Abstract: A cooling fan module may include a fan assembly and a shroud. The fan assembly including a number of fan blades and the shroud including a first sidewall and a first ring. The first sidewall defining an opening and the first ring extending in an axial direction from the first sidewall. The first ring including an inner periphery provided with a number of first serrations, each serration of the number of first serrations extending in a radial direction. The radial direction is substantially orthogonal to the axial direction.

Abstract: [Object] To maximize static thrust of a ducted fan. [Solving Means] This ducted fan 1 includes a duct 10, a fan 20, a motor 30, a housing 40, and stators 50. The fan 20 includes a hub 21 disposed concentric with the duct 10 and four blades 22 arranged at equal intervals on the outer circumference of the hub 21. A chord length CL of the blade 22 gradually decreases toward a tip 22A from the root. In contrast, the chord length CL of the blade 22 increases to the tip 21B from a tip vicinity portion 22B.

Abstract: A gas turbine engine including: a high pressure turbine, a low pressure turbine, a high pressure compressor coupled to the high pressure turbine by a high pressure shaft, a propulsor and a low pressure compressor coupled to the low pressure turbine via a low pressure shaft and a reduction gearbox; wherein the high pressure compressor defines an average stage pressure ratio at cruise conditions of between 1.25 and 1.35 and consists of 10 or 11 stages; and the high pressure compressor and low pressure compressor together define a core overall pressure ratio at cruise conditions of between 40:1 and 60:1.

Abstract: Provided is a reversible fan that produces a current of air in both of a normal direction and a reverse direction, the reversible fan including: an impeller configured to be rotatable about a rotation axis; a motor configured to rotate the impeller; a base portion supporting the motor; a tubular frame housing the impeller, the motor, and the base portion; a spoke extending from an inner peripheral surface of the frame toward the rotation axis, the spoke supporting the base portion; and a holding portion configured to hold at least a part of a lead wire provided along the spoke to apply power to the motor, wherein the holding portion is provided with a housing space opening in the reverse direction and extending along the spoke.

Abstract: A gas turbine engine including: a high pressure turbine, a low pressure turbine, a high pressure compressor coupled to the high pressure turbine by a high pressure shaft, a propulsor and a low pressure compressor coupled to the low pressure turbine via a low pressure shaft and a reduction gearbox; wherein the high pressure compressor defines an average stage pressure ratio at cruise conditions of between 1.25 and 1.35 and consists of 10 or 11 stages; and the high pressure compressor and low pressure compressor together define a core overall pressure ratio at cruise conditions of between 40:1 and 60:1.

Abstract: A blade including at least one web and a vane having a leading edge and a trailing edge, wherein, for at least one aerofoil of the vane in the vicinity of the web, a maximum sweep angle associated with a position along a chord of the aerofoil extending from the leading edge to the trailing edge of the vane corresponding to a relative chord length of at least 50%.

Abstract: Contoured fan blades and associated systems and methods are disclosed herein. A representative embodiment includes a hub and multiple curved fan blades circumferentially arranged around, and coupled to, the hub. Individual fan blades can have a tip, a first curved edge, and a second curved edge. The first and second curved edges extend over at least part of the length between the hub to the tip of the fan blade. The fan blade is formed with multiple upper channels and multiple lower channels. The multiple upper and lower channels extend from the first curved edge to the second curved edge.

Abstract: An axial fan for conveying cooling air, in particular for an internal combustion engine of a motor vehicle. The axial fan includes a hub, on which a plurality of fan blades extending radially outward is arranged, which each have a rear blade edge. In the case of an axial fan having an optimal relationship between efficiency and flow output, a contour of the rear blade edge of the fan blades extends curved in a circumferential direction with respect to a plane spanned by an axis of rotation of the axial fan and a longitudinal extent of the fan blade.

Abstract: An air purifier device is provided including a fan arranged to produce an air flow through the air purifier device, and a fan duct for guiding the air flow produced by the fan. The fan duct extends in an upright direction of the air purifier device. The air purifier device further includes an air intake arranged below a lower end of the fan duct, and an exhaust arranged at an upper end of the fan duct so as to exhaust purified air in an upward direction from the air purifier device when the air purifier device is in use. The fan duct is flared in direction from an intermediate portion of the fan duct towards both it ends, and the fan is arranged at least partly in the intermediate portion. A facilitated circulation of air through the room and through the air purifier device standing in the room is provided.

Abstract: This disclosure relates generally to fan shrouds for machine fans, and, more particularly, to the structure and design of double bell mouth shrouds and placement of double bell mouth shrouds relative to a machine fan. In some examples, a fan shroud encircling a circular fan having a plurality of fan blades can be provided. Some example fan shrouds can include an inlet adapted to receive air and an outlet adapted to outlet air. The inlet can include an inlet radius, and the outlet can include an outlet radius. In some examples, the outlet radius can each be about 10% of the fan diameter.

Abstract: A diffuser for a ram air fan assembly includes a perforated cone, an inlet ring seal, and an outlet ring seal. The perforated cone has a frustoconical shape symmetrical about an axis of the diffuser. The inlet ring seal is attached to, and axially disposed about, a first end of the perforated cone. The inlet ring seal includes a fan housing connection having a cylindrical shape. The outlet ring seal is attached to, and axially disposed about, a second end of the perforated cone. An average external diameter of the second end is greater than an average external diameter of the first end such that the perforated cone extends away from the inlet ring seal and radially outward from the axis of the diffuser.

Abstract: A free-tipped axial fan assembly includes fan having a blade tip geometry which provides a desired blade loading in the presence of a tip gap. The maximum camber exhibits a sudden and significant increase as the blade tip radius R is closely approached in the direction of increasing radial position. In some constructions, the maximum camber at the blade tip radius R is at least 10 percent greater than the maximum camber at a radial position r where r/R=0.95. In some constructions, the blade angle increases by more than 0.01 radians from a radial position r where r/R=0.95 to the blade tip radius R. The maximum camber at the blade tip radius R is at least 0.06 times the chord length in some constructions.

Abstract: The present disclosure relates to a propfan engine comprising: one or more rotor stages comprising a plurality of rotors; and an outer wall comprising an outer profile, at least a portion of the outer profile defining a substantially circular cross-section, wherein the diameter of the substantially circular cross-section increases in the direction of flow over the outer wall and downstream of a leading edge of the rotors, and the diameter increases at substantially all points defining the circumference of the substantially circular cross-section.

Abstract: A fan includes a frame, rotor supported by this frame and having a central hub and a number of blades and a drive mechanism for rotatably driving the rotor, in addition to a ring to which the end zones of the blades are connected. The ring is assembled from two part-rings of the same form which each include a circular strip of sheet material, the free ends of which are mutually connected to form the outer surface of a truncated cone, and a third part-ring which mutually connects the inner edges of the first two part-rings. The end zones of the blades are connected to the third part-ring. The ring has a diameter of more than about 1.50 m. The number of blades amounts to at least eight. The blades are hollow and include a framework structure which is provided with a skin connected thereto.

Abstract: An axial fan is provided. The axial fan includes a hub, an impeller having a plurality of blades mounted on an outer peripheral surface of the hub, and a housing surrounding the impeller. Each of the blades has a front edge angle (?) within a range of ?8° to ?20°, a mounting angle (?) within a range of 36° to 50°, and a twisted angle (?) within a range of 10°±2°.

Abstract: An improved intake arrangement, for a compressor having a compressor blading, includes a manifold divided by a barrier into two sections, to convey, from one section, a flue gas stream, and, from other section, an air stream. Further, the intake arrangement includes a converging section configured to the manifold and extends convergingly to the compressor defining an inlet to the compressor blading. The converging section includes inner and outer ring members disposed coaxially to each other, between which there extends, coaxially and convergingly, the barrier to at least up to a certain distance within the converging section, defining a converging nozzle therebetween. The converging nozzle includes a mixing feature adapted to enhance mixing of the flue gas and air streams.

Abstract: An apparatus comprising: (a) a bladeless rotatable element with a smooth outer surface, said rotatable element connected to a drive mechanism; and (b) a dynamo powered by said drive mechanism so as to output an electric current.

Abstract: A turbocompressor that is suitable for conveying a multi-phase mixture, comprising a housing having a guiding device and comprising a shaft having at least one impeller, wherein the turbocompressor has an expansion chamber through which the multi-phase mixture can flow on the suction side and a contraction chamber arranged downstream is provided.

Abstract: A fan has a fan, an impeller and a motor. The impeller is disposed in the fan frame, and the motor is disposed in the fan frame for driving the impeller. The fan frame has a housing, a base and at least one connecting element. The housing has an inlet and an outlet, and the base is disposed in the housing and at the outlet. The connecting element is disposed between the housing and the base. The base has a first airflow guiding structure disposed on the circumference of the base. The housing has a second airflow guiding structure disposed on the inner circumference thereof and adjacent to the outlet. The first airflow guiding structure and the second airflow guiding structure are correspondingly disposed.

Abstract: This alternative hybrid wind concentrator generator (the “device”) provides low wind environments with improved added capabilities for various power generation applications. A hybrid solar power system such a solar panel is incorporated on top of the device adding power assistance in low wind conditions and or added power generation. Incorporating in a 2 part housing is a tapering inner shroud that concentrates wind inward then down or up depending on placement. Other added benefits included are the outer housings ability to incorporate added batteries and or electronics for improved multi-function and or plug in functionality. Protection from elements birds, trash, etc. is a key ramification that can help expedite wind permitting procedures as well as improve current laws and restrictions. This alternative wind concentrator device provides discreet placement in urban settings houses, retail buildings, and or office buildings.

Abstract: A blower device includes an axial flow fan having blades to blow air, and a fan shroud that includes a cylindrical portion surrounding an outer circumference of the fan at a distance from the outer circumference, and an air guiding portion guiding air drawn by the fan. The fan shroud includes a short end part shorter in distance to the outer circumference of the fan than another part in an outer end portion of the fan shroud, and a protruding end part provided at a position advanced in a rotational direction from the short end part, protruding upstream in a flow of the drawn air more than the fan and protruding outward of the air guiding portion. Accordingly, the blower device which includes the fan shroud capable of reducing rotational noise can be provided.

Abstract: A fan system may generate an air flow during use. In various implementations, a fan system may include a fan and an orifice. The orifice may include a converging section, a diverging section, and a minimum radius section disposed between the converging section and the diverging section.

Abstract: A wind turbine is disclosed which uses energy in air moving relatively toward the turbine to focus and increase the velocity of air entering a turbine inlet air flow passage. The inlet flow passage discharges focused and accelerated air to blades of a rotor where the blades interact with that air to turn the rotor. Rotor motion can be used to operate an electrical generator. The plane of rotation of the rotor can be at substantially right angles to the plane of the passage inlet opening. Baffles in the flow passage and stator vanes adjacent the rotor blades cause the mass flow of the accelerated air to be substantially uniform, and desirably directed, throughout the rotor's blade area. The turbine is compact and operates quietly.

Abstract: A fluid turbine apparatus which is able to increase the fluid velocity and consequently increase the rotation speed of the fluid turbine. The fluid turbine apparatus has a convergent section, a fluid turbine section and a divergent section. The fluid enters into the fluid turbine through the convergent section, passes through the fluid turbine and exits through the divergent section. The combination of the convergent section and the divergent section creates a Venturi effect and increases the fluid velocity and thus the energy density entering turbine for increasing the energy extracted by the turbine.

Abstract: A propeller fan includes a hub 1 and a plurality of blades 2, which are radially arranged on the outer circumference of the hub 1. A plurality of bent surface-shaped recesses 21 to 23 are formed on the positive pressure surface at a trailing edge 2b of each blade 2. The recesses 21 to 23 extend in the rotation direction of the fan and are arranged in a radial direction. Protrusions 24, 25 are each formed between adjacent pair of the recesses 21 to 23. The bent surfaces of the recesses 21 to 23 and the protrusions 24, 25 reduces air flow caused by centrifugal force. This allows the air flow on the positive pressure surface of the blade 2 to easily flow along the recesses 21 to 23. As a result, air flow does not concentrate on the outer periphery of the blade 2, which reduces the differences in the velocity and volume of air flow between the outer tip 2c of the blade 2 and the hub 1. Accordingly, the blade 2 functions as a whole.

Abstract: A nozzle box 10 includes: a lead-in pipe 20; a bent pipe 30 connected to the lead-in pipe 20 and formed so as to change a direction of a channel center line 50 to an axial direction of a turbine rotor 212; and an annular pipe 40 connected to the bent pipe 30 and leading steam to a first-stage nozzle 213a while spreading the steam in a circumferential direction of the turbine rotor 212. In the steam channel lead-in part structure 10, from an inlet of the lead-in pipe 20 toward an outlet of the annular pipe 40, steam channel widths Sa-1 to Sn-1 in a first direction intersecting with the channel center line 50 gradually increases and steam channel widths Sa-2 to Sn-2 in a second direction intersecting with the channel center line 50 and perpendicular to the first direction gradually decreases.

Abstract: A cone-shaped air flow system has improved efficiency, increased plenum chamber exit air flow speeds and reduced noise levels in comparison to box-shaped and triangular air flow systems. The heater may be of half or full cone configuration for perimeter or central plenum locations, respectively.

Abstract: Exhaust apparatus for exhausting “dirty” exhaust gases accept a core flow of such exhaust gases and combine that with an annularly-surrounding “rooftop” flow of ambient air for diluting the exhaust gases as well as expelling the diluted flow in a forcibly expelled plume in order to ensure that the “effective” expulsion distance of the expelled diluted flow is at least the physical length of the exhaust apparatus plus the gains gotten from efflux velocity and flowrate.

Abstract: A leading edge of a rotating blade of an impeller is formed in an arc recessed in a direction opposite to a rotating direction of the impeller. An angle where an extended line of the recessed arc of the leading edge meets another extended line of a curve of a side edge is set in an acute angle of 30 to 37 degrees in a front view so that a leading tip of the rotating blade may be projected in the rotating direction. An opening angle of a suction-side slant portion of a venturi casing is set in the range of 12 to 17 degrees and an opening angle of a discharge-side slant portion is set in the range of 30 to 35 degrees.

Abstract: A transition duct assembly for a turbine engine includes a transition duct with an inner liner removably received therein. The duct is hollow with an inner peripheral surface and an outer peripheral surface. The duct can have an inlet end and an outlet end. The inner peripheral surface of the duct can be convergent along a majority of the length of the duct when moving from the inlet end to the outlet end thereof. The liner is hollow body with an inner peripheral surface and an outer peripheral surface. The outer peripheral surface of the liner can be correspondingly convergent to the inner peripheral surface of the duct. The inner peripheral surface of the liner can define an internal flow passage through the assembly. Such a construction permits the use of different materials for the liner and the duct and can allow the liner to be readily removed and replaced.

Abstract: A columnar air moving device can comprise separately formed modular stator vanes in a stator vane assembly. The stator vanes can be arranged in a radial pattern, and can direct air in an axial direction. The modular stator vanes, as well as other components of the stator vane assembly, can be replaced, adjusted, and/or removed from the columnar air moving device.

Abstract: An axial flow fan assembly includes a plurality of fan blades surrounded by a shroud. The shroud includes an annular first wall which extends radially outwardly, an annular second wall which extends axially and radially outwardly, and an annular third wall which joins the first wall to the second wall. The third wall has a curved cross sectional shape, and has a minimum diameter part which is positioned approximately half-way between the upstream and downstream edges of the fan blades. There is a desired relationship between the radius of curvature of the third wall and the diameter of the fan. There is a desired relationship between the height of the first wall and the diameter of the fan. The fan blades have an upstream edge which is upstream with respect to the first wall.

Abstract: A drying fan has a shroud with a shape selected to improve fan efficiency by designated fluid dynamics of air flow through the fan.

Abstract: Implementations of an enhanced axial air mover system address various issues such as drying performance, transportability, storage, use, and assembly. Some implementations include ergonomic positioning of a carrying handle relative to positioning of a fan-assembly to make the system easier to carry. Enclosures with variable diameter profiles increase air flow performance. A floor edge allows for flush positioning of the air mover's outlet to improve flow of air. Various supports and engagement members allow for horizontal and/or vertical engagement of a plurality of the air movers for storage or increased air moving capacity for a given application. An alignment guide assists with positioning of the air mover with respect to a room wall to enhance air flow within the room. A cord retaining system provides an enhanced approach for securing the air mover's electrical cord. Grill guards have slotted ends to assist with assembly of the air mover.

Abstract: In accordance with at least some embodiments, a computer system includes an enclosure (202) configured to hold at least one resource unit (204). The computer system also comprises a plurality of mixed-flow ducted fans units (400) selectively attached to the enclosure (202). Each mixed-flow ducted fan unit (400) comprises a duct (102) having an intake diameter, a bellmouth diameter, and an exhaust diameter. The bellmouth diameter is less than the intake diameter and the exhaust diameter.

Abstract: A fan includes an impeller rotatable about a rotation axis and having a plurality of rotating vanes, and a plurality of stationary vanes connecting an outer casing to a supporting body which supports a motor rotating the impeller. At least in a portion of each stationary vane in a radial direction, an axial distance between that stationary vane and one of the rotating vanes closest thereto and a slant angle of that stationary vane with respect to an axial direction increase as that stationary vane moves outwardly in the radial direction.

Abstract: First and second axial fans are coaxially connected to each other. Each axial fan includes an impeller rotatable about a center axis; a motor rotating the impeller about the center axis, a housing member surrounding the impeller and having a hollow body and approximately square flanges at axial ends of the body, and a group of wires electrically connected to the motor. The axial fans are joined together with their flanges coincident with each other as seen along the center axis. The housing member is provided with first and second receiving portions at least one flange on a center-axis side of an outer periphery of the flange. The groups of wires of the axial fans are pulled out therefrom and extend axially toward a side of the first axial fan opposite to the second axial fan, with passing through the first and second receiving portions, respectively.

Abstract: The rear side outer peripheral edge of a propeller fan rotated and driven by a motor, of a propeller fan drive unit, is surrounded by a bell mouth. An upper plate, a lower plate, a side plate, and a machine room plate constitute an air duct at the suction side, outside the radial direction of the propeller fan. The cross-section of the bell mouth, at a first position in the vicinity where a blade of the propeller fan is closest, and where the distance between the propeller fan and the plate constituting the air duct outside the radial direction is relatively narrow, is made to be such that an expansion angle ?1 of the bell mouth suction side is made small. The overlapped height Hb of the propeller fan and the bell mouth is made large against a cross-section at a second position where the distance between the propeller fan and a plate is relatively large. The shape of the cross-section of the bell mouth is made to change gradually between the first position and the second position.

Abstract: A wind turbine is disclosed which uses energy in air moving relatively toward the turbine to focus and increase the velocity of air entering a turbine inlet air flow passage. The inlet flow passage discharges focused and accelerated air to blades of a rotor where the blades interact with that air to turn the rotor. Rotor motion can be used to operate an electrical generator. The plane of rotation of the rotor can be at substantially right angles to the plane of the passage inlet opening. Baffles in the flow passage and stator vanes adjacent the rotor blades cause the mass flow of the accelerated air to be substantially uniform, and desirably directed, throughout the rotor's blade area. The turbine is compact and operates quietly.

Abstract: Implementations of an enhanced axial air mover system address various issues such as drying performance, transportability, storage, use, and assembly. Some implementations include ergonomic positioning of a carrying handle relative to positioning of a fan-assembly to make the system easier to carry. Enclosures with variable diameter profiles increase air flow performance. A floor edge allows for flush positioning of the air mover's outlet to improve flow of air. Various supports and engagement members allow for horizontal and/or vertical engagement of a plurality of the air movers for storage or increased air moving capacity for a given application. An alignment guide assists with positioning of the air mover with respect to a room wall to enhance air flow within the room. A cord retaining system provides an enhanced approach for securing the air mover's electrical cord. Grill guards have slotted ends to assist with assembly of the air mover.

Abstract: The present invention provides a construction machine, capable of enhancing the cooling efficiency of an air-cooled cooler for EGR without deterioration of the cooling effect of a heat exchanger in spite of the arrangement of the air-cooled cooler for EGR near a cooling fan. The construction machine includes: an EGR line 20 for extracting and recirculating a part of exhaust gas from the exhaust side of an engine 9 to the intake side; and an air-cooled cooler 21 for EGR for cooling the recirculating gas flowing in the EGR line 20. The air-cooled cooler 21 for EGR is provided on the outer circumferential side of a cooling fan 11 in a position between the engine 9 and the cooling fan 11 or a position on the downstream side of the cooling fan 11, and cooled with cooling air flowing on the outer circumferential side of the cooling fan 11.

Abstract: A wind turbine engine comprising rotor blades disposed within an outer casing and a half-spherical head located in front of the rotor blades and blocking the inner 50% of the radius of the rotor blades, the casing and head creating an acceleration chamber wherein incoming wind is speeded up and redirected around the head, and the accelerated wind then rotates the wind turbine rotor blades to generate power.

Abstract: A shroud includes a body portion 5B, a mount 7 positioned at a center of the body portion 5B and supporting rotary vane wheel driver 6, and multiple support beams 10 radially extending from the mount 7 and joining the mount 7 and the body portion 5B, where each of the support beams 10 becomes thicker from an upstream side of a flow direction of air toward a downstream side thereof, and an edge portion 10ti of each of the support beams 10 on the downstream side of the flow direction of the air discharged by the rotary vane wheel 8 is oriented in a direction parallel to a rotation axis of the rotary vane wheel 8, and the edge portion on the upstream side is oriented in a direction opposite to a rotation direction of the rotary vane wheel 8.

Abstract: A suction stage for a pump with a centrifugal wheel, the suction stage including a rotational impeller equipped with a hub and arranged upstream of the centrifugal wheel, the suction stage further including a diffuser arranged between the impeller and the centrifugal wheel, the diffuser including a plurality of blades. The hub has a downstream surface extending axially so as to converge toward the centrifugal wheel, and the blades of the diffuser have free ends, the blades protruding radially toward the downstream surface.

Abstract: A ducted fan includes a fan that generates an airflow that flows substantially parallel with the axis of the rotating shaft of the fan; a duct, arranged around the fan, that extends in the direction of the rotating shaft of the fan and includes an airflow inlet defined by the upstream end and an airflow outlet defined by the downstream end, and that has a ramp portion formed in the inner face of the airflow inlet; an airflow guide portion, provided at the airflow outlet, that introduces air from outside of the duct to a position downstream of the airflow outlet; and a negative-pressure forming portion, provided at the downstream end of the airflow guide portion. The negative-pressure forming portion generates a negative pressure near the downstream end of the airflow guide portion when air passes by the negative-pressure forming portion.

Abstract: Turbine system including a turbine and a tubular arrangement having an exit opening. The tubular arrangement is arranged on a downstream side of the turbine. At least one flow controlling device at least partially prevents a fluid flow through the tubular arrangement from becoming detached from the tubular arrangement. The at least one flow controlling device is positioned within the fluid flow and in an area of the exit opening. The turbine system is configured to operate efficiently in an environment wherein at least an upper edge of the exit opening is arranged above a downstream liquid level.

Abstract: An in-line motor and pump assembly is supported at the bottom of a fuel storage tank by a pipe and an internal concentric conduit for housing electrical conductors extending therewithin to the motor. An impeller, coaxial with the rotor of the motor, draws the fuel into an annular passageway surrounding the stator of the motor. Further passageways convey the fuel to an annular passageway defined between the pipe and the conduit for discharge external of the storage tank. A low pressure environment attendant the inflow of the fuel is used to channel fuel for lubrication and cooling purposes to a lower journal bearing and thrust bearing supporting a common shaft for the impeller and the motor. A high pressure environment attendant outflow of fuel is used to channel fuel for lubrication and cooling purposes to a journal bearing supporting the upper end of the shaft.

Abstract: An intake housing for axial fluid flow engines, especially for axial-flow compressors, is proposed. The intake housing comprises an intake shaft (1) with a radial inlet (4) on one side and with an axial, rotationally symmetrical inlet cone (5), which forms an axial flow part (2) together with a jacket (6) protruding into the intake shaft (1) with an inlet edge (7). The axial flow part (2) is in connection with the inlet cross section of the fluid flow engine. The inlet edge (7) of the jacket (6) is connected with an annular diaphragm (9), which is directed at right angles to the axis (10) of the axial flow part (2). Furthermore, the diaphragm (9) is arranged mirror symmetrically at right angles to the axis (10) of the axial flow part (2) and asymmetrically in relation to the axis (10) of the axial flow part (2).

Abstract: Exhaust apparatus for exhausting “dirty” exhaust gases accept a core flow of such exhaust gases and combine that with an annularly-surrounding “rooftop” flow of ambient air for diluting the exhaust gases as well as expelling the diluted flow in a forcibly expelled plume in order to ensure that the “effective” expulsion distance of the expelled diluted flow is at least the physical length of the exhaust apparatus plus the gains gotten from efflux velocity and flowrate.

Abstract: In an axial flow fan, for reducing fluid noise and further reducing the noise by suppressing solid-conveyed noise (structure-borne noise) generated by the vibration of an electric motor or the like, the axial flow fan is equipped with a propeller, a motor for driving the propeller, and a venturi portion disposed on the outer circumference side of the propeller and provided on its inner circumferential side with a bellmouth through which an air flow generated by the revolution of the propeller passes, wherein the bellmouth has an intake portion whose diameter contracts in a curved shape in the direction of the air flow, a cylindrical portion having a cylindrical shape, and a discharge portion whose diameter slantingly expands in the direction of the air flow.