Franco Tosi (formerly known as Franco Tosi & C., now called Franco Tosi Meccanica) is an Italian engineering business currently concentrated on the production of turbines, boilers, heat exchangers and pumps. It is located in Legnano near Milan. The firm was created during the fourth quarter of the nineteenth century by the Italian engineer Franco Tosi (1858 – 1898).
Tilting Pad Journal Bearings (TPJBs) are essential components in rotating machines and are widely used in the oil & gas and energy sectors, where they ensure smooth and reliable high-speed operation. In recent years, there has been a strong push to reduce the size of these machines while increasing power density, improving efficiency, and minimizing environmental impact. One effective approach is the implementation of internal cooling within TPJBs, allowing for smaller bearings without compromising load capacity, in line with the trend toward more compact and efficient designs. Additionally, this reduces oil consumption, improving the overall environmental footprint. In particular, internal gyroid lattice structures can significantly enhance cooling performance. However, their complex geometry makes standard CFD-based heat exchange analysis challenging. This study applies the innovative Moving Particle Semi-Implicit (MPS) method to investigate the heat exchange capabilities of different cooled pad designs for TPJBs. Performance is evaluated through both simulations and experiments. The MPS method, based on a Lagrangian approach that tracks individual particles, offers a more flexible alternative to traditional control-volume techniques. While successfully applied in fields such as nuclear and marine engineering, its use in rotordynamics provides new insights into optimizing TPJB designs. Experimental results are used to compare different pad configurations and to address the limitations of the MPS method in this novel application.
High efficiency, flexibility and competitive capital costs make supercritical CO2 (sCO2) systems a promising technology for renewable power generation in a low carbon energy scenario. Recently, innovative supercritical systems have been studied in the literature and proposed by DOE-NETL (STEP project) and by a few projects in the EU Horizon 2020 (H2020) program aiming to demonstrate supercritical CO2 Brayton power plants, promising superior techno-economic features than steam cycles particularly at high temperatures. The H2020 SOLARSCO2OL project, which started in 2020, is building the first European MW-scale sCO2 demonstration plant and has been specifically tailored for Concentrating Solar Power (CSP) applications. After a detailed explanation of the modelling approach for steady and unsteady cycle simulations, this paper presents the off-design and dynamic analysis of such plant layout, which is based on a simply recuperated sCO2 cycle. The entire system model has been developed in TRANSEO environment. The part-load analysis ranged from 50% of nominal up to a 105% peak load, discussing the impact on compressor and turbine operating conditions. Full operational envelop has been determined considering cycle main constraints, such as maximum turbine inlet temperature and minimum pressure at compressor inlet. The off-design performance analysis highlights the most relevant relationships among the main part-load regulating parameters, namely molten salt mass flow rate, CO2 mass flow rate, total CO2 mass in the loop, and shaft line speed. The results show specific features of different control approaches, discussing the pros and cons of each solution, considering also its upscale towards commercial applications. In particular, the analysis shows that at 51% of load an efficiency decrease of 20% is expected. Finally, the dynamic characterization of the closed loop shows the relatively fast responsiveness of the plant to compressor speed variations, causing quick changes in CO2 mass flow rate, together with longer time scale phenomena related to the plant heat exchangers. In this respect, sCO2 plants demonstrate to have the potential to provide primary reserve for the electrical grid, as far as thermal stresses on main plant components are kept under acceptable limits.
High efficiency, flexibility and competitive capital costs make supercritical CO2 (sCO2) systems a promising technology for renewable power generation in a low carbon energy scenario. Recently, innovative supercritical systems have been studied in the literature and proposed by DOE-NETL (STEP project) and a few projects in the EU Horizon 2020 program aiming to demonstrate supercritical CO2 Brayton power plants, promising superior techno-economic features than steam cycles particularly at high temperatures. The H2020 SOLARSCO2OL project1, which started in 2020, is building the first European MW-scale sCO2 demonstration plant and has been specifically tailored for Concentrating Solar Power (CSP) applications. This paper presents the first off-design analysis of such a demonstrator, which is based on a simply recuperated sCO2 cycle. The part-load analysis ranged from 50% of nominal up to a 105% peak load, discussing the impact on compressor and turbine operating conditions. The whole system dynamic model has been developed in TRANSEO MATLAB® environment. Full operational envelop has been determined considering cycle main constraints, such as maximum turbine inlet temperature and minimum pressure at compressor inlet. The off-design performance analysis highlights the most relevant relationships among the main part-load regulating parameters, namely mass flow rate, total mass in the loop, and available heat source. The results show specific features of different control approaches, discussing the pros and cons of each solution, considering also its upscale towards commercial applications. In particular, the analysis shows that at 51% of load an efficiency decrease of 20% is expected.
Electrical power production from CSP is worldwide still limited in its diffusion by a higher LCOE with respect to other renewable sources, nevertheless it offers some unique features such as the possibility of a reliable energy storage capability. Among the most interesting, emerging-to-industrial ready technologies, CO2 power cycles seem to have the potential to provide a major step toward the average plant efficiency and equipment cost levels needed to achieve the marketability. Today, in most cases, supercritical CO2 power loops are seen as an opportunity to achieve a major step in thermodynamic efficiencies if applied in supercritical condition and with a quite complicated cycle configurations (e.g. Recompressed and ReHeated, or other combined solutions), with cycle maximum temperature above 650°C. Current cycle configurations are affected by a relative complexity of the power block, including non-negligible technological uncertainties with respect to simpler Brayton cycle solutions, possibly causing delay in the commercial application of the CO2 power block, at least for CSP applications. The aim of this article is to present some possible CO2 power closed cycle solutions, including supercritical as well as transcritical options, in order to propose cost-effective alternatives to current state-of-the-art steam power block of CSPs, highlighting that relatively simple CO2 cycle arrangements can enhance CSP competitiveness, representing a valid intermediate step towards next more advanced sCO2 cycles.
The aim is to obtain simple models that can be coupled to shaft models which are used in general purpose software for analyzing its rotor-dynamic behavior. Two modal models of the blade row have been developed and introduced in the 1D beam model of the rotor, for analyzing its behavior, separately for lateral and torsion vibrations. The methodology has been applied to the last stage blade row of a steam turbine. The results of the analysis show that besides the known influence of shaft torsion vibrations on blade row vibrations, also lateral shaft vibrations can excite easily the blade row vibrations and conversely that blade row vibrations excited by the steam flow can be detected by lateral vibration measurements in the bearings of the steam turbine.
