Patent Publication Number: US-2021172686-A1

Title: Heat exchange tube, heat exchanger, and manufacturing method for heat exchange tube

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. national phase entry under 35 USC § 371 of the International Patent Application No. PCT/CN2019/100631, filed on Aug. 14, 2019, which claims the benefit of and priority to Chinese Application No. 201810922238.8, filed on Aug. 14, 2018 and Chinese Application No. 201910126254.0, filed on Feb. 20, 2019, the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a field of heat exchange technologies, and more particularly, to a heat exchange tube, and a heat exchanger having the same and a manufacturing method for the heat exchange tube. 
     BACKGROUND 
     A flat tube is a key component of a multi-channel heat exchanger. For the multi-channel heat exchanger in a related art, a fin and a flat tube are two independent components, and the fin needs to be welded to an outer side of a multi-hole flat tube. Since the heat of the flat tube is basically transferred to the fin through the welded portion, there is a heat exchange resistance between the flat tube and the fin, thereby affecting a heat exchange efficiency of the flat tube and the fin. 
     SUMMARY 
     An object of the present disclosure is to provide a heat exchange tube so as to improve a heat exchange efficiency between a fluid inside and a fluid outside a tube wall. 
     Another object of the present disclosure is to provide a heat exchanger having the heat exchange tube. 
     Yet another object of the present disclosure is to provide a manufacturing method for the heat exchange tube. 
     According to embodiments of the present disclosure, the heat exchange tube includes a tube wall and an outer fin, the tube wall is folded into a tube body, the tube body is provided with an inner fin therein, and the inner fin divides an inner chamber of the tube body into a plurality of flow channels. The outer fin is arranged outside the tube body. The outer fin is folded from a same plate with at least one of the tube wall and the inner fin. 
     The heat exchanger according to another object of the present disclosure includes a header and a plurality of heat exchange tubes, two ends of the heat exchange tube are inserted into the header, and the plurality of heat exchange tubes are stacked. The heat exchange tube includes a tube wall and an outer fin, the tube wall is folded into a tube body, the tube body is provided with an inner fin therein, and the inner fin divides an inner chamber of the tube body into a plurality of flow channels. The outer fin is arranged outside the tube body. The outer fin is folded from a same plate with at least one of the tube wall and the inner fin. 
     In the manufacturing method for the heat exchange tube according to yet another object of the present disclosure, the heat exchange tube includes a tube wall and an outer fin, the tube wall is folded into a tube body, the tube body is provided with an inner fin therein, and the inner fin divides an inner chamber of the tube body into a plurality of flow channels. The outer fin is arranged outside the tube body. The outer fin is folded from a same plate with at least one of the tube wall and the inner fin. The manufacturing method includes: processing a first plate portion into the inner fin, a second plate portion surrounding the inner fin by at least one circle to be processed into the tube wall, and processing a third plate portion into the outer fin outside the tube wall. The third plate portion and at least one of the first plate portion and the second plate portion are adjacent parts of a same plate body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 2  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 3  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 4  is a front view of the heat exchange tube in  FIG. 3 . 
         FIG. 5  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 6  is a front view of the heat exchange tube in  FIG. 5 . 
         FIG. 7  is a top view of the heat exchange tube in  FIG. 5 . 
         FIG. 8  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 9  is a front view of the heat exchange tube in  FIG. 8 . 
         FIG. 10  is a top view of the heat exchange tube in  FIG. 8 . 
         FIG. 11  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 12  is a schematic view of a heat exchange tube of an embodiment of the present disclosure. 
         FIG. 13  is a front view of the heat exchange tube in  FIG. 12 . 
         FIG. 14  is a top view of the heat exchange tube in  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are further described. Examples of the embodiments are illustrated in the accompanying drawings. Same or similar reference signs represent the same or similar components or components that have the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary, are merely used to explain the present disclosure, and cannot be construed as a limitation to the present disclosure. 
     As illustrated in  FIGS. 1-14 , a heat exchange tube  100  according to embodiments of the present disclosure includes a tube body and an outer fin  2 . 
     Specifically, the tube body is enclosed by a tube wall  1  and provided with an inner fin  3  therein, and the inner fin  3  divides an inner chamber of the tube body into a plurality of flow channels  101 . A fluid may flow through the flow channel  101 , and the fluid inside and outside the tube body may exchange heat with each other. 
     The outer fin  2  is arranged to an outer side of the tube body and is folded from the same plate with at least one of the tube wall  1  and the inner fin  3 . That is, the outer fin  2  and the tube wall  1  are folded from the same plate, or the outer fin  2  and the inner fin  3  are folded from the same plate, or the outer fin  2 , the tube wall  1  and the inner fin  3  are folded from the same plate. 
     In the heat exchange tube  100  according to the embodiments of the present disclosure, since the outer fin  2  is folded from the same plate with at least one of the tube wall  1  and the inner fin  3 , the heat of the fluid inside the tube wall  1  may be quickly transferred to the outer fin  2 , thereby realizing a rapid heat exchange between the fluid inside and outside the tube wall  1 , and effectively improving a heat exchange efficiency of the fluid inside and outside the tube wall  1 . 
     In the present disclosure, the flow channel  101  may be formed in the tube wall  1  in various manners. For example, one cavity is enclosed by the tube wall  1 , the inner fin  3  includes a plurality of ribs spaced apart in the tube wall  1 , and the cavity in the tube body is separated into a plurality of flow channels  101  through the plurality of ribs. For another example, one cavity is enclosed by the tube wall  1 , the inner fin  3  extends in a wavy shape in the tube wall  1 , and a plurality of flow channels  101  are separated in the tube wall  1  by the inner fin  3 . For Yet another example, a plurality of inner chambers are enclosed by the tube wall  1 , and each (or at least a part) of the plurality of inner chambers is/are provided with the inner fin  3  therein, and the flow channels  101  are separated in the corresponding inner chamber by the inner fin  3 . Of course, the above description just directs to some specific manners of forming the plurality of flow channels  101  in the present disclosure, the present disclosure cannot exhaustively describe all the manners of forming the flow channels  101 , and the heat exchange tube  100  obtained on a basis of the above technical features should be fallen within the scope of the present disclosure. For example, the inner fin  3  may also be directly extruded to form the plurality of flow channels  101 , and then the inner fin  3  may be arranged into the tube wall  1 . 
     In the above description of the present disclosure, “folded from the same plate” includes but is not limited to forming processes such as bending, extrusion, punching, flanging or the like. Taking the outer fin  2  and the inner fin  3  being folded from the same plate as an example, a part of the plate is made into the inner fin  3 , and another part of the plate is made into the outer fin  2 . The outer fin  2  is extended out of the tube wall. Moreover, the tube wall  1  is mounted and fitted with the inner fin  3  and the outer fin  2  by means of covering and clamping, and then the tube wall  1 , the inner fin  3  and the outer fin  2  are fixed by welding. In following embodiments of the present disclosure, a lot of descriptions are made in regards to the folding and forming manners of the same plate, which cannot be construed as a limitation to the present disclosure. 
     In the present disclosure, each of the tube body, the inner fin  3  and the outer fin  2  may be formed in a plurality of manners. The respective structures and forming manners of the tube wall  1 , the inner fin  3  and the outer fin  2  will be described below, respectively. 
     First, the tube wall  1  may have following structures. 
     1. The tube wall  1  has a ring structure formed by bending one end of a plate to the other end thereof. 
     2. The tube wall  1  has a multi-ring structure formed by bending both ends of a plate to a middle thereof. Specifically, the tube wall  1  includes a bottom wall  11 , two opposite side walls  12  are arranged at both ends of the bottom wall  11 , ends of the two side walls  12  extend inwards to form a top wall  13 , and two ends of the top wall  13  extend to the bottom wall  11  to form two middle walls  14 . 
     Second, the inner fin  3  may have following structures. 
     1. The inner fin  3  has a wavy shape formed by bending a plate. 
     2. The inner fin  3  includes a multi-wave structure formed by bending a plate. 
     3. The inner fin  3  includes a multi-wave structure formed by bending a plurality of plates, respectively. 
     4. The inner fin  3  includes a square-wave structure formed by bending a plate. 
     Third, the outer fin  2  may have following structures. 
     1. The outer fin  2  is a wavy structure extending along a circumferential direction of the heat exchange tube  100 . For example, the outer fin  2  includes a plurality of fin units  21  extending along an axial direction of the heat exchange tube  100  and spaced apart along the circumferential direction of the heat exchange tube  100 , and a connecting portion  22  connected with adjacent fin units  21 . The fin unit  21  and the connecting portion  22  are connected in sequence such that the connecting portion  22  serves as a wave crest or a wave trough. 
     2. An air channel  201  is defined in the outer fin  2  in preceding item  1 , and the air channel  201  runs through the fin unit  21 . 
     3. A through hole is defined in the fin unit  21  in preceding item  2  to form the air channel  201 . 
     4. A flow guide portion  27  is arranged at an edge of the air channel  201  in preceding items  2  and  3 . 
     5. The outer fin  2  includes a base plate  23  laid on an outer surface of the tube wall  1 , and the base plate  23  is provided with a plurality of turnups  24  extending away from the tube wall  1 . 
     6. The turnup  24  in preceding item  5  is a plate structure extending along the circumferential direction of the heat exchange tube  100 , and the plurality of turnups  24  are arranged along the axial direction of the heat exchange tube  100 . 
     7. The plurality of turnups  24  in preceding item  5  are arranged into a plurality of turnup groups  202  spaced apart along the axial direction of the heat exchange tube  100 , and each turnup group  202  includes multiple turnups  24  spaced apart along the circumferential direction of the heat exchange tube  100 . 
     8. The turnup  24  in preceding items  5 ,  6  and  7  is provided with at least one of a louver, a through hole and a protrusion, or the turnup  24  has a corrugated structure. 
     The respective structures and forming manners of the tube body, the inner fin  3  and the outer fin  2  are described above, which cannot be construed as a limitation to the present disclosure. The tube body, the inner fin  3  and the outer fin  2  formed in other manners should also be fallen within the scope of the present disclosure, as long as the outer fin  2  is formed from the same plate with at least one of the inner fin  3  and the tube body in the heat exchange tube  100 . 
     Some specific embodiments for combinations of the tube body, the inner fin  3  and the outer fin  2  are listed below with reference to the accompanying drawings. 
     In some embodiments, as illustrated in  FIG. 1 , the tube wall  1  and the outer fin  2  are folded from the same plate, the tube wall  1  is a ring structure formed by bending one end of a plate to the other end thereof, and at least one end of the tube wall  1  extends outwards to form the outer fin  2 . 
     Specifically, in  FIG. 1 , the tube wall  1  surrounds the inner fin  3  by at least one circle to form the tube body, the inner fin  3  is enclosed through the tube body, the inner fin  3  divides the inner chamber of the tube body into a plurality of flow channels  101 , and an end of the tube wall  1  continues to extend outwards to form the outer fin  2 . The outer fin  2  may be the outer fin  2  described in the preceding embodiments or may be the outer fin  2  in other forms. As illustrated in  FIG. 1 , the heat exchange tube  100  is a flat tube, and the outer fin  2  has a wavy structure extending along a width direction of the heat exchange tube  100 . The outer fin  2  includes a plurality of fin units  21  extending along an axial direction of the heat exchange tube  100  and spaced apart along the width direction of the heat exchange tube  100 , and a connecting portion  22  connected with adjacent fin units  21 . The fin unit  21  and the connecting portion  22  are connected in sequence such that the connecting portion  22  serves as a wave crest or a wave trough. The fin unit  21  is provided with a rectangular through hole which serves as an air channel  201 , a flow guide portion  27  is arranged at a side edge of the rectangular through hole, and the flow guide portion  27  and the rectangular through hole are formed by flanging the fin unit  21 . 
     In some embodiments, in a process of the tube wall  1  surrounding the inner fin  3 , the two ends of the tube wall  1  are lapped together to realize an effective sealing of the tube body. 
     In addition, the outer fin  2  may surround the tube body by one circle, or may be arranged at a side of the tube body, or may surround ¼ or ⅔ of the tube body. For example, in  FIG. 1 , the heat exchange tube  100  is a flat tube, and the outer fin  2  is arranged on a side of the tube body and extends from one end of the tube body to the other end of the tube body. In some embodiments, a tail end of the outer fin  2  is lapped on the other end of the tube body, so as to effectively improve the stability of connection between the outer fin  2  and the tube body. 
     One end and the other end of the tube wall  1  refer to two ends of a plate body which forms the tube body, while one end and the other end of the tube body refer to two ends of a cross section of the tube body after the tube wall  1  surrounds the inner fin  3  to form the tube body. 
     For example, a second plate portion and a third plate portion are adjacent parts of the same plate body in sequence. During manufacturing, a first plate portion may be processed into the inner fin  3 , the second plate portion may surround the inner fin  3  by at least one circle to be processed into the tube wall  1 , and the third plate portion may be processed into the outer fin  2  outside the tube wall  1 . 
     In some embodiments, as illustrated in  FIG. 2 , the tube wall  1  is a ring structure formed by bending one end of a plate to the other end thereof, the inner fin  3  and the outer fin  2  are folded from the same plate, and at least one end of the inner fin  3  passes through an end of the tube wall  1  to extend outwards to form the outer fin  2 . 
     Specifically, in  FIG. 2 , the tube wall  1  surrounds the inner fin  3  by at least one circle to form the tube body, the tube body encloses the inner fin  3 , and the inner fin  3  divides the inner chamber of the tube body into a plurality of flow channels  101 . One end of the inner fin  3  extends outwards from a joint of the two ends of the tube wall  1  to form the outer fin  2 . The outer fin  2  may be the outer fin  2  described in the preceding embodiments or may be the outer fin  2  in other forms. 
     In some embodiments, in a process of the tube wall  1  surrounding the inner fin  3 , the two ends of the tube wall  1  are lapped with parts of the inner fin  3  and the outer fin  2  at a junction thereof, so as to realize an effective sealing of the tube body. 
     In addition, the outer fin  2  may surround the tube body by one circle, or may be arranged on a side of the tube body, or may surround ¼ or ⅔ of the tube body. For example, in  FIG. 2 , the outer fin  2  is arranged on a side of the tube body and extends from one end of the tube body to the other end of the tube body. In some embodiments, a tail end of the outer fin  2  is lapped on the other end of the tube body, so as to effectively improve the stability of connection between the outer fin  2  and the tube body. 
     For example, a first plate portion and a third plate portion are adjacent parts of the same plate body. During manufacturing, the first plate portion may be processed into the inner fin  3 , the second plate portion may surround the inner fin  3  by at least one circle to be processed into the tube wall  1 , and the third plate portion may be processed into the outer fin  2  outside the tube wall  1 . 
     In some embodiments, as illustrated in  FIGS. 3-10 , the tube wall  1  is a ring structure formed by bending one end of a plate to the other end thereof, and the inner fin  3 , the tube body and the outer fin  2  are folded from the same plate. 
     Specifically, as illustrated in  FIGS. 3-10 , at least a part of a plate is divided into three adjacent parts in sequence, a first part is made into the inner fin  3 , a second part surrounds the inner fin  3  by at least one circle to form the tube body, and the inner fin  3  is enclosed by the tube body. The inner fin  3  divides an inner chamber of the tube body into a plurality of flow channels  101 , and an end of the tube wall  1  continues to extend outwards to form the outer fin  2 . The outer fin  2  may be the outer fin  2  described in the preceding embodiments or may be the outer fin  2  in other forms. As illustrated in  FIGS. 3 and 4 , the structure of the outer fin  2  is the same with that in  FIGS. 1 and 2 , which both are wavy structures extending along the width direction of the heat exchange tube  100 . As illustrated in  FIGS. 5-7 , the outer fin  2  includes a base plate  23  laid on an outer surface of the tube wall  1 , and the base plate  23  is provided with a plurality of turnups  24  extending away from the tube wall  1 . The turnup  24  extends along a width direction of the flat tube, and the plurality of turnups  24  are arranged along the axial direction of the heat exchange tube  100 . The turnup  24  is provided with a louver, which includes a heat conducting plate  26  arranged at an angle with respect to the turnup and an opening  25  between the heat conducting plate  26  and the turnup  24 . Besides the louver, the turnup  24  may be also provided with a through hole, a protrusion or the like, or may be processed into a corrugated structure. As illustrated in  FIGS. 8-10 , the outer fin  2  includes a base plate  23  laid on the outer surface of the tube wall  1 , and the base plate  23  is provided with a plurality of turnup groups  202  extending away from the tube wall  1 . The turnup groups  202  are arranged in a plurality of rows spaced apart along the axial direction of the heat exchange tube  100 , and each turnup group  202  includes a plurality of turnups  24  spaced apart along the width direction of the heat exchange tube  100 . The turnup  24  in the turnup group  202  has a needle structure due to its small width. 
     The above outer fins  2  of various structures may be also applicable to the heat exchange tube  100  of other folding manners, such as the heat exchange tube  100  in these embodiments and the heat exchange tube in these embodiments, and its outer fin  2  may adopt any one of the above structures. 
     In some embodiments, in a process of the tube wall  1  surrounding the inner fin  3 , two ends of the tube wall  1  are lapped together to realize an effective sealing of the tube body. 
     In addition, the outer fin  2  may surround the tube body by one circle, or be arranged at a side of the tube body, or may surround ¼ or ⅔ of the tube body. For example, in  FIG. 1 , the outer fin  2  is arranged on a side of the tube body and extends from one end of the tube body to the other end of the tube body. In some embodiments, a tail end of the outer fin  2  is lapped on the other end of the tube body, so as to effectively improve the stability of connection between the outer fin  2  and the tube body. 
     For example, a first plate portion, a second plate portion and a third plate portion are adjacent parts of the same plate body in sequence. During manufacturing, the first plate portion may be processed into the inner fin  3 , the second plate portion may surround the inner fin  3  by at least one circle to be processed into the tube wall  1 , and the third plate portion may be processed into the outer fin  2  outside the tube wall  1 . 
     In some embodiments, as illustrated in  FIG. 11 , the tube wall  1  and the outer fin  2  are folded from the same plate. The tube wall  1  includes a bottom wall  11 , two opposite side walls  12  are arranged at both ends of the bottom wall  11 , ends of the two side walls  12  extend inwards to form a top wall  13 , and two ends of the top wall  13  extend to the bottom wall  11  to form two middle walls  14 . An end of at least one of the middle walls  14  extends outwards to form the outer fin  2 . 
     Specifically, as illustrated in  FIG. 11 , the inner fin  3  is made and formed, two ends of the tube wall  1  are respectively bent around different parts of the inner fin  3  to a middle thereof so as to form two inner chambers enclosing the different parts of the inner fin  3 , the inner fin  3  is enclosed through the tube body, and the inner fin  3  defines a plurality of flow channels  101  in the inner chamber of the tube body. One end or two ends of the tube wall  1  continues to extend out of the tube body to form the outer fin  2 . The outer fin  2  may be the outer fin  2  described in the preceding embodiments or may be the outer fin  2  in other forms. As illustrated in  FIG. 11 , the heat exchange tube  100  is a flat tube, and the outer fin  2  is a wavy structure extending along the width direction of the heat exchange tube  100 . The outer fin  2  includes a plurality of fin units  21  extending along the axial direction of the heat exchange tube  100  and spaced apart along the width direction of the heat exchange tube  100 , and a connecting portion  22  connected with adjacent fin units  21 . The fin unit  21  and the connecting portion  22  are connected in sequence such that the connecting portion  22  serves as a wave crest or a wave trough. The outer fin  2  is provided with an air channel  201 . The outer fin  2  is formed by the two ends of the tube wall  1  extending outwards, and includes two base plates attached to an outer side of the tube wall  1 . Ends of the two base plates continue to extend to form a wavy portion, an end of the wavy portion is connected with the end of the corresponding base plate, and the wave trough  302  of the wavy portion is attached to the outer side of the tube wall  1 . Of course, the outer fin  2  of this embodiment may also adopt the structure in  FIGS. 5-10 . 
     In some embodiments, in a process of the tube wall  1  surrounding the inner fin  3 , the two ends of the tube wall  1  are lapped together to realize an effective sealing of the tube body. 
     In addition, the outer fin  2  may surround the tube body by one circle, or may be arranged at a side of the tube body, or may surround ¼ or ⅔ of the tube body. For example, in  FIG. 1 , the outer fin  2  is arranged on a side of the tube body. 
     Further, the inner fin  3  may be folded from the same plate, and different parts of the inner fin  3  are located in different chambers of the tube body. Or, separate inner fins  3  may be provided, and different inner fins  3  are located in different chambers of the tube body. 
     For example, a second plate portion and a third plate portion are adjacent parts of the same plate body, and the third plate portion is arranged on either side of the second plate portion. During manufacturing, the first plate portion may be processed into two inner fins  3 , two sides of the second plate portion are bent to a middle thereof so as to form structures surrounding the two inner fins  3 , respectively, and the third plate portion may be processed into the outer fin  2  outside the tube wall  1 . 
     In some embodiments, as illustrated in  FIGS. 12-14 , the tube wall  1  includes a bottom wall  11 , two opposite side walls  12  are arranged at both ends of the bottom wall  11 , ends of the two side walls  12  extend inwards to form a top wall  13 , and two ends of the top wall  13  extend to the bottom wall  11  to form two middle walls  14 . The inner fin  3  and the outer fin  2  are folded from the same plate, and a middle portion of the inner fin  3  passes through a gap between the two middle walls  14  and extends outwards to form the outer fin  2 . 
     Specifically, as illustrated in  FIGS. 12-14 , the two inner fins  3  spaced apart and the outer fin  2  are made and formed, two ends of the tube wall  1  are respectively bent around different parts of the inner fin  3  to a middle thereof so as to form two inner chambers enclosing the different parts of the inner fin  3 , the inner fin  3  is enclosed through the tube body, and the inner fin  3  defines a plurality of flow channels  101  in the inner chamber of the tube body. Parts of the two inner fins  3  therebetween extend out of the tube body to form the outer fin  2 . The outer fin  2  may be the outer fin  2  described in the preceding embodiments or may be the outer fin  2  in other forms. As illustrated in  FIGS. 12-14 , the heat exchange tube  100  is a flat tube, and the outer fin  2  is a wavy structure extending along the width direction of the heat exchange tube  100 . The outer fin  2  includes a plurality of fin units  21  extending along the axial direction of the heat exchange tube  100  and spaced apart along the width direction of the heat exchange tube  100 , and a connecting portion  22  connected with adjacent fin units  21 . The fin unit  21  and the connecting portion  22  are connected in sequence such that the connecting portion  22  serves as a wave crest or a wave trough. The outer fin  2  is provided with an air channel  201 . The outer fin  2  is formed by the ends of the two inner fins  3  extending outwards, and includes two base plates attached to an outer side of the tube wall  1 . Ends of the two base plates continue to extend to form a wavy portion, two ends of the wavy portion are connected with the ends of the corresponding base plates, and the wave trough  302  of the wavy portion is attached to the outer side of the tube wall  1 . Of course, the outer fin  2  of this embodiment may also adopt the structure in  FIGS. 5-10 . 
     In some embodiments, in a process of the tube wall  1  surrounding the inner fin  3 , the two ends of the tube wall  1  are lapped with parts of the inner fin  3  and outer fin  2  at a joint thereof to realize an effective sealing of the tube body. 
     In addition, the outer fin  2  may surround the tube body by one circle, or may be arranged at a side of the tube body, or may surround ¼ or ⅔ of the tube body. For example, in  FIG. 1 , the outer fin  2  is arranged on a side of the tube body. 
     Further, the outer fin  2  may be folded from the same plate, and different parts of the outer fin  2  enclose different inner fins  3 . Or, separate outer fins  2  may be provided, and different outer fins enclose different inner fins  3 . 
     For example, a first plate portion and a third plate portion are adjacent parts of the same plate body, and the first plate portion is arranged at either side of the third plate portion. During manufacturing, the two first plate portions may be processed into the inner fins  3 , respectively, the two ends of the second plate portion are bent to the middle thereof to form structures surrounding the two inner fins  3 , respectively, and the third plate portion may be processed into the outer fin  2  outside the tube wall  1 . 
     In some embodiments, as illustrated in  FIGS. 1-4  and  FIGS. 11-14 , the outer fin  2  is a wavy structure extending along the circumferential direction of the heat exchange tube  100 . The outer fin  2  includes a plurality of fin units  21  extending along the axial direction of the heat exchange tube  100  and spaced apart along the circumferential direction of the heat exchange tube  100 , and a connecting portion  22  connected with adjacent fin units  21 . The fin unit  21  and the connecting portion  22  are connected in sequence, such that the connecting portion  22  serves as a wave crest or a wave trough. The outer fin  2  is also provided with an air channel  201 , and the air channel  201  runs through the fin unit  21 . 
     In other words, the outer fin  2  includes a plurality of fin units  21  and a plurality of connecting portions  22 , the plurality of fin units  21  are spaced apart along the circumferential direction of the heat exchange tube  100 , and each fin unit  21  extends along the axial direction of the heat exchange tube  100 . Two ends of each fin unit  21  in a direction perpendicular to the axial direction and the circumferential direction of the heat exchange tube  100  are connected with the connecting portion  22 , respectively, and the two connecting portions  22  connected to the same fin unit  21  extend away from each other along a direction perpendicular to the fin unit  21 , such that the plurality of fin units  21  are connected through the plurality of connecting portions  22 , thus forming the outer fin  2  of a wavy shape. 
     In some embodiments, as illustrated in  FIGS. 1-4 and 11 to 14 , the fin unit  21  is provided with a through hole, and the through hole is configured as an air channel  201 . 
     In addition, a channel is also formed between two adjacent fin units  21 , and an outside-tube fluid (a fluid outside the heat exchange tube  100 ) may flow in the air channel  201  and the channel, so as to realize the heat exchange between the fluid inside and the fluid outside the heat exchange tube  100 . The fluid may be a liquid, a gas or another fluid. 
     In some embodiments, a flow guide portion  27  is provided at an edge of the through hole. The flow guide portion  27  may further increase a contact area between the heat exchange tube  100  and the outside-tube fluid, which may effectively improve the heat exchange efficiency. 
     In some embodiments, as illustrated in  FIGS. 5-10 , the outer fin  2  includes a base plate  23  laid on the outer surface of the tube wall  1 , and the base plate  23  is provided with a plurality of turnups  24  extending away from the tube wall  1 . 
     The turnup  24  of the base plate  23  may be bent from the base plate  23 , that is, a part of the base plate  23  is bent to form the turnup  24 , which may leave a hole in the base plate  23 . Of course, the turnup  24  of the base plate  23  may also be formed in other manners. For example, the turnup  24  is connected or integrally formed with the base plate  23 . 
     The base plate  23  and the tube wall  1  are stacked. The turnup  24  extends away from the tube wall  1 . The base plate  23  is laid on the outer surface of the tube body so as to further effectively improve the heat exchange efficiency. Moreover, the heat exchange may be effectively performed between the turnup  24  and the base plate  23 , which may improve the heat exchange efficiency of the heat exchange tube  100  to a certain extent. 
     A plurality of turnups  24  extending away from the tube body may be formed by a cutting process. The outer fin  2  may be formed on one surface of the tube body. When a heat exchanger is assembled, the outer fin  2  is welded with the other surface of an adjacent tube body. Of course, the outer fin  2  may be formed on both surfaces of the tube body, and an ordinary flat tube without the outer fin  2  may be welded between two heat exchange tubes  100 . 
     In some embodiments, as illustrated in  FIGS. 5-7 , the turnup  24  is a plate structure extending along the circumferential direction of the heat exchange tube  100 , and the plurality of turnups  24  are arranged along the axial direction of the heat exchange tube  100 . 
     In these embodiments, the plurality of turnups  24  are arranged into a plurality of turnup groups  202  spaced apart along the axial direction of the heat exchange tube  100 , and each turnup group  202  includes multiple turnups  24  spaced apart along the circumferential direction of the heat exchange tube  100 . As illustrated in  FIGS. 8-10 , the heat exchange tube  100  is a flat tube, and the multiple turnups  24  in each turnup group  202  are spaced apart along the width direction of the flat tube. The heat exchange tube  100  may also have other shapes. For example, the heat exchange tube  100  is a flat tube with a convex side surface, and the multiple turnups  24  in each turnup group  202  are spaced apart along the circumferential direction of the heat exchange tube. 
     In some embodiments, as illustrated in  FIGS. 5-10 , the turnup  24  is provided with at least one of a louver, a through hole and a protrusion, or the turnup  24  is a corrugated structure. 
     The turnup  24  provided with the at least one of the louver, the through hole and the protrusion, and the turnup  24  having the corrugated structure may effectively destroy a boundary layer of an airflow and improve the heat exchange efficiency by a turbulent flow. 
     For example, an opening  25  is defined in the turnup  24 , and a heat conducting plate  26  inclined with respect to the opening  25  is arranged at the opening  25 . The heat conducting plate  26  has a function of heat conduction. When the airflow outside the tube body flows through the opening  25 , the airflow exchanges heat with the heat conducting plate  26 , thus further increasing the contact area between the turnup  24  and the airflow outside the tube body, and effectively improving the heat exchange efficiency. Moreover, the heat conducting plate  26  also has a function of guiding the flow, so as to lengthen a flow path and prolong a heat exchange time of the airflow outside the tube body. 
     Furthermore, a plurality of openings  25  may be defined in the turnup  24 , and the heat conducting plates  26  arranged at at least two openings  25  have different orientations. 
     In some embodiments, the heat conducting plates  26  at the plurality of openings  25  are arranged symmetrically. 
     In some embodiment, as illustrated in  FIGS. 1-14 , the inner fin  3  has a plurality of wave crests  301  and a plurality of wave troughs  302 , and the wave crests  301  and the wave troughs  302  are alternately arranged to separate a plurality of flow channels  101  in the tube wall  1 . 
     In the present disclosure, the technology of bending the flat tube may be used to effectively realize the lightweight of the heat exchange tube  100 . Compared with the extruded flat tube, the forming speed and the yield are greatly improved, which is suitable for a mass scale on-site production, and the logistics and procurement cycles may be greatly shortened. Moreover, the alloy combination solution of the material of the flat tube is flexible. For example, the multi-layer alloy may be applied, which greatly improves the corrosion resistance. 
     The present disclosure proposes an integral design of a multi-hole tube body and the outer fin  2 , the outer fin  2  is processed together with at least one of the inner fin  3  and the tube wall  1 , and may be folded from one plate directly. 
     A thickness of a part of the plate folded to form the outer fin  2  may be smaller than a thickness of another part of the plate folded to form the tube wall  1 . On the premise of ensuring the strength of the outer fin  2 , the weight of the outer fin  2  is reduced, such that the material is saved and the cost is decreased. 
     In the present disclosure, the outer fin  2  is processed together with the at least one of the inner fin  3  and the tube wall  1  by a piece of aluminum foil, which provides a high bonding strength and a great heat exchange effect. Further, the assembling process of the heat exchanger is simple. 
     In addition, the aluminum foil of a part of an outer wall surface of the tube body is folded into 90°, and the folded aluminum foil is provided with the louver to form the outer fin  2 . The aluminum foil of the outer fin  2  may also be processed into a needle fin, which has a simple structure and a high heat exchange coefficient. 
     In addition, the heat exchange tube  100  processed according to the present disclosure enables the thickness of the outer fin  2  to be less than the thickness of the wall of the folded flat tube  1 , which reduces the product cost on the premise of ensuring the strength. 
     While folding and processing of the heat exchange tube  100 , the fin of the heat exchanger is processed, i.e. the outer fin  2  of the heat exchange tube  100  is processed, so as to form an integrated assembly, which facilitates to realize an automatic processing of the heat exchanger, improves the fit relationship between the flat tube and the fin, reduces the heat resistance and improves the heat exchange efficiency. 
     According to another object of the present disclosure, the heat exchanger includes a header and a plurality of heat exchange tubes  100 . The heat exchange tube  100  is the heat exchange tube  100  described above, two ends of the heat exchange tube  100  are inserted into the header, and the plurality of heat exchange tubes  100  are stacked. 
     The heat exchanger according to the embodiments of the present disclosure may effectively improve the fluid heat exchange between internal and external spaces of the heat exchanger and effectively improve the heat exchange efficiency by using the structure of the heat exchange tube  100  described above. 
     The outer fin  2  may be formed on one surface of the tube body. When the heat exchanger is assembled, the outer fin  2  is welded with the other surface of the adjacent tube body. Of course, the outer fin  2  may be formed on both surfaces of the tube body, and an ordinary flat tube without the outer fin  2  may be welded between the two heat exchange tubes  100 . 
     In a manufacturing method of a heat exchange tube  100  according to yet another object of the present disclosure, the heat exchange tube  100  is the heat exchange tube  100  described above. The manufacturing method includes: processing a first plate portion into the inner fin  3 , a second plate portion surrounding the inner fin  3  by at least one circle to be processed into the tube wall  1 , and processing a third plate portion into the outer fin  2  outside the tube wall  1 . The third plate portion and at least one of the first plate portion and the second plate portion are adjacent parts of the same plate body. 
     The first plate portion and the third plate portion are processed to form the inner fin  3  and the outer fin  2  by means of bending, extrusion, punching, flanging or the like. After the inner fin  3  and the outer fin  2  are processed, the second plate portion is processed into a structure of the tube wall  1  of the folded flat tube. While the tube wall  1  is processed, the tube wall  1  is mounted and fitted with the inner fin  3  and the outer fin  2  by means of covering and clamping, and is completely fixed with the inner fin  3  and the outer fin  2  by means of welding. 
     According to the manufacturing method for the heat exchange tube  100  according to the embodiments of the present disclosure, the outer fin  2  and at least one of the tube wall  1  and the inner fin  3  are folded from the same plate, such that the heat of the fluid in the tube wall  1  may be quickly transferred to the outer fin  2 , so as to realize the rapid heat exchange between the fluid inside and the fluid outside the tube wall  1 , thus effectively improving the heat exchange efficiency of the fluid inside and the fluid outside the tube wall  1 . Moreover, the production process may also be simplified. The tube wall  1  and the outer fin  2  may be made from the same plate, or the inner fin  3  and the outer fin  2  may be made from the same plate, or the tube wall  1 , the inner fin  3  and the outer fin  2  may be made from the same plate. 
     In addition, the order of processing and forming the inner fin  3 , the outer fin  2  and the tube wall  1  is not limited herein. The tube wall  1  surrounding the inner fin  3  means that tube wall  1  surrounds the inner fin  3  after manufacturing, which does not mean that the tube wall  1  is formed by surrounding the inner fin  3 . Instead, the inner fin may be placed in the tube wall  1  after the inner fin and the tube wall  1  are formed respectively. 
     Of course, the order of processing the inner fin  3 , the outer fin  2  and the tube wall  1  may also be limited. According to practical needs, the processing may be performed in a following order, for example, the inner fin  3 , the outer fin  2  and the tube wall  1 , or the inner fin  3 , the tube wall  1  and the outer fin  2 , or the outer fin  2 , the inner fin  3  and the tube wall  1 , or the outer fin  2 , the tube wall  1  and the inner fin  3 , or the tube wall  1 , the outer fin  2  and the inner fin  3 , or the tube wall  1 , inner fin  3  and outer fin  2 . 
     Reference throughout this specification to “an embodiment,” “some embodiments,” “an example,” “a specific example,” or “some examples,” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the phrases such as “in some embodiments,” “in one embodiment,” “in an example,” “in a specific example,” or “in some examples,” in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the related art may combine and incorporate different embodiments or examples and their features described in the specification, without mutual contradictions. 
     Although explanatory embodiments have been illustrated and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications may be made in the embodiments without departing from spirit, principles and scope of the present disclosure.