The　steam-cooled　channels　with　rib　angles　of　30°,　60°　and　90°,　ducts　aspect　ratio　2:1　and　Reynolds　number　ranging　from　1×104to　6×104are　numerically　simulated.　The　vortex　generation,　evolution,　morphological　changes　and　its　distribution　are　numerically　analyzed　with　flow　field　vortex　core　technology　and　the　effect　of　vortex　distribution　of　ribbed　channels　on　heat　transfer　performance　are　also　investigated.　The　result　indicates　that　morphology　and　distribution　of　vortex　in　ribbed　channels　strongly　depend　upon　the　rib　angles.　In　90°　channels　transverse　vortex　dominates,　and　in　30°　and　60°　channels　longitudinal　vortex　and　main　vortex　do;　the　average　heat　transfer　coefficient　in　30°　and　60°　channels　is　higher　than　that　in　90°　channel　because　of　better　heat　transfer　performance　of　longitudinal　vortex　than　that　of　transverse　vortex;　the　average　heat　transfer　coefficient　in　30°　channel　is　lower　than　in　60°　channel　without　bifurcated　longitudinal　vortex　because　the　bifurcated　longitudinal　vortex　in　30°　channel　and　viscous　dissipation　of　fluid　result　in　the　decreased　strength　and　scale　of　the　longitudinal　vortex　to　weaken　the　heat　transfer　performance;　the　vortex　strength,　vortex　core　location　relative　to　boundary　layer　and　radius　of　vortex　are　all　the　important　parameters　for　vortex　heat　transfer　performance.　©,　2015,　Xi＇an　Jiaotong　University.　All　right　reserved.