47results about How to "Reduce secondary flow" patented technology

The invention belongs to the technical field of kitchen appliances, and particularly relates to an integrated cooker. The integrated cooker comprises a machine body and a range hood body; the range hood body comprises an air inlet, an air collecting box and a fan assembly; the air collecting box communicates with the air inlet; the fan assembly is arranged in the air collecting box; a volute air duct of the fan assembly extends downwards to the wall face of the bottom of the air collecting box and extends out of the bottom of the air collecting box to be rotationally provided with an air outlet base; and an air outlet is formed in one side of the air outlet base. According to the integrated cooker, the volute air duct extends downwards to the wall face of the bottom of the air collecting box and extends out of the bottom of the air collecting box to be rotationally provided with the air outlet base; the air outlet base is directly located on the outer side of the air collecting box, and the situation that a channel is located inside and occupies too much space is avoided; a through hole does not need to be additionally formed in the side edge of the machine body, and leakproofnessof the side face of the machine body is guaranteed; and meanwhile, the air outlet base is rotatably arranged, so that a user can conveniently adjust the air outlet direction according to actual needs,and humanization is achieved.

A blade cascade of a turbomachine whose at least one side wall is configured to be circumferentially undulated and which has at least two elevations and at least one depression or at least two depressions having at least one elevation, as well as a turbomachine having a blade cascade of this kind.

The invention discloses a space guide blade which is used for a deep well centrifugal pump or other forms of multi-level centrifugal pumps and provided with auxiliary vanes. The auxiliary vanes are arranged in the middle of all runners of the space guide blade, the change rule of the auxiliary vanes in the axial direction conforms to the streamline shape of vanes of the space guide blade, the thickness of the auxiliary vanes is smaller than that of the vanes of the space guide blade, and the auxiliary vanes occupy small space. The space guide blade is simple in structure, the flowing form that the middle of the space guide blade is attached to a lower cover plate area of the space guide blade can be effectively improved, the probability of vortex and secondary flow is reduced, the hydraulic loss in the runners of the space guide blade can be reduced, and the overflowing efficiency of the space guide blade is improved.

The invention relates to an impeller and volute chamber guide device in a double-suction centrifugal pump. The impeller and volute chamber guide device comprises a centrifugal pump volute casing, blades, impeller guide plates, volute chamber guide plates, a front cover plate, a rear cover plate and an impeller rotary shaft. The impeller front cover plate and the rear cover plate are fixed with the impeller guide plates between the adjacent blade working surfaces and the blade back surfaces so as to guide liquid flow which just enters the impeller; the impeller guide plates are welded between the front cover plate and the rear cover plate; an included angle between each of the tail parts of the guide plates and the outer diameter of the impeller is equal to the blade outlet angle. The volute chamber guide plates are distributed on the inner wall of the centrifugal pump volute casting at different angles along an Archimedes spiral line. According to the impeller and volute chamber guide device disclosed by the invention, the pump operation efficiency can be greatly improved.

A blade channel of a turbomachine that is delimited in the circumferential direction of the turbomachine by a pressure side of an airfoil and by an opposite suction side of an adjacent airfoil that, in the radial direction of the turbomachine, is delimited by two opposing side walls, and whose extent in the axial direction of the turbomachine is delimited by leading edges and by trailing edges of airfoils; at least one of the side walls being provided with localized contours, of which at least two are formed as elevations and at least two as depressions; a saddle surface being formed between the contours that, in one rotation, alternately merges into an elevation and a depression; a blade cascade having such blade channels, as well as a turbomachine having such a blade cascade.

A blade cascade of a turbomachine having at least one shape variation of a blade situated on the blade side in the proximity of a side wall and extending downstream, and at least one side wall contouring of the side wall or at least one second shape variation of an adjacent blade near the side wall, as well as a turbomachine, are disclosed.

The invention discloses an axial flow fan ternary impeller with a vein-shaped structure and a nonuniform empennage. The axial flow fan ternary impeller comprises a hub, and a connecting piece for a shaft sleeve fixed on the hub. The axial flow fan ternary impeller further comprises twisted blades and splitter blades fixedly connected to the hub; the twisted blades include suction surfaces and pressure surfaces; wing-shaped grooves are formed in the tops of the twisted blades; vein-shaped grooves are formed in the upper half parts of the pressure surfaces of the twisted blades; the wing-shaped grooves are communicated with the vein-shaped grooves through exhaust ports; winglet projections and dense winglets are arranged at the tail parts of the suction furnaces of the twisted blades; the dense winglets are arranged on two sides of the winglet projections; parabola small holes are formed in the twisted blades; the splitter blades are arranged between two adjacent twisted blades; and the heights of the splitter blades are smaller than the heights of the twisted blades by one half.

The invention relates to spatial guide vanes with vortex elimination and drag reduction holes, wherein the spatial guide vanes are used for a deep-well centrifugal pump or multistage centrifugal pumps in other forms. One to three semicircular holes with the same size are arranged in the root portion of each of the spatial guide vanes and close to a lower cover plate, and the vortex elimination and drag reduction holes penetrate through the pressure faces and the suction faces of the guide vanes and are inclined. The guide vanes with the vortex elimination and drag reduction holes are simple in structure and convenient to machine, high-speed liquid flow flows to the suction faces from the pressure faces through the vortex elimination and drag reduction holes, low-speed liquid remaining near the suction faces can be dispersed, the form of flow of the suction faces of the guide vanes close to the lower cover plate area can be effectively improved, the probability of generating secondary flow and vortexes is reduced, hydraulic loss is reduced, and the overflow efficiency of the guide vanes is remarkably improved.

A Francis turbine with an improved shape of blades, which can reduce a circumferential velocity component generated in the flow downstream of the blades in a condition of a partial load operation, or reduce the secondary flow around the blades, is provided. A Francis turbine comprises a crown, a plurality of blades, and a band. The crown can rotate around a rotating axis. The blades are circumferentially arranged on the crown, each of which including an inner end as a trailing edge. The band is coaxially coupled with the crown by the blades. A distance Rc can be defined as a distance between the rotation axis and an end by the crown side of the trailing edge. A distance Rb can be defined as a distance between the rotation axis and an end by the band side of the trailing edge. The distance Rc and the distance Rb satisfy $0.2\le \frac{R_c}{R_b}\le 0.4.$

The invention discloses an axial flow fan with blade suction surfaces having vortex breaking structures and with grooves formed in blade tops. The vortex breaking structures are additionally arranged on the portions, close to roots, of the suction surfaces of blades of an impeller, the airfoil grooves are machined in the tops of the blades, a labyrinth seal structure is additionally arranged in the clearance between a hub and an inner barrel, rectangular grooves are machined in the tails of the suction surfaces of guide vanes, the size of channel vortexes in an impeller passenger can be restrained, and radial secondary flow is reduced. Development of leakage flow can be impeded, mixing of the leakage flow and main flow is weakened, and therefore leakage losses of the blade tops are reduced. A high throttling effect can be generated, the stability of airflow on an outlet of the impeller is improved, and the leakage amount of airflow at the roots of the blades is reduced. The thicknesses of boundary layers on the tails of the guide vanes can be well controlled, separation of the boundary layers is avoided, disengagement of the vortexes is restrained, and the disengaging frequency of the vortexes is reduced. By improving different positions of the axial flow fan, the axial flow fan is higher in efficiency, lower in noise and more environmentally friendly and saves more energy.

The invention relates to an impulse type secondary jet flow thrust vector control system which comprises a rocket engine (1), an annular high pressure gas storage tank (2), a gas transporting pipeline(3), a pressure maintaining valve (4), a gas collecting cavity (5), an impulse jet flow control valve (6), a jet flow spout (7) and an engine jet pipe (8). The system facilitates flight control of anaircraft and adopts the secondary jet flow thrust vector control to reduce energy consumption, enhance the deflection capacity of secondary flow and effectively reduce the flow rate of the secondaryflow needed to be sprayed into.

A blade cascade for a continuous-flow machine having a non-axisymmetrical side wall contour, whereby the side wall contour has at least one suction-side depression that, in the circumferential direction, is at a distance from a suction-side wall, and having a section located upstream from the leading edges and a section located downstream from the leading edges, it has a pressure-side elevation that makes a transition to a pressure-side wall and that is located in a front blade area, and it has a pressure-side depression that is located upstream from the pressure-side elevation, and also discloses a continuous-flow machine having such a blade cascade.

A Francis turbine with an improved shape of blades, which can reduce cavitations generated on the surface of the blades or reduce the secondary flow around the blades, is provided. A Francis turbine comprises a rotating shaft, a crown, a plurality of blades, and a band. The crown can rotate with the rotating shaft. The blades are circumferentially arranged on the crown, each of which including an inner end as a trailing edge. The band is coaxially coupled with the crown by the blades. The rotating shaft, the crown, the blades, and the band as a whole rotate toward a turbine direction during a turbine operation. A projected profile of the trailing edge on a perpendicular plane, which is perpendicular to a center axis of the rotating shaft, is curved toward a direction opposite to the turbine direction at least in the crown side.

A blade/vane cascade segment of a blade/vane cascade for a turbomachine is disclosed, which comprises a stage with a stage surface as well as a first blade/vane element and a second blade/vane element. The stage surface comprises a first elevation reaching as far as the pressure side of the first blade/vane element and a second elevation reaching as far as the suction side of the second blade/vane element. A furthest downstream point of a boundary of the second elevation has an axial position which differs from the axial position of at least one highest point of the first elevation by a maximum of 10% of an axial cascade span. Furthermore, a blade/vane cascade, a blade/vane channel, a stage, a turbomachine and an aircraft engine are disclosed.

The invention relates to a method for acquiring the load distribution curve of a blade of a double-suction centrifugal pump. The method comprises the following steps: working out the specific speed and drawing the axial projection drawing of the blade according to performance parameters of the double-suction centrifugal pump, working out the key parameters of load distribution curves of a front cover plate flow line and a rear cover plate flow line of the double-suction centrifugal pump, drawing the load distribution curves of the front cover plate flow line and the rear cover plate flow line, thickening the blade of the double-suction centrifugal pump according to the size, the working capacity and the casting level of the blade, working out the flow lines of a front cover plate and a rear cover plate according to the load distribution curves of the front cover plate flow line and the rear cover plate flow line and the thickening value, and performing numerical prediction to the efficiency and the inside fluid field of a conventional double-suction centrifugal pump model and a double-suction centrifugal pump model acquired through the method provided by the invention by adopting an analogue simulation method. The blade of the double-suction centrifugal pump, acquired through the invention, has the advantages that the surface pressure variation is uniform, a secondary flow in the outlet area of the blade is reduced remarkably, and the range of a high-efficiency area is broadened.

Described are an airfoil array segment (100, 200, 300) having at least two airfoils (20, 30) and a platform (10) that features an axis asymmetrical platform surface (12). This platform surface features an elevation (110, 210, 310) that extends from the pressure side (21) of the first to the suction side (32) of the second airfoil (30). A highest point (111, 211, 311) of the elevation is more proximate to the suction side 32 of the second airfoil (30) than to the pressure side (21) of the first airfoil (20). Also described are an airfoil, a platform, an airfoil passage and a turbomachine.

A blower capable of reducing secondary flow comprises a frame and a wheel blade part. The wheel blade part is mounted in the frame. The wheel blade part is composed of a hub and a plurality of blades surrounding the hub. The frame is composed of a base and an upper lid plate with a projection part being provided at inner side of the base. The projection part corresponds to the blades on the wheel blade part. A first guide part and a second guide part are provided at an air passage of the base near an opening thereof. The secondary flow produced in the blower can be reduced by way of the projection at the inner side of the base and the first and second guide parts at the air passage of the base near the opening thereof.

A labyrinth seal (25,...,27), for sealing the annular interspace (11) between the rotor (12) and the stator (10) of a steam turbine or gas turbine, comprises a multiplicity of sealing strips (13) which are arranged in series in the axial direction, are fastened on the stator (10) and project into the interspace (11), which sealing strips interact, with sealing effect, with rotor-side sealing elements (14, 19) which are arranged in a staggered manner. With such a labyrinth seal (25,...,27), an improved sealing effect is achieved by the sealing strips (13) in the cold installed state being offset in relation to a symmetrical position, wherein the offset has the reverse direction and the same amount as the distance (29) by which the sealing strip (13) is displaced relative to adjacent rotor-side sealing elements (14, 19) as a result of thermal expansions of the stationary and rotating components and support structure when being heated from the cold installed state to a hot steady-state operating condition.

The invention discloses an axial flow fan three-dimensional impeller with leaf vein structures and arc cylindrical splitter blades. The axial flow fan three-dimensional impeller comprises a hub and further comprises curved-twisted blades and splitter blades, wherein a shaft sleeve is fixed on the hub by a connecting piece; the curved-twisted blades and splitter blades are fixedly connected onto the hub; the curved-twisted blades comprise suction surfaces and pressure surfaces; wing grooves are formed in the tops of the curved-twisted blades; leaf vein shaped grooves are formed in upper half parts of the pressure surfaces of the curved-twisted blades; the wing grooves are communicated with the leaf vein shaped grooves through air outlets; small wing protrusions are arranged at the tails of the suction surfaces of the curved-twisted blades; parabolic pinholes are formed in the curved-twisted blades; a splitter blade is arranged between every two adjacent curved-twisted blades; and the height of each splitter blade is smaller than one half of that of the curved-twisted blade.

The invention discloses a centrifugal pump which comprises a volute, a rear cover plate and an impeller. The impeller is rotationally arranged between the volute and the rear cover plate, and blades are connected to the impeller; axial holes are formed in each blade, and the axial holes penetrate through the blades and the impeller; and the multiple axial holes are formed in the blades in the extending directions of the blades at intervals, and at least one of the following effects including reduction of liquid backflow in blade top gaps and reduction of cavitation and axial force can be achieved, so that the efficiency of the centrifugal pump is improved.