In this work, we present the validation of a numerical model of a greenhouse thermally in-sulated on three sides with a tomato crop. A CFD software (Ansys-Fluent) was used to solve the numerical model. The discrete ordinate model was included to solve the radiative trans-fer equation. The results of the numerical model were compared with the values of air tem-perature observations at different points in the greenhouse. Good agreement was obtained between the simulated and measured values, with coefficients of determination R2 = 0.77, R2 = 0.84, R2 = 0.99, and R2 = 0.89 for the temperatures of the points 10 cm, 80 cm, and 210 cm above the ground and the average temperature in the greenhouse, respectively. A third-order polynomial curve was drawn between the simulated and measured values of relative humidity in the greenhouse. These R2 values are 0.9786 and 0.7165, the simulated and measured relative humidity, respectively. The simulation results showed low velocity values with an average of 0.525 m/s located between 1.5 m and 2 m from the ground.

The present work presents a numerical study of the evaporation of a sessile liquid droplet deposited on a substrate and subjected to different heating configurations. The physical formulation accounts for evaporation, the Marangoni effect, conductive transfer in the support, radiative heating, and diffusion–convection in the droplet itself. The moving interface is solved using the Arbitrary Lagrangian–Eulerian (ALE) method. Simulations were performed using COMSOL Multiphysics. Different configurations were performed to investigate the effect of the heating conditions on the shape and intensity of the Marangoni circulations. A droplet can be heated by the substrate (different natures and thicknesses were tested) and/or by a heat flux supplied at the top of the droplet. The results show that the Marangoni flow can be controlled by the heating configuration. An upward Marangoni flow was obtained for a heated substrate and a downward Marangoni flow for a flux imposed at the top of the droplet. Using both heat sources generated two vortices with an upward flow from the bottom and a downward flow from the top. The position of the stagnation zone depended on the respective intensities of the heating fluxes. Controlling the circulation in the droplet might have interesting applications, such as the control of the deposition of microparticles in suspension in the liquid, the deposition of the solved constituent, and the enhancement of the evaporation rate.

The present work represents a numerical study of a solar desalination system that operates on the humidification-dehumidification (HDH) principle. This system consists essentially of a humidifier integrated into a solar collector and a tubular condenser. A mathematical model governing evaporation and condensation in the desalination unit has been elaborated. This model is based on energy and mass balances at the humidifier and the condenser. The work consists essentially of a parametric study to improve the desalination unit production installed at the faculty of sciences of Bizerte, Tunisia.

Water spraying in exchanger systems is widely used to allow cooling and improving their performance. However, transfers within the spray mixture are difficult to express because the combined mass and heat are transferred between phases, which complicates the design of the spray systems. This article presents a numerical study of the influence of water volume fraction on the distribution of the temperature in a canal. A 2D numerical model of a horizontal channel was generated and the equations governing the continuous phases (air) and the dispersed phase (water) were developed. These equations were solved using Comsol multiphysics. A comparison of the simulation results and those of the experiment reveals an acceptable concordance.