Turbine nozzle for air cycle machine

A turbine nozzle for an air cycle machine includes a base with a multiple turbine vanes which each extend for a vane height H, a throat width W defined between each of the multiple of turbine vanes, wherein a ratio W/H is 0.101-0.112.

BACKGROUND

The present disclosure relates to an air cycle machine, and more particularly, to an air cycle machine turbine nozzle.

An air cycle machine may include a centrifugal compressor and a turbine mounted for co-rotation on a shaft. Typically, the centrifugal compressor further compresses partially compressed air, such as bleed air received from a compressor of a gas turbine engine. In one example, the compressed air discharges to a downstream heat exchanger or other system before return to the centrifugal turbine. The compressed air expands in the turbine to thereby drive the compressor. The air output from the turbine may be utilized as an air supply system for a vehicle, such as the cabin of an aircraft.

SUMMARY

A turbine nozzle for an air cycle machine according to an exemplary aspect of the present disclosure includes a base with multiple turbine vanes that extend a vane height H from the base, a throat width W defined between each of the turbine vanes, wherein a ratio W/H is 0.101-0.112.

A turbine nozzle for an air cycle machine according to an exemplary aspect of the present disclosure includes a base with turbine vanes which extend therefrom, each of the turbine vanes have an airfoil profile section defined by a set of points in Table T-1 scaled by a desired factor, the set of points include paired chord and thickness dimensions.

An air cycle machine according to an exemplary aspect of the present disclosure includes a turbine nozzle with multiple turbine vanes, which each extend for a vane height H, a throat width W defined between each of the multiple of turbine vanes wherein a ratio W/H is 0.101-0.112.

A method of installing a turbine nozzle in an air cycle machine according to an exemplary aspect of the present disclosure includes mounting a turbine nozzle to at least partially define a turbine flowpath, the turbine nozzle having turbine vanes, a throat width W is defined between each of the turbine vanes and each of the turbine vanes define a vane height H, wherein a ratio W/H is 0.101-0.112.

DETAILED DESCRIPTION

FIG. 1schematically illustrates an example air cycle machine (ACM)10that is incorporated into an air supply system11of a vehicle, such as an aircraft, helicopter, or land-based vehicle. The ACM10includes a shaft14supported by bearings16within a housing12. The housing12is typically constructed of multiple pieces secured to one another to facilitate assembly. A compressor rotor18and first and second turbine rotors20,22are mounted on the shaft14for co-rotation about an axis A.

In the example ACM10, the housing12provides a compressor inlet24and a compressor outlet26. A compressor diffuser27is fluidly arranged between the compressor inlet24and the compressor outlet26. Compressed air from the compressor outlet26is received by a first turbine inlet28and passed through a first turbine nozzle32before being expanded over the first turbine rotor20. The expanded fluid exits a first turbine outlet30and is routed to a second turbine inlet34. Fluid passes through a second turbine nozzle38and is expanded over the second turbine rotor22. A seal plate40separates a bearing compartment and the second turbine rotor22. Expanded fluid is supplied by a second turbine outlet36to the air supply system11.

The fluid connections and flow between the compressor and turbine sections are not shown for clarity and are illustrated schematically by arrows respectively into and out of the inlets and outlets. The second turbine nozzle38is retained between a second turbine inlet housing33and a turbine shroud35, which define a flow path between the second turbine inlet and outlet34,36.

With reference toFIGS. 2A-4, the second turbine nozzle38generally includes a base43defined about the central axis A and circumferentially arranged turbine vanes42which extend axially along the central axis A. In one non-limiting embodiment, thirty-four turbine vanes42are provided. The turbine vanes42are located upstream from the second turbine rotor22(FIG. 1). Multiple bosses44extend from the base43and include apertures46to receive fasteners (not shown) for securing the inlet housing33, the turbine shroud35and the second turbine nozzle38to one another, as shown inFIG. 1. As depicted inFIGS. 2A and 3, the bosses44and apertures46are separate and independent from vanes42.

The turbine vanes42are designed to provide desired airfoil characteristics. Characteristics of the airfoil include, but are not limited to, curvature, maximum thickness, axial chord length, twist, taper from root to tip, radius of the leading edge, radius of the trailing edge, straightness of the leading and trailing edge from root to tip, etc. It is possible to directly scale up or scale down the airfoil shape to meet different requirements.

Each turbine vane42includes a leading edge48and a trailing edge50which define the chord of the vane42. A pressure side52and a suction side54extend between the leading edge48and the trailing edge50. In one disclosed non-limiting dimensional embodiment, a throat width W between each adjacent vane42is 0.1110-0.1210 inches (2.82-3.07 mm). Each vane42also defines a vane height dimension H which, in one disclosed non-limiting dimensional embodiment, is 1.084-1.096 inches (27.53-27.84 mm). In this disclosed non-limiting dimensional embodiment, a ratio W/H is 0.101-0.112. Such a relationship facilitates desired flow control characteristics into the second turbine rotor22.

With reference toFIG. 3, because of the difficulty involved in giving an adequate word description of the particular profile of each turbine vane52being described herein, coordinates for one non-limiting dimensional embodiment therefore are set forth in Vane Contour Table T-1. The 0,0 X,Y coordinate corresponds to the trailing edge.

Each turbine vane42is dimensionally defined by a paired chord dimension X and a thickness dimension Y based from the trailing edge50. Chord dimension X is perpendicular to the thickness dimension Y. Chord dimension X has a slight angular offset alpha from a line L which extends radially from centerline A to the trailing edge50. Offset alpha, in one non-limiting dimensional embodiment, is about 5.1 degrees. The paired dimensions X, Y are provided in Table T-1 to define the profile of each turbine vane38along the span thereof.

Table values are shown to four decimal places. However, in view of manufacturing constraints, actual values useful for manufacture of the component are considered to be within the indicated values to determine the claimed profile of the component. That is, there are typical manufacturing tolerances which must be accounted for in the profile of the component. Accordingly, the values for the profile given in the disclosed Table are for a nominal component. It will therefore be appreciated that plus or minus typical manufacturing tolerances are applicable to the table values and that a component having a profile substantially in accordance with those values includes such tolerances. For example, a manufacturing tolerance of about +/−0.03 inches (0.76 mm) should be considered within design limits for the component. Thus, the mechanical and aerodynamic function of the components is not impaired by manufacturing imperfections and tolerances, which in different embodiments may be greater or lesser than the values set forth in the disclosed Table. As appreciated by those in the art, manufacturing tolerances may be determined to achieve a desired mean and standard deviation of manufactured components in relation to the ideal component profile points set forth in the disclosed Table.

In addition, the component may also be coated for protection against corrosion and oxidation after the component is manufactured, according to the values of the Table and within the tolerances explained above. Consequently, in addition to the manufacturing tolerances for the values set forth in the Table, there may also be an addition to those values to account for the coating thicknesses. It is contemplated that greater or lesser coating thickness values may be employed in alternative embodiments.