Evaluating Stresses Caused from Expanding Gases

This model analyzes the stresses that a pressure vessel experiences from expanding and contracting gases. If a pressure vessel is filled with a gas that is colder than the ambient temperature, the pressure inside the vessel will increase as heat is absorbed. This can lead to significant variations in pressure levels, especially if it is exposed to a varying ambient temperature. Characteristics for different gases are built in, taken from the Modelica.Media library.

To run this example, you'll need

SystemModeler 5.

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The Model

The gas or liquid medium that is present in the vessel can be changed by altering the Medium parameter. In the downloadable model, you can access a drop-down list of preset gases taken from the Media library. The choice of medium will influence the heat capacity of the vessel, as well as the relationship between temperature and pressure.
Changing the gas medium is as simple as choosing from a drop-down menu.

Easily Switch Media

Change between different gases using a simple GUI.

Simulate Using Real Data

In the model, the ambient temperature is determined by a data table with preset values. The data is from a spring day in Linköping, Sweden and has been gathered using Wolfram|Alpha. To see the query, follow this link.
Wolfram|Alpha query of ambient temperatures in Linköping, Sweden on May 18.
Heat transfer between the ambient environment and the content of the pressure vessel is determined by the conductance of the vessel material. Different heat conduction can be selected by accessing a drop-down menu with a list of materials.

Prevent Critical Failures

See how the pressure varies over the course of a day and predict if it will lead to a pressure vessel failure. You can easily test different scenarios by using different gases, vessel materials, locations and dates.
Diagram showing the pressure variations during a day and their relation to the thresholds set in the model.

Built-in Data

Data for gas characteristics, vessel materials and daily temperatures can be easily accessed.