The thermodynamic-hydraulic behaviour of light hydrocarbon gas differs from that of natural gas. Therefore, this study employs a combined method using the BWRS equation of state, the Colebrook-White friction model, and a revised iterative equivalent length method. The results show that increasing the pipeline diameter reduces pressure loss by up to 98% and increases exergy efficiency from 0.41 to 0.65. In the case study, the DN 75 configuration achieves the most balanced trade-off among economic, hydraulic, and thermodynamic performance. The proposed framework unifies exergy analysis and hydraulic optimisation to guide efficient and sustainable design of urban gas systems. The highlights of the paper are: 1) a methodology with modelling, optimising and evaluating is established; 2) a model with embedded iterative method is constructed and validated; 3) optimisation process is conducted by simulation experiment and comparative analysis; 4) a systematic exergy-based assessment is performed for pipeline network optimisation; 5) multi-dimensional evaluation method is developed to quantify system performance.
This study examines exergy and environmental modelling for sustainable manufacturing systems to reduce environmental impact and enhance energy efficiency through multi-objective optimisation, life cycle assessment, and exergy analysis. The framework combines thermodynamic modelling, life cycle assessment (LCA), data collecting, computer simulations, and multi-objective optimisation that focuses on cost, emissions, and energy. A study of a 210 MW coal-fired thermal power plant found that the boiler was the most effective in destroying exergy, even when the turbines worked at different levels of efficiency. Improvements in exergy efficiency show that emissions, resource use, and total environmental effect are all lower. This strategy helps stakeholders make strong decisions by linking technical, financial, and environmental factors in sustainable manufacturing.
This work simultaneously employs the three contemporary power generation technologies in a single power generation system. The current study created a hybrid power plant that concurrently uses a gas turbine (GT), solid oxide fuel cell (SOFC), and transcritical CO2 cycle. Exergy, energy, environmental and economic (4E) analysis was performed numerically. The results showed that the proposed hybrid plant performed 7.50% better thermodynamically than that of the traditional SOFC-GT system. However, there was a 6.95% decrease in CO2 emissions per MWh of power output and overall cost of the hybrid plant went up by 6.20% in proposed plant.
This study investigates the thermal behaviour of four brake disc geometries using computational fluid dynamics (CFD). A standard full rotor (SFR), a standard radial vane rotor (SRV-R), a circular pillar design (CP) and a novel Y-shaped disc with cooling fins are analysed under identical braking conditions. In addition to heat distribution and airflow characteristics examination, an exergy analysis is conducted to identify the most efficient configuration. Results indicate that the Y-shaped design delivers superior cooling with 20%-30% lower heat build-up and reduce exergy destruction, demonstrating its clear thermodynamic advantage for enhancing braking performance and safety.
This study presents a novel investigation of the entropy generation rate (EGR) in a re-entrant auxetic structure using finite element analysis. Timoshenko beam stiffness and mass matrices are derived using a modified couple stress theory (MCST) to capture the size effects at micro/nano scales via a length scale parameter (LSP) l. Numerical simulations show the importance of LSP on the EGR for the structure. The results indicate that as the LSP ratio l / L increases from 0 to 0.1, the peak value of the EGR during the simulation period of 0 to 0.04 seconds decreases from 6 & times; 10(-3) W/K to 0.3 & times; 10(-3) W/K.
