Pure Phase-Transition Fluid: The phase-change (PC) model can be used to determine states of sub-cooled (compressed) liquid, super-heated vapor, and saturated mixture of liquid and vapor phases. Based on the saturation and super-heated tables, the model is quite accurate. Sub-cooled liquid is modeled with the compressed-liquid sub-model, except for species with an asterisk (H2O* as opposed to H2O), which uses compressed liquid table for better accuracy. Working fluids such as H2O, R-12, NH3, R-134a, N2, CO2, etc., should be treated as PC fluids if there is any possibility of a phase transition.

Examples:Evaluate the pressure of a known mass of steam in a tank of known volume if the pressure is given. For specific examples, click on the help icon at the bottom margin of the daemon.

SL Model

Pure Solid and Pure Liquid: Constant density and constant specific heats (cp = cv = c) characterize the solid/liquid (SL) model. Beside a wide selection to choose from, a new solid or liquid can be created by assigning custom material properties. Working substances such as steel, iron, copper, aluminum, wood, water, oil, etc., which can be assumed to maintain their condensed (solid or liquid) phase when a system undergoes other changes, can be analyzed with the SL model.

Examples:Evaluate the change in entropy of a block of solid as it is heated from a given initial temperature to a given final temperature. For specific examples, click on the help icon at the bottom margin of the daemon.

PG Model

Pure Perfect Gas: The perfect gas (PG) model is the simplest gas model. It obeys the ideal gas equation of state (pv=RT); moreover, the specific heats are assumed constants. Noble gases, He, Ar, Ne, etc., are genuinely perfect gases. Beside a wide selection, new gases can be constructed by assigning custom material properties. A perfect gas can be considered as a simplified ideal gas.

Examples:Evaluate the change in entropy of a fixed volume of argon, heated from a given initial pressure and temperature to a given final state. For specific examples, click on the help icon at the bottom margin of the daemon.

IG Model

Pure Ideal Gas: An ideal gas (IG) is a gas that obeys the ideal gas equation of state (pv=RT). Specific heats are temperature dependent. As a result the IG model is more accurate than the PG model when variation in temperature is significant. Choose from an wide selection of gases. `

Examples: Evaluate the change in internal energy of a fixed volume of carbon dioxide, heated from a given initial pressure and temperature to a given final state. For specific examples, click on the help icon at the bottom margin of the daemon.

RG Model

Pure Real Gas: Based on the generalized compressibility chart (pv=ZRT), the real gas (RG) model can handle a large number of fluids in their liquid, vapor or gaseous states. But generality comes at the expense of accuracy.

Examples: Evaluate the change in entropy of a fixed mass of propane, compressed from a given initial pressure and temperature to a given final pressure at the super critical region. For specific examples, click on the help icon at the bottom margin of the daemon.

Gases:

Binary Mixture

Binary Mixture: The mixture of two gases, A and B, is expressed in terms of the mass or mole fraction of gas-A. Select one of the mixture models. Moist air is a special case of a binary mixture (PG+PG) of dry gas and water vapor.

Examples: Evaluate properties of a flow of a mixture of two gases, O2 and CO2, given the mass or mole fraction of O2 (gas-A). For specific examples, click on the help icon at the bottom margin of the daemon.

General Mixture

General Mixture: Mixture can contain an unlimited number, n, of species. Composition can be specified through mass, volume, mass fraction, or mole fraction.

Examples:Evaluate mixture and partial properties (including chemical potential) of a mixture of several gases For specific examples, click on the help icon at the bottom margin of the daemon.

IGE Model

Ideal Gas Equilibrium (IGE) Mixture: An initial (reactants) mixture, (say, 1 kmol of O2 and 3.76 kmol of N2) is specified. Thereafter, any state can be calculated (say, for a given temperature and pressure) with the mixture composition itself a variable. Possible species in the equilibrium mixture are user selected (say, O2, N2, NO, NO2, O, N, and O3) to keep computational time reasonable.

Examples: Suppose air is heated at 100 kPa from 300 K to 5000 K. The difference in any property, say, enthalpy, calculated from the PG model, IG model, and the IGE model will be different. While the PG and IG model are based on frozen composition, the IGE model will include the effect of dissociation and new species formation. However the result will also depend on if all the likely species are included by the user during the mixture set up. For specific examples, click on the help icon at the bottom margin of the daemon.

Simulator:IG Model

State Simulation by Interactive Animations: These rich internet applications (Interactive Animations ) can be used to explore an equilbrium state. Unlike the daemons, the Interactive Animations do not require a thorough thermodynamic background and can be used to to gain practical insight alongside learning the underlying theory.

Examples:Explore how the volume of a gas changes as the temperature or pressure of the gas is changed. For specific examples, click on the help icon at the bottom margin of the daemon.

TESTcalc

PC Model