work is done irreversibly, heat transfer is necessary, so that the process is not adiabatic, and an accurate artificial control mechanism is necessary; such is ...
In an isentropic process, system entropy (S) is constant. Under these conditions, p 1 V 1 γ = p 2 V 2 γ, where γ is defined as the heat capacity ratio, which is constant for a calorifically perfect gas. The value used for γ is typically 1.4 for diatomic gases like nitrogen (N 2) and oxygen (O 2), (and air, which is 99% diatomic).
Thermodynamic data is usually presented as a table or chart of function values for one mole of a substance (or in the case of the steam tables, one kg). A thermodynamic datafile is a set of equation parameters from which the numerical data values can be calculated.