Pumps as Turbines (PATs) by Analysis with CFD Models

Abstract

Pumps as turbines (PATs) are the typical solution for electrification using micro hydropower plants (MHP) in the rural sector. Other engineering applications where lately the use of PATs have increased are irrigation, water supply, and energy recovery systems due to their availability, short delivery time, long service life, economic feasibility, construction, and maintenance advantages. However, selecting the suitable pump(s) is difficult because manufacturers only provide performance curves when operating in pump mode; therefore, there is no universal method to predict that issue. For this reason, theoretical, analytical, experimental, and numerical simulation research have been made to predict these curves and the PATs' performance. The present paper analyzes PATs with Computational Fluid Dynamics (CFD) based on advanced research. For this aim, information from a wide range of types of pumps with different rotation speeds was classified to examine case approaches, computational domains, mesh generation, boundary conditions, optimization of elements, and CFD package used to establish the effectiveness of this tool and to find characteristics which have not been enough investigated at present. Most studies used CFD simulations with ANSYS code and K- turbulence closure model, which presented adequate results. Finally, this paper shows that numerical simulations with CFD analysis were successfully carried out to determine pump performance and predict curves in direct and reverse mode, improving certain components and conducting more profound research on certain specific issues.

Variable Speed Control in PATs: Theoretical, Experimental and Numerical Modelling

“…Table 1 [27] shows different PAT installations in power generation projects. CFD techniques have been widely used to predict characteristic curves and the performance of pumps in direct and reverse modes and proven to be an effective solution in PAT approaches [40][41][42][43]. Additionally, an experimental investigation is fundamental for obtaining reliable results for PATs under different optimisation stages [14,21,44,45].…”

Metodología de análisis para la mejora de la predicción de las curvas características de bombas trabajando como turbina operando a velocidad variable

“…La tabla 24 [20]muestra diferentes instalaciones de PATs en proyectos de generación de energía. Las técnicas CFD se han utilizado ampliamente para predecir curvas características y el rendimiento de bombas en modos directo e inverso y han demostrado ser una solución eficaz en enfoques PATs [21], [26], [27], [57]. Además, una investigación experimental es fundamental para obtener resultados confiables para PATs en diferentes etapas de optimización [14], [28], [31], [58].…”

“…Plua et al [57] presentó una investigación en la que se muestran los principales parámetros y técnicas que se han simulado para PATs a través de CFD y se mencionan los principales rangos de simulación: velocidad específica: 0.8-306, velocidad de rotación: 250-3900 rpm, caudal: 2.9-300 l/s, y flujo másico: 13-17.8 kg/s. En cuanto a las simulaciones numéricas, los modelos de turbulencia fueron las ecuaciones estacionarias y no estacionarias de Navier Stokes promediadas por Reynolds (RANS, URANS).…”

“…Table 1 [20] shows different PATs installations in power generation projects. CFD techniques have been widely used to predict characteristic curves and the performance of pumps in direct and reverse modes and proven to be an effective solution in PATs approaches [21], [26], [57]. Additionally, an experimental investigation is fundamental for obtaining reliable results for PATs under different optimization stages [14], [31], [58].…”

“…Plua et al [57] presented research in which the main parameters and techniques that have been simulated for PATs through CFD are shown and which main simulation ranges are mentioned: specific speed: 0.8-306, rotational speed: 250-3900 rpm, flow rate: 2.9-300 L/s, and mass flow: 13-17.8 kg/s. Concerning the numerical simulations, the principal turbulence models used were Reynolds Average Navier-Stokes (RANS) and Unsteady Reynolds Average Navier-Stokes (URANS).…”