Through-flow arrangement for the volute inlet of a radial turbine

摘要

1. An exhaust gas turbine with a variable flow, in particular for driving turbochargers of internal combustion engines, comprising a rotor (28) which is rotatable about an axis and which has a multiplicity of rotor blades (34) which are arranged at peripheral spacings from each other, a turbine casing (13) in which the rotor is rotatable and which has an outlet (32) which is coaxial with respect to the rotor, a volute casing portion (16) and a curved intake portion (14) with an inlet (22) arranged at a spacing from the axis, a partitioning wall which forms an outer and an inner flow path (56, 54) in the intake portion (14) and in the volute casing portion (16), which is curved within the volute casing portion (16) in the same direction as said volute casing portion and which is so arranged in the volute casing portion (16) that there is formed a fixed guide surface tip (52) which lies substantially tangentially at the outer periphery of the rotor (22) and which keeps the outer and inner flow paths separate and the inner flow path (54), within the volute casing portion (16) to directly to the periphery of the rotor (28), is of a cross-sectional area which decreases as said flow path (54) increasingly approaches the rotor, and a valve-like member (36) with actuating means for varying the intake flow cross-section of one of the two flow paths in the intake portion (14), characterised in that the intake portion (14) which extends between its connection (18) to the exhaust gas manifold of the internal combustion engine and the connection to the volute casing portion (16) and the part of the partitioning wall (50) which is disposed in the intake portion (14) are curved in the same direction as the volute casing portion (16), that the partitioning wall (50) extends in the volute casing portion (16) in such a way that the end thereof itself forms the guide surface tip (52) which lies substantially tangentially at the periphery of the rotor (28) and the cross-sectional areas of the outer flow path (56) as well as those of the inner flow path (54), within the volute casing to directly to the periphery of the rotor (28), progressively decrease in the direction in which the flow path increasingly approaches the rotor (28), and that the valve-like member (36) is so associated with the inner flow path (54) that upon movement of the valve-like member (36) towards the position of closing off the inner flow path (54) both the average radius of curvature of the mass flow and the flow speed of the exhaust gases increase.