A centrifugal fan is provided that includes a main plate configured to be rotated about a rotational axis, a shroud, having a suction opening, and a plurality of blades arranged in a circumferential direction between the main plate and the shroud to allow air suctioned in through the suction opening to flow from a front edge to a rear edge of each blade. Assuming a first cross section, a second cross section, a third cross section, and a fourth cross section of each blade sequentially taken at layers from the shroud to the main plate, a front edge of the first cross section is located farther from the rotational axis than a front edge of the fourth cross section, and a rear edge of the first cross section is located closer to the rotational axis than a rear edge of the fourth cross section.

A method of assembling a radial turbine rotor includes manufacturing turbine blades, a flowpath ring, and a hub. The method includes fixing the turbine blades circumferentially around the flowpath ring by a blade joint between the turbine blades and the flowpath ring to form a ring assembly. The method includes spinning the hub and moving the hub into engagement with the flowpath ring to locate the hub radially inwardly of the flowpath ring and to form a hub joint between the flowpath ring and the hub.

An impeller includes a shell having a plurality of blades. The shell may also define a cavity. The impeller may further include a backplate that engages at least a portion of the shell. The backplate can include a post which can be coupled to the impeller through a fastener such as a threaded nut. The backplate can be thereafter clamped to the impeller shell. Seals can be provided in the impeller, such as in the backplate. The backplate and impeller shell can be piloted onto each other. In some forms splines can be used to secure the backplate to the impeller shell.

An impeller includes a shell having a plurality of blades. The shell may also define a cavity. The impeller may further include a backplate that engages at least a portion of the shell. The backplate can include a post which can be coupled to the impeller through a fastener such as a threaded nut. The backplate can be thereafter clamped to the impeller shell. Seals can be provided in the impeller, such as in the backplate. The backplate and impeller shell can be piloted onto each other. In some forms splines can be used to secure the backplate to the impeller shell.

Disclosed aspects relate to cooling electronics. A set of recirculation flaps is coupled with a cooling fan. At least one recirculation flap has a ferrous material. In various embodiments, the set of recirculation flaps is arranged in an open position in response to air pressure from the cooling fan, and is arranged in a closed position in response to substantially no air pressure from the cooling fan. A controller is coupled with the cooling fan. The controller indicates a set of indicated positions for the set of recirculation flaps based on a tachometer value. An electromagnet is connected with the controller to position the set of recirculation flaps in the set of indicated positions using the ferrous material. In various embodiments, the electromagnet engages the ferrous material to arrange the set of recirculation flaps in an open position.

Disclosed aspects relate to cooling electronics. A set of recirculation flaps is coupled with a cooling fan. At least one recirculation flap has a ferrous material. In various embodiments, the set of recirculation flaps is arranged in an open position in response to air pressure from the cooling fan, and is arranged in a closed position in response to substantially no air pressure from the cooling fan. A controller is coupled with the cooling fan. The controller indicates a set of indicated positions for the set of recirculation flaps based on a tachometer value. An electromagnet is connected with the controller to position the set of recirculation flaps in the set of indicated positions using the ferrous material. In various embodiments, the electromagnet engages the ferrous material to arrange the set of recirculation flaps in an open position.

A multi-piece radial turbine rotor includes a hub, turbine blades, and a flowpath ring that couples the turbine blades to the hub. Joints between the components of the rotor are adapted for inspection during manufacture to identify potential defects in the joints.

A multi-piece radial turbine rotor includes a hub, a plurality of turbine blades, and a flowpath ring that couples the turbine blades to the hub. The flowpath ring is coupled with each of the plurality of turbine blades and the hub to locate the flowpath ring radially between the hub and each of the plurality of turbine blades. The flowpath ring is formed to include a plurality of apertures spaced apart from one another about the flowpath ring and extending radially through the flowpath ring. Each of the plurality of apertures receives a corresponding one of the plurality of turbine blades therein. The hub is fixed to the flowpath ring by a friction weld joint and each of the plurality of turbine blades is fixed to the flowpath ring by a blade joint.