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Vacuum membrane distillation (VMD) is an attractive method for water desalination due to its high pure water permeability under lower operating temperatures, resulting in less energy consumption, lower heat loss via conduction through the membrane surface, and negligible heat transfer by conduction due to the low pressure on the permeate side. The aim of this study is to establish a comprehensive numerical model that describes the water vapor transfer across a hydrophobic micro-porous membrane in single-stage and multi-stage VMD processes for seawater desalination. The numerical predictions are compared to previous experimental data, and a good correlation is observed. The investigation also conducted a sensitivity analysis of process variables and membrane specifications on VMD performance, as well as an assessment of the impact of temperature and concentration polarization. The obtained results showed that the permeation flux reached 18.42 kg/m²·h at 35 g/L feed concentration, 65°C feed temperature, 50 L/h feed flow rate, and 3 kPa vacuum pressure. Moreover, the findings revealed that feed temperature was the most significant factor, while feed flow rate was the least important in determining permeation flux. Additionally, the results indicated that the structure and porosity of support materials play important roles in determining the performance of VMD process. Finally, results confirmed that temperature polarization had a more significant effect on the reduction of permeate flux than concentration polarization. [ABSTRACT FROM AUTHOR]