Abstract: Economic Load Dispatch (ELD) is one of the fundamental operational problems in power systems. Its objective is to determine the optimal power generation of generating units while minimizing fuel costs and satisfying operational constraints. In this study, a hybrid GWO-HPSO algorithm is developed to improve the balance between exploration and exploitation. To enhance the search capability of the proposed method, three mechanisms, including nonlinear inertia weight reduction, adaptive Cauchy mutation, and SQP-based local search, are incorporated into the algorithmic framework. The performance of the proposed method is evaluated on standard 3-, 13-, and 40-unit systems under various operating conditions, including the valve-point effect, transmission losses, and the Combined Economic and Emission Dispatch (CEED) problem. The results for the 40-unit system show that the improved algorithm achieves a best cost of $121,595.63/h and a mean cost of $122,584.98/h, outperforming PSO, GWO, and the original hybrid algorithm. Compared with the standard GWO algorithm, the proposed method achieves an approximately 1.744% reduction in the best cost. Furthermore, in a direct comparison with the WHOA algorithm reported in the reference study, the obtained cost is approximately 0.0165% lower. In the environmental analysis, emission coefficients are explicitly reported, while the actual generation cost and emissions are calculated independently. The CEED analysis indicates that moving from a purely economic operating condition to a condition with full environmental priority reduces emissions by approximately 14.98%, 87.88%, and 52.33% in the 3-, 13-, and 40-unit systems, respectively. The results demonstrate that the proposed method has a strong capability to solve non-convex, multimodal, and large-scale optimization problems and can provide an appropriate trade-off between economic and environmental objectives. Keywords Economic Load Dispatch (ELD); Hybrid Optimization; PSO-GWO; Multi-objective Optimization   

Ejectors, as essential devices in industrial processes, play a vital role in energy transfer and fluid suction. In this thesis, the performance of an air ejector experimentally investigated by Tang Liu and co-workers was studied using Computational Fluid Dynamics (CFD) in a two-dimensional axisymmetric model. The main objective of the study was to analyze the effects of nozzle throat diameter and mixing chamber diameter on the entrainment ratio, the influence of primary and secondary flow pressures on entrainment ratio and critical back pressure, and to compare the simulation results with experimental data, which showed good agreement. Velocity, pressure, and Mach number contours were plotted and analyzed under different operating conditions. The results indicated that increasing the nozzle throat diameter reduces the entrainment ratio but raises the critical back pressure. Enlarging the mixing chamber diameter increases the entrainment ratio while decreasing the critical pressure. Moreover, the maximum entrainment ratio was observed with a larger mixing chamber and a smaller nozzle. The effects of primary and secondary flow pressures on mass flow rate and entrainment ratio were also investigated. It was found that, for all geometries, an increase in primary flow inlet pressure increases the primary mass flow rate, whereas the entrainment ratio or entrained mass flow initially rises and then decreases. The increase in secondary mass flow rate was attributed to higher nozzle exit velocity at elevated primary pressures, which enhances suction. However, beyond a certain limit, further increases in primary pressure cause excessive expansion of the converging-diverging nozzle flow, blocking the secondary stream, as confirmed by Mach number contours. Furthermore, with a constant nozzle throat diameter, higher primary flow pressure results in an increased maximum entrainment ratio and a higher corresponding optimum primary pressure. In contrast, with a fixed mixing chamber diameter, increasing the nozzle throat gradually decreases the maximum entrainment ratio and lowers the optimum primary pressure. It was also observed that ejectors with smaller nozzle throats require higher secondary pressures to initiate operation. Results further revealed that, when the nozzle size is fixed and the mixing chamber diameter gradually increases, the minimum secondary pressure required for startup increases, and the entrainment ratio grows more rapidly with increasing secondary pressure. Conversely, with a fixed mixing chamber diameter, reducing the nozzle throat diameter leads to a faster rise in entrainment ratio with increasing secondary pressure. Finally, recommendations for future research were proposed, including three-dimensional simulations, multiphase flow analysis, multi-parameter optimization, investigation of working fluid effects, and transient flow studies. The findings demonstrate that numerical simulation is a powerful tool for analyzing and optimizing high-performance industrial ejectors.  

در اين تحقيق رفتار لرزه‌اي ساختمان بتني با تعداد طبقات مختلف با 3 سيستم باربر قاب خمشي بتني بدون ميراگر، قاب با مهاربند شورون و قاب با ميراگر   TADASمورد بررسي قرار گرفت. سازه‌هاي 5، 8، 12 و 15 طبقه مدل‌سازي و تحليل شد. مقادير برش پايه و جابه‌جايي نسبي در فاز خطي و جابه‌جايي نسبي در فاز غيرخطي بدست آمد. سپس ضريب بزرگنمايي ديناميكي محاسبه شد.   نتايج نشان داد كه براي سازه‌هاي با سيستم باربر قاب خمشي بدون ميراگر مقدار ضريب بزرگنمايي Cd   در سازه 5 طبقه برابر 9.157 در سازه 8 طبقه برابر 18.029 در سازه 12 طبقه برابر 26.522 و در سازه 15 طبقه برابر 48.606 بدست آمد. براي سازه‌هاي با سيستم باربر مهاربند شورون مقدار ضريب بزرگنمايي Cd   در سازه 5 طبقه برابر 9.35 در سازه 8 طبقه برابر 22.65 در سازه 12 طبقه برابر 21.34 و در سازه 15 طبقه برابر 57.582 بدست آمد.   براي سازه‌هاي با سيستم باربر   ميراگر مقدار ضريب بزرگنمايي Cd   در سازه 5 طبقه برابر 10.176 در سازه 8 طبقه برابر 21.96 در سازه 12 طبقه برابر 22.90 و در سازه 15 طبقه برابر 54.510 بدست آمد. براي سازه با ميراگر حداكثر ضريب بزرگنمايي ديناميكي در سازه 15 طبقه و برابر 54.510 بدست آمد. در مقايسه ضريب بزرگنمايي ديناميكي Cd براي سازه‌هاي با سيستم باربر مختلف و تعداد طبقات 15 طبقه نتايج نشان مي‌دهد كه براي قاب خمشي برابر 48.606 براي مهاربند برابر 57.582 و براي ميراگر برابر 54.510 بدست آمد.   در مقايسه ضريب بزرگنمايي ديناميكي Cd براي سازه‌هاي با سيستم باربر مختلف و تعداد طبقات 12 طبقه نتايج نشان مي‌دهد كه براي قاب خمشي برابر 26.522 براي مهاربند برابر 21.34 و براي ميراگر برابر 22.90 بدست آمد. در مقايسه ضريب بزرگنمايي ديناميكي Cd براي سازه‌هاي با سيستم باربر مختلف و تعداد طبقات 8 طبقه نتايج نشان مي‌دهد كه براي قاب خمشي برابر 18.029 براي مهاربند برابر 22.65و براي ميراگر برابر 21.96 بدست آمد.   به‌عنوان نتيجه گيري كلي مقدار ضريب بزرگنمايي ديناميكي Cd با توجه به نوع سيستم باربر و طبقات متغير است. براي سازه با ميراگر در تعداد طبقات 5 طبقه اين ضريب از قاب خمشي و مهاربند بيشتر بدست آمد. براي سازه‌هاي 8 طبقه ضريب بزرگنمايي ديناميكي در سيستم باربر مهاربند بيشترين مقدار بدست آمد. براي سازه‌هاي 12 طبقه ضريب Cd براي سازه با سيستم باربر قاب خمشي بيشترين مقدار بدست آمد. براي سازه 15 طبقه ضريب Cd براي سيستم باربر مهاربند بيشترين مقدار بدست آمد. كليد واژگان: ضريب بزرگنمايي ديناميكي، قاب‌هاي خمشي، مهاربند شورون، ميراگر TADAS   

   Combustion, as one of the primary methods of energy conversion in various industries, plays a vital role in energy production and heating. Despite significant advancements in renewable energy technologies, fossil fuels still constitute a major share of global energy supply. This study investigates the combustion process in industrial boilers using Computational Fluid Dynamics (CFD) methods and analyzes system performance optimization with a focus on pollutant reduction and efficiency enhancement. In this research, the theoretical fundamentals of combustion, its various types, and the relevant chemical and physical mechanisms are first outlined. A three-dimensional simulation of a water-tube boiler used at Ilam Gas Refinery was then conducted using ANSYS Fluent software. Key parameters such as temperature distribution, fluid velocity, and pollutant concentrations under different operating conditions were examined. The results revealed that adjusting the excess air ratio and optimizing burner design could significantly reduce emissions of nitrogen oxides (NOx) and carbon monoxide (CO). Moreover, the use of blended fuels—such as mixtures of methane with ethane-propane—was found to maintain boiler efficiency while decreasing pollutant levels. Additionally, the influence of boiler geometry and tube arrangement on heat transfer and pressure drop was analyzed. The findings indicated that an optimized design could enhance thermal efficiency by up to 5%. Finally, several strategies were proposed for improving boiler performance and minimizing environmental impacts, including the application of advanced combustion technologies, waste heat recovery, and precise control of operational parameters. As an applied research study, this work provides a foundation for the more efficient design and operation of industrial boilers and demonstrates that integrating numerical and experimental approaches can lead to significant advances in combustion system optimization. Keywords: Combustion, Industrial Boiler, Computational Fluid Dynamics (CFD), Optimization, Pollutants, Thermal Efficiency.