Water cooling plate with mixed fin structure

Abstract

The utility model belongs to the technical field of heat dissipation, and particularly relates to a water cooling plate with a mixed rib structure, which comprises a shell, the top surface of the shell is used for being in direct contact with a heating element, the shell is provided with a water inlet and a water outlet, and the interior of the shell is sequentially provided with a first flow channel and a second flow channel along the direction from the water inlet to the water outlet; a plurality of rectangular fins which are transversely arranged are arranged in the first flow channel and are used for guiding cooling liquid to flow along a straight line; a plurality of rhombic fins are arranged in the second flow channel and used for changing the flowing path of the cooling liquid and increasing disturbance, so that the cooling liquid is fully mixed in the flow channel. The technical problems that in the prior art, a water cooling plate is single in runner design and uneven in heat dissipation effect are solved, the heat transfer efficiency of cooling liquid is effectively improved by adopting the fin structures of different shapes and arrangement modes, and therefore the overall heat dissipation performance of the water cooling plate is enhanced.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat dissipation, and in particular relates to a water cooling plate with a mixed fin structure. Background Art

[0002] In the prior art, water-cooled plates (or liquid-cooled plates), as an important component of liquid-cooled heat dissipation systems, are widely used in high-power electronic equipment, industrial equipment, and new energy vehicles. The main function of a water-cooled plate is to dissipate heat efficiently through liquid cooling to ensure that the heating elements operate at a stable temperature, thereby extending the service life of the equipment and improving its reliability. Existing water-cooled plates are usually made of metal materials with high thermal conductivity (such as aluminum, copper, etc.), and a complex liquid flow channel structure is formed inside the metal plate through CNC processing or etching technology. The coolant enters the water inlet of the water-cooled plate, flows evenly through the preset flow channel, and is in direct contact with the metal wall. The coolant absorbs heat from the heating element in the flow channel, and gradually takes away the heat through heat transfer with the metal water-cooled plate. Typically, a water-cooled plate is used in conjunction with a cooling pump and a radiator to form a complete liquid cooling circulation system.

[0003] However, existing water cooling plate flow channel designs have some significant drawbacks. Current designs often employ a single, linear flow channel or incorporate rectangularly arranged heat dissipating fins or columns within the flow channel. While this design can improve heat dissipation to a certain extent, the following issues still exist in practical applications:

[0004] 1. Uneven heat dissipation: When the coolant flows through the flow channel, due to its low initial temperature, the temperature difference between the coolant and the heating element at the beginning of the flow channel is large, resulting in a high heat exchange efficiency. However, as the coolant gradually flows along the flow channel, its temperature continues to rise, resulting in a decrease in the temperature difference between the liquid and the heating element in the second half of the flow channel, and a significant decrease in heat exchange efficiency. This uneven temperature distribution, especially at the end of the flow channel, can cause different heat dissipation effects in different areas of the heating element, affecting the overall heat dissipation performance of the device.

[0005] 2. Simple flow channel design: Existing flow channel structures are mostly linear. Even with the addition of rectangular fins or heat sinks, the fluid flow path remains relatively monotonous, making it difficult to effectively guide the coolant for turbulent heat exchange, resulting in insufficient local heat dissipation performance. Furthermore, this simple flow channel design is difficult to adapt to the heat dissipation requirements of different areas when faced with complex heat-generating component layouts.

[0006] In summary, the flow channel design of existing water-cooled plate technology has limitations in terms of heat dissipation uniformity and heat exchange efficiency, which affects the overall heat dissipation performance of the system. Therefore, to address these issues in the existing technology, an improved water-cooled plate design is urgently needed to optimize the coolant flow path and temperature distribution, thereby improving heat dissipation. Utility Model Content

[0007] In response to the deficiencies in the prior art, the utility model provides a water-cooled plate with a hybrid fin structure. By adopting fin structures of different shapes and arrangements, the heat transfer efficiency of the coolant is effectively improved, thereby enhancing the overall heat dissipation performance of the water-cooled plate.

[0008] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0009] A water-cooled plate with a mixed fin structure includes a shell, the top surface of the shell is used to directly contact a heating element, the shell is provided with a water inlet and a water outlet, and the interior of the shell is provided with a first flow channel and a second flow channel in sequence along the direction from the water inlet to the water outlet; a plurality of transversely arranged rectangular fins are arranged in the first flow channel to guide the coolant to flow in a straight line; a plurality of diamond-shaped fins are arranged in the second flow channel to change the flow path of the coolant and increase disturbance so that the coolant is fully mixed in the flow channel.

[0010] In a preferred implementation, further, the rectangular fins in the first flow channel are arranged in multiple groups at intervals, and each group includes a plurality of rectangular fins parallel to each other.

[0011] In a preferred implementation, further, a plurality of straight flow channels of equal width are provided between adjacent rectangular fins in each group.

[0012] In a preferred implementation, further, the diamond-shaped fins in the second flow channel are arranged in multiple groups at intervals, and each group includes a plurality of diamond-shaped fins arranged in a staggered array.

[0013] In a preferred implementation, further, the first flow channel and the second flow channel form a continuous flow channel structure, and the flow channel structure adopts a U-shaped flow channel or a straight flow channel.

[0014] In a preferred implementation, further, the curved area of ​​the U-shaped flow channel is provided with a rounded corner, and the top angle of the diamond-shaped ribs in the curved area matches the flow direction of the coolant.

[0015] In a preferred implementation, further, in the linear flow channel, the top angles of the diamond-shaped ribs near the water outlet converge toward the water outlet at a certain angle.

[0016] In a preferred implementation, further, each of the diamond-shaped fins adopts a symmetrical diamond-shaped structure, and the vertex angles at both ends thereof have a certain angle with the flow direction of the coolant.

[0017] In a preferred implementation, further, the heights of the rectangular fins and the diamond-shaped fins match the height of the flow channel.

[0018] In a preferred implementation, further, the shell includes an upper shell and a lower shell, and the upper shell and the lower shell are buckled together to form an internal cavity structure.

[0019] The beneficial effects of the utility model are:

[0020] First, the present invention arranges a mixed fin structure in the water-cooled plate, utilizes the rectangular fins in the first flow channel to guide the coolant to flow steadily in a straight line, and arranges diamond fins in the second flow channel to change the flow path of the coolant and increase liquid disturbance, so that the coolant is fully mixed in the flow channel, thereby improving the overall heat exchange efficiency and effectively improving the heat dissipation performance of the water-cooled plate.

[0021] Second, in a preferred implementation, the utility model can effectively guide the coolant to flow evenly and stably, thereby reducing liquid flow resistance, by arranging multiple groups of mutually parallel rectangular fins at intervals in the first flow channel and forming multiple straight flow channels of equal width between each group of adjacent fins.

[0022] Third, in the preferred implementation, the present invention adopts a U-shaped or straight continuous flow channel structure, wherein the curved area of ​​the U-shaped flow channel is provided with a chamfered corner, and the top angle of the diamond ribs in the curved area matches the flow direction of the coolant, thereby reducing the liquid flow resistance in the curved area; in the straight flow channel, the top angles of the diamond ribs close to the water outlet converge toward the water outlet at a certain angle, guiding the coolant to flow out smoothly, thereby optimizing the flow path of the coolant and improving the overall heat dissipation efficiency.

[0023] Fourth, in a preferred implementation, the diamond-shaped fins of the present invention adopt a symmetrical diamond-shaped structure, and the top angles at both ends are designed to form a certain angle with the flow direction of the coolant, which helps to change the flow path of the coolant.

[0024] Fifth, in the preferred implementation, the present invention can fully utilize the flow channel space by matching the height of the rectangular fins and the diamond fins with the flow channel height, thereby increasing the contact area between the fins and the coolant, thereby enhancing the heat conduction effect and improving the overall heat dissipation efficiency.

[0025] Sixth, in the preferred implementation, the present invention forms a stable internal cavity structure by snapping together the upper shell and the lower shell, which is convenient for assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The structure of the water cooling plate with mixed fin structure in the embodiment of the present invention is Figure 1 ;

[0027] Figure 2 The structure of the water cooling plate with mixed fin structure in the embodiment of the present invention is Figure 2 ;

[0028] Figure 3 Schematic diagram of the coolant flow of a water-cooled plate with a hybrid fin structure according to an embodiment of the present invention;

[0029] Figure 4 This is a three-dimensional structural diagram of the assembled state of a water-cooling plate with a hybrid fin structure and a heating element according to an embodiment of the present invention;

[0030] Figure 5 It is a variant structure of the water-cooling plate with a mixed fin structure in the embodiment of the utility model.

[0031] Among them, 1-shell; 10-water inlet; 11-water outlet; 2-rectangular fins; 3-diamond fins; A-heating element. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present application, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] The terms "up", "down", "left", "right", "front", and "back" in this application are based on the positional relationships shown in the accompanying drawings. The corresponding positional relationships may vary depending on the drawings, and should not be construed as limiting the scope of protection.

[0034] In this application, the terms "installed," "connected," "connected," "connected," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, integral connection, mechanical connection, electrical connection, or mutual communication. They can also be directly connected or indirectly connected through an intermediate medium. They can also refer to internal communication between two components or interaction between two components. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] The present invention describes a water-cooled plate with a mixed fin structure, the top surface of which is in direct contact with a heating element. The water-cooled plate is provided with a water inlet and a water outlet, and a first flow channel and a second flow channel are arranged in sequence from the water inlet to the water outlet. A plurality of transversely arranged fins are arranged at intervals inside the first flow channel to guide the coolant to flow in a straight line, so that the coolant can quickly absorb the heat of the heating element in the initial stage of entering the water-cooled plate. A plurality of fins with an included angle are arranged inside the second flow channel to change the flow path of the coolant to increase disturbance, so that the coolant is fully mixed in the flow channel.

[0036] Example 1:

[0037] As the instruction manual Figure 1-2 The water-cooled plate with a hybrid fin structure includes a shell 1, rectangular fins 2 and diamond fins 3. The shell 1 is a cavity structure and is provided with a water inlet and a water outlet, which are used for the inlet and outlet of the coolant respectively.

[0038] The housing 1 is composed of an upper housing and a lower housing. The upper and lower ends of each rectangular fin 2 and diamond fin 3 are connected to the upper and lower inner surfaces of the housing 1.

[0039] In the first flow channel, multiple groups of transversely arranged fins are spaced apart along the flow direction of the coolant. Each group of fins includes multiple mutually parallel rectangular fins 2. These rectangular fins 2 are arranged in parallel to form multiple straight flow channels of equal width between adjacent rectangular fins 2, so that the coolant can maintain a stable straight flow state between each group of fins. Figure 1 Taking the illustrated state as an example, this embodiment employs four groups of transversely arranged fins within the first flow channel, with each group maintaining a certain spacing to ensure that the coolant is evenly distributed across each group and fully absorbs heat. Within each group, five rectangular fins 2 are arranged parallel to each other, with equal spacing between each fin, thus forming a stable coolant flow channel. This design effectively increases the contact area between the coolant and the fins, improving heat transfer efficiency and rapidly absorbing heat from the heat-generating element within the first flow channel, providing a good heat transfer foundation for the subsequent cooling process.

[0040] Specifically, the height of each rectangular fin 2 matches the height of the flow channel to ensure that the coolant can pass evenly through the straight flow channel between the fins. This highly matched design can make full use of the effective space in the flow channel, increase the contact area of ​​the coolant, and enhance the heat transfer effect. The thickness of the rectangular fin 2 is mainly optimized based on the coolant flow rate and flow rate in the flow channel. On the premise of ensuring that the fins have sufficient mechanical strength, the thickness of the fins should be reduced as much as possible to reduce the flow resistance, while increasing the number of fins in the unit flow channel, thereby increasing the contact frequency and heat transfer efficiency between the coolant and the fins. The spacing between adjacent rectangular fins 2 is determined by the width of the flow channel and the flow rate of the coolant. The size of the spacing needs to be reduced as much as possible while ensuring sufficient circulation of the coolant to increase the total surface area of ​​the fins and improve the circulation effect and heat exchange efficiency of the coolant.

[0041] The second flow channel is equipped with an array of diamond-shaped fins 3. These disrupt the coolant's laminar flow by creating moderate disturbances within the channel, thereby promoting uniform distribution of the coolant. Multiple diamond-shaped fins 3 form a group, with multiple groups spaced apart in the second flow channel. The staggered arrangement of the diamond-shaped fins 3 within each group creates multiple localized vortices and turbulent regions, increasing the frequency of contact between the coolant and the fin surfaces and significantly improving heat transfer efficiency.

[0042] Specifically, each diamond rib 3 adopts a symmetrical diamond structure design, and the top angles at both ends form a certain angle with the flow direction of the coolant. The setting of this angle is intended to guide the coolant to generate a tangential velocity difference when flowing through the fins, thereby inducing a vortex effect and increasing the fluid disturbance. The diamond ribs 3 are arranged in a staggered array, that is, adjacent diamond ribs are staggered in the flow direction. This staggered design can form a complex flow path, so that the coolant is subjected to tangential forces in different directions in the flow channel, further enhancing the turbulent effect and increasing the contact area between the coolant and the fins, thereby improving the overall heat transfer efficiency. The length, width and thickness of the diamond ribs 3 are optimized according to the width of the flow channel, the flow rate of the coolant and the target cooling performance. The length of the diamond ribs should occupy 10% to 30% of the flow channel width to ensure that the coolant can pass smoothly while generating favorable disturbances. The size design needs to maximize the contact between the coolant and the fin surface while maintaining sufficient fluid channel area to improve heat transfer efficiency. The width and thickness of the fins must minimize resistance to coolant flow while ensuring mechanical strength.

[0043] To maintain a suitable flow path, the spacing between adjacent diamond-shaped fins 3 should be controlled within a range of 2mm to 5mm. The top and bottom angles are typically set between 45° and 60° to ensure uniform turbulence when the coolant flows through the fins, further improving heat exchange.

[0044] In this embodiment, the width of each rectangular fin 2 is 2 mm, the height is 10 mm, and the length is 62 mm. In the group of transversely arranged fins, the parallel rectangular fins 2 are spaced 2 mm apart. The side length of each diamond rib 3 is 4 mm, the angle is 60°, and the height is 10 mm. The coolant enters the shell 1 through the water inlet and first enters the first flow channel area. In this area, the coolant exchanges heat with the rectangular fins 2. Due to the transverse arrangement of the rectangular fins 2, the coolant can fully contact the surface of each fin in this area. After preliminary cooling in the first flow channel, the coolant continues to enter the second flow channel. In the second flow channel, the coolant flows through the area where the diamond ribs 3 are arranged. The array layout of the diamond ribs 3 causes turbulence in the coolant, further enhancing the heat transfer effect. The temperature of the coolant after passing through the diamond rib 3 area is further uniformized and discharged through the water outlet of the shell, completing the entire heat dissipation process.

[0045] Example 2

[0046] This embodiment includes all the structures of Example 1, wherein the first and second flow channels of the housing 1 form a U-shaped flow channel structure, with the openings at both ends of the U-shaped flow channel structure being a water inlet 10 and a water outlet 11. The water inlet 10 and the water outlet 11 are located on the same side of the housing 1. The coolant flows in one direction through the flow channel and then flows back to the water outlet 11, forming a flow path similar to the letter "U".

[0047] As the instruction manual Figure 3 , Figure 3 The arrows in the figure indicate the coolant flow path. In the curved area of ​​the U-shaped flow channel structure, a chamfered corner design is used to reduce the flow resistance of the coolant at sharp turns. The chamfered corner design can smooth the flow path of the coolant, avoid turbulence or separation caused by sharp turns, reduce unnecessary pressure loss, and ensure the continuity of the fluid and the stability of the flow rate. The top angles at both ends of the diamond ribs 3 in the curved area of ​​the U-shaped flow channel structure are consistent with the flow direction of the coolant. Such a design helps to guide the coolant to reduce tangential resistance when flowing through the ribs, thereby reducing the pressure drop of the coolant. The top angle consistent with the flow direction can avoid turbulence or dead zone phenomena caused by unreasonable angles, so that the coolant maintains a smooth and continuous flow state in the curved area and the flow channel.

[0048] This U-shaped flow channel design extends the coolant flow path within a limited space. The rounded corners and optimized diamond-shaped fin arrangement reduce flow resistance, lower pressure drop, and ensure flow consistency. The overall compact design is suitable for devices that require efficient heat dissipation but have limited installation space, such as high-density electronic devices, server radiators, and small cooling modules.

[0049] Example 3

[0050] As the instruction manual Figure 4 , multiple heating elements A are distributed on the top surface of the shell 1. Each heating element A covers the first flow channel and the second flow channel area. The shell 1 adopts a copper plate with a thickness of 20mm, an inner cavity height of 10mm, and a water inlet and outlet diameter of 12mm. The water inlet of the shell 1 is connected to the external heat dissipation system through a coolant supply pipeline, and the coolant is driven into the water-cooled plate by a coolant pump (such as a water pump). After the coolant enters the internal flow channel, it conducts convection heat exchange with the rectangular fins and diamond fins in the shell, taking away the heat in the shell 1. The water outlet is connected to the return pipe to bring the heat to an external cooling device (such as a radiator or cooling tower) to achieve continuous circulation of the coolant.

[0051] Four 500W uniform heating elements A are distributed on the top surface of the shell 1. The height of the diamond fins 3 and the rectangular fins 2 are both 10mm. The heat dissipation performance of the water-cooled plate was simulated using Fluent simulation software. The specific settings are as follows: ambient air temperature: 45°C, air side heat transfer coefficient: 10W / (m 2 ·K), inlet water temperature: 38℃, gravity coefficient: 9.8m / s 2 , Main heat exchange form: water cooling (primary) and natural convection (secondary), Simulation model: standard k-ε model, Water flow rate: 8LPM, Working fluid: water, Heating element: 4 500W uniform body heating elements.

[0052] After 200 iterations, all parameters reached a stable state. In the simulation, the coolant, at an inlet water temperature of 38°C, gradually absorbed heat through the first and second flow channels, causing the water temperature to rise. The simulation results showed that the maximum temperature of the heat source reached 49.45°C, a temperature rise of 11.45°C compared to the inlet water temperature. This demonstrates that the water cooling plate is efficiently absorbing heat generated by the heating element.

[0053] Under the water flow condition of 8LPM, the average total pressure at the inlet is 12.4KPa, the average total pressure at the outlet is 0.96KPa, and the total pressure drop at the inlet and outlet is 11.5KPa. The simulation results show that the coolant flows in from the inlet and gradually passes through the first flow channel and the second flow channel. The total pressure of the entire water-cooled plate gradually decreases from the inlet to the outlet. The rectangular fin area of ​​the first flow channel has a small pressure loss, while the diamond fin area of ​​the second flow channel has a large pressure loss. The rectangular fin area of ​​the first flow channel achieves efficient initial heat absorption of the coolant through a lower pressure drop, and causes the coolant temperature to rise rapidly. The diamond fin design in the second flow channel enhances the disturbance of the coolant through a staggered arrangement, so that it forms a uniform turbulence when flowing through, significantly improving the heat exchange effect. Therefore, after passing through the second flow channel, the coolant temperature is further uniformed.

[0054] Example 4

[0055] As the instruction manual Figure 5, this embodiment is a variant structure of the shell 1. In this embodiment, the shell 1 is a long strip structure, and its flow channel is a straight flow channel as a whole, and the water inlet 10 and the water outlet 11 are arranged on both sides of the shell 1. The coolant flows along a straight path, enters from the water inlet 10, and flows straight all the way to the water outlet 11, forming a continuous and simple flow path. The straight flow channel reduces the turning of the coolant during the flow process, so the pressure drop is small, which helps to improve the flow stability of the coolant. The straight flow channel is simple in design, which can simplify the manufacturing process and reduce manufacturing costs. It is suitable for cooling systems that require high flow rate and small pressure loss, such as long strip water cooling plates, large area radiators, etc.

[0056] The top corners of the diamond-shaped fins 3 near the water outlet 11 converge toward the water outlet 11 at a certain angle, which can effectively guide the coolant to flow smoothly toward the water outlet 11, thereby reducing liquid flow resistance and improving the flow efficiency of the coolant.

[0057] The difference between the linear flow channel in this embodiment and the U-shaped flow channel in Example 2 is that the U-shaped flow channel is suitable for extending the flow path within a limited space, thereby enhancing heat dissipation, while the linear flow channel emphasizes smooth flow and low pressure drop, making it suitable for heat dissipation over long distances or over large areas. Depending on the heat dissipation requirements and installation conditions, the appropriate choice of these two flow channel types can optimize the overall performance of the cooling system.

[0058] The utility model arranges a mixed fin structure in the water-cooling plate, guides the coolant to flow steadily in a straight line with rectangular fins, and changes the flow path and increases liquid disturbance through diamond fins, thereby improving heat exchange efficiency; adopts a U-shaped or straight continuous flow channel structure, and reduces liquid flow resistance and optimizes the flow path of the coolant by rationally designing the top angle direction of the diamond fins; the rectangular fins in the first flow channel are arranged at intervals to form a plurality of equal-width straight flow channels, which guide the coolant to flow evenly; and by matching the fin height with the flow channel height, the heat conduction effect is enhanced and the overall heat dissipation efficiency is improved.

[0059] The above is only an embodiment of the present application, and common knowledge such as the specific structure and characteristics of the scheme are not described in detail here. For those skilled in the art, it is obvious that the present application is not limited to the details of the above-mentioned exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or basic characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present application is defined by the attached claims rather than the above description, and it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present application. Any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A water-cooled plate with a hybrid fin structure, characterized in that: The invention comprises a shell (1), the top surface of the shell (1) is used for directly contacting with a heating element, the shell (1) is provided with a water inlet (10) and a water outlet (11), and the interior of the shell (1) is provided with a first flow channel and a second flow channel in sequence along the direction from the water inlet (10) to the water outlet (11); a plurality of transversely arranged rectangular fins (2) are arranged in the first flow channel for guiding the coolant to flow in a straight line; a plurality of diamond-shaped fins (3) are arranged in the second flow channel for changing the flow path of the coolant and increasing disturbance so that the coolant is fully mixed in the flow channel.

2. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: A plurality of groups of rectangular fins (2) are arranged at intervals in the first flow channel, and each group comprises a plurality of mutually parallel rectangular fins (2).

3. The water-cooling plate with a hybrid fin structure according to claim 2, characterized in that: A plurality of straight flow channels of equal width are provided between adjacent rectangular fins (2) in each group.

4. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: The diamond-shaped fins (3) in the second flow channel are arranged in multiple groups at intervals, and each group includes a plurality of diamond-shaped fins (3) arranged in a staggered array.

5. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: The first flow channel and the second flow channel form a continuous flow channel structure, and the flow channel structure adopts a U-shaped flow channel or a straight flow channel.

6. The water-cooling plate with a hybrid fin structure according to claim 5, characterized in that: The curved area of ​​the U-shaped flow channel is provided with a rounded corner, and the top angle of the diamond-shaped ribs (3) in the curved area matches the flow direction of the coolant.

7. The water-cooling plate with a hybrid fin structure according to claim 5, characterized in that: In the linear flow channel, the top corners of the diamond-shaped fins (3) near the water outlet (11) converge toward the water outlet (11) at a certain angle.

8. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: Each of the diamond-shaped fins (3) adopts a symmetrical diamond-shaped structure, and the vertex angles at both ends thereof form a certain angle with the flow direction of the coolant.

9. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: The heights of the rectangular fins (2) and the diamond-shaped fins (3) match the height of the flow channel.

10. The water-cooling plate with a hybrid fin structure according to claim 1, characterized in that: The housing (1) comprises an upper housing and a lower housing, and the upper housing and the lower housing are buckled together to form an internal cavity structure.

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