Patent ID: 12221976

DETAILED DESCRIPTION

In many applications, such as air cycle machines (ACMs) of supersonic aircrafts, maximizing speed may be required to achieve required performance level of a turbo-expander. This has recently led to development of relatively small rotors for maximum mass flow rate. For high rotor speed (NS) rotors, increasing flow rate tends to be challenging however due unfavorable exducer angles and/or exducer chocking. To minimize these issues, it has been found that exducer area for flow should be maximized.

Maximizing exducer area for flow presents further challenges. For example, the exducer area cannot typically be larger than a shroud outer diameter, less a minimum hub diameter that has been generally held constant. This is because, in typical machine, support at an impeller eye dictates the minimum hub diameter. Therefore, the only choice for maximizing exducer area has been to maximize the shroud outer diameter, which requires a substantial modification of rotor design. These challenges can be exacerbated by the need for rotor balance and the additional need to service all dynamic loads (i.e., on a plane).

Thus, as will be described below, a minimized or zeroed rotor hub internal diameter (ID) is provided for use in turbomachinery. The minimized or zeroed rotor hub ID is achieved through the use of a one-piece or two-piece rotor impeller to which a rotor shaft is directly coupled. The one-piece or two-piece rotor impeller has a blade section that converges to a point at a rotational axis of the rotor shaft with a minimized or zeroed ID at that point without sacrificing balance and the ability to service dynamic loads.

With reference toFIG.1, a rotor assembly101is provided and includes a rotor impeller110and a rotor shaft120. The rotor impeller110can be a one-piece rotor impeller and includes a blade section111and a forward section112from which the blade section111extends in the aft direction. The rotor shaft120is rotatable about a rotational axis A thereof and includes an aft section121at which the rotor shaft120terminates. The aft section121is directly attached to the forward section112of the rotor impeller110by, e.g., a threaded connection130. The blade section111of the rotor impeller110includes an exit blade113and a converging blade114that is configured to converge to a point P with a minimized or zeroed ID. The point P can be defined along the rotational axis A. For purposes of clarity and brevity, the following description will relate to the case of the converging blade114converging to the point P with the zeroed ID.

In accordance with embodiments, as shown inFIG.1, since the converging blade114converges to the point with the zeroed ID, a flow area FA of the rotor assembly101can be increased without changing a diameter of the outer shroud102.

As shown inFIG.1, the converging blade114extends in the aft direction aft from the forward section112and converges toward the point P with a non-linear profile1140. The non-linear profile1140can include a steep forward portion1141, a shallow aft portion1142and a curved portion1143that is axially interposed between the steep forward portion1141and the shallow aft portion1142.

In accordance with embodiments, the converging blade114extends aft from an aft edge1130of the exit blade113by a length L which is not more than 1/10 of a diameter D of the exit blade113.

With reference toFIG.2, a rotor assembly201is provided and includes a two-piece rotor impeller210and a rotor shaft220. The two-piece rotor impeller210includes a blade section211and a forward section212, which is connected to the blade section211and from which the blade section211extends in the aft direction. The forward section212and the blade section211can be connected by at least one or more of a threaded connection, a bolted connection, a brazed connection, a welded connection and an adhesive connection225. The rotor shaft220is rotatable about a rotational axis A thereof and includes an aft section221at which the rotor shaft220terminates. The aft section221is directly attached to the forward section212of the rotor impeller210by, e.g., a threaded connection230. The blade section211of the rotor impeller210includes an exit blade213and a converging blade214that is configured to converge to a point P with a minimized or zeroed ID. The point P can be defined along the rotational axis A. For purposes of clarity and brevity, the following description will relate to the case of the converging blade214converging to the point P with the zeroed ID.

In accordance with embodiments, the blade section211and the forward section212can be formed of different materials. For example, the blade section211can include polymeric material and the forward section212can include metallic material.

In accordance with embodiments, as shown inFIG.1, since the converging blade214converges to the point with the zeroed ID, a flow area FA of the rotor assembly201can be increased without changing a diameter of the outer shroud202.

As shown inFIG.2, the converging blade214extends in the aft direction aft from the forward section212and converges toward the point P with a non-linear profile2140. The non-linear profile2140can include a steep forward portion2141, a shallow aft portion2142and a curved portion2143that is axially interposed between the steep forward portion2141and the shallow aft portion2142.

In accordance with embodiments, the converging blade214extends aft from an aft edge2130of the exit blade213by a length L which is not more than 1/10 of a diameter D of the exit blade213.

Technical effects and benefits of the present disclosure are the provision of a rotor assembly with improved rotor extruder angles and corresponding aerodynamic performance. This leads to improved stage efficiency, increasing choking area (i.e., by about 15% which in turn leads to reduced choking incidence) and an increased operating margin.

The corresponding structures, materials, acts and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the technical concepts in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

While the preferred embodiments to the disclosure have been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the disclosure first described.