In　this　study,　computational　fluid　dynamics　(CFD)　method　is　employed　to　investigate　the　effects　of　the　mixing　chamber　geometries　on　the　performance　of　steam　ejectors　used　for　multi-effect　distillation　systems.　The　internal　flow　characteristics　of　the　steam　ejector　and　the　effects　of　the　length　and　convergence　angle　of　the　mixing　chamber　were　obtained.　It　is　found　that　there　is　an　optimum　range　of　the　mixing　chamber　length　at　which　the　ejector　will　acquire　its　largest　entrainment　ratio　and　the　mixing　chamber　also　has　an　optimum　convergence　angle　at　which　the　steam　ejector　performance　is　the　best.　(C)　2014　Elsevier　B.V.　All　rights　reserved.