JP3296325B2 - Heat transfer tube with internal groove - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an inner grooved heat transfer tube having a groove on an inner peripheral surface of a tube main body.

[0002]

2. Description of the Related Art Heat transfer tubes of heat exchangers such as evaporators and condensers for air conditioners have been disclosed in, for example, JP-A-9-42881 from the viewpoint of improving the heat transfer coefficient. So that a spiral groove is provided on the inner peripheral surface of the pipe,
What adopted the thing which increased the stirring effect by enlarging the heat transfer area and making the refrigerant | coolant which flows through a pipe circularly flow is employ | adopted.

However, in the case of the heat transfer tube having the above structure, when the condensation action progresses to a certain extent, the liquid film portion becomes substantially uniformly distributed in the tube, and the thickness gradually increases. The diffusion resistance increases and the heat transfer performance decreases.

To cope with such a problem, the inner peripheral surface of the tube is divided into a plurality of regions in the circumferential direction as shown in, for example, Japanese Patent Application Laid-Open No. 9-42880. A plurality of rows of V-shaped grooves that are symmetrical in the direction and are equal in width in the circumferential direction are provided.

[0005] In this configuration, the heat transfer tube having the spiral groove is symmetrical in the tube axis direction provided on the inner peripheral surface of the tube, and
Due to the merging or branching action of the V-shaped grooves in a plurality of rows having the same width in the circumferential direction, the distribution of the refrigerant flowing in the pipe in the pipe circumferential direction can be made non-uniform. Then, a high heat transfer coefficient is realized in the thinned region of the liquid refrigerant, so that the heat transfer coefficient at the time of condensation is improved.

[0006]

However, in the case of a heat transfer tube having a V-shaped groove which is symmetric in the tube axis direction and has the same width in the circumferential direction on the inner circumferential surface of the tube as described above, Because the flow of the refrigerant collides and joins by the V-shaped groove,
When the flow resistance is large and, for example, it is used as a heat transfer tube for an evaporator, the effect of a high pressure loss is exerted, and a sufficient heat transfer performance improving effect cannot always be obtained.

[0007] 2. In a region where the flow velocity of the refrigerant is low (a region where the amount of circulating refrigerant is small), the effect of making the distribution of the refrigerant uneven by the V-shaped groove is small. In particular, when used as, for example, a heat transfer tube for an evaporator due to the structure of the groove, the liquid refrigerant cannot be supplied sufficiently in the circumferential direction of the tube, so that the heat transfer performance promoting effect cannot be obtained. That is, the ability cannot be expected to be improved depending on the use area.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to reduce the pressure loss and to more appropriately control the flow of the refrigerant in the pipe even when the flow rate of the refrigerant is small. It is an object of the present invention to provide a heat transfer tube with an inner surface groove having improved heat transfer performance as much as possible.

[0009]

Means for Solving the Problems In order to achieve the above objects, the present invention has the following means for solving the problems.

(1) The invention of claim 1 First, the heat transfer tube with an inner groove according to the invention of claim 1 of the present application comprises a tube body 1
the inner peripheral surface 2 of a formation, Rutotomoni provided grooves 3,3, ... of the V-shaped symmetrical multiple in the axial direction of the tube, the grooves 3,3, ... of the V-shaped plurality of The width in the circumferential direction of the plurality of rows of groove groups A to E is made to be unequal width.

As described above, the inner peripheral surface of the tube main body 1a of the heat transfer tube.
, A plurality of V-shaped grooves 3, 3...
And the plurality of V-shaped grooves 3, 3,...
The circumferential width of the plurality of rows of groove groups A to E formed by
If the width is irregular, a plurality of V-shaped grooves 3, 3.
The refrigerant liquid flowing in a non-uniform state in the pipe axis direction while repeating the merging and branching at each of the grooves 3, 3... A flow generating action can be obtained, and a stirring effect is realized, thereby improving heat transfer performance.

[0012] (2) The present invention also claims herein inner surface grooved heat transfer tube of claim 2 of the invention of claim 2, in the configuration of the invention according to the first aspect, grooves 3,3 ... V-shaped in multiple Are formed in at least a part of the ridges 5, 5... Formed between the ridges 3, 3,... From the top 5a side to the base 5b side. , 6 ...
Is formed.

[0013] In this way, the grooves of the V-shaped multiple 3,3-
..Protrusions 5,5 formed between respective grooves 3,3 ...
, At least in part, from the top 5 a side to the bottom 5
When the secondary grooves 6, 6... having a predetermined depth are formed toward the b side, the flow resistance of the refrigerant flowing in the pipe is further reduced by the secondary grooves 6, 6,. Even when the flow rate of the refrigerant is small, the heat transfer performance is effectively improved.

(3) The heat transfer tube with an inner surface groove according to the third aspect of the present invention is the same as the second aspect of the present invention, except that the secondary grooves 6, 6,.
Is characterized by being a spiral cutout groove.

In the case of this configuration, the flow resistance of the refrigerant flowing in the pipe is effectively reduced by the secondary grooves 6, 6... Is increased, and the heat transfer performance is further improved.

[0016] (4) the inner surface grooved heat transfer tube of the invention the invention also appended claims 5 according to claim 4, in the constitution of the invention according to the first aspect, grooves 3,3 ... V-shaped in multiple Are formed on at least a part of the protruding portions 5, 5,... Formed between the respective grooves 3, 3,. Is formed.

As described above, a plurality of V-shaped grooves 3, 3,.
..Protrusions 5,5 formed between respective grooves 3,3 ...
Are formed on at least a part of the outer peripheral surface thereof at a predetermined depth.
The flow resistance of the refrigerant flowing through the pipe is reduced by 7..., The pressure loss is reduced, and the heat transfer performance is effectively improved even when the flow rate of the refrigerant is small.

(5) The heat transfer tube with an inner surface groove according to the fifth aspect of the present invention is the same as the fourth aspect of the invention, wherein the secondary grooves 7, 7,.
Are characterized in that they are minute grooves extending from one side surface to the other side surface of the convex ridges 5, 5,....

[0019] The In the case of configuration, by 2 Tsugimizo 7,7 ... from one side of the ridge 5, 5 made of fine grooves extending in the other side of the refrigerant flowing through the pipe flow resistance Is effectively reduced, and the heat transfer performance is improved. Also, even when the pipe is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

[0020]

As described above, the heat transfer with an inner groove according to each invention of the present application is described above.
According to the pipe, even if it is configured as a heat exchanger of either the condenser or the evaporator, or if it is configured as an evaporator and the refrigerant flow rate is small, the pressure loss and the internal Heat resistance and dispersion resistance are reduced, and a heat exchanger having sufficiently high heat transfer performance can be provided.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1 to 3 show the structure of a heat transfer tube with an inner groove according to Embodiment 1 of the present invention.

First, an inner grooved heat transfer tube 1 according to the present embodiment is provided on an inner peripheral surface 2 of an electric resistance welded tube main body 1a, as shown in FIGS. In order to promote the turbulence of the flowing refrigerant liquid and to form a dense portion by branching or merging with the flow of the refrigerant liquid to promote the thinning of the refrigerant liquid, the main groove is symmetrical in the pipe axis direction. A plurality of V-shaped grooves having a relatively sharp shape having an irregular width in the circumferential direction;
Are provided, and the plurality of V-shaped grooves 3, 3 are provided.
First to fifth plurality of rows of grooves group A~E consisting lateral inclination groove portion ... it is being arranged in a state of mutually made different inclination direction of the lead angle θ with unequal width in the circumferential direction ing.

[0023] Reference numeral 5 in FIG. 3 is an convex portion formed between grooves 3,3, ... of the V-shaped grooves 3, 3, ... of the plurality of V-shaped , 5a indicate its top, and 5b indicates its base.

Thus, the lead angle θ is
Left-right inclination of V-shaped grooves 3, 3 ... with different inclination directions
When juxtaposed with unequal width groove group A~E of the first to fifth plurality of rows composed of groove portions in the circumferential direction, each of said V-shaped groove 3,
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating the branching and merging at the part 3... Will further generate a component in the swirling direction, which is a V-shaped groove combined with a conventional spiral groove. , And an effective stirring effect is realized, and the heat transfer performance is improved.

The first to fifth plural rows of groove groups A to
V-shaped grooves 3 and 3 provided with left and right inclined grooves forming E
Are formed with a predetermined lead angle θ, a predetermined depth H, and a predetermined number N so that the flow resistance of the groove portion is reduced as much as possible to reduce the pressure loss. ing. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved. .. Of the plurality of V-shaped grooves 3, 3... Provided with left and right inclined grooves forming the first to fifth groove groups A to E. According to the experimental results of the inventors of the present invention, for example, in the case of a heat transfer tube having an outer diameter φ = 7 mm,
5 to 15 °, H = 0.2 to 0.3 mm, N = 45 to 55
In the range, the flow resistance was the smallest, and the pressure loss was effectively reduced.

[0026] As described above, according to the configuration of the inner surface grooved heat transfer tube of the present embodiment, first lead angle of lateral inclination groove portion θ
Grooves in the inclination directions are different from each other a plurality of V-shaped 3,3-
..A plurality of rows of groove groups A to E comprising the same left and right inclined groove portions
Is set to be unequal width instead of equal width in the circumferential direction,
The refrigerant in the pipe has a swirling flow component like a conventional spiral groove pipe. Thus, even when the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The V-shaped grooves 3, 3... Of a plurality of rows of grooves A to E provided on the inner peripheral surface 2 of the pipe are inclined left and right.
The lead angle θ of the groove portion , the groove depth H, and the number N of the grooves are set to values corresponding to the above-described experimental results that minimize the flow resistance. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss, so that a heat transfer tube for a heat exchanger having sufficiently high performance can be obtained even when used as an evaporator.

(Embodiment 2) FIGS. 4 to 6 show the structure of a heat transfer tube with an inner surface groove according to Embodiment 2 of the present invention.

First, in the heat transfer tube 1 with an inner groove according to the present embodiment, the turbulence of the refrigerant liquid flowing in the tube main body 1a is formed on the inner peripheral surface 2 of the tube main body 1a having the same electric resistance welded pipe structure as described above. The main groove is symmetrical in the pipe axis direction and has an irregular width in the circumferential direction, in order to promote fluidization and to form a dense portion by branching or merging with the refrigerant liquid to promote thinning of the refrigerant liquid. Are provided with a plurality of V-shaped grooves 3, 3...
Left and right inclined grooves of the plurality of V-shaped grooves 3, 3,...
Groove group A~E of the first to fifth plurality of rows composed of minute, mutual
Are arranged at unequal widths in the circumferential direction with different inclination directions of the lead angle θ.

Reference numeral 5 in FIG. 5 and FIG.
Each of the plurality of V-shaped grooves 3, 3,...
Reference numeral 5a denotes a top portion, and 5b denotes a base portion. In the case of this embodiment, there are provided secondary grooves 6, 6,... Formed by spiral notches having a predetermined depth d from the top 5a to the base 5b. This reduces the flow resistance of the refrigerant and further increases the component in the swirling direction.

As described above, the V-shaped grooves 3, 3 in which the inclination directions of the lead angle θ of the left and right inclined grooves are different from each other.
When juxtaposed with unequal widths first to fifth groove groups A~E plural rows consisting of the lateral inclination groove portion in a circumferential direction of ..., respectively on
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating the branching and merging at the V-shaped grooves 3, 3... An annular flow generation action close to that of a conventional combination of spiral grooves can be obtained, an effective stirring effect is realized, and the heat transfer performance is improved.

The first to fifth plural rows of groove groups A to
V-shaped grooves 3 and 3 provided with left and right inclined grooves forming E
Are secondary grooves 6, 6, which are formed by spiral notches as described above so that the flow resistance of the grooves is reduced as much as possible to reduce pressure loss. And a predetermined lead angle θ, a predetermined depth H, and a predetermined number N of lines similar to those of the first embodiment. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved.

The first to fifth groove groups A to E are formed.
A plurality of V-shaped grooves 3 and 3 with left and right inclined grooves
The lead angle of the left and right oblique groove portion · theta, groove depth H,
According to the experimental results of the present inventors as described above, the number of threads N is, for example, θ = 5 in the case of a heat transfer tube having an outer diameter φ = 7 mm.
15 °, H = 0.2-0.3 mm, N = 45-55, 2
Next groove depth d / H = 0.25 to 0.75
The flow resistance was the smallest, and the pressure loss was effectively reduced.

As described above, according to the configuration of the heat transfer tube with inner grooves according to the present embodiment, first, as described above, the left and right inclined groove portions are formed.
Rather than equal width of the width of the circumferential direction of the lead angle θ plurality of rows of grooves group A~E the inclination direction is formed of grooves 3,3 same lateral inclination groove portion ... of different V-shape of one another Since the width is set to be unequal, the refrigerant in the pipe has a swirling flow component like a conventional spiral groove pipe. Thus, even when the flow rate of the refrigerant is small and the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The V-shaped grooves 3, 3... Of the plurality of rows of grooves A to E provided on the inner peripheral surface 2 of the pipe are inclined left and right.
The lead angle θ, the groove depth H, and the number N of the grooves are set to values that minimize the flow resistance, respectively, and the convex grooves between the V-shaped grooves 3, 3,. 5,5 ...
. Are provided with secondary grooves 6, 6,... Formed of cutout grooves directed in the spiral direction from the top 5a to the base 5b. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss and the swirl component in the spiral direction can be further increased, so that a heat exchanger tube for a heat exchanger with higher performance can be obtained. .

(Embodiment 3) FIGS. 7 and 8 show the structure of a heat transfer tube with an inner surface groove according to Embodiment 3 of the present invention.

First, in the heat transfer tube 1 with an inner surface groove according to the present embodiment, the turbulence of the refrigerant liquid flowing in the tube body 1a is formed on the inner peripheral surface 2 of the tube body 1a having the same electric resistance welded tube structure as described above. The main groove is symmetrical in the pipe axis direction and has an irregular width in the circumferential direction, in order to promote fluidization and to form a dense portion by branching or merging with the refrigerant liquid to promote thinning of the refrigerant liquid. Are provided with a plurality of V-shaped grooves 3, 3...
Left and right inclined grooves of the plurality of V-shaped grooves 3, 3,...
The first to fifth plural rows of groove groups A to E are arranged in the circumferential direction at unequal widths .

Reference numeral 5 in FIG. 7 and FIG.
Each of the plurality of V-shaped grooves 3, 3,...
Reference numeral 5a denotes a top portion, and 5b denotes a base portion. In the case of the present embodiment, a secondary, e.g., spiral groove having a predetermined depth is formed from one side surface to the other side surface of the outer peripheral surface of the ridges 5, 5,. .. Are provided so as to reduce the flow resistance of the refrigerant and to further increase the component in the swirling direction.

As described above, the V-shaped grooves 3, 3 in which the inclination directions of the lead angle θ of the left and right inclined grooves are different from each other.
When the first to fifth rows of groove groups A to E composed of the same right and left inclined groove portions are arranged side by side in an unequal width in the circumferential direction, V
The refrigerant liquid flowing non-uniformly in the circumferential direction while repeating branching and merging at the U-shaped grooves 3, 3... It is possible to obtain an annular flow generating action close to that obtained by combining the spiral grooves, and an effective stirring effect is realized, and the heat transfer performance is improved.

The first to fifth rows of the groove groups A to A
V-shaped grooves 3 and 3 provided with left and right inclined grooves forming E
Are provided on the outer peripheral surfaces of the ridges 5, 5... Formed between them so that the flow resistance of the grooves is reduced as much as possible to reduce the pressure loss. Are formed from the side surface side to the other side surface and formed of, for example, fine grooves having a predetermined depth extending in a spiral direction. The predetermined lead angle θ is the same as in the first embodiment. It is formed to have a depth H and a predetermined number N. Therefore, even when used as a heat transfer tube for an evaporator and the flow rate of the refrigerant is small, the pressure loss is effectively reduced and the heat transfer performance is improved. Also, even when the pipe is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

The first to fifth groove groups A to E are formed.
A plurality of V-shaped grooves 3 and 3 with left and right inclined grooves
The lead angle of the left and right oblique groove portion · theta, groove depth H,
According to the experimental results of the present inventors as described above, the number of threads N is, for example, θ = 5 in the case of a heat transfer tube having an outer diameter φ = 7 mm.
Those having a range of 15 °, H = 0.2 to 0.3 mm, and N = 45 to 55 had the smallest flow resistance and effectively reduced the pressure loss.

[0042] As described above, according to the configuration of the inner surface grooved heat transfer tube of the present embodiment, first lateral inclination groove portions as described above
The groove groups A~E plurality of rows of inclined directions is formed of grooves 3,3 same lateral inclination groove portion ... of different V-shape of the lead angle θ unequal width instead of equal width in the circumferential direction of the Since it is set, the refrigerant in the pipe has a swirling flow component like a conventional spiral groove pipe. Thus, even when the flow rate of the refrigerant is small and the flow velocity of the refrigerant is low, the refrigerant is effectively supplied in the pipe circumferential direction, so that the heat transfer promoting effect is not impaired.

The V-shaped grooves 3, 3... Of each of the plurality of rows of grooves A to E provided on the inner circumferential surface 2 of the pipe are inclined leftward and rightward.
Lead angle of the groove portion theta, groove depth H, the number of threads N, with most flow resistance each set to smaller values, the V a plurality of V-shaped grooves 3, 3, ... as the main groove Character-shaped strip
With respect to the ridges 5, 5, ... Between the grooves 3, 3,... , The secondary grooves 7, which are, for example, fine grooves extending in the helical direction from one side of the outer peripheral surface to the other side. 7 are provided. Accordingly, the flow resistance can be reduced as much as possible to reduce the pressure loss, and the spiral component of the refrigerant flow in the spiral direction can be further increased. A heat transfer tube for the exchanger can be obtained. Also, even when the pipe is expanded, the fine grooves on the side portions are not collapsed, and the heat transfer performance is not reduced.

(Other Embodiments) In each of the above embodiments, an electric resistance welded tube type heat transfer tube has been described as an example. However, the inner surface groove structure of each of the above embodiments is, for example, a seam tube type heat transfer tube. It goes without saying that the same can be applied to the case of a heat tube.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing a structure of a tube main body of an internally grooved heat transfer tube according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view of a main part of the inner peripheral surface of the pipe main body.

FIG. 3 is a perspective view of a cut portion of a main part of the inner peripheral surface of the pipe main body.

FIG. 4 is an enlarged view showing a structure of a main part of an inner peripheral surface of a tube main body of an internally grooved heat transfer tube according to a second embodiment of the present invention.

FIG. 5 is an enlarged perspective view of the main part.

FIG. 6 is a perspective view of a cut portion of a main part of the inner peripheral surface of the pipe main body.

FIG. 7 is an enlarged view showing a structure of a main part of an inner peripheral surface of a tube main body of an internally grooved heat transfer tube according to Embodiment 3 of the present invention.

FIG. 8 is an enlarged perspective view of a cut portion of the main part.

[Explanation of symbols]

1 heat transfer tube, 1a is a tube body, 3 is V-shaped grooves, 5 ridge portion, 5a is a top, 5b is the base, 6,7 Ru Oh <br/> the secondary grooves.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tetsuaki Okamoto 1304 Kanaokacho, Sakai-shi, Osaka Daikin Industries, Ltd.Sakai Factory Kanaoka Factory (72) Inventor Yu Uchimitsu 1304, Kanaokacho, Sakai-shi, Osaka Daikin Industries (56) References JP10-47880 (JP, A) JP10-206060 (JP, A) JP11-83368 (JP, A) JP2 JP-A-165875 (JP, A) JP-A-4-339530 (JP, A) JP-A-11-90530 (JP, A) JP-A-55-60089 (JP, U) (58) Fields investigated (Int. . ^7, DB name) F28F 1/00 - 1/44

Claims (5)

(57) [Claims] To 1. A pipe inner peripheral surface of the main body (1a) (2), grooves (3) of the V-shaped symmetrical multiple in the axial direction of the tube, (3) ...
The provided Rutotomoni, the plurality of V-shaped grooves (3),
(3) ... a plurality of rows of groove groups (A) to
(E) A heat transfer tube with an inner surface groove, wherein the width in the circumferential direction is unequal. As claimed in claim 1, wherein the groove (3) of the multiple V-shaped, (3) ...
, At least a part of the ridges (5), (5),... Formed between the grooves (3), (3),. 2) of predetermined depth toward the side
The heat transfer tube with an inner surface groove according to claim 1, wherein the next grooves (6) are formed. 3. The heat transfer tube with an inner surface groove according to claim 2, wherein the secondary grooves (6), (6)... Are cutout grooves in a spiral direction. 4. A groove (3) of the multiple V-shaped, (3) ...
And at least part of the ridges (5), (5)... Formed between the grooves (3), (3). 2. A heat transfer tube with an inner surface groove according to claim 1, wherein the next grooves are formed. 5. The secondary grooves (7), (7)... Are fine grooves extending from one side surface to the other side surface of the convex ridge portions (5). The heat transfer tube with an inner surface groove according to claim 4, characterized in that: