Predicción de la tensión superficial de n-H2 puro en presencia de campo eléctrico externo.
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Date
2026
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Publisher
Universidad de Concepción
Abstract
La tensión superficial es una propiedad interfacial relevante en el manejo del hidrógeno, pero su medición experimental es difícil y costosa a las temperaturas criogénicas en que este fluido se procesa. Este trabajo predice la tensión superficial del hidrógeno normal puro en función de la temperatura, tanto en ausencia como en presencia de un campo eléctrico. Para ello se acopla la ecuación de estado SAFT-VRQ Mie, con correcciones cuánticas de Feynman-Hibbs de segundo orden, a la Teoría del Gradiente Cuadrado. El efecto del campo eléctrico se incorpora a través de su contribución al potencial químico del sistema. Los resultados muestran que las correcciones cuánticas son necesarias para describir el equilibrio de fases del hidrógeno. El modelo cuántico reproduce la temperatura crítica con una desviación de +0.9 %, frente al −3.4 % del modelo clásico. En la tensión superficial, las correcciones cuánticas reducen la desviación respecto a los datos experimentales, aunque persiste una sobreestimación cercana al 25 %, mayor que la documentada para fluidos clásicos. El campo eléctrico aumenta la tensión superficial solo a intensidades muy elevadas, y este efecto crece con la temperatura, alcanzando su mayor influencia cerca del punto crítico. El acoplamiento captura la física cualitativa de las interfaces del hidrógeno bajo campo eléctrico, aunque su predicción cuantitativa de la tensión superficial aún presenta limitaciones.
Surface tension is a relevant interfacial property in hydrogen handling, but its experimental measurement is difficult and costly at the cryogenic temperatures at which this fluid is processed. This work predicts the surface tension of pure normal hydrogen as a function of temperature, both in the absence and presence of an electric field. To this end, the SAFT-VRQ Mie equation of state, with second-order Feynman-Hibbs quantum corrections, is coupled to Square Gradient Theory. The effect of the electric field is incorporated through its contribution to the chemical potential of the system. The results show that quantum corrections are necessary to describe the phase equilibrium of hydrogen. The quantum model reproduces the critical temperature with a deviation of +0.9 %, compared to −3.4 % for the classical model. For the surface tension, the quantum corrections reduce the deviation from experimental data, although a systematic overprediction of about 25 % remains, larger than that documented for classical fluids. The electric field increases the surface tension only at very high intensities, and this effect grows with temperature, reaching its greatest influence near the critical point. The coupling captures the qualitative physics of hydrogen interfaces under a field, although its quantitative prediction of surface tension still presents limitations.
Surface tension is a relevant interfacial property in hydrogen handling, but its experimental measurement is difficult and costly at the cryogenic temperatures at which this fluid is processed. This work predicts the surface tension of pure normal hydrogen as a function of temperature, both in the absence and presence of an electric field. To this end, the SAFT-VRQ Mie equation of state, with second-order Feynman-Hibbs quantum corrections, is coupled to Square Gradient Theory. The effect of the electric field is incorporated through its contribution to the chemical potential of the system. The results show that quantum corrections are necessary to describe the phase equilibrium of hydrogen. The quantum model reproduces the critical temperature with a deviation of +0.9 %, compared to −3.4 % for the classical model. For the surface tension, the quantum corrections reduce the deviation from experimental data, although a systematic overprediction of about 25 % remains, larger than that documented for classical fluids. The electric field increases the surface tension only at very high intensities, and this effect grows with temperature, reaching its greatest influence near the critical point. The coupling captures the qualitative physics of hydrogen interfaces under a field, although its quantitative prediction of surface tension still presents limitations.
Description
Tesis presentada para optar al título de Ingeniero/a Civil Químico/a.
Keywords
Hidrógeno, Fluidos, Cálculo