Software application for Mollier diagram
The most widely used thermodynamic fluid for the thermal power industry is water, as it is cheap and readily available and has very good thermal and chemical properties. But the thermodynamic properties of water in its different phases vary widely with varying temperatures and pressures, adding complexities. Important properties of steam and water used in industry are pressure, temperature, enthalpy, entropy, quality, specific volume, and also thermal conductivity, specific heat, and viscosity.
Determining those properties from basic formulas is cumbersome for regular engineering calculations due to computational complexities. For many years, steam tables and graphs have served industry and academics to discover such properties. In steam tables, the properties of steam and water are shown in tables at certain intervals of temperature, pressure, etc. Charts (graphs) or diagrams are of many types since in a two-dimensional plane, only two main properties can be used as axes and others are shown as lines of constant values at different intervals. For example, on an enthalpy-entropy plane (usually called a Mollier diagram), lines of constant pressure, lines of constant temperature, and lines of constant specific volume are shown at different intervals. Graphs such as temperature-entropy, pressure-temperature, pressure-enthalpy, etc. they are also available with different properties displayed as constant lines. Both standard printed steam charts and tables give rationally accurate results, but generally require interpolation leading to some inaccuracies, albeit small in nature. Software for the properties of water and steam has eliminated this accuracy problem and has minimized the use of printed steam tables and graphs in the industry. However, the use of graphs (usually called Mollier diagrams) remains important in the academic world, where an understanding of the fundamentals and conception is of paramount importance.
Software for steam and water properties and steam tables give the value of the property at a particular point with the input of at least two properties for that point and mostly help in further calculations etc. but they do not provide an idea of the relative position of the point in the whole range. There comes the importance of the Mollier diagram. In the Mollier diagram, a point can be conveniently located on the desired plane and the consequence of the change in input properties can be clearly understood by giving a perfect idea instead of negotiating with numbers alone. It also graphically explains how the phase of water changes with the change of its properties.
Handling a large Mollier plot with adequate resolution is a burden, forcing teachers, students, and practicing engineers to restrict the plot’s use in daily calculations, even if it provides more information. Under such circumstances, Mollier diagram software has become an advantage. It may sound unusual to use software to generate a Mollier plot, but it is also true and very useful. It is a perfect combination of both the power of computer computational skills and graphical facilities. In fact, the same steam and water properties software is conveniently used to generate the Mollier diagrams using a package that can handle graphs and switching.
There are many benefits of using Mollier plotting software. This eliminates the need to own and use printed diagrams. The diagram can be viewed directly on the computer screen and can be saved to a file and printed according to requirements. With the help of the software, diagrams can be interactively created to fit any range with as many constant line properties as desired. Any constant property line for any value can be drawn on the diagram totally eliminating the interpolation requirement as is generally required on printed diagrams. A point with two input parameters can be easily located interactively on the diagram, giving an understandable picture of its position over the entire range. The clarity of the diagram can be greatly improved by using many colors available from the computer screen. In academia, the software can be extremely useful as it can greatly help scholars to explore, investigate and explain the nature of variation of properties with each other with just a few commands. An example may reveal the supremacy of such software. We are aware that using steam/water property software or steam tables or printed Mollier diagrams, steam properties can be determined by providing two input parameters, such as pressure and temperature. By using the Mollier diagram software, the point can also be located on the diagram and all the properties can be obtained. But an additional advantage can be gained by using the software to show that the constant lines generated on the plot using the input value of any property, say a specific volume, pass through the point already located on the plot. This decisively proves the correctness of the software and the comprehensive understanding of the subject. Such methods assume great importance in the teaching and academic field.
Mollier diagram software is not widely available like properties of steam and water software. Internet search reveals that only a few offer all the options described above. Some of them are linked with steam and water properties software and show schematic diagrams with only the saturation line and the facility to locate the specific point without the provision of printing. Some of them show preloaded standard diagrams and only with the ability to locate the specific point. Only a few of them provide complete freedom to generate fully customized diagrams based on the user’s specific requirements using any value of the user’s choice.
It can be summarized that there is a high potential of using Mollier diagram software, especially in institutions and in the academic world, as long as a suitable one is chosen. It can be a substitute for printed diagrams and can be of great help in conceptualization and regular use by professionals, students, teachers and academics.
For more information on Mollier’s diagram software, visit http://www.steam-water-properties.com