A nanofluid stabilizer suitable for a transformer heat dissipation loop

Abstract

The application discloses a nanofluid stabilizer suitable for a transformer heat dissipation loop, which comprises an elbow body, an injection impactor, a flow director, a rectifier and a nanofiltration assembly. After passing through the rectifier, the nanofluid reaches uniform distribution of the spanwise velocity, is divided into two paths through the flow director, one path enters a ring cavity between the injection impactor and the elbow body through an acceleration and pressure reduction process, and the other path enters the inside of the injection impactor through a nanofiltration assembly and a deceleration and pressure increase process. The internal medium enters the ring cavity through a first through hole array and a second through hole array, forms continuous shearing flow, makes the generated nanometer particle agglomerates break again, and continuously flushes the easy deposition area of the elbow area. The nanofluid stabilizer is suitable for the transformer heat dissipation loop using nanofluid to strengthen heat transfer, the heat dissipation medium is regenerated when passing through the elbow, particle deposition and flow channel blockage are avoided, long-term high-efficiency heat dissipation is maintained, the operation cycle of the heat dissipation system is greatly prolonged, and the operation and maintenance are convenient.

Description

Technical Field

[0001] This invention relates to the field of power transformer technology, and more specifically to a nanofluid stabilizer suitable for transformer heat dissipation circuits. Background Technology

[0002] During the operation of a power transformer, its core winding continuously generates a large amount of heat, which must be dissipated to the outside in a timely manner, otherwise it will cause the equipment to overheat and be damaged. Currently, mineral oil is often used as a heat dissipation medium to conduct the heat from the winding to the heat sink and finally achieve cooling through air convection. To improve heat dissipation efficiency, technicians have attempted various modifications to the heat sink structure. However, limited by the inherent thermal properties of mineral oil, the technology path based on heat sink structure improvements has consistently struggled to overcome efficiency bottlenecks. Therefore, mixing solid nanoparticles with mineral oil to obtain nanofluids with entirely different thermal properties has become a promising alternative, potentially leading to a significant leap in heat dissipation efficiency. However, after prolonged operation, nanofluids are prone to particle agglomeration, deposition, and even blockage of oil passages, negatively impacting heat dissipation and shortening the maintenance cycle of the cooling equipment. While surface modification of nanoparticles or the use of high-temperature dispersants can partially delay agglomeration, deposition, and blockage, they cannot fundamentally solve the stability problem of nanofluids. Furthermore, while ultrasonic cavitation can break up agglomerates, it not only incurs additional energy consumption but also, with prolonged exposure, can cause particles to re-agglomerate, making it difficult to maintain long-term stable system operation. These issues hinder the widespread application of nanofluids in power transformer cooling systems. Summary of the Invention

[0003] The purpose of this invention is to provide a nanofluid stabilizer suitable for transformer heat dissipation circuits, so as to solve the problems mentioned in the background art.

[0004] The technical solution proposed by this invention to solve the problems mentioned in the background art is as follows: A nanofluid stabilizer suitable for transformer heat dissipation circuits includes an elbow body and internal components, the internal components including an ejector impactor, a flow guide, a rectifier, and a nanofiltration assembly.

[0005] The ejector impactor is located inside the elbow body and is arranged coaxially with the elbow body, forming an annular cavity with the elbow body. The ejector impactor surface has a first through-hole array facing the outside of the elbow body and a second through-hole array facing the inside of the elbow body.

[0006] The flow guide is fixed to the front end of the ejector impactor, and the nanofiltration assembly is snapped onto the top of the flow guide.

[0007] The rectifier is snapped into the ring block of the nanofiltration module, and its circumference is fixed to the inner wall of the elbow body, which plays a role in fixing the overall nanofluid stabilizer.

[0008] The width of the annular cavity between the ejector and the elbow body is smaller than the inner radius of the ejector. Both the first and second through-hole arrays consist of through holes arranged in a staggered manner along the flow direction. The through-hole axes are arranged at an inclination relative to the wall normal of the ejector. The outlet of the through-hole in the first through-hole array faces the outer recess of the elbow body, and the outlet of the through-hole in the second through-hole array faces the backflow area on the inner downstream side of the elbow body.

[0009] The flow guide has a convex parabolic surface with a flat top, which allows the heat dissipation medium to flow through.

[0010] The rectifier is a grid with a central annular surface and teardrop-shaped bars.

[0011] Both the first and second through-hole arrays have wedge-shaped holes with an inlet diameter smaller than the outlet diameter, and the average hole diameter gradually increases along the flow direction.

[0012] The diameter of the bottom end of the flow guide is equal to the diameter of the ejector impactor. There is an annular protrusion on the top circumference of the flow guide for locking the nanofiltration assembly. The nanofiltration assembly consists of an annular block and a nanofiltration membrane. The annular block has a first slot and a second slot.

[0013] There are grommets on the central ring of the rectifier, and the width of the teardrop-shaped grid bars gradually decreases from the windward side to the leeward side.

[0014] The first slot is used to engage the flow guide, and the second slot is used to fix the nanofiltration membrane.

[0015] The ring block has a connecting rod for inserting into a locking hole to limit the remaining internal components except for the rectifier.

[0016] The length of the connecting rod is at least twice the flow diameter of the nanofiltration module.

[0017] By adopting the above technical solution, the long-term stable operation of the nanofluid heat dissipation circuit of the transformer radiator has been achieved.

[0018] Compared with the prior art, the beneficial effects of the present invention are: for the transformer heat dissipation circuit with enhanced heat dissipation performance using nanofluids, the aggregation, deposition and blockage of nanoparticles are effectively avoided, and the operating cycle of the heat dissipation circuit is greatly extended.

[0019] The dense shear array formed by multi-stage ejection causes the agglomerates of nanofluid to break down under shearing action when passing through the stabilizer, turning them back into small particles, which is equivalent to regenerating the nanofluid. This invention ensures that the area prone to deposition at the bend is constantly subjected to high-frequency scouring, preventing deposition from occurring. Even if deposition has already occurred, the impact effect of high-speed ejection can decompose the deposits, preventing blockage. Since deposition and blockage in the bend area are the main causes of failure in transformer heat dissipation systems using nanofluids, this invention actually provides a nanofluid stabilizer for the entire heat dissipation system, enabling the system to maintain long-term, uninterrupted, and efficient heat dissipation. The stabilizer elbow and nanofiltration module are independent of the cooling oil circuit, and can be disassembled for cleaning or replacement. There is no need for comprehensive maintenance of the entire heat dissipation system, making operation and maintenance quick and convenient. Attached Figure Description

[0020] Figure 1 This is an overall cross-sectional view of a nanofluid stabilizer suitable for transformer heat dissipation circuits according to the present invention. Figure 2 This is an overall three-dimensional view of a nanofluid stabilizer suitable for transformer heat dissipation circuits according to the present invention; Figure 3 This is a cross-sectional view of the internal component (excluding the rectifier) ​​of a nanofluid stabilizer suitable for a transformer heat dissipation circuit according to the present invention; Figure 4 This is a three-dimensional view of the internal components (excluding the rectifier) ​​of a nanofluid stabilizer suitable for a transformer heat dissipation circuit according to the present invention; Figure 5 This is a front view of a rectifier for a nanofluid stabilizer suitable for a transformer heat dissipation circuit according to the present invention; Figure 6 This is a three-dimensional view of a rectifier with a flanged connector, which is a nanofluid stabilizer suitable for transformer heat dissipation circuits according to the present invention. Figure 7 This is a three-dimensional view of the rectifier grid of a nanofluid stabilizer suitable for transformer heat dissipation circuits according to the present invention; In the figure: 1. Elbow body; 2. Ejector impactor; 21. First through-hole array; 22. Second through-hole array; 3. Flow guide; 31. Annular protrusion; 4. Rectifier; 41. Central annular surface; 411. Snap hole; 42. Grid bar; 5. Nanofiltration assembly; 51. Ring block; 511. First slot; 512. Second slot; 513. Connecting rod; 52. Nanofiltration membrane; 61. First flange; 62. Second flange; 63. Third flange; 64. Fourth flange. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example like Figures 1-7 As shown, a nanofluid stabilizer suitable for transformer heat dissipation circuits includes an elbow body 1 and internal components. The internal components include an ejector impactor 2, a flow guide 3, a rectifier 4, and a nanofiltration assembly 5. The ejector impactor 2 is located inside the elbow body 1 and is arranged coaxially with the elbow body 1, forming an annular cavity between the ejector impactor 2 and the elbow body 1. The surface of the ejector impactor 2 has a first through-hole array 21 facing the outside of the elbow body 1 and a second through-hole array 22 facing the inside of the elbow body 1. The flow guide 3 is fixed to the front end of the ejector impactor 2. The nanofiltration assembly 5 is snapped onto the top end of the flow guide 3. The rectifier 4 is snapped onto the ring block 51 of the nanofiltration assembly 5, and its circumference is fixed to the inner wall surface of the elbow body 1, which plays a role in fixing the overall nanofluid stabilizer.

[0023] Optionally, the inlet of the ejector impactor 2 is located upstream of the elbow, and its outlet is located downstream of the elbow. Its arc portion is concentric with the arc portion of the elbow body 1. The first through-hole array 21 and the second through-hole array 22 are both opened on the arc section of the ejector impactor 2. The guide 3 has a convex parabolic shape and is integrally formed or welded to the ejector impactor 2. The nanofiltration component 5 is annular and is concentric with the top of the guide 3. The outer edge of its ring block 51 has a rounded corner at the rear end. The pipe section between the circumference of the rectifier 4 and the first flange 61 and the second flange 62 is fixedly connected. The function is as follows: after passing through the rectifier 4, the heat dissipation medium forms a uniform velocity profile in the spanwise direction. After smoothly flowing through the annular block 51, the nanofluid enters the annular cavity between the elbow body 1 and the ejector impactor 2 through the outside of the guide 3 via an accelerated decompression process. The nanoparticle-free medium, after being filtered by the nanofiltration membrane 52, enters the interior of the ejector impactor 2 through the inside of the guide 3 via a deceleration and pressurization process. Under the action of the pressure difference between the inside and outside of the ejector impactor 2, the pure medium inside it enters the outer annular cavity through the first through-hole array 21 and the second through-hole array 22, forming a stable jet in the annular cavity. Its continuous flow shear effect causes the nanoparticle agglomerates from the upstream to be efficiently broken up. At the same time, it continuously scours the easily deposited areas inside the elbow body 1, preventing nanoparticles from depositing in the elbow and ensuring that the internal components do not cause additional particle agglomeration and deposition due to the flow steps. The rectifier 4 forms a single module independent of the other internal components, which facilitates the overall installation and maintenance of the device.

[0024] The width of the annular cavity between the ejector 2 and the elbow body 1 is smaller than the inner radius of the ejector 2. The first through-hole array 21 and the second through-hole array 22 are both composed of through holes arranged in a staggered manner along the flow direction. The through-hole axis is inclined relative to the wall normal of the ejector 2. The through-hole outlet of the first through-hole array 21 faces the outer recess of the elbow body 1, and the through-hole outlet of the second through-hole array 22 faces the backflow area on the inner downstream side of the elbow body 1. The guide 3 has a convex parabolic surface with a flat top for passing heat dissipation medium. The rectifier 4 is a grid containing a central annular surface 41, and its grid bars 42 are teardrop-shaped.

[0025] Optionally, the width of the annular cavity between the ejector impactor 2 and the elbow body 1 is 1 / 5 to 3 / 5 of the inner radius of the ejector impactor 2. The first through-hole array 21 and the second through-hole array 22 are both composed of staggered circular holes arranged along the flow direction. The first through-hole array 21 consists of six rows of holes, and the second through-hole array 22 consists of two rows of holes. The inclination angle of the through-hole axis relative to the normal of the ejector impactor 2 wall is 45° to 75°. The central annular surface 41 of the rectifier 4 is welded to or integrally formed with the grid. The wide end of the grid bar 42 faces the incoming flow, and the narrow end faces the wake. The effect is to increase the velocity gradient of the jet in the annular cavity between the ejector impactor 2 and the elbow body 1, thereby strengthening the shear effect, efficiently breaking up nanoparticle agglomerates, and expanding the coverage area of ​​the jet impact zone, thus forming a thorough scouring of easily deposited areas. Simultaneously, it ensures that no additional nanoparticle agglomeration occurs due to the rectifier 4.

[0026] The through holes of the first through hole array 21 and the second through hole array 22 are wedge-shaped holes with an inlet diameter smaller than the outlet diameter. The average hole diameter gradually increases along the flow direction. The bottom diameter of the flow guide 3 is equal to the diameter of the ejector impactor 2. There is an annular protrusion 31 on the top periphery of the flow guide 3 for locking the nanofiltration assembly 5. The nanofiltration assembly 5 is composed of an annular block 51 and a nanofiltration membrane 52. The annular block 51 has a first slot 511 and a second slot 512. There is a locking hole 411 on the central annular surface 41 of the rectifier 4. The width of the teardrop-shaped grid bars 42 of the grid gradually decreases from the windward side to the leeward side.

[0027] Optionally, the inlet and outlet aperture ratio of the first through-hole array 21 and the second through-hole array 22 is 2 / 3 to 1 / 3, the average aperture increases linearly along the flow direction, the nanofiltration membrane 52 is as close as possible to the front end face of the annular block 51, and 2 to 4 circular ferrules 411 are centrally symmetrically arranged on the central annular surface 41 of the rectifier 4. The cross-sectional shrinkage ratio of the teardrop-shaped grid bars 42 is 1 / 2 to 1 / 3. The effect is that it effectively resists the disturbance of crossflow accumulation on the jet core in the annular cavity between the ejector impactor 2 and the elbow body 1, keeps the jet flow rate from decaying, thereby maintaining the efficient nanoparticle agglomeration breaking process, while ensuring a stable connection between the rectifier 4 and the other internal components, and maintaining a low local resistance when the nanofluid passes through the rectifier 4, preventing additional agglomeration of nanoparticles in the wake of the grid bars 42.

[0028] The first slot 511 is used to engage the flow guide 3, and the second slot 512 is used to fix the nanofiltration membrane 52.

[0029] Optionally, a sealing sheet is installed in the first slot 511, and the ring block 51 is spliced ​​in half. The specific parameters of the nanofiltration membrane 52 are selected based on the empirical size of the nanoparticle agglomerates or the maintenance cycle requirements of the heat dissipation equipment. The advantage is that it ensures that the heat dissipation medium does not penetrate into the narrow slit of the nanofiltration component, and at the same time, it facilitates the embedding and fixing of the nanofiltration membrane 52 in the second slot 512. The parameters of the nanofiltration membrane 52 can be flexibly determined or adjusted according to the specific operating conditions of the heat dissipation circuit, and it ensures that no nanoparticle agglomerates are deposited and blocked in the through holes of the downstream first through-hole array 21 and second through-hole array 22, thereby indirectly maintaining the nanoparticle agglomerate breaking efficiency in the annular cavity for a long time without decay.

[0030] The ring block 51 has a connecting rod 513 for inserting into the clasp 411 to limit the remaining internal components except for the rectifier 4.

[0031] Optionally, the connecting rod 513 is a round rod symmetrical about the center of the channel axis, and the number is 3 to 4. The advantage is that while maintaining the stability of the internal components, the rectification effect is not affected by the connecting rod.

[0032] The length of the connecting rod 513 is at least twice the flow diameter of the nanofiltration module 5.

[0033] Optionally, the length of the connecting rod 513 is 2 to 4 times the flow diameter of the nanofiltration assembly 5. The advantage is that a uniform velocity distribution is maintained on the flow-facing surface of the guide vane 3, allowing the heat dissipation medium to enter the annular cavity and the interior of the ejector impactor 2 in an ideal proportion, achieving the desired nanoparticle agglomeration breaking effect, while facilitating the loading and unloading operations between the module containing the rectifier 4 and the modules containing the other internal components.

Claims

1. A nanofluid stabilizer suitable for transformer heat dissipation circuits, comprising an elbow body (1) and internal components, characterized in that: The internal components include an ejector impactor (2), a flow guide (3), a rectifier (4), and a nanofiltration assembly (5). The ejector impactor (2) is located inside the elbow body (1) and is arranged coaxially with the elbow body (1), forming an annular cavity with the elbow body (1). The ejector impactor (2) has a first through hole array (21) facing the outside of the elbow body (1) and a second through hole array (22) facing the inside of the elbow body (1). The flow guide (3) is fixed to the front end of the ejector impactor (2), and the nanofiltration assembly (5) is snapped onto the top end of the flow guide (3). The rectifier (4) is snapped into the ring block (51) of the nanofiltration component (5), and its circumference is fixed to the inner wall of the elbow body (1), which plays a role in fixing the overall nanofluid stabilizer.

2. The nanofluid stabilizer suitable for transformer heat dissipation circuits according to claim 1, characterized in that: The width of the annular cavity between the ejector impactor (2) and the elbow body (1) is smaller than the inner radius of the ejector impactor (2). The first through-hole array (21) and the second through-hole array (22) are both composed of through holes arranged in a staggered manner along the flow direction. The through-hole axis is inclined relative to the wall normal of the ejector impactor (2). The through-hole outlet of the first through-hole array (21) faces the outer recess of the elbow body (1), and the through-hole outlet of the second through-hole array (22) faces the backflow area on the inner downstream side of the elbow body (1). The flow guide (3) has a convex parabolic surface with a flat top, which allows the heat dissipation medium to flow through. The rectifier (4) is a grid containing a central annular surface (41) with teardrop-shaped bars (42).

3. A nanofluid stabilizer suitable for transformer heat dissipation circuits as described in claim 2, characterized in that: The through holes in the first through hole array (21) and the second through hole array (22) are wedge-shaped holes with an inlet diameter smaller than the outlet diameter, and the average hole diameter gradually increases along the flow direction; The bottom diameter of the flow guide (3) is equal to the diameter of the ejector impactor (2), and there is an annular protrusion (31) on the top periphery for engaging the nanofiltration assembly (5). The nanofiltration assembly (5) is composed of the annular block (51) and the nanofiltration membrane (52). The annular block (51) has a first slot (511) and a second slot (512). There is a card hole (411) on the central annular surface (41) of the rectifier (4), and the width of the teardrop-shaped grid (42) gradually decreases from the windward side to the leeward side.

4. A nanofluid stabilizer suitable for transformer heat dissipation circuits as described in claim 3, characterized in that: The first slot (511) is used to engage the flow guide (3), and the second slot (512) is used to fix the nanofiltration membrane (52).

5. A nanofluid stabilizer suitable for transformer heat dissipation circuits as described in claim 3, characterized in that: The ring block (51) has a connecting rod (513) for inserting into the clasp (411) to limit the remaining internal components except for the rectifier (4).

6. A nanofluid stabilizer suitable for transformer heat dissipation circuits as described in claim 5, characterized in that: The length of the connecting rod (513) is at least twice the flow diameter of the nanofiltration assembly (5).

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