International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The Stirling engine represents one of the most promising technologies for the efficient conversion of thermal energy into mechanical work, due to its ability to operate with almost any heat source and to achieve theoretical efficiencies approaching the Carnot cycle. This article aims to provide a detailed study of the Stirling cycle, the development of a mathematical model, numerical simulation using MATLAB and the analysis of the engine performance as a function of the main thermodynamic parameters, with special emphasis on applications in micro-power generation. A distinctive aspect of this study lies in the comprehensive treatment of the polynomial dependence of specific heat in all thermodynamic processes, enabling a more accurate representation of real gas behavior compared to idealized classical models. The mathematical model is formulated using the fundamental laws of thermodynamics and the ideal gas equation, as well as the well-known Schmidt model for the analytical description of pressure and volume throughout the cycle. A numerical simulation is then performed in MATLAB, where the work per cycle is calculated, p–V and T–s diagrams are generated, and the theoretical efficiency is evaluated for different operating temperatures and pressures. The simulation results show that increasing the temperature difference and average gas pressure significantly increases the mechanical output of the engine and the power output, while an efficient regenerator significantly improves the overall performance and brings the engine closer to Carnot efficiency. The study shows that the Stirling engine has significant potential for sustainable power generation systems, while the developed modeling and simulation framework provides a solid foundation for further experimental development and design optimization.

The use of solar energy to generate electricity in Power Plant (PP) based on the Rankine cycle is currently a strongly developed CSP system (Concentrating Solar Power) technology. Combining CSP systems with an existing Rankine cycle in coal-fired Power Plant (PP) or Combined Heat and Power Plant (CHP) can increase the maximum output of a power plant and effectively provide a transition for fossil fuel-based technologies to the use of renewable energy sources such as hybrid or renewable energy-only systems. The paper presents simulation results of a steam Rankine cycle with solar power plant components. The hybrid power system makes it possible to reduce the use of coal fuel and provide high efficiency and output power. The calculations were carried out using Ebsilon Professional software.

Aluminum alloys are critical in industries such as aerospace and automotive due to their lightweight, strength, and corrosion resistance. Optimizing their properties is challenging and benefits from advanced predictive tools. This paper explores the use of mathematical modeling in understanding and designing aluminum alloys. Techniques like thermodynamic modeling (e.g., CALPHAD), phase transformation kinetics, and mechanical property simulations are reviewed. Computational methods, including finite element analysis and machine learning, are highlighted for their roles in alloy design and manufacturing, such as casting and additive manufacturing. Comparisons between model predictions and experimental results demonstrate accuracy and limitations. Applications in optimizing material properties and improving manufacturing processes are discussed. By accelerating alloy development and enabling tailored properties, mathematical modeling emerges as a transformative tool, advancing aluminum alloy research and driving innovation across industries.