| 摘要 |
<p>A radially inward flow turbine has an annular nozzle arrangement (25) through which pressurized gas is passed in a generally radially inward direction from an annular inlet passage (24) to a bladed turbine wheel (16). The nozzle arrangement (25) is defined by parts (26, 28) of the turbine housing (10) which are relatively displaceable axially of the turbine for varying the dimensions of the nozzle arrangement (25) and hence for varying the turbine air pressure ratio. In order to enable the dimensions of the nozzle arrangement (25) to be varied without problems of seizure of the relatively displaceable parts, the latter parts are in the form of relatively displaceable rings (26, 28) which each carry a respective annular array of angularly spaced vanes (36, 34) for directing the gas flow from the annular inlet passage (24) onto the turbine blades (20). The angular positions of the vanes (36, 34) on the rings (26, 28) are such that the vanes (34) on the ring (28) are interposed with the vanes (36) on the ring (26). Relative axial displacement of the rings (26, 28) varies the extent of axial overlap of the vanes (36, 34) when they are in their interposed state.</p> |
