Microchannel Heat Exchanger
By adopting a flat tube structure with exponential or polynomial variation in the width direction in the microchannel heat exchanger, the problem of mismatch between the air flow and the refrigerant temperature in the prior art is solved, and a higher heat exchange efficiency is achieved and material utilization.
Patent Information
- Application Number
- CN202110995050.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-05-05
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2039-05-05
AI Technical Summary
In existing microchannel heat exchangers, the same cross-sectional area of side-by-side runners of flat tubes leads to mismatch between the air flow and the refrigerant temperature, reducing heat exchange efficiency, and different channels along the wind blowing direction lead to waste of materials and increased thermal resistance.
The cross-sectional area of the microchannel flat tube changes exponentially or polynomially along the width direction, the hole width and hole height are equal, and are sandwiched between two adjacent flat tubes through fins to improve heat exchange performance.
Effective utilization of materials improves heat exchange efficiency, reduces material waste, and optimizes the channel structure to improve heat exchange rate.
Smart Images
Figure CN113720175B_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of heat exchange, and in particular, to a microchannel heat exchanger. Background Art
[0002] Microchannel heat exchanger is a heat exchange device commonly used in automobile, household or commercial air conditioning systems. It can be used as an evaporator of the air conditioning system or as a condenser. Microchannel heat exchanger is a heat exchanger composed of flat tubes, fins, manifolds, etc. When the wind generated by the external fan acts on the microchannel fins and flat tubes, the refrigerant in the flat tube flow channel of the microchannel heat exchanger exchanges heat with the air. Each flat tube of the microchannel heat exchanger has a flow channel composed of multiple side-by-side small holes, and the refrigerant evaporates or condenses in the side-by-side flow channels of the flat tubes; when used as a condenser, the refrigerant is cooled in the side-by-side flow channels of the flat tubes; when used as an evaporator, the refrigerant is evaporated in the side-by-side flow channels of the flat tubes. The flat tubes used in the related technology have multiple side-by-side flow channels with the same cross-sectional area. When wind flows through the heat exchanger, due to the heat transfer between the wind and the refrigerant, the refrigerant temperature in each side-by-side flow channel is different along the wind flow direction. Therefore, along the refrigerant flow direction, the refrigerant evaporates or condenses at different positions in the side-by-side flow channels, resulting in a mismatch between the refrigerant flow distribution in the flow channel and the heat exchange temperature difference, thereby reducing the heat exchange efficiency of the heat exchanger.
[0003] like Figure 1 As shown, another related technology uses the cross-section of the microchannel flat tube to gradually decrease from the windward side to the leeward side. The temperature difference of the windward side channel is relatively large, and the refrigerant flow rate is relatively large, so more heat exchange can be performed at a high heat exchange rate. The flow rate of the leeward side channel is relatively small, and its heat exchange rate is also low, so the heat exchange is very small. In this related technology, the cross-sectional area of all flat tube channels decreases linearly along the wind blowing direction, and the improvement of heat exchange performance is limited.
[0004] In addition, in this related art, along the wind blowing direction, the width of all flat tube channels remains unchanged, and the height of the flat tube channels gradually decreases. Due to the different heights of the flat tube channels arranged in this way, the wall thickness of the flat tube channels with smaller heights on the leeward side is larger, resulting in waste of flat tube materials and increased costs; and the thermal resistance of the channels at the thicker wall increases. Summary of the invention
[0005] According to one aspect of the present application, a microchannel heat exchanger is provided, comprising: a first header, a second header, a plurality of microchannel flat tubes and fins, wherein the plurality of microchannel flat tubes are connected side by side between the first header and the second header, the fins are sandwiched between two adjacent microchannel flat tubes, the flat tubes comprise a flat tube body and a row of channels located in the flat tube body, the row of channels communicating with an inner cavity of the first header and an inner cavity of the second header;
[0006] The flat tube body comprises a first plane, a second plane, a first side surface and a second side surface, wherein the first plane and the second plane are respectively located at opposite sides of the thickness direction of the flat tube body, the first side surface and the second side surface are respectively located at opposite sides of the width direction of the flat tube body, the first side surface connects the first plane and the second plane, and the second side surface connects the first plane and the second plane;
[0007] The row of channels at least includes a first channel, a second channel and a third channel arranged along the width direction, wherein the cross-sectional areas of the first channel, the second channel and the third channel along the width direction vary exponentially.
[0008] The cross-sectional areas of the first channel, the second channel and the third channel of the microchannel heat exchanger of the present application vary exponentially or polynomially, thereby achieving better heat exchange performance.
[0009] In addition, each of the channels includes a hole width along the width direction and a hole height along the thickness direction, the hole heights of the first channel, the second channel and the third channel are equal, the hole widths of the first channel, the second channel and the third channel vary exponentially, or the hole widths of the first channel, the second channel and the third channel vary in a polynomial relationship. The materials of the microchannel flat tubes with equal hole heights are effectively utilized, reducing material waste and improving the heat exchange efficiency of the third channel. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 It is a schematic diagram of a microchannel flat tube of the related art;
[0011] Figure 2 is a three-dimensional schematic diagram of a microchannel heat exchanger according to an embodiment of the present application;
[0012] Figure 3 like Figure 2 A schematic cross-sectional view of a microchannel flat tube;
[0013] Figure 4 for Figure 3 The relationship between the channel width, chamfer radius and channel number of the microchannel flat tube channel is shown in the comparison table.
[0014] Figure 5 for Figure 3 Schematic diagram of the relationship between the channel width and channel number of the microchannel flat tube channel shown. DETAILED DESCRIPTION
[0015] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.
[0016] The terms used in this application are only for the purpose of describing specific embodiments, and are not intended to limit this application. In the description of this application, it should be understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.
[0017] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0018] In the present application, unless otherwise expressly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features not being in direct contact but being in contact through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The exemplary embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features in the following embodiments and implementations may complement or combine with each other.
[0019] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.
[0020] The exemplary embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.
[0021] like Figures 2 to 5 The microchannel heat exchanger 100 according to the present invention is shown, which includes a first header 11, a second header 12, a plurality of microchannel flat tubes 2 and a plurality of fins 3. The plurality of microchannel flat tubes 2 are arranged in parallel and spaced apart from each other, and are connected side by side between the first header 11 and the second header 12, and each fin 3 is sandwiched between two adjacent microchannel flat tubes 2.
[0022] The microchannel flat tube 2 includes a flat tube body 21 and a row of channels 22 that penetrate the flat tube body 21. The length of the flat tube body 21 is greater than its width, and the width is greater than its thickness. The flat tube body 21 includes a first plane 211, a second plane 212, a first side surface 213 and a second side surface 214. The first plane 211 and the second plane 212 are arranged on opposite sides of the flat tube body 21 in the thickness direction H, and the first side surface 213 and the second side surface 214 are arranged on opposite sides of the flat tube body 21 in the width direction W. The first side surface 213 connects the first plane 211 and the second plane 212, and the second side surface 214 connects the first plane 211 and the second plane 212. In this embodiment, the first side surface 213 and the second side surface 212 are arc-shaped. In other optional implementations, the first side surface 213 and the second side surface 212 can also be planes or other shapes, as long as they can connect the first plane 211 and the second plane 212, and the present application is not limited to this shape.
[0023] A row of channels 22 connects the inner cavity of the first header 11 and the inner cavity of the second header 11, and the row of channels 22 is arranged in the flat tube body 21 along the width direction W, and the row of channels 22 penetrates the flat tube body 21 along the length direction L. Each channel 22 includes a hole width 22W along the width direction W and a hole height 22H along the thickness direction H. The row of channels 22 includes a first channel 221, a second channel 222, and a third channel 223 arranged along the width direction, wherein the hole heights 22H of the first channel 221, the second channel 222, and the third channel 223 are equal, and the hole widths 22W of the first channel 221, the second channel 222, and the third channel 223 decrease exponentially. Therefore, the cross-sectional areas of the first channel 221, the second channel 222, and the third channel 223 along the width direction W vary exponentially.
[0024] The cross-sectional areas of the first channel 221, the second channel 222, and the third channel 223 are all in the shape of a rounded rectangle. The first channel 221 includes four first chamfers 231, the second channel 222 includes four second chamfers 232, and the third channel 223 includes four third chamfers 233. The radius of the first chamfer 231, the radius of the second chamfer 232, and the radius of the third chamfer 233 are equal or decrease at a fixed ratio. In this embodiment, the radius of the first chamfer 231, the radius of the second chamfer 232, and the radius of the third chamfer 233 are equal.
[0025] As an optional embodiment of the present invention, the width of the microchannel flat tube 2 is 25.4 mm, and the thickness of the microchannel flat tube 2 is 1.3 mm. The hole heights 22H of the first channel 221, the second channel 222, the third channel 233, the fourth channel 224, and the fifth channel 225 are equal, all of which are 0.74 mm. The distances of all channels 22 from the first plane 211 are 0.28 mm, and the distances from the second plane 212 are 0.28 mm. The dimensions of the hole widths 22H of all channels 22 from left to right are: 1.45, 1.36, 1.27, 1.19, 1.12, 1.05, 0.98, 0.92, 0.86, 0.81, 0.76, 0.71, 0.66, 0.62, 0.58, 0.55, 0.51, 0.48, 0.45, 0.42, 0.4 mm. The hole width 22W of a row of channels 22 satisfies y=1.369e -0.065x , wherein x represents the sequence number of a channel row 22 from left to right, and y represents the hole width 22W of the corresponding x-th channel.
[0026] Of course, since the specific size of the hole width 22W in the present application is an optional embodiment, other specific sizes can also be selected, as long as the hole width 22W size of a row of channels 22 changes in an exponential curve in sequence. In addition, this exponential curve change can also be expressed by other polynomials: for example, y = 0.0017n 2 -0.0879n+1.5227, wherein n represents the sequence number of the channels in a row of channels 22 from left to right, and y represents the hole width 22W of the corresponding nth channel. As long as the change conforms to this polynomial relationship, the present application is not limited thereto.
[0027] In addition, since the width 22W of the channel holes near the second side surface 214 differs by less than 0.03 mm, in order to avoid processing errors and poor control of processing accuracy, the widths of several holes near the second side surface can also be set to be equal. For example, the hole widths 22W of the fourth channel 224 and the fifth channel 225 can be set to be equal, and the cross-sectional areas are equal.
[0028] As an optional embodiment of the present invention, the chamfer radii of all channels 22 are: 0.3, 0.3, 0.3, 0.3, 0.3, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.2, 0.1, 0.1, 0.1, 0.1mm. The spacing between adjacent channels 22 is: 0.34mm. Of course, slight changes in the above dimensions caused by processing errors are also within the scope of protection of this application.
[0029] As an optional embodiment of the present invention, the first side 213 of the microchannel flat tube 2 is the windward side, and the second side 214 of the microchannel flat tube 2 is the wind outlet side, that is, the channel cross-section of the microchannel flat tube 2 decreases exponentially or polynomially along the wind blowing direction, which is beneficial to improving the heat exchange performance of the heat exchanger 100.
[0030] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of the technical solution of the present application.
Claims
1. A microchannel heat exchanger, characterized in that: include: A first header, a second header, a plurality of microchannel flat tubes and fins, wherein the plurality of microchannel flat tubes are connected side by side between the first header and the second header, the fins are sandwiched between two adjacent microchannel flat tubes, the flat tubes include a flat tube body and a row of channels located in the flat tube body, the row of channels communicates with the inner cavity of the first header and the inner cavity of the second header; The flat tube body comprises a first plane, a second plane, a first side surface and a second side surface, wherein the first plane and the second plane are respectively located at opposite sides of the thickness direction of the flat tube body, the first side surface and the second side surface are respectively located at opposite sides of the width direction of the flat tube body, the first side surface connects the first plane and the second plane, and the second side surface connects the first plane and the second plane; The row of channels at least includes a first channel, a second channel and a third channel arranged along the width direction, wherein the cross-sectional areas of the first channel, the second channel and the third channel along the width direction vary exponentially, or the hole widths of the first channel, the second channel and the third channel vary in a polynomial relationship; Each of the channels comprises a hole width along a width direction and a hole height along a thickness direction, and the hole heights of the first channel, the second channel and the third channel are equal; The hole widths of the first channel, the second channel and the third channel satisfy: y=1.369e -0.065x , where x represents the order number of a row of channels along the width direction, and y represents the hole width of the corresponding x-th channel; or, the hole widths of the first channel, the second channel, and the third channel satisfy: 𝑦=0.0017𝑛 2 -0.0879n+1.5227, where n represents the order number of a row of channels along the width direction, and y represents the hole width of the corresponding nth channel.
2. The microchannel heat exchanger according to claim 1, characterized in that: The exponential change is a natural exponential change.
3. The microchannel heat exchanger according to claim 1, characterized in that: The cross-sectional areas of the first channel, the second channel and the third channel are all in the shape of a rounded rectangle. The first channel includes four first chamfers, the second channel includes four second chamfers, and the third channel includes four third chamfers.
4. The microchannel heat exchanger according to claim 3, characterized in that: The radius of the first chamfer, the radius of the second chamfer, and the radius of the third chamfer are equal or decrease at a fixed ratio.
5. The microchannel heat exchanger according to claim 4, characterized in that: The row of channels also includes a fourth channel and a fifth channel arranged along the width, the first channel is close to the first side, the fifth channel is close to the second side, the fourth channel is located between the third channel and the fifth channel, and the fourth channel and the fifth channel have equal cross-sectional areas along the width direction.
6. The microchannel heat exchanger according to claim 1, characterized in that: The spacing between the first channel and the second channel is equal to the spacing between the second channel and the third channel.
7. The microchannel heat exchanger according to claim 1, characterized in that: The length of the flat tube body is greater than its width, and the width of the flat tube body is greater than its thickness.