Airflow generator
Through the combined design of electric ducted fan and spiral air multiplier, the problems of high noise, complex structure and low cooling efficiency of the transformer cooling system are solved, and a compact and efficient transformer cooling effect is achieved.
Patent Information
- Application Number
- CN202480010161.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-02-13
- Filing Date
- 2024-01-17
- Publication Date
- 2025-08-29
AI Technical Summary
The existing transformer cooling systems have problems such as high noise, complex structure, difficult maintenance and low cooling efficiency. Especially for high-power transformers, natural convection is not enough to cool and forced cooling is required.
The combination design of electric ducted fan and spiral air multiplier is connected through fluid ducts to provide an efficient air flow generator. The spiral air multiplier controls the airflow speed over a larger area, reducing power consumption and noise.
A compact and efficient transformer cooling system is realized, reducing power consumption and noise, improving cooling efficiency and simplifying the structure.
Smart Images
Figure CN120569792A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to an airflow generator and a transformer assembly including such an airflow generator. The airflow generator is used to cool a heat exchanger disposed outside a transformer so as to cool the transformer. Background Art
[0002] Power transformers are devices used in the power grid of power systems. They convert voltage and current to transport and distribute electrical energy. Power transformers handle large currents; therefore, heat generation is inevitable. This heat is dissipated in the oil within the transformer tank. For proper operation of the transformer, it is important to release this heat to the surrounding environment. A significant portion of oil cooling is achieved by placing external devices (such as radiators, cooler banks, etc.) next to the transformer, through which the transformer oil circulates and is cooled. Current state-of-the-art air cooling for transformers is performed using conventional fans (i.e., bladed fans) or natural convection. Current state-of-the-art cooling systems using bladed fans are typically noisy, complex, heavy, and difficult to maintain. For high-power transformers, natural convection is insufficient to cool the transformer, and therefore forced cooling is required.
[0003] External transformer cooling typically uses one or more heat sinks external to the transformer that allow oil to circulate out of the transformer to the heat sink where heat is dissipated from the oil to the surrounding ambient air. The cooling process typically uses natural or forced convection to move ambient air across the heat sink.
[0004] This disclosure relates to cooling systems using forced convection. Forced convection is typically achieved using one or more large fans that blow air over or onto heat sink(s). Cooling efficiency depends on the airflow rate and, therefore, the fan's power consumption.
[0005] It is therefore an object of the present disclosure to provide a compact and power efficient air flow generator cooling arrangement for a transformer. Summary of the Invention
[0006] According to a first aspect of the present invention, these and other objects are achieved by an airflow generator as defined in claim 1, with alternative embodiments defined in the dependent claims. The airflow generator is suitable for cooling an oil-to-air external heat exchanger of a transformer. The airflow generator comprises an electrically driven ducted fan having an inlet and an outlet; a fluid duct; and an air multiplier for discharging air along a first axis. The air multiplier comprises an inlet and an outlet.
[0007] A fluid duct fluidly connects the outlet of the ducted fan to the inlet of the air multiplier. The air multiplier includes a spiral portion extending about a first axis. The spiral may include one or more portions having a smooth curvature, and / or it may include one or more straight portions. Figure 8 An alternative spiral shape is shown in .
[0008] A fan provides airflow into the fluid discharge device. Providing an air multiplier to the fluid discharge device allows the air discharge device to discharge a significantly greater volume of air than supplied by the fan. This reduces power consumption compared to conventional fans that directly blow air. Furthermore, the noise emitted by the fan and air multiplier combination is lower than the corresponding noise level emitted by a fan achieving the same airflow.
[0009] Prior art air multipliers are often shaped as a ring with a central opening through which air is accelerated by the air discharged from the air multiplier.The flow rate of air through the ring is higher closer to the ring and lower further away from the ring.
[0010] By making the air multiplier spiral-shaped, the air multiplier discharges air over a larger portion of the cross section of the air flow provided by the air discharge device, thereby improving control of the flow rate over the entire cross section of the air flow emitted by the air discharge device.
[0011] and providing separate concentric air multiplier rings such as Figure 2a Compared to the air multiplier ring shown in FIG-b, providing a spiral air multiplier allows the air multiplier to be supplied with fluid at only one location rather than at each individual air multiplier. Since no additional fluid conduit is required for each discrete air multiplier, the simplified structure promotes more uniform airflow through the air discharge device.
[0012] The helical portion may be substantially planar.
[0013] By arranging the spiral such that it extends in a plane, the fluid discharge device is very compact.
[0014] The helical portion may be inclined along the first axis.
[0015] By arranging the spiral so that it extends in a non-planar manner, the distance between adjacent loops of the spiral will be increased compared to a planar spiral. The increased distance makes it easier for airflow to pass through the fluid discharge device, on the contrary, Figure 2a The individual air multipliers shown in -b result in a certain degree of constriction in the area available for the air to flow through, which is caused by all the air multiplier rings being arranged in the same plane (see Figure 2b finite channel width as indicated by arrows d1 and d2 in FIG.
[0016] The helical portion may be helix-shaped.
[0017] By arranging the spiral so that it extends at an angle, the distance between adjacent loops of the spiral is increased compared to a flat spiral. This increased distance allows airflow to pass more easily through the fluid discharge device. When viewed from one end of the loop, the spiral extends so that it has a component extending along the flow direction axis, thereby contributing to the inclined nature of the spiral shape.
[0018] According to a second aspect of the present disclosure, these and other objects are achieved by a transformer arrangement as defined in claim 10. The transformer arrangement comprises an airflow generator according to any of the alternatives defined above, and a transformer provided with an oil-air external heat exchanger. The airflow generator is configured to discharge air towards the oil-air heat exchanger.
[0019] Transformers provided with an oil-air heat exchanger are known. By providing such a transformer with the claimed air flow generator, an energy efficient and compact cooling system for the transformer is achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1a A prior art air flow generator including an air multiplier is shown.
[0021] Figure 1b Shown also Figure 1a A side view of a prior art airflow generator (shown without a ducted fan and without fluid ducts) is shown in FIG.
[0022] Figure 2a Another prior art air flow generator is shown in which a plurality of air multipliers are concentrically aligned and arranged in a planar manner.
[0023] Figure 2b Shown also Figure 2a A side view of a prior art airflow generator (shown without a ducted fan and without fluid ducts) is shown in FIG.
[0024] Figure 3a A first embodiment of an air flow generator according to the present disclosure is shown, the air flow generator being provided with an air multiplier comprising a helical portion extending in a substantially planar manner about a first axis.
[0025] Figure 3b Shown also Figure 3a A side view of the airflow generator is shown in FIG.
[0026] Figure 4aA second embodiment of an air flow generator according to the present disclosure is shown, which is provided with an air multiplier comprising a helical portion extending about a first axis and inclined along the first axis in a downstream direction.
[0027] Figure 4b Shown also Figure 4a A side view of the airflow generator is shown in FIG.
[0028] Figure 5a A second embodiment of an air flow generator according to the present disclosure is shown, which is provided with an air multiplier comprising a helical portion extending around a first axis and inclined along the first axis in an upstream direction.
[0029] Figure 5b Shown also Figure 4a A side view of the airflow generator is shown in FIG.
[0030] Figure 6 A perspective view of a cross section of one of the air multipliers is shown. All air multipliers are based on the same general cross-sectional design.
[0031] Figure 7 A transformer device is shown, which also includes Figure 4a The air flow generator shown in FIG, and the transformer provided with an external oil-air heat exchanger.
[0032] Figure 8 An alternative shape to the spiral shape of the air multiplier is shown, having a combination of straight sections and rounded corners.
[0033] All figures are schematic representations and not drawn to scale. DETAILED DESCRIPTION
[0034] Hereinafter, embodiments of the present disclosure will be explained with reference to the accompanying drawings.
[0035] FIG1 shows a prior art airflow generator comprising an electric ducted fan 2 provided with an inlet 3 and an outlet 4. The airflow generator 1 further comprises a fluid duct 5 and an air multiplier 7 for discharging air along a first axis A. The air multiplier 7 comprises an inlet 8 and an outlet. The fluid duct 5 fluidly connects the outlet 4 of the ducted fan 2 to the inlet 8 of the air multiplier 7.
[0036] The term air multiplier is used in the prior art and should therefore be known to the skilled person. An air multiplier is a nozzle commonly used in bladeless fans. In this document, the term air multiplier may refer to any type of air discharge device / nozzle designed to discharge air through an outlet, which is usually in the form of one or more elongated slits, so that the air discharged from the outlet carries the air around the discharge device at a rate of at least 5-15 times the amount of air discharged from the outlet. Another term that may be used instead of air multiplier is coanda effect air multiplier. Such air discharge devices can vary greatly in design, but are often shaped like extruded hollow profiles (an example of which is shown in FIG. Figure 6 ), although any other suitable shape is possible. The profile typically has an elongated cross-sectional shape, and the outlet is typically configured to discharge air in a direction along a longitudinal axis (the longitudinal axis extending along the length of the elongated cross-sectional shape), such as Figure 6 The profile may have an aerodynamic wing shape. The outlet may be provided anywhere along the length of the profile cross-sectional shape as appropriate, such as at the leading edge of the profile (e.g. Figure 6 The profile may be straight but is typically curved to form a ring circumscribing the inner cross-sectional area of the air multiplier.
[0037] The air multiplier may be provided with a convexly curved wall portion, in which the outlet may be provided so that air is discharged along and adjacent to the curved portion, wherein the discharged air 'sticks' to the curved wall portion. This results in an increased suction force acting on the ambient air on the opposite side of the discharged airflow relative to the curved wall portion.
[0038] exist Figure 1b In, also Figure 1a The air flow generator 1 shown in FIG. 1 is shown without the ducted fan 2 and without the fluid duct 5 .
[0039] The fan 2 provides airflow into the air multiplier 7. The ducting nature of the fan 2 enables it to efficiently pressurize the fluid duct 5. By providing the air multiplier 7 to the airflow generator 1, it is possible to Figure 7 Oil-air heat exchanger 6 (shown in FIG) discharges a much larger volume of air than supplied by fan 2. Depending on the specific design of air multiplier 7, airflow generator 1 can therefore output an airflow ten to fifteen times greater than that generated by fan 2. This reduces power consumption compared to using a conventional fan that blows air directly against the object to be cooled (such as oil-air heat exchanger 6 located on transformer 11).
[0040] Such air multipliers 7 are typically configured as a ring having a central opening through which air is moved forward by air discharged from the air multiplier along a first axis A. The flow rate of the air through the ring is higher closer to the ring and lower farther away from the ring, as indicated by the dashed arrows in FIG1 , the length of the arrows indicating the strength of the local airflow.
[0041] Figure 2a and Figure 2b Another embodiment of a prior art air flow generator is shown in FIG.
[0042] Figure 2a and Figure 2b The air flow generator 1 of FIG. 1 corresponds to the air flow generator 1 of FIG. 1 , but is provided with additional air multipliers which are arranged radially inwardly of the larger outer air multiplier 7. The air multipliers 7 are arranged in the same plane as Figure 2a As indicated in Figure 2b As shown in FIG, the total cross-sectional area inside the larger air multiplier 7 is limited by the thickness of the two inner air multipliers, and air is only allowed to flow through the channels indicated by arrows d1 and d2. The additional inner air multipliers provide increased airflow and improved control of the airflow over the cross-sectional area inside the largest air multiplier 7. However, the additional air multipliers result in a decrease in the energy efficiency of the airflow generator 1.
[0043] In order to improve energy efficiency while allowing improved control of the exhausted air flow, the present disclosure proposes the use of an air multiplier configured with a spiral section, such as Figure 3a 、 Figure 3b 、 Figure 4a 、 Figure 4b 、 Figure 5a and Figure 5b As shown in .
[0044] By making the air multiplier into a spiral shape, one inlet is sufficient to supply air into the air multiplier, thereby alleviating the Figure 2a The need for additional fluid conduits to supply air to each air multiplier as in prior art arrangements where the additional fluid conduits locally restrict the air flow and create additional turbulence. Figure 1a The helical portion provides improved control of the discharged air flow over a greater portion of its cross-sectional area than prior art devices.
[0045] The air multiplier 7 can be configured such that the discharge direction of the air multiplier 7 is parallel to the first axis or at least substantially parallel to the first axis, such as within the range of 0-20 degrees, or within 0-15 degrees, or 0-10 degrees. It will be understood that the local movement direction of the ambient air moving through the air multiplier (according to the Coanda effect) naturally differs from the discharge direction and varies locally across the cross section of the airflow generator 1.
[0046] Because air multipliers can be formed from extruded profiles that are bent into their final shape, such profiles are open-ended and therefore require closure at any open ends to limit air leakage, which could lead to undesirable pressure drops in the air multiplier 1. Typically, such open ends are capped with end caps or sealed in any other suitable manner, such as with plugs. For example, the free end of an air multiplier having the cross-sectional shape shown in FIG5 would need to be closed so that air can be forced through the outlet opening 9 rather than through the open end.
[0047] exist Figure 3a 、 Figure 3b 、 Figure 4a 、 Figure 4b 、 Figure 5a and Figure 5b In an embodiment, the fluid duct is formed by a portion of the housing in which the ducted fan is located, wherein the housing forms the duct for the fan, and wherein the housing also provides the ducting required to deliver air to the inlet of the air multiplier 7. Any other configuration of fluid duct 5 capable of delivering air from the ducted fan to the air multiplier 7 may alternatively be used instead, such as a tube or pipe extending from the ducted fan located remotely from the air multiplier 7.
[0048] exist Figure 3a and Figure 3b In an embodiment, the helical portion is substantially planar. By arranging the helix so that it extends in a plane, the fluid discharge device is very compact.
[0049] exist Figure 4a 、 Figure 4b 、 Figure 5a and Figure 5b In the embodiment, the spiral portion is inclined downstream along the first axis A (e.g. Figure 4a ) or tilted upstream (as in Figure 5a By arranging the spiral so that it extends in a non-planar manner, the distance between adjacent loops of the spiral will be increased compared to a planar spiral. The increased distance makes it easier for air to flow through the fluid discharge device. Conversely, Figure 2a The individual air multipliers shown in -b result in a certain degree of constriction in the area available for the air to flow through, which is caused by all the air multiplier rings being arranged in the same plane (see Figure 2b finite channel width as indicated by arrows d1 and d2 in FIG.
[0050] Figure 4a 、 Figure 4b 、 Figure 5a and Figure 5b The spiral portion of the embodiment is helical. By arranging the spiral so that it extends at an angle, the distance between adjacent loops of the spiral is increased compared to a flat spiral. This increased distance facilitates airflow through the fluid discharge device. When viewed from one end of the loop, the spiral extends so that it has a component extending along the flow direction axis, thereby contributing to the inclined nature of the spiral shape.
[0051] The air flow generator 1 of the present disclosure is particularly useful for providing an air flow directed toward a heat exchanger 6 mounted externally on a transformer 11. Figure 7 Schematically illustrated in FIG. The transformer device 10 comprises an air flow generator 1 as described above, which comprises an air multiplier 7. The transformer device 10 further comprises a transformer 11 provided with an oil-air external heat exchanger 6. The air flow generator 1 is configured to discharge air towards the oil-air heat exchanger 6.
[0052] The oil-air external heat exchanger 6 is external in the sense that it is mounted externally on the transformer 11, thereby being able to radiate and conduct heat to the surrounding air. Typically, oil from the interior of the transformer 11 is pumped through the oil-air heat exchanger 6, wherein the oil transports the heat generated within the transformer 11 out to the heat exchanger 6, so that the air flow from the air flow generator 1 cools the heat exchanger 6.
[0053]
[0054] Reference numeral table
Claims
1. An airflow generator (1), comprising: An electric ducted fan (2) having an inlet (3) and an outlet (4); Fluid pipeline (5); as well as an air multiplier (7) for discharging air along a first axis (A), said air multiplier (7) comprising an inlet (8) and an outlet (9), The fluid duct (5) fluidly connects the outlet (4) of the ducted fan (2) to the inlet (8) of the air multiplier (7), Wherein, the air multiplier (7) comprises a spiral portion extending around the first axis (A).
2. The airflow generator (1) according to claim 1, wherein: The helical portion is substantially planar.
3. The airflow generator (1) according to claim 1, wherein: The helical portion is inclined along the first axis (A).
4. The airflow generator (1) according to claim 1 or 3, wherein: The helical portion is helical.
5. A transformer device (10), comprising an airflow generator (1) according to any one of claims 1 to 4, and a transformer (11) provided with an oil-air external heat exchanger (6), wherein the airflow generator (1) is configured to discharge air toward the oil-air heat exchanger (6).