ETSi SCIENTIFIC ARTICLE OF THE QUARTER PRIZE FAILED: JANUARY-MARCH 2024 

The Jury of the Prize for the Scientific Article of the Quarter of the Higher Technical School of Engineering (ETSi): January-March 2024, made up of Emilio Freire Macías, Alfonso Miguel Gañán Calvo, Juana María Mayo Núñez, Consuelo Arahal Junco, Lourdes García Rodríguez, and Alejandro Carballar Rincón, after evaluating the articles submitted to the Award, the members of the Jury exchange opinions and agree in valuing the high quality of all the publications.

After the appropriate deliberations in which criteria based on various bibliometric indicators are taken into account, the Jury decides, unanimously among its members, to award the Prize for the Scientific Article of the Quarter of the ETSi: January-March 2024, ex aequo to the following jobs:

“A semi-analytical matrix formalism for stress singularities in anisotropic multi-material corners with frictional boundary and interface conditions”, Theoretical and Applied Fracture Mechanics, vol. 129, February 2024, pp. 104160. DOI: 10.1016/j.tafmec.2023.104160 whose authors are María Ángeles Herrera Garrido, Vladislav Mantič Lescisin and Alberto Barroso Caro.

“A flexible methanol-to-methane thermochemical energy storage system (TCES) for gas turbine (GT) power production”, Applied Energy, vol. 356, February 15, 2024, pp. 122398. DOI: 10.1016/j.apenergy.2023.122398 whose authors are Diego Antonio Rodríguez Pastor, Alejandra García Guzmán, Israel Marqués Valderrama, C. Ortiz, Elisa Carvajal Trujillo, José Antonio Becerra Villanueva, Víctor Manuel Soltero Sánchez and Ricardo Chacartegui Ramírez.
 

In the work entitled “A semi-analytical matrix formalism for stress singularities in anisotropic multi-material corners with frictional boundary and interface conditions” the development of a computational code in MATLAB based on a semi-analytical procedure to characterize elastic singular solutions in single-material or multi-material anisotropic corners through asymptotic series expansion.

This general tool is capable of analyzing both open and closed (periodic) corners, composed of one or multiple materials with isotropic, transversely isotropic or orthotropic constitutive laws, covering both mathematically non-degenerate and degenerate materials within the framework of the Stroh formalism.

The variability of the covered configurations is enormous, since in addition to a wide variety of homogeneous or friction boundary conditions, it has the possibility of introducing perfectly glued interface conditions and sliding with or without friction. In the case of contact with friction, Coulomb's law of contact by friction is assumed. One of the novelties is that, in addition to the singularity exponent λ, the angle ω of the tangential stress vector caused by friction on each contact surface must be calculated by solving a non-linear eigenvalue system, as it is an a priori unknown value.

The procedure is based on Stroh's anisotropic elasticity formalism, assuming generalized plane deformation conditions (2.5D), and on the semi-analytical matrix formalism for wedge transfer matrices and matrices of boundary and interface conditions. This makes it, first of all, very suitable for computational implementations; secondly, very efficient, especially in cases with several homogeneous wedges perfectly joined together; and, thirdly, very precise due to its completely semi-analytical nature. The developed code has been verified by solving a wide variety of examples, comparing the results obtained with those obtained through the analytical expressions deduced by other authors previously for specific configurations, confirming the extremely high precision of the present code in the calculation of λ and ω. The differences observed in some cases with anisotropic materials are explained by the fact that some of the previous authors did not take into account the true 3D Coulomb friction law. After exhaustive verification, the tool has been translated into Python and is now accessible to the scientific community through the SingSol Web-APP at https://www.germus.es/corner-singularity-app/.

The study “A flexible methanol-to-methane thermochemical energy storage system (TCES) for gas turbine (GT) power production” presents an innovative solution to combat volatility in the natural gas market and the growing implementation of renewable energy sources in the energy sector. The proposed system uses renewable methanol (CH₃OH) through its intermediate step to synthesis gas (CO/H₂) for its conversion into methane (CH₄), offering thermochemical storage strategies (charge/discharge) and energy integration. concentration solar. The proposed configuration is highly flexible and adaptable to existing industries, and allows reducing dependence on imported natural gas and replacing it with green methanol, without modifying the industrial park.

The loading phase consists of the thermal decomposition of methanol at moderate temperatures (below 350 °C), with commercial Cu/ZnO catalysts. The syngas generated is compressed at 40 bar, stored and discharged in the methanation phase, where methane is produced at high temperatures (above 500 °C) and with heat of reaction, which can be used energetically in other processes. The resulting methane is used as fuel for gas turbines and can also serve as a raw material in the chemical industry.

The simulations carried out achieve global system efficiencies that exceed 29% and round trip efficiencies of 44%. Through optimization of reaction conditions, levelized fuel costs (LCOF) of €172/MWh and future LCOE values ​​of €145/MWh are obtained, values ​​currently competitive with other more mature technologies. These results provide an innovative strategy in the field of thermochemical storage and its integration in gas turbine cycles, as well as new conversion routes for green methanol, a vector of incipient growth.