Effect of non-ideal gas working fluid on power and efficiency performances of an irreversible Otto cycle

Abstract

Based on the irreversible Otto cycle model, applying finite-time-thermodynamic theory, this paper takes power and efficiency as the objective functions, further studies the cycle performance under the condition of non-ideal gas working fluid, analyzes the effects of different loss items and freedom degree (d) of monatomic gas on the cycle performance, and compares performance differences of ideal gas and non-ideal gas under different specific heat models. The results demonstrate that, with the increase of d, the maximum-power-output (P max), the maximum-thermal-efficiency (η max), the corresponding optimal compression-ratio ( ( γ opt ) p ${({\gamma }_{\text{opt}})}_{p}$ ) and efficiency (η P ) at the P max point, and the corresponding optimal compression ratio ( ( γ opt ) η ${({\gamma }_{\text{opt}})}_{\eta }$ ) and power (P η ) at the η max point will all increase; the P max, ( γ opt ) p ${({\gamma }_{\text{opt}})}_{p}$ , η max, ( γ opt ) η ${({\gamma }_{\text{opt}})}_{\eta }$ , η p and P η will decrease with the increases of three irreversible losses; the specific heat model has only quantitative effect on cycle performance but no qualitative effect; under condition of non-ideal gas specific heat model, the power and efficiency are the smallest.

Multi-Objective Optimization for Quantum Rectangular Cycle with Power, Efficiency and Efficient Power

“…Since Scovil and Schulz-DuBois [7] first proposed a three-level quantum heat engine model in 1959, many scholars have proposed quantum energy conversion devices and quantum thermodynamic cycles using various quantum systems as working fluids, such as particles in one-dimensional infinite potential well (OIPW) [8], relativistic particles in OIPW [9], spin system [10], resonance subsystem [11], quantum gas [12], etc. Using these common quantum working media (WM) and applying finite-time thermodynamics (FTT) [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27], many scholars have studied the thermodynamic properties of quantum Stirling cycle [8], Carnot cycle [10,11,28], Diesel cycle [29], Brayton cycle [30,31], Otto cycle [32,33], etc. and got numerous meaningful results.…”