This learning object discusses and provides animations of the basic processes and components in a thermal electric power plant. It is comprised of two main parts: 1)Rankine cycle descriptions and animations, and 2)a Rankine cycle calculator.
Cycle descriptions and animations include the Carnot cycle, the basic Rankine cycle, and advanced Rankine cycles with reheating and feedwater heating.
The Rankine cycle calculator allows the user to vary several operating parameters and observe the effect on power output and cycle efficiency.It is capable of simulating a Rankine cycle that includes a single reheat stage and a single open feedwater heater. As the setpoints of various parameters are changed by the user, performance parameters are recalculated. In addition, a T-s diagram is continuously updated as parameters are changed.
Type of Material:
Learning object for visual demonstration of an engineering power cycle and java applet for performing interactive calculations.
This module may be used as supplementary material for teaching vapor power cycle principles. Students can also be assigned exercises that would involve use
of the simulation applet.
Browser with both JAVA and Shockwave support.
Identify Major Learning Goals:
The major learning goals are:
To learn about the ideal Rankine cycle for power generation and about modifications of the cycle for improved performance.
To learn how to analyze the performance of a Rankine cycle that may include a single reheater and a single open feedwater heate by varying several operating parameters.
Target Student Population:
Undergraduates taking classes in thermodynamics or power generation.
Prerequisite Knowledge or Skills:
Elementary thermodynamics with some knowledge of power cycles.
The object presents a collection of thermodynamic cycles that are useful in understanding modern electrical power generation. It starts with the Carnot cycle and concludes with a Rankine cycle incorporting superheating, reheating, and feedwater heating. By combining cycle schematics with thermodynamic diagrams, a better understanding of each cycle variant is achieved.
This learning object can definitely be useful in explaing the fundamentals of power cycles. It culminates with a "Rankine Calculator" that allows the user to vary a number of pertinent parameters such as boiler, condenser and reheat pressures, superheat and reheat temperatures, and turbine and efficiencies. Once
the parameters are entered, the simulator presents the cycle in a familiar temperature-entropy (T-S)diagram and the various cycle performance parameters such as efficiency and turbine net work.
Comparing the values provided by the Rankine Calculator with those determined from steam tables, excellent agreement is observed.
Potential Effectiveness as a Teaching Tool
The animations make this object well suited for classroom demonstration. By including a plant schematic and a T-s diagram in the same animated graphic, the user can clearly see how the various processes are represented on the thermodynamic chart.
The online Rankine calculator is an excellent tool for demonstrating cycle performance and for developing parametric studies as homework assignments. Since it removes much of the tedium normally associated with steam cycle analyses, students can focus more on the effects of each parameter (e.g., boiler pressure, condensing temperature, etc.) on the overall cycle operformance.
The "Issues" section on each of the cycle simulations is a nice touch for it shows the student the problems inherent in each typeof cycle and how further <
br/>cycle embellishments (e.g. reheat) can overcome these problems to some extent.
The learning object can be used to teach an applied thermodynamics course and also used in a technical elective course that involves vapor power cycle analyses. It can also be used as a reference source for a design purposes.
A bit of confusion can arise in the superheat and reheat portions of the Rankine Calculator. At first glance, it would appear that the actual boiler leaving temperatures are to be entered, but in fact the amount of superheat occurring in the boiler is what is expected.
Ease of Use for Both Students and Faculty
This learning object is very easy and inviting to use. The cycle animations are excellent and the material is presented in ways familiar to engineering students and faculty alike. The slider bars on the Rankine calculator offer a convenient way to change input parameters quickly, and the nearly instantaneous response provides excellent feedback.
It has been used successfully with Internet Explorer 6, Netscape Navigator 7.1 and Firefox 1.0 browsers. In all cases, the appropriate JAVA and Shockware plug-ins were installed.
The aforementioned possibility for confusion in the superheat/reheat section of the Rankine Calculator detracts a bit from its potential effectiveness as a teaching and learning tool. While not a serious problem since it can be easily explained, it does detract from the ease of use. Perhaps it would be better to simply have the user enter the actual temperatures rather than the amount of superheat.
It would be nice if on the "Cycle" home page, the user could immediately go to the particular cycle of interest instead of having to go through each of the cycles in a series fashion. Also,
there is no way to get to the next cycle unless the "Issues" are explored for each cycle.
Other Issues and Comments:
Users should be informed that review progression to the other modifications to the cycles listed on the cycles page can only be accessed when the "issues" button is selected after the review of a cycle.
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