A turbine nozzle assembly system includes a plurality of nozzle sets, where each nozzle set forms an annulus. The nozzles in each set include an inner endwall and an outer endwall that include joint openings to receive the respective endwall mount ends of an airfoil. The airfoils across the plurality of nozzle sets have an inner endwall mount end and an outer endwall mount end that are identical amongst the plurality of nozzle sets. A wing portion of the airfoil has a selected wing shape that is identical within the respective nozzle set but different amongst the plurality of nozzle sets. In this manner, the endwalls can be removed from an airfoil and replaced with an airfoil having a different wing shape that provides a different pairwise throat area. The system allows changing of a pairwise throat area for a nozzle set without replacing the entirety of each nozzle.

The invention relates to a side-channel compressor (1) for a fuel cell system (37) for conveying and/or compressing a gas, particularly hydrogen, comprising a housing (3), the housing (3) comprising a housing upper part (7) and a housing lower part (8), a compressor chamber (30) located in the housing (3), comprising at least one peripheral side channel (19), a compressor wheel (2) arranged in the housing (3), which is rotatably arranged about an axis of rotation (4), the compressor wheel (2) comprising blades (5) arranged on the periphery thereof in the region of the compressor chamber (30), and respectively a gas inlet (14) embodied in the housing and a gas outlet (16) which are fluidically interconnected by means of the compressor chamber (30), particularly the at least one side channel (19). According to the invention, the compressor wheel (2) comprises a peripheral stop ring (11) on the periphery thereof, which extends around the compressor wheel (2) in a rotationally symmetric manner in relation to the axis of rotation (4).

An impeller with impeller blades arranged around a rotational axis of the impeller. Integral, seamless, and notch-free transitions are formed into a disc body on at least one of their two axial sides. The disc body connects the impeller blades in the circumferential direction around the rotational axis. Covering portions, between the impeller blades, determine the flow channels of the impeller.

A fan blade (1) has a front leading edge (2) and a rear trailing edge (3). The fan blade (1) has a leading edge (4), at least some portions, that are undulated. The edge forms a wave (W) with a specific three-dimensional waveform.

A power tool having a built-in fan, the fan including a plurality of blades at uneven pitches. The fan includes a centrifugal fan which blows out air in all radial directions. The fan is provided with means for correcting unstable outflow which may be caused by the uneven pitches between the blades. The blades have unevenly configured inducers for correcting unstable outflow.

Provided is a regenerative blower. According to an illustrative embodiment of the present invention, the regenerative blower comprises an impeller comprising a plurality of blades disposed spaced apart in the circumferential direction, wherein, in the plurality of blades, each blade gap is arranged at an incremental angle (ΔΘi).

A blisk fan is provided for a turbine engine propulsion system. The blisk fan includes a hub configured to rotate about a rotational axis at a maximum rotational speed, and a plurality of blades extending radially outward from the hub to define a fan leading edge tip diameter. Each of the blades has a first vibratory mode at a natural frequency, which is greater than a first fan order and less than a second fan order at the maximum rotational speed. The compression system preferably has a balance factor of the compression system between 1.9 and 3.2.

A compact respiratory therapy device suitable for use by a patient during sleep to provide respiratory pressure therapy such as at a pressure between 4-30 cmH2O includes a housing, an inlet, an outlet, a motor including a rotor, and an impeller configured to be rotated by the rotor to deliver a flow of air from the inlet toward the outlet. The impeller includes a set of impeller blades, each impeller blade comprising a leading edge and a trailing edge; and a first shroud and a second shroud, each shroud at least partly defining a flow passage through the impeller, the first shroud comprising a wall defining a periphery of an impeller inlet. The compact respiratory therapy device is configured to deliver the flow of air from the outlet for delivery to the patient at a pressure between 4-30 cmH2O at an overall sound power level of less than 50 dB(A) thereby reducing any disturbance to a quality of sleep for the patient. A diameter of the impeller is less than 50 mm. The first shroud and the second shroud are configured such that the flow passage is narrower in an axial direction at an outer portion of the impeller than at an inner portion of the impeller; and a diameter of the impeller inlet is at least 50% of the diameter of the impeller.

An impeller includes Z blades, where Z is an integer equal to 5 or more, arranged in a circumferential direction of the impeller and extending radially, and pitch angles between adjacent blades are all different. In terms of an arbitrary pitch angle θ, when a pitch angle α1 adjacent to the pitch angle θ, and a pitch angle α2 adjacent to the pitch angle θ, different from the pitch angle α1, satisfy a relation, α1<α2, a pitch angle β1 different from the pitch angle θ adjacent to the pitch angle α1 and a pitch angle β2 adjacent to the pitch angle α2, different from the pitch angle θ, satisfy a relation, β2<β1.

A housing element for a pump or of a pump has a housing inner wall defining a flow channel for a fluid medium extending along a central axis. The cross section of the flow channel is greater in a main flow direction and the housing inner wall has a surface structure configured such that it counteracts a return flow counter to the main flow direction along the housing inner wall of the fluid medium. The housing element can act as a pump housing and be combined with a pump.