Design and prediction performance of Venturi injectors in drip irrigation

[EN] The design and prediction performance of four Venturi injector prototypes have been studied using Computational Fluid Dynamics (CFD) techniques. Results were compared with experimental tests carried out in the laboratory of the Universitat Politecnica de Valencia, Valencia, Spain. The analysed and selected geometries for each prototype were used to simulate the operation without nutrient injection (G1) and with nutrient injection (G2). In first case (G1), the results were presented in the form of pressure profile at the injector axe under different velocities and the pressure distribution in the whole geometry. Additionally, this paper analysed the evolution of pressures and head loss versus main water flow in the different prototypes. The relative error was estimated to compare CFD and experimental results. The second case (G2), the graphical representation for the relations between the nutrient aspiration flow and water main flow were obtained for numerical and experiment approaches. In conclusion, CFD techniques appear as a suitable tool for the analysis of the Venturi injector operation, but its validation with experimental data is recommended.[ES] En la Universitat Politècnica de València, Valencia, España, se ha estudiado el diseño y funcionamiento de cuatro prototipos del inyector Venturi con técnicas de Dinámica de Fluidos Computacional (CFD), comparándo las con ensayos en laboratorio. Para cada prototipo, las geometrías definidas y analizadas han permitido simular el funcionamiento sin (G1) y con inyección (G2) para quimigación. En el caso G1, se presentan los gráficos del perfil de presiones en el eje del inyector para diversas velocidades, así como la distribución del campo de presiones y de la evolución de las diferencias de presión y pérdidas de carga frente al caudal principal. Para comparar los resultados obtenidos con CFD frente al resultado experimental, se calculó el error relativo. En el caso G2, se obtuvo la representación gráfica del el caudal de inyección frente al caudal principal. Las técnicas CFD exigen un buen ajuste del modelo para dar un resultado aceptable. Son interesantes para comparar geometrías, analizar sus variantes, realizar prediseños y aproximar ordenes de magnitud, pero es recomendable su ensayo en laboratorio para validar los resultados.Manzano Juarez, J.; De Azevedo, BM.; Do Bomfim, GV.; Royuela, A.; Palau Estevan, CV.; Viana, TVDA. (2014). Diseño y predicción del funcionamiento de inyectores Venturi en riego localizado. 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