As　the　most　important　structure　to　enhance　fuel　assembly　CHF　and　increase　economic　efficiency　of　reactors,　mixing　vane　spacer　grids　have　always　been　the　focus　of　numerical　simulations　and　experimental　studies.　Currently,　the　design　of　commercial　mixing　vane　grids　strongly　depends　on　full-scale　thermal　hydraulic　experiments,　which　are　expensive　and　time　consuming.　With　the　recent　development　of　computer　technology,　numerical　studies　using　computational　fluid　dynamics　(CFD)　have　been　conducted　to　enhance　the　understanding　and　design　of　commercial　mixing　vane　grids.　In　current　numerical　simulations　of　spacer　grid　mixing　effect,　most　researchers　do　not　distinguish　the　impact　from　different　components,　but　look　to　encompass　all　component　effects　of　the　entire　spacer　grid　including　those　of　vanes,　dimples,　springs,　and　straps　for　their　overall　mixing　performance.　In　this　paper,　two　spacer　grids　were　modeled　to　obtain　the　effects　of　the　mixing　vane　and　dimple　respectively.　Four　grids　of　different　vane　angles　and　three　grids　of　different　dimple　shapes　were　examined.　First,　the　effect　of　vane　angle　was　examined　using　four　different　grids　of　different　vane　angles　without　the　presence　of　dimples　or　spring.　Then,　both　mixing　vanes　and　dimples　were　added　to　the　grids　in　order　to　investigate　the　compound　mixing　effects　caused　by　dimples　with　the　presence　of　mixing　vane.　During　this　series　of　study,　the　dimple　shape　was　changed　while　keeping　the　vane　angle　fixed.　Two　different　commercial　codes,　CFX　and　STAR-CD,　were　applied　to　study　the　flow　field　under　the　same　operating　conditions　to　provide　code-to-code　benchmarking.　As　a　basic　verification,　the　results　of　CFD　simulated　pressure　drop　were　compared　against　experimental　data.　Relatively　good　agreement　between　the　experimental　and　simulated　pressure　drops　was　obtained.　Code　to　code　comparison　indicated　that　different　CFD　codes　provide　similar　results　with　slight　variations.　Further　work　is　needed　with　more　experimental　data　to　verify　the　turbulence　effects　and　benchmark　the　CFD　results　under　various　thermal　hydraulic　conditions.