Liquid & Gas Properties Module

Model Gas, Liquid, and Gas–Liquid Mixtures

When setting up and running CFD, heat transfer, and acoustics simulations, modeling the material properties correctly is crucial. With the Liquid & Gas Properties Module, you can accurately and easily compute density, viscosity, thermal conductivity, heat capacity, and other properties as functions of composition, pressure, and temperature.

All of the functionality available in the Liquid & Gas Properties Module is also included in the following products: Chemical Reaction Engineering Module, Battery Design Module, and Fuel Cell & Electrolyzer Module.

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Properties for CFD Simulations

The density and viscosity of fluids may depend on composition, pressure, and temperature. Obtaining accurate values for these properties is relevant, and may affect the design of devices and processes. The Liquid & Gas Properties Module gives you the tools to compute density and viscosity for gas mixtures of arbitrary composition. In addition, the module contains property models for liquid solutions, such as for aqueous solutions and solutions with organic solvents. For two-phase flow systems, the module features models to compute the equilibrium composition of the vapor and liquid phases as a function of pressure and temperature.

Properties for Heat Transfer Simulations

The simulation of heat transfer in fluids requires properties such as thermal conductivity and heat capacity, in addition to density and viscosity. As an example, when designing climate control and ventilation systems, the properties of air depend on relative humidity, pressure, and temperature, and these dependencies may be important to the accuracy of such modeling and simulation studies. This is also valid for coolants, as well as gases and fluids used in processes throughout different industries.

The Liquid & Gas Properties Module includes models for the computation of thermal conductivity and heat capacity as a function of pressure and temperature. These properties can be computed for gas mixtures and liquid mixtures of arbitrary composition, and used for accurate heat transfer models and simulations.

Properties for Acoustics Simulations

Pressure acoustic waves propagate in fluids, often water or air, and depend on pressure, temperature, bulk viscosity, heat capacity, and thermal conductivity. In air, the relative humidity affects these properties. The accuracy of these properties, and thereby the accuracy of the pressure acoustics simulation results, depends on the variables mentioned above, all of which can be calculated with the Liquid & Gas Properties Module.

Features and Functionality in the Liquid & Gas Properties Module

Find tailor-made functionality for specifying properties of liquids and gases.

A closeup view of the Model Builder with the Vapor-Liquid System node highlighted and the Thermodynamic System settings shown.

Thermodynamic Properties

The Liquid & Gas Properties Module includes models and parameters for calculating the following properties:

  • Heat of reaction
  • Heat of formation
  • Heat capacity
  • Viscosity
  • Density
  • Thermal conductivity
  • Binary diffusivities
  • Activity and fugacity

These properties can be calculated for liquid mixtures and gas mixtures. In addition, it can perform equilibrium calculations for gas–liquid systems, so-called flash calculations; gas–liquid–liquid systems; and liquid–liquid systems.

A closeup view of the Thermodynamic System settings and a heat pipe model in the Graphics window.

Thermodynamic Models and Property Models

The Liquid & Gas Properties Module uses a number of different thermodynamic models. The variety of models available reflect the fact that no thermodynamic model is able to describe all gases and liquids. The choice of model depends on the type of mixture and the conditions. In addition to the thermodynamic models, you can specify the model for the properties individually.

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