Friday, January 29, 2010

Software : CyclePad, construct and learn about thermodynamic cycles

This is an old software but this is very useful. Through using CyclePad I can build and practice my design skills and learn how to reason about thermodynamic cycles. A thermodynamic cycle is a collection of components which either takes in heat and produces energy, or takes in work and produces some transfer of heat, perhaps as a refrigerator or as a heat pump. Examples of thermodynamic cycles include power plants, refrigerators, propulsion plants, and engines. CyclePad helps you:
  • Specify the structure of your design , in terms of the parts of the cycle and how they are connected together.
  • Analyze your design, by figuring out the consequences of assumptions you make about it. Such assumptions include numerical values, e.g. operating temperatures and pressures, and modeling assumptions, e.g., whether or not to consider a turbine as isentropic.
  • Perform sensitivity analyses to understand how different choices of your design contribute to its performance. For example, CyclePad can figure out how the efficiency of a system changes as a function of other parameters, such as a turbine inlet temperature.

CyclePad is the first articulate virtual laboratory the Qualitative Reasoning Group has implemented. CyclePad enables students to construct and analyze a wide variety of thermodynamic cycles. A hypertext explanation facility provides the student with access to the chain of reasoning underlying the derivation of each value. CyclePad is currently being field-tested in undergraduate engineering classes at Northwestern University, The U.S. Naval Academy, and Oxford University.

CyclePad performs steady-state analyses of both open and closed cycles.Steady-state analyses provide the kind of initial guidance needed in conceptual design, because in the conceptual design of thermodynamic cycles the important questions concern the operating conditions and estimates of efficiency and cooling/heating/power produced by the cycle.

CyclePad works in two phases, build mode and analyze mode. In the first phase (build), you use a graphical editor to place components and connect them with stuffs. A thermodynamic cycle consists of a collection of components connected together in some appropriate fashion. The components CyclePad knows about include compressors, turbines, heaters, coolers, pumps, mixers, splitters, throttles, and heat exchangers. CyclePad describes connections in terms of the properties of the material at the connection, that is, the properties of the stuff that is flowing between the components.

Simple Rankine Cycle

In the above diagram, for example, you will see that there are four components: a heater, a turbine, a cooler, and a pump. These components are connected via four stuffs, S1, S2, S3, and S4. The major source of information about the cycle is the set of parameters associated with each stuff and each component. CyclePad knows what parameters are associated with each component and with each stuff. It knows that the set of what parameters are relevant can vary; when a stuff is saturated, for example, its dryness (quality) becomes relevant, and a turbine which is not approximated as isentropic requires some specification of its presumed efficiency. Part of your job as a designer is selecting numerical values and modeling assumptions to see if a particular design can satisfy your performance criteria (e.g., desired work output, efficiency, etc.)


Source/References : Northwestern University- CyclePad

DOWNLOAD :
CYCLEPAD.RAR



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Thursday, January 21, 2010

Software : Computer-Aided Thermodynamic Tables 2


Computer-Aided Thermodynamic Tables 2 (CATT2) provides you with a means to access various thermodynamic tables normally found in text or reference books. There is no need to interpolate values from a table. You simply enter a property value you want to evaluate, and let the computer do the work.
The good things here is the software is a Windows application so it is more user friendly. Another advantage is the better visual steam or gas table that can show the point of the state.

The CATT2 screen is divided into an upper and lower section. The upper section displays the values last evaluated and, in some cases, a graphical representation of those values. The lower section contains a spreadsheet-like log of all previous values evaluated for a particular substance. The sections are separated by a draggable bar, which allows you to view more or less of each section.

You can evaluate all of the tables using one of four predefined sets of units. You can select units prior to performing any calculations, using Change Units from the menu or clicking the Units button.
The tables are grouped as following :
- Water
- Refrigerants
- Cryogenics
- Air
- Ideal Gases
- Compressibility
- Psychrometrics

You can access each group by clicking on the corresponding tabs, at the bottom of the display, or by selecting the group from the Tables menu.

System Requirements :
Windows (98/2000/XP). (I do not have any experiences using Vista...)


DOWNLOAD : CATT.RAR



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