The　flow　and　heat　transfer　in　a　pre-swirl　rotor-stator　cavity　with　rim　radial　seal　are　numerically　investigated　by　RANS　equations　and　SST　turbulence　model,　and　the　additional　passive　tracer　method　is　used　to　simulate　the　mainstream　ingestion　phenomenon.　The　variations　of　flow　coefficient　in　cavity,　the　Nusselt　number　on　rotor　surface　and　sealing　efficiency　with　different　sealing　flow　rate　or　pre-swirl　ratio　are　investigated.　The　numerical　results　show　that　in　the　split,　pre-swirl　ratio　increases　with　the　increase　of　the　ratio　of　inlet　pre-swirl.　Static　pressure　coefficient　along　the　radial　direction　increases　linearly.　On　account　of　the　mainstream　ingestion　which　makes　adiabatic　temperature　on　rotor　rise,　The　nusselt　number　calculated　by　the　flow　state　is　slightly　larger　than　the　actual.　Inlet　pre-swirl　is　beneficial　to　sealing　efficiency.　©　2017,　Science　Press.　All　right　reserved.