Modelització mitjançant dinàmica de fluids computacional del mòdul hidromètric del segle xix de la sèquia de manresa
- Autores: Jordi Vives Costa
- Directores de la Tesis: José Juan de Felipe Blanch (dir. tes.), Esteban Peña Pitarch (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2019
- Idioma: español
- Tribunal Calificador de la Tesis: Víctor Martínez Moll (presid.), Josep María Casas Sabata (secret.), Guillermo Reyes Pozo (voc.)
- Programa de doctorado: Programa de Doctorado en Recursos Naturales y Medio Ambiente por la Universidad Politécnica de Catalunya
- Materias:
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- Resumen
The main objective of the present Doctoral Thesis is to verify, by using Computational Fluid Dynamics (CFD) techniques, the hypothesis that the Mòdul Hidromètric (MH) of the Sèquia de Manresa, built during the 19th century to limit the full capacity of the fountain to 1000 l/s, complied with this nominal design value.
In order to be able to configure the model it has been necessary to create, describe and implement a CFD methodology that allows simulating and validating a model that reproduces the dynamic behaviour of this hydraulic regulation device, the MH. This contribution is preliminary to the main objective and cannot be underestimated, given the complexity of the phenomena involved in the problem: non-stationary, three-dimensional and turbulent flow, with one inlet flow and three outlet flows; with two flooded weir and a hydraulic jump; with the interaction of the flow with the regulation mechanism, composed of two relaxing chambers plus two control tanks, the first of which is equipped with a slice gate, plus a float and a discharge valve that is automatically activated mechanically depending on the water level in the second control tank.
The configuration of the model has been elaborated from the dimensions and the design of the original project obtained from the documentary sources and from the measurements taken in field work on the still standing hydraulic structures. On the model we have proceeded to execute a set of simulations for different input flows using our own CFD methodology and tools.
The results obtained by means of numerical simulations have been validated analytically based on the principles of Fluid Mechanics, specifically those that characterise the flow on a liquid surface and, in particular, the flow phenomena on slopes flooded with raw wall, the hydraulic relief and the discharge of holes under a load height.
The results obtained have shown that the MH was effective for the incoming flow at 1500 l/s, limiting the flow rate to 1000 l/s, with a maximum error of 7%. However, the regulation system, based on the maintenance of adequate water levels in the two chambers, implies the need to liberate a certain amount of water through the slice gate. If this is not the case, the water from the lateral weir would flood the system. This condition implies the cost of a constant loss of water through the slice gate of feeding and maintaining the regulation system. At the same time, it has been noted that the maximum capacity of the discharge valve is set at 200 l/s, which is insufficient to regulate inlet flows greater than 1500 l/s.
The research has also revealed a focalized problem in the functioning of the lateral weir. The oscillations of the level in the liquid surface of the main flow cause variations in the elevation of the water sheet on the weir wall and, consequently, cause large variations in the flow rate on the lateral weir, inducing fluctuations in the dynamic behavior of the regulation system.
In addition, in order to place the MH in its historical situation, a documentary research has been carried out on its social and economic context, which has an impact on the aspects related to water management in the canal. This has highlighted evidence of conflicting interests between the agricultural and industrial uses of the water of the Sèquia de Manresa, which ultimately led to its construction.
