Four-Objective Optimization for an Irreversible Porous Medium Cycle with Linear Variation in Working Fluid's Specific...

Area of Science:

• Thermodynamics
• Engineering Science
• Energy Systems

Background:

• Traditional thermodynamic cycles often assume constant specific heat, neglecting real-world fluid behavior.
• Irreversibilities like heat transfer and friction significantly impact engine performance and efficiency.
• Porous medium cycles offer potential for improved thermodynamic performance.

Purpose of the Study:

• To perform thermodynamic analysis and multi-objective optimization of an irreversible porous medium cycle.
• To investigate the impact of variable specific heat and irreversibilities on cycle performance.
• To determine optimal operating conditions for power density and ecological function.

Main Methods:

• Application of finite time thermodynamic theory.
• Utilizing the Non-dominated Sorting Genetic Algorithm II (NSGA-II) for multi-objective optimization.
• Analysis of variable specific heat, heat transfer, friction, and internal irreversibility losses.

Main Results:

• Variable specific heat and irreversibilities were found to significantly affect power density and ecological function.
• Optimal operation for maximum power density yields higher thermal efficiency and smaller engine size.
• A Pareto front was generated for four objectives: dimensionless power density, power output, thermal efficiency, and ecological function.

Conclusions:

• Multi-objective optimization provides a more comprehensive understanding of cycle performance than single-objective optimization.
• Balancing power output and thermal efficiency in a two-objective optimization yielded the best results.
• The porous medium cycle demonstrates potential for efficient energy conversion under specific operating conditions.