A control method for a centrifugal compressor and an air conditioning system. The control method for the centrifugal compressor includes: S100, when an inlet opening of the centrifugal compressor is below a first preset value, shutting down a drive motor of the centrifugal compressor; or S200, when the inlet opening of the centrifugal compressor is not below the first preset value, performing the following operations in a preset order: decreasing the inlet opening of the centrifugal compressor, and increasing a rotate speed of the centrifugal compressor.

A method and device is provided for increasing the efficiency of jet drives by recuperating effective power from the propulsion flow. A ducted propeller in the propeller housing, driven by a driving engine via a drive shaft, conveys the fluid for the jet drive out of the interior V.sub.i of a radial turbine. The fluid is accelerated axially and ejected backwards against the direction of travel. This creates thrust. Because the pressure in the interior of the turbine decreases, new fluid from the environment flows directly via the blades of the rotating radial turbine from the outside to the inside, thereby driving them. A guide apparatus is missing. The power of the radial turbine is transmitted via a transmission to the drive shaft of the propeller, which relieves the driving engine and increases the efficiency of the jet drive. The invention is particularly suitable for electric drives.

A compressor housing includes: an intake flow path-forming section configured to form an intake flow path; a shroud portion including a shroud surface curved in a protruding manner to face blades of an impeller; and a scroll flow path-forming section configured to form a scroll flow path through which gas is guided outside the compressor housing. A groove portion extending in a circumferential direction is defined in the shroud surface and, in a cross-sectional view taken along an axis of the impeller, the groove portion includes a downstream side wall surface, wherein a distance from the axis of the impeller to the downstream side wall surface increases toward an upstream side from a downstream side end portion of the groove portion, and an upstream side curved surface that is recessed between an upstream end of the downstream side wall surface and an upstream side end portion of the groove portion.

The present invention relates to an adjustment mechanism (100) for variably adjusting the cross-section of a compressor inlet (22) and further relates to a corresponding compressor (20) including such an adjustment mechanism (100). The adjustment mechanism (100) comprises a plurality of rotatable orifice elements (110) and an actuation ring (120). The actuation ring (120) is mechanically coupled to the plurality of orifice elements 110 such that rotation of the actuation ring 120 causes movement of the orifice elements 110. The movement of the orifice elements (110) thereby adjusts the cross-section of a compressor inlet (22). The adjustment mechanism (100) further comprises a plurality of support members (140) which are arranged axially between the plurality of orifice elements (110) and the actuation ring (120). Additionally, the adjustment mechanism (100) comprises a spring (130), more specific a ring-shaped wave spring. The spring (130) is adapted to axially preload the plurality of orifice elements (110) and the actuation ring (120) when being in a mounted state.

A vehicle heater includes a heater housing (12′), through which heating air to be heated can flow, with a heating air inlet area and with a heating air outlet area. A burner unit is arranged in the heater housing. A combustion air blower (46′) is arranged in the heater housing for delivering combustion air to the burner unit. A heat exchanger unit is arranged in the heater housing (12′). Heating air flowing through the heater housing (12′) can flow around the heat exchanger unit. A combustion air intake muffler (76) is arranged essentially in the heater housing (12′). A muffler housing (78) made in one piece with the heater housing (12′) is associated with the combustion air blower (46′).

An impeller for a centrifugal turbomachine includes: a hub having a small-diameter portion positioned at a first end portion in an axial direction and a large-diameter portion positioned at a second end portion in the axial direction, the large-diameter portion having a greater diameter than the small-diameter portion; and a blade having a first edge positioned at an axial-directional position of the small-diameter portion and a second edge positioned at an axial-directional position of the large-diameter portion, the blade being disposed on an outer peripheral surface of the hub. The impeller is configured such that, when a first radial-directional cross section is a cross section of the impeller at an axial-directional position passing a tip of the first edge, at least a part of the first radial-directional cross section in a blade-height range of 50% or more is inclined downstream in a rotational direction of the impeller with respect to a radial direction.

A centrifugal compressor includes: an impeller which is allowed to rotate around an axis; a casing in which the impeller is accommodated and a guide flow path guiding fluid to the impeller is formed; and a guide vane which is disposed in the guide flow path and is extended from a hub side wall surface of the guide flow path, which is continued to a hub side of the impeller, to a shroud side wall surface of the guide flow path to a shroud side of the impeller, wherein the guide vane is twisted forward the impeller in a rotating direction thereof as close to the shroud side wall surface from the hub side wall surface.

This document describes a cooling device for cooling a heatsink having a plurality of cooling fins provided on a heatsink base. The cooling device includes a centrifugal fan having a fan inlet and a fan outlet, a support for mounting the fan above the heatsink, and a baffle locatable between the support and the heatsink base. The baffle defines an inlet pathway for feeding air between the cooling fins over the heatsink base to the fan inlet and an outlet pathway for expelling air from the fan outlet.

A turbofan gas turbine engine includes, among other things, a fan section including a fan hub and an outer housing, the fan hub including a hub diameter supporting a plurality of fan blades, a turbine section including a fan drive turbine, and a geared architecture that interconnects the fan drive turbine and the fan hub, the geared architecture including a gear volume.

A counter-rotating fan, comprising an impeller assembly and an air guide structure. The impeller assembly comprises a first stage impeller and a second stage impeller, of which the rotation directions are opposite. The pressure surfaces of first blades of the first stage impeller are configured to be opposite the suction surfaces of second blades of the second stage impeller, and from the blade root to the blade tip, each of the first blades and the second blades bends toward its own rotation direction. The air guide structure comprises a flow guide cover. The flow guide cover is provided at the center position of the air intake side of the first stage impeller, and the air intake side surface of the flow guide cover at least partially forms a flow guide surface, the flow guide surface extending along the axis of the first stage impeller in the direction away from the counter-rotating fan.