Radial-inflow type axial flow turbine and turbocharger

Abstract

An object is to provide an axial flow turbine of radial-inflow type whereby it is possible to suppress a decrease in turbine efficiency due to tip leakage, and a turbocharger having the same. An axial flow turbine of radial-inflow type includes a housing having a scroll part for swirling working fluid flowing into the housing () along a circumferential direction of a rotation shaft and a bend part () for changing a flow direction of the working fluid flowing inwardly in the radial direction from the scroll part into a direction along the axial direction to direct the working fluid to turbine blades (). The bend part includes a tip-side inner wall surface () of a bend shape at least in a region at an upstream side, in the axial direction, of a portion (H) of a leading edge () of the turbine blades, the portion being adjacent to a hub. The bend shape of the tip-side inner wall surface along the axial direction has a minimum curvature radius Rat a position Xnear the turbine blades, and a curvature radius R (>R) at the upstream side of the position X.