MODELING APPROACH TO TEACH GAS TURBINE BASED POWER CYCLES

Farshid Zabihian, California State University, Sacramento, Department of Mechanical Engineering
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Summary

In these teaching activities students developed several simple models and conduct sensitivity analysis and interpreted the results through modeling. First, they are asked to find various properties of a stream using the software and compare them with the values they found from the conventional thermodynamic tables. In this step students learn how to retrieve stream properties and how to validate them. Then, they develop a cycle composted of a compressor followed by a gas turbine. In this stage, they learn how to define characteristics and specifications of components in the model. Also, they experience the influences of these specifications on the performance of the equipments. As a next step, they add a combustion chamber to the model to make a complete model of a sample gas turbine cycle. As a part of this step they calculate the net output power, specific work, and efficiency of the cycle. They utilize this model to evaluate effects of the compressor pressure ratio, turbine inlet temperature, ambient temperature and pressure, efficiency of compressor and turbine, and pressure drop in the combustion chamber on the system overall performance parameters including output power, specific work, and efficiency of the cycle. Eventually, some students work on this model and combined it with other cycles to make a hybrid cycle or other cycles as their projects.

Learning Goals

These activities are to combine conceptual learning, system level learning, and problem/project-based teaching to help students to learn Thermodynamics in general and gas turbine cycles in particular through the integration of a simulation and modeling software. The expected learning outcomes include:
- defining characteristics and specifications of components in the model
- validating the results using manual calculations
- developing the model of an actual systems
- comparing the results of the models with the performance data of actual cycles
- improving students communication skills by preparing a technical report for each assignment based on the provided technical report preparation guideline

Context for Use

These activities were developed to teach gas turbine based power engines to undergraduate and graduate students in mechanical engineering program. They are first introduced as classroom activities and assignments. Then, a longer project can be developed based on them. Collectively they are a semester-long activities.
I first developed these assignments for a commercial process modeling software Aspen Plus to deepen student understanding of the gas turbine-based cycles and evaluation of effects of various parameters on the cycle performance. Then, I adjust them for Engineering Equation Solver (EES). My objective is to convert them to MATLAB assignments.

Description and Teaching Materials

As noted, these activities have not been implemented in MATLAB. My future plan is to utilize the same approach in MATLAB platform.
Detailed step-by-step activity guideline (Acrobat (PDF) 289kB Aug19 19)



Teaching Notes and Tips

Assessment

The students learning was evaluated by their written reports for the assignments, activities, and projects.

References and Resources

Zabihian, F., Alternative Approach to Teach Gas Turbine-Based Power Cycles, American Society for Engineering Education's (ASEE) 122nd Annual Conference, Seattle, Washington, U.S.A., June 2015