In this paper, the flow field and mass transfer characteristics were evaluated numerically via Large Eddy Simulation in the presence and absence of the electric field in flat channel that is included cavity containing water. Comparison of the numerical results with the experimental data were in a good agreement with experimental data at prediction of flow field and mass transfer. Then, the effect of the Reynolds number variations in the different applied voltage on the water evaporation rate is investigated. The results indicate that applying the high voltage at the wire electrode can generate vortex and produce perturbation on the water surface. It is shown that at constant Reynolds number with the presence of the electric field, the Sherwood number will be increased but in constant applied voltage the Sherwood number will increase to the Reynolds of 3391 and then will decrease due to reduction in the size of generated vortex. Also, a linear relationship was obtained relationship exists between the Sherwood number factor and the EHD number at Reynolds numbers greater than 3391. Finally, a relationship between dimensionless numbers like the relative Sherwood number, the Reynolds number and the EHD number was obtained.