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Local-stability analysis of a low-dissipation heat engine working at maximum power output.
I Reyes-Ramírez1, J Gonzalez-Ayala2, A Calvo Hernández3
1Instituto Politécnico Nacional-UPIITA, Av. IPN 2580, Ciudad de México 07340, México.
Physical Review. E
|January 20, 2018
Summary
This study analyzes the stability of low-dissipation (LD) heat engines (HEs) operating at maximum power. Findings reveal that optimizing irreversibility location and understanding contact time dynamics are crucial for enhancing HE stability and efficiency.
Area of Science:
- Thermodynamics
- Non-equilibrium systems
- Heat engine optimization
Background:
- Heat engines (HEs) are crucial for energy conversion.
- Understanding stability under maximum power conditions is key for efficiency.
- Low-dissipation (LD) models offer insights into practical HE performance.
Purpose of the Study:
- To investigate the stability of LD heat engines operating at maximum power.
- To analyze the influence of contact times and restitutive forces on system dynamics.
- To explore two distinct scenarios governing contact time dynamics.
Main Methods:
- Analysis of LD system dynamics based on contact times with heat reservoirs.
- Modeling restitutive forces as linear functions of heat amounts or heat fluxes.
- Comparison of relaxation times with total cycle time.
Main Results:
- Locating irreversibility at the hot-reservoir coupling enhances stability and efficiency.
- Reduced thermal gradients increase efficiency but decrease stability.
- In heat flux-dependent scenarios, total cycle time exhibits complex steady-state behavior.
Conclusions:
- System stability and efficiency are significantly influenced by irreversibility distribution and contact time dynamics.
- Dissipation asymmetries play a critical role in HE performance metrics.
- The study provides constraints on system dynamics for stable operation.
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