Effect of hydraulic configuration on lettuce growth in hydroponic bed using Deep water culture technique (DWC).

• Three inlets pulsatile water flow in hydroponic bed allowed the best lettuce yield. • Water temperature in 14.1–18.6 °C range reduced the harvesting period of lettuce. • Hydroponic system design by predicted fluid mechanics/heat transfer for waterflow. • CFD described water flow and water temperature in lettuce hydroponic bed. Experiments and computational modeling were developed to determine the effect of different types of hydraulic configurations on water quality variables to improve growth of lettuce in hydroponic beds. The variants in the hydraulic configurations consider water recirculation in hydroponic modules using Deep Water Culture technique (DWC), for continuous (CWF) and pulsatile water flow (PWF) using either one or three water flow inlets (TWF). These data were used to generate fluid mechanics and heat transfer models for the described hydraulic configurations to assess the effect of the hydraulic configuration on lettuce growth. The results obtained from the mathematical model by the finite volume method allowed to explain the influence of water flow and temperature on the rate of growing for lettuce during summer and autumn in the southern hemisphere. The main findings obtained from the hybrid numerical – experimental model to achieve high lettuce yield were that the number of water inlets has an effect on influenced nutrient transport and water quality variation, where the variant with three water inlets (TWF), and the climatic condition for autumn achieve better plant growth performance than summer. Computational modelling of fluid mechanics and heat transfer allowed to predict the variation of water quality variables in DWC bed, being a suitable technique with a high potential for achieving new accurate agriculture standards. [ABSTRACT FROM AUTHOR]