Boundary layer reversion slitted fin
Technical field
The utility model belongs to field of heat exchange, is specifically related to a kind of boundary layer reversion slitted fin, is applicable to the heat exchanger such as fin-tube type, plate-fin.
Background technology
The fin-tube type applied in field of heat exchange, plate-fin heat exchanger, and in the heat exchanger of other types, fluid, in the outer flowing of pipe, in order to strengthen heat exchange, has fin in fluid side, to increase heat exchange area, reduces fluid side thermal resistance.Use general plain fin pipe, along fluid flow direction, the boundary layer of progressive additive can be formed at fin surface, the speed at fluid flow downstream place and the field coordination of thermograde are deteriorated, fin heat transfer property is declined.
In order to improve the heat transfer property of finned tube exchanger further, have employed the better fin of enhanced heat exchange performance, slitted fin is the wherein more effective enhanced heat exchange mode of one, and crack Various Types of Dams, and the impact of heat exchanging effect is also different.So far many documents and patent symmetry slot fin is had to be studied.
Employ trapezoidal shutter in patent CN96113216.7 to decline rib, and requirement has been carried out to the arranged direction of the trapezoidal long limit of micro-rib and minor face; Patent CN97117302.8 provides four kinds of multi-form type of incision at fin surface; Patent CN03108079.0 at fin surface erection bridge shape silver, and has carried out requirement to the layout density of silver.Although above-mentioned several method can improve the heat exchange property of fin, but still there is following problem: 1) processing difficulties; 2) along with forward fluid motion, fluid flow resistance increases obviously.
Known in conjunction with prior art, research and development is a kind of, and reasonably slot opening form is very important, this slot opening form must have following characteristics: the disturbance to fluid and the destruction to boundary layer few, field coordination can better be improved, simultaneously less to the inhibition of flowing, the resistance of whole heat exchanger is increased less, and heat transfer property improve obviously.
Utility model content
For existing technical problem, the purpose of this utility model is to provide a kind of boundary layer reversion slitted fin, the disturbance of the utility model to fluid and the destruction to boundary layer few, field coordination can better be improved, less to the inhibition of flowing, the resistance of whole heat exchanger is increased less, heat transfer property improves obviously, can effectively reduce the volume of the heat exchanger such as fin-tube type, plate-fin.
For solving the problem, the technical solution adopted in the utility model is:
A kind of boundary layer reversion slitted fin, comprise substrate (21) and be opened in the miniature fin of domatic (22) on substrate (21), the miniature fin of domatic (22) one end is connected with substrate (21), one end is stuck up from substrate (21), (23) are cracked in the upper formation of substrate (21), the miniature fin of described domatic (22) is arranged in pairs on substrate (21), often pair by a short micro-rib (22a) and long micro-rib (22b) composition, short micro-rib (22a) and long micro-rib (22b) tilt at substrate (21) homonymy and point to the other side mutually, long micro-rib (22b) is highly being greater than short micro-rib (22a) tilting height in the same direction perpendicular to the tilting on substrate direction, in often pair of miniature fin of domatic (22), short micro-rib (22a) is positioned at fluid flowing upstream, and long micro-rib (22b) is positioned at fluid flow downstream.
As to further improvement of the utility model, the miniature fin of each domatic (22) is 0 ° ~ 45 ° relative to the tilting angle of substrate (21).
As to further improvement of the utility model, on fluid flow direction, the both sides being arranged on substrate (21) that often pair of miniature fin of domatic (22) replaces.
As to further improvement of the utility model, on substrate (21), between two adjacent heat exchanger tubes (11), be provided with a pair or several to the miniature fin of domatic (22).
As to further improvement of the utility model, (23) length of cracking that often pair of short micro-rib (22a) of the miniature fin of domatic (22) and long micro-rib (22b) are formed is called spacing, on substrate (21), the spacing of the miniature fin of domatic (22) of fluid flowing upstream is greater than the spacing of the miniature fin of domatic (22) of fluid flow downstream.
As to further improvement of the utility model, on substrate (21), the logarithm of the miniature fin of domatic (22) of fluid flowing upstream is less than the logarithm of the miniature fin of domatic (22) of fluid flow downstream.
As to further improvement of the utility model, the miniature fin of described domatic (22) is on the direction of flowing perpendicular to fluid, and the part near heat exchanger tube (11) is curved.
The beneficial effects of the utility model are:
Due to Unique physical design of the present utility model, when fluid flows to long micro-rib from short micro-rib time, boundary layer can be inverted, this boundary layer Umklapp process repeats when flowing through the miniature fin of the often pair of domatic, the disturbance of fluid can increase, the collaborative degree of fluid velocity and thermograde is improved, enhance heat exchange, simultaneously because often pair of miniature fin of domatic is arranged alternately, comply with fluid flow tendencies, thus fluid resistance increases not obvious, so substantially increase the heat transfer property of finned tube exchanger, thus reduce the volume of heat transmission equipment, reduce product cost.
Accompanying drawing explanation
Fig. 1 is the perspective view adopting heat exchanger of the present utility model.
Fig. 2 is the partial elevation view of the utility model first embodiment.
Fig. 3 is the enlarged drawing of dashed rectangle part in Fig. 2.
Fig. 4 is the profile of A-A line in Fig. 3.
Fig. 5 is the partial elevation view of the second embodiment of the present utility model.
Fig. 6 is the partial elevation view of the 3rd embodiment of the present utility model.
Fig. 7 is the partial elevation view of the 4th embodiment of the present utility model.
Fig. 8 is the partial elevation view of the 5th embodiment of the present utility model.
Fig. 9 is the partial elevation view of the 6th embodiment of the present utility model.
In figure: 10-pipe; 11-heat exchanger tube; 20-fin; 21-substrate; The miniature fin of 22-domatic; The short micro-rib of 22a-; The long micro-rib of 22b-; 23-cracks.
Detailed description of the invention
Below in conjunction with drawings and Examples, the utility model is further described.
As shown in Figure 1, it is the perspective view adopting heat exchanger of the present utility model, this heat exchanger comprises the pipe (10) of multiple U-shaped bending and multiple parallel fin (20) be contained on pipe (10), fin (20) is made with thin plate, be designed to contact with the outer rim of pipe (10), to increase and fluid contact area, increase heat transfer area, reduce thermal resistance, thus improve heat exchanger effectiveness.
As Fig. 2, shown in Fig. 3 and Fig. 4, it is the first embodiment of utility model, in the present embodiment, a kind of boundary layer reversion slitted fin, comprise substrate (21) and be opened in the miniature fin of domatic (22) on substrate (21), the miniature fin of domatic (22) one end is connected with substrate (21), one end is stuck up from substrate (21), (23) are cracked in the upper formation of substrate (21), the miniature fin of described domatic (22) is arranged in pairs on substrate (21), often pair by a short micro-rib (22a) and long micro-rib (22b) composition, short micro-rib (22a) and long micro-rib (22b) tilt at substrate (21) homonymy and point to the other side mutually, long micro-rib (22b) is highly being greater than short micro-rib (22a) tilting height in the same direction perpendicular to the tilting on substrate direction, in often pair of miniature fin of domatic (22), short micro-rib (22a) is positioned at fluid flowing upstream, and long micro-rib (22b) is positioned at fluid flow downstream,
Shown in Fig. 4, in the present embodiment, on fluid flow direction, the both sides being arranged on substrate (21) that often pair of miniature fin of domatic (22) replaces.
In a first embodiment, the miniature fin of each domatic (22) is 0 ° ~ 45 ° relative to the tilting angle of substrate (21); The miniature fin of each domatic (22) is along symmetrical relative to the center line in heat exchanger tube (11) cross section on fluid flow direction.
Be explained to the working condition of the finned type heat exchanger that above-mentioned fin structure is housed below:
Along pipe (10) flowing, during the space that fluid is formed by fin (20), there is heat exchange in fluid.Here, first time heat exchange is there is in the fluid flowing into this space when flowing through first short micro-rib (22a), and form boundary layer on the micro-rib surface of domatic, subsequently, fluid leaves short micro-rib (22a), because long micro-rib (22b) is slightly high, fluid is along long micro-rib (22b) flowing, the boundary layer simultaneously formed on short micro-rib (22a) surface is inverted, namely former press close to substrate (21) side (inner side) of carrying out heat exchange be inverted out, and the miniature fin of a upper domatic (22) is inverted to substrate (21) away from the side (outside) of fin (20), outside makes heat exchange strengthen owing to preserving higher heat exchange potential energy relative to inner side.Above boundary layer Umklapp process obtains repetition when fluid flows through lower a pair domatic miniature fin (22), thus fluid is constantly disturbed, strengthen heat transfer effect, simultaneously, because often pair of miniature fin of domatic (22) is arranged alternately in substrate (21) both sides, comply with fluid flow tendencies, do not produced eddy flow and even reflux, very little to its inhibition produced in flow process.
In the utility model, on substrate (21), a pair or several is provided with to the miniature fin of domatic (22) between two adjacent heat exchanger tubes (11), (23) length of cracking that often pair of short micro-rib (22a) of the miniature fin of domatic (22) and long micro-rib (22b) are formed is called spacing, and between every two adjacent heat exchanger tubes (11), the logarithm of the miniature fin of domatic (22) and the spacing of often pair of miniature fin of domatic (22) can be identical or different.In a first embodiment, be provided with two pairs of miniature fins of domatic (22) between every two adjacent heat exchanger tubes (11), the spacing of the spacing of often pair of miniature fin of domatic (22) is all identical.
Fig. 5 and Fig. 6 is the second embodiment of the present utility model and the 3rd embodiment, the difference of these two embodiments and the first embodiment is: between two adjacent heat exchanger tubes (11), the miniature fin of domatic (22) logarithm increases, and increases in substrate (21) upper density.In implementing second, between two adjacent heat exchanger tubes (11), there are three pairs of miniature fins of domatic (22).In implementing the 3rd, between two adjacent heat exchanger tubes (11), there are four pairs of miniature fins of domatic (22).The logarithm reasonably arranging the miniature fin of domatic (22) between two adjacent heat exchanger tubes (11) contributes to continuous disturbance fluid, strengthens heat transfer effect.
Fig. 7, Fig. 8 are the 4th embodiment of the present utility model and the 5th embodiment, the difference of these two embodiments and previous embodiment is: on substrate (21), with the center of fluid flow direction for boundary, the spacing of the miniature fin of domatic (22) of fluid flowing upstream is greater than the spacing of the miniature fin of domatic (22) of fluid flow downstream; Meanwhile, on substrate (21), with the center of fluid flow direction for boundary, the logarithm of the miniature fin of domatic (22) of fluid flowing upstream is less than the logarithm of the miniature fin of domatic (22) of fluid flow downstream.In the fourth embodiment, there is 1 pair of miniature fin of domatic (22) between the heat exchanger tube (11) that fluid flowing two, upstream is adjacent, between the heat exchanger tube (11) that fluid flow downstream two is adjacent, have 2 pairs of miniature fins of domatic (22).In the 5th embodiment, there are 2 pairs of miniature fins of domatic (22) between the heat exchanger tube (11) that fluid flowing two, upstream is adjacent, between the heat exchanger tube (11) that fluid flow downstream two is adjacent, have 4 pairs of miniature fins of domatic (22).
Shown by the result of the transient flow zone of flat fin being carried out to numerical simulation: in finned flow flowing upstream, the concertedness in velocity field and temperature field is relatively good, and in finned flow flow downstream, the concertedness in velocity field and temperature field is poor.The utility model utilizes field coordination principle to be optimized for the layout of cracking, result shows in finned flow downstream, namely work in coordination with the poor place of situation in velocity field and temperature field and open more seam, produce the field coordination situation that the more micro-rib of domatic can improve this region, the reason of arrangement close after dredging before the 4th embodiment that Here it is and the 5th embodiment adopt.
Fig. 9 is the 6th embodiment of the present utility model, and the difference of the 6th embodiment and previous embodiment is: the miniature fin of described domatic (22) is on the direction of flowing perpendicular to fluid, and the part near heat exchanger tube (11) is curved.The special setting of the 6th embodiment contributes to uniform heat exchange, improves heat exchange efficiency.
Due to second and third, four, five, the working mechanism of six preferred embodiments is identical with the first preferred embodiment, detailed description is omitted for it.
It should be noted that; the foregoing is only preferred embodiment of the present utility model; instead of the restriction to technical solutions of the utility model, any equivalent replacement of doing the utility model technical characteristic or corresponding improvement, still within protection domain of the present utility model.