To　reduce　the　leakage　and　increase　the　aerodynamic　efficiency　and　rotor　stability　of　turbomachinery,　five　hole　seals　with　odd-shaped　geometrical　structures　including　a　ball-shaped　concave　cavity,　two　circumferentially　oblique　hole　geometries　and　two　axially　oblique　hole　geometries　were　presented　based　on　the　typical　hole-pattern　seal　model.　A　steady　numerical　approach　was　used　to　investigate　the　influence　of　odd-shaped　hole　geometry　on　the　leakage　performance　and　rotor　drag　torque　of　hole-pattern　seals.　The　leakage　flow　rate,　cavity　flow　field,　turbulent　kinetic　energy　dissipation　rate　and　the　rotor　drag　torque　were　calculated　and　analyzed　for　the　six　hole　seals　(one　typical　hole　seal　and　five　odd-shaped　hole　seals)　with　different　hole　geometries　at　various　rotational　speeds　(0,　2　000,　4　000,　6　000　r/min).　Results　showed　that　compared　with　the　typical　hole-pattern　seal,　the　ball-shaped　concave　cavity　can　markedly　reduce　the　leakage　flow　rate　at　the　rotational　speed　range　from　0　to　4　000　r/min;　circumferentially　oblique　holes　can　obviously　decrease　the　circumferential　swirl　velocity　in　the　seal　gap.　The　circumferentially　oblique　hole　with　an　oblique　angle　α=30°　has　the　minimum　leakage　flow　rate,　and　the　axially　oblique　hole　results　in　a　slight　decrease　in　the　rotor　drag　torque.　The　axially　oblique　hole　with　an　oblique　angle　β=20°can　reduce　the　leakage　flow　rate.　Contrarily,　the　axially　oblique　hole　with　an　oblique　angle　β=-20°　results　in　an　increase　in　leakage　flow　rate.　©　2020,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.