To　reduce　the　total　pressure　loss　of　the　tangential　admission　volute　and　improve　the　uniformity　of　outlet　air　flow,　the　factors　affecting　the　aerodynamic　characteristics　and　flow　field　of　the　tangential　admission　volute　are　investigated.　The　effects　of　transverse　distance　and　cross　section　shape　on　the　aerodynamic　performance　of　the　tangential　admission　volute　of　steam　turbine　are　numerically　evaluated　with　the　three-dimensional　RANS　equations　and　SST　turbulence　model.　The　obtained　numerical　mass　flow　rate　and　outlet　Mach　number　of　the　partial　alignment　tangential　admission　volute　coincide　well　with　the　experimental　data　to　verify　the　accuracy　of　the　numerical　approach.　The　flow　fields　and　aerodynamic　parameters　of　five　kinds　of　tangential　admission　volutes　coupled　with　stationary　vanes　are　compared　and　discussed　under　different　inlet　total　pressure　conditions.　The　results　show　that　the　outlet　flow　angles　of　five　kinds　of　tangential　admission　volutes　with　stationary　vanes　almost　remain　constant　with　the　increase　of　the　inlet　total　pressure.　The　total　pressure　loss　coefficient　and　mass　flow　rate　of　five　kinds　of　tangential　admission　volutes　with　stationary　vanes　increase　with　the　increasing　inlet　total　pressure.　The　outflow　angle　of　tangential　admission　volute　increases　with　the　increasing　transverse　distance.　The　outflow　angle　of　the　tangential　admission　volute　with　circular　cross　section　is　larger　than　that　with　the　polygon　cross　section　under　the　same　flow　conditions.　With　the　increasing　transverse　distance,　the　total　pressure　loss　of　the　individual　tangential　admission　volute　increases　and　the　total　pressure　in　the　vane　decreases.　With　the　increasing　transverse　distance,　the　total　pressure　loss　of　five　kinds　of　tangential　admission　volutes　coupled　with　stationary　vanes　decreases　at　first　and　then　increases.　The　influence　of　the　cross　section　on　the　total　pressure　loss　of　the　tangential　admission　volute　is　greater　than　that　of　transverse　distance.　The　total　pressure　loss　of　the　tangential　admission　volute　with　polygon　cross　section　is　obviously　higher　than　that　with　circular　cross　section.　The　transverse　distance　and　the　cross　section　shape　hardly　influence　the　outflow　angle　from　the　stationary　vane.　The　smallest　total　pressure　loss　coefficient　of　the　partial　alignment　tangential　admission　volute　with　circular　cross　section　is　obtained　among　five　kinds　of　tangential　admission　volutes.　The　optimum　distribution　uniformity　of　the　outflow　angle　of　the　perfect　alignment　tangential　admission　volute　with　circular　cross　section　is　achieved　among　five　kinds　of　tangential　admission　volutes.　©　2020,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.