CN218915144U

CN218915144U - Heat exchange tube, heat exchanger and air conditioner

Info

Publication number: CN218915144U
Application number: CN202223214944.8U
Authority: CN
Inventors: 赵夫峰; 唐华; 于海峰; 李成恩; 彭启; 苏明泽; 李日新; 吴铨发; 梁兆勇
Original assignee: GD Midea Air Conditioning Equipment Co Ltd
Current assignee: GD Midea Air Conditioning Equipment Co Ltd
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2023-04-25
Anticipated expiration: 2032-11-30

Abstract

The utility model discloses a heat exchange tube, a heat exchanger and an air conditioner, wherein the heat exchange tube is used for circulating R290 refrigerant, the heat exchange tube comprises a tube body and a plurality of internal threads, each internal thread extends spirally along the inner wall of the tube body, the outer diameter of the tube body is D, the helix angle of each internal thread is beta, and the outer diameter and the helix angle meet the following relational expression: d is more than or equal to 5.5mm and less than or equal to 10mm, and beta is more than or equal to 0 degree and less than or equal to 15 degrees. The internal thread helix angle beta with a small influence weight on pressure drop is set to satisfy the following conditions: beta is more than or equal to 0 degree and less than or equal to 15 degrees, and the heat exchange performance of the heat exchange tube is improved while the pressure drop of the refrigerant R290 is reduced.

Description

Heat exchange tube, heat exchanger and air conditioner

Technical Field

The utility model relates to the field of heat exchange, in particular to a heat exchange tube, a heat exchanger and an air conditioner.

Background

The heat exchange tube is used for heat exchange, and a refrigerant generally circulates in the heat exchange tube to accelerate the heat exchange process. The refrigerant R290 is being used in an air conditioner to gradually replace the conventional refrigerants such as R410A, R32, because of its cleanliness, without damaging the ozone layer and with little influence on the greenhouse effect. Because the dynamic viscosity of the refrigerant R290 is high, the heat exchange performance of the refrigerant R290 can be reduced by directly using the heat exchange pipe on the market to flow the refrigerant R290, and the heat exchange effect of the heat exchange pipe is affected.

Disclosure of Invention

The present utility model aims to solve at least one of the technical problems existing in the prior art. Therefore, an object of the present utility model is to provide a heat exchange tube in which R290 refrigerant flows with a small pressure drop and which has improved heat exchange performance.

Another object of the utility model is to propose a heat exchanger.

It is still another object of the present utility model to provide an air conditioner.

According to the heat exchange tube for the heat exchanger, which is provided by the embodiment of the utility model, the heat exchange tube is used for circulating R290 refrigerant and comprises a tube body and a plurality of internal threads, each internal thread spirally extends along the inner wall of the tube body, the outer diameter of the tube body is D, the helix angle of each internal thread is beta, and the outer diameter and the helix angle satisfy the following relation: d is more than or equal to 5.5mm and less than or equal to 10mm, and beta is more than or equal to 0 degree and less than or equal to 15 degrees.

According to the heat exchange tube for the heat exchanger, the heat exchange performance of the heat exchange tube is greatly influenced, and meanwhile, the internal thread helix angle beta with smaller influence weight on pressure drop is set to be satisfied: beta is more than or equal to 0 degree and less than or equal to 15 degrees, and the heat exchange performance of the heat exchange tube is improved while the pressure drop of the refrigerant R290 is reduced.

In some embodiments, the number N of internal threads satisfies the following relationship: n is more than or equal to 60 and less than or equal to 80.

In some embodiments, the crest angle α of each of the internal threads satisfies the following relationship: alpha is more than or equal to 5 and less than or equal to 18 degrees.

In some embodiments, grooves are defined between two adjacent internal threads, and at least two parts of the grooves have different extending directions.

Specifically, at least a portion of the grooves having different extending directions are disposed so as to intersect to define a mesh shape.

Further, the ratio of the length of the pipe body provided with the mesh shape to the entire length of the pipe body is not less than eighty percent.

In some embodiments, the pitch of the internal threads corresponding to the grooves with the same extending direction is M, where the ratio of M to D ranges from 3 to 5.

In some embodiments, the ratio between the number of internal threads N and the outer diameter D of the tube is 4-10.

In some embodiments, in the extending direction of the pipe body, the pipe body includes a first portion and a second portion, and the spiral extending direction of the groove provided on the inner wall of the first portion is opposite to the spiral extending direction of the groove provided on the inner wall of the second portion.

Specifically, the ratio between the length L1 of the first portion and the outer diameter D of the pipe body satisfies the following relation: L1/D is less than or equal to 1.5 and less than or equal to 3.5; and/or the ratio between the length L2 of the second portion and the outer diameter D of the tubular body satisfies the following relation: L2/D is less than or equal to 1.5 and less than or equal to 3.5.

The heat exchanger according to the embodiment of the utility model comprises any one of the heat exchange tubes.

According to the heat exchanger provided by the embodiment of the utility model, the heat exchange tube is arranged, so that the heat exchange efficiency of the heat exchanger is higher, and the heat exchange effect is better.

The air conditioner comprises the heat exchanger.

According to the air conditioner provided by the embodiment of the utility model, by arranging the heat exchanger, the refrigerating and heating efficiency of the air conditioner is higher, the use cleanliness of the air conditioner is better, and the environmental protection performance is better.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The foregoing and/or additional aspects and advantages of the utility model will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 is a schematic structural view of a heat exchange tube according to an embodiment of the present utility model;

FIG. 2 is a schematic partial structure diagram of the example shown in FIG. 1;

FIG. 3 is a schematic illustration of the effects of tooth top angle, tooth height, helix angle and tooth number on refrigerant pressure drop;

FIG. 4 is a schematic view showing the effects of tooth top angle, tooth height, helix angle and tooth number on heat exchange performance;

fig. 5 is a schematic structural view of a heat exchange tube according to a first partial embodiment of the present utility model;

FIG. 6 is a schematic view showing the influence of the ratio of the pitch to the pipe diameter in the heat exchange pipe on the overall performance enhancement ratio of the heat exchange pipe according to the first partial embodiment of the present utility model;

fig. 7 is a schematic structural view of a heat exchange tube according to a second partial embodiment of the present utility model;

FIG. 8 is a schematic view showing the influence of the ratio of the length to the pipe diameter of the pipe body having grooves in the same extending direction on the heat exchange coefficient enhancement ratio and the pressure drop enhancement ratio in the heat exchange pipe according to the second partial embodiment of the present utility model;

fig. 9 is a schematic view showing the influence of the ratio of the length of the tube body having grooves in the same extending direction to the tube diameter on the overall performance enhancement ratio of the heat exchange tube according to the second partial embodiment of the present utility model.

Reference numerals:

a tube body 100; and internal threads 200.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.

Furthermore, features defining "first", "second" may include one or more such features, either explicitly or implicitly. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

A heat exchange tube for a heat exchanger according to an embodiment of the present utility model is described below with reference to fig. 1 to 9.

According to the heat exchange tube provided by the embodiment of the utility model, the heat exchange tube is used for circulating R290 refrigerant, the heat exchange tube comprises a tube body 100 and internal threads 200, the number of the internal threads 200 is multiple, each internal thread 200 spirally extends along the inner wall of the tube body 100, the outer diameter of the tube body 100 is D, the helix angle of each internal thread 200 is beta, and the outer diameter and the helix angle satisfy the following relation: d is more than or equal to 5.5mm and less than or equal to 10mm, and beta is more than or equal to 0 degree and less than or equal to 15 degrees.

The heat exchange tube is used for circulating R290 refrigerant, and compared with traditional refrigerant such as R410A, R32, the R290 refrigerant has good cleaning performance. The ODP (ozone depletion potential ozone depletion potential) of the R290 refrigerant is 0, the R290 refrigerant does not damage the ozone layer, and the GWP (Global Warming Potential global warming potential) of the R290 refrigerant is also very low by only 3. However, the R290 refrigerant has specific combustibility, so the use safety performance of the R290 refrigerant is more ensured.

The inner surface of the heat exchange tube is provided with the plurality of toothed internal threads 200, so that the inner surface area of the heat exchange tube can be effectively increased, the heat exchange area of the inner surface of the heat exchange tube and the refrigerant can be increased, and the heat exchange efficiency of the heat exchange tube is improved. And the capacity of the internal thread 200 for piercing the liquid film is improved, so that the heat exchange efficiency of the heat exchange tube is further improved. In addition, the internal thread 200 provided on the inner wall of the tube body 100 can also serve as a reinforcing rib to improve the mechanical strength of the heat exchange tube.

The internal thread 200 according to the embodiment of the present utility model may be a left-handed thread or a right-handed thread, and the helix angle is an acute angle formed between the extending direction of the internal thread 200 and the axial direction of the pipe body 100.

The outer diameter D of the tube body 100 of the heat exchange tube according to the embodiment of the utility model has the following dimensions: d is more than or equal to 5.5mm and less than or equal to 10mm, alternatively, the outer diameter D of the tube body 100 of the heat exchange tube can be 5.5mm, 6mm, 6.35mm, 6.5mm, 6.8mm, 7mm, 7.4mm, 7.5mm, 8mm, 9.52mm, 10mm and the like.

The heat exchange coefficient of the traditional refrigerant such as R410A, R is improved along with the increase of the pressure drop of the refrigerant, but compared with the traditional refrigerant, the dynamic viscosity of the refrigerant R290 is high, and the friction pressure drop is large. The pressure drop of the refrigerant R290 is greatly increased, so that the heat exchange coefficient is reduced, the heat exchange performance is seriously attenuated, and the service life of the heat exchange tube is also influenced.

The utility model aims to reduce the pressure drop of the refrigerant R290 flowing in the heat exchange tube, thereby improving the system performance of the heat exchange tube and prolonging the service life of the heat exchange tube.

In order to explore the influence of factors on the heat exchange tube on the pressure drop of R290 refrigerant, four influencing factors of the tooth top angle alpha, the tooth height H, the helix angle beta and the tooth number N are selected, and the experiment is carried out by a finite element experimental design method, and the obtained experiment result is shown in figure 3. The influence weights of four influence factors of the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N on the pressure drop are shown in fig. 3, the influence weights of the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N on the pressure drop can be visually seen to be the largest, the influence weights of the spiral angle beta on the pressure drop are the second time, the influence weights of the tooth top angle alpha on the pressure drop are the third among the four influence factors, and the influence weights of the tooth number N on the pressure drop are the smallest.

However, four influencing factors, namely the tooth top angle α, the tooth height H, the helix angle β and the number of teeth N, have an influence on not only the pressure drop but also the heat exchange performance of the heat exchange tube through which the R290 refrigerant flows. For example, when the tooth top angle alpha is smaller, the heat exchange area of the inner surface of the heat exchange tube is increased, the liquid film thickness of the refrigerant is thinned, the vaporization core for evaporation heat transfer is increased, and the heat exchange performance of the heat exchange tube is improved. However, too small a tooth top angle α may cause too small expansion resistance of the heat exchange tube, and increase deformation of tooth shape, which may rather reduce heat exchange performance of the heat exchange tube.

Therefore, the design of the change of the tooth height H of the internal thread 200 cannot be directly modified by the maximum weight of the influence of the tooth height H on the pressure drop shown in fig. 3, and the influence of four influencing factors, namely the tooth top angle α, the tooth height H, the spiral angle β and the tooth number N, on the heat exchange performance of the heat exchange tube flowing with the R290 refrigerant is required, otherwise, the pressure drop of the R290 refrigerant in the heat exchange tube is reduced, but the heat exchange performance of the heat exchange tube is not improved, and even is reduced.

Therefore, four influencing factors, namely the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N, are continuously explored to influence the heat exchange performance of the heat exchange tube through which the R290 refrigerant flows, and the experiment result is shown in fig. 4 through a finite element experimental design method. The influence weights of four influence factors of the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N on the heat exchange performance are shown in fig. 4, the influence weights of the tooth top height H on the heat exchange performance are the largest, the influence weights of the spiral angle beta on the heat exchange performance are the second, the influence weights of the tooth number N on the heat exchange performance are the third among the four influence factors, the influence weights of the tooth top angle alpha on the heat exchange performance are the smallest, but the influence weights of the spiral angle beta, the tooth number N and the tooth top angle alpha on the heat exchange performance are very similar.

It should be noted that, compared with the traditional refrigerants such as R410A, R, the R290 refrigerant has good cleanliness, so that the R290 refrigerant is gradually replacing the traditional refrigerants and is applied to the heat exchanger, and the characteristics of the R290 refrigerant are different from those of the traditional refrigerants such as R410A, R, so that the heat exchange tube through which the traditional refrigerants such as R410A, R32 circulate cannot be directly carried as designed. The component of R290 is propane, the combustibility is A3 grade, and R290 has the characteristics of inflammability, explosiveness and the like. Therefore, when the risk factor of the test is larger for R290, the influence of factors on the heat exchange tube on the pressure drop of R290 refrigerant and the influence of four influencing factors of the tooth top angle α, tooth height H, helix angle β and tooth number N on the heat exchange performance of the heat exchange tube flowing with R290 refrigerant are explored, the test flow of the conventional refrigerant such as R410A, R is not simple, and meanwhile, because R290 refrigerant is a novel refrigerant, the test data capable of being referenced do not exist.

Combining the influence weights of four influence factors of the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N shown in fig. 3 on the pressure drop and the influence weights of four influence factors of the tooth top angle alpha, the tooth height H, the spiral angle beta and the tooth number N shown in fig. 4 on the heat exchange coefficient, the influence weights of the tooth height H on the pressure drop are the largest, the influence weights of the tooth height H on the heat exchange performance are the largest, and the influence weights of the tooth height H on the pressure drop are similar to the influence weights of the tooth height H on the heat exchange performance. When the increment of the tooth height H is larger, the heat exchange performance of the heat exchange tube is improved more. The increase of the tooth height H of the internal thread 200 of the heat exchange tube can effectively increase the internal surface area of the heat exchange tube, and the circulating refrigerant in the heat exchange tube has larger contact area with the heat exchange tube, thereby improving the heat exchange performance of the heat exchange tube. When the increase of the tooth height H is larger, the increase of the pressure drop of the R290 refrigerant is larger. The increase of the tooth height H of the internal thread 200 of the heat exchange tube increases the contact area between the R290 refrigerant flowing in the heat exchange tube and the heat exchange tube, and the flow resistance of the R290 refrigerant increases, thereby increasing the pressure drop of the R290 refrigerant. Therefore, the pressure drop of the refrigerant R290 flowing in the heat exchange tube cannot be reduced by reducing the size of the tooth height H, and even if the pressure drop of the refrigerant R290 flowing in the heat exchange tube is reduced, the heat exchange performance of the heat exchange tube is reduced, which is contrary to the idea that the heat exchange performance of the heat exchange tube is improved by reducing the pressure drop of the refrigerant R290.

The influence weight of the helix angle beta on the pressure drop is second among the four influence factors, and the influence weight of the helix angle beta on the heat exchanging performance is second, but in practice, the influence weights of the helix angle beta, the tooth number N and the tooth top angle alpha on the heat exchanging performance are similar and far smaller than the influence weight of the tooth height H on the heat exchanging performance. And the influence weight of the helix angle beta on the heat exchange performance is far smaller than the influence weight of the helix angle beta on the pressure drop. Therefore, the heat exchange performance of the heat exchange tube can be improved while the pressure drop of the medium R290 is reduced by changing the helix angle beta of the internal thread 200.

In this embodiment of the present application, the ratio of the heat exchange performance to the pressure drop of four influencing factors in the tooth top angle α, the tooth height H, the spiral angle β and the tooth number N is 0.98, 1.12, 0.74 and 1.13 respectively, the ratio of the heat exchange performance to the pressure drop of the tooth top to the tooth number is greater than 1, which means that increasing 1 time of the resistance increases the heat exchange effect of more than 1 time, the ratio of the heat exchange performance to the pressure drop of the spiral angle β is far less than 1, which means that increasing 1 time of the resistance increases the heat exchange effect of 0.74 times, so that the beneficial effect of reducing the pressure drop by reducing the spiral angle β is greater than the detrimental effect of the heat exchange performance (reducing the heat exchange performance), and the beneficial effect of reducing the pressure drop by changing the tooth height is less than the detrimental effect of the heat exchange performance (reducing the heat exchange performance).

The spiral angle beta is used for rotating the fluid, so that the fluid in the pipeline generates secondary flow which is different from radial direction, the strength of turbulent flow is increased, the convection heat exchange is enhanced, and the heat exchange coefficient is increased. When the increment of the helix angle beta is larger, the heat exchange performance of the heat exchange tube is improved more. The larger the increase in the helix angle β, the larger the increase in the R290 refrigerant pressure drop. Therefore, by reducing the helix angle beta of the internal thread 200, the pressure drop of the R290 refrigerant can be reduced, and when the pressure drop of the R290 refrigerant is reduced, the heat exchange performance of the heat exchange tube is improved, and the heat exchange performance of the heat exchange tube can be reduced due to the spiral reduction, so that the overall heat exchange performance of the heat exchange tube is improved. Therefore, the helix angle beta of the internal thread 200 of the heat exchange tube of the utility model meets the following conditions: beta is more than or equal to 0 DEG and less than or equal to 15 deg. Alternatively, the internal thread 200 helix angle β of the heat exchange tube may be 0 °, 1 °, 2 °, 3 °, 4 °, 5 °, 6 °, 7.5 °, 10 °, 12.5 °, 13.8 °, 14.5 °, 15 °, etc.

According to the heat exchange tube of the embodiment of the utility model, the outer diameter D of the tube body 100 of the heat exchange tube has the following dimensions: d is more than or equal to 5.5mm and less than or equal to 10mm, the heat exchange performance of the heat exchange tube is greatly influenced, and meanwhile, the helix angle beta of the internal thread 200 with smaller influence weight on pressure drop is set to be satisfied: beta is more than or equal to 0 degree and less than or equal to 15 degrees, and the heat exchange performance of the heat exchange tube is improved while the pressure drop of the refrigerant R290 is reduced.

The heat exchange tube can be a heat exchange copper tube, and the heat exchange copper tube has high heat exchange efficiency, good plasticity and low processing difficulty. In other embodiments, the heat exchange tube may also be an aluminum heat exchange tube.

In the labels of fig. 1 and 2, β is the thread angle, F is the tooth bottom width, W is the tooth groove width, H is the tooth height, α is the tooth top angle, M is the pitch of the internal thread, T is the wall thickness of the pipe body 100, and D is the outer diameter of the pipe body 100.

The heat exchange tube reduces the pressure drop of the medium R290 and improves the heat exchange performance of the heat exchange tube by reducing the helix angle beta of the internal thread 200. The change of the helix angle β of the internal thread 200 will also necessarily drive the change of other parameters of the heat exchange tube.

The number N of internal threads 200 is the number of teeth, and in some embodiments of the present utility model, the number N of internal threads 200 satisfies the following relationship: n is more than or equal to 60 and less than or equal to 80.

When the number of teeth N is increased more, the heat exchange performance of the heat exchange tube is improved more. The number of teeth N of the internal thread 200 of the heat exchange tube is increased, so that the number of vaporization cores can be increased, the boiling heat exchange measure is facilitated, the inner surface area of the heat exchange tube can be effectively increased, and the circulating refrigerant in the heat exchange tube has a larger contact area with the heat exchange tube, so that the heat exchange performance of the heat exchange tube is improved. When the number of teeth N increases, the pressure drop of R290 refrigerant increases.

The influence weights of four influence factors of the tooth top angle, the tooth height, the spiral angle and the tooth number shown in fig. 3 on the pressure drop and the influence weights of four influence factors of the tooth top angle, the tooth height, the spiral angle and the tooth number shown in fig. 4 on the heat exchange coefficient are combined, the influence weights of the tooth number on the pressure drop are the smallest in the four influence factors, and the influence weights of the tooth number on the heat exchange performance are rearranged to be third. Therefore, by increasing the number N of the internal threads 200, the heat exchange performance of the heat exchange tube can be improved, and the pressure drop improvement amount of the refrigerant R290 is smaller.

The number N of the internal threads 200 is the number of teeth, and the more the number N of the internal threads 200 of the heat exchange tube is, the number of vaporization cores can be increased, thereby being beneficial to boiling heat exchange measures and increasing the heat exchange area of the inner surface of the heat exchange tube, and further improving the heat exchange performance of the heat exchange tube. However, too many internal threads 200 of the heat exchange tube may make the tooth space too small, but rather reduce the stirring strength of the fluid in the tube, increase the thickness of the liquid film between teeth, increase the thermal resistance, and reduce the heat exchange capacity, so that the heat exchange efficiency of the threaded tube approaches to that of the light pipe, and the heat exchange performance of the heat exchange tube is reduced, so that the number N of the internal threads 200 is preferably controlled within a certain range.

The number N of the internal threads 200 of the heat exchange tube according to the embodiment of the utility model satisfies the following relation: n is more than or equal to 60 and less than or equal to 80, the heat exchange performance of the heat exchange tube can be effectively improved, and the pressure drop increment of the refrigerant R290 is smaller.

In some embodiments of the present utility model, the crest angle α of each internal thread 200 satisfies the following relationship: alpha is more than or equal to 5 degrees and less than or equal to 18 degrees.

The smaller the crest angle α of the female screw 200, the greater the amount of improvement in heat exchange performance of the heat exchange tube. The smaller the tooth crest angle alpha of the internal thread 200 of the heat exchange tube is, the heat exchange area of the internal surface of the heat exchange tube is increased, the thickness of a liquid film of a refrigerant is reduced, and the vaporization core of evaporation heat transfer is increased, so that the heat exchange performance of the heat exchange tube is improved. As the crest angle α of the female screw 200 is smaller, the flow resistance increases, and the amount of increase in the pressure drop of the R290 refrigerant increases.

Combining the impact weight of four impact factors of the tooth top angle, tooth height, spiral angle and tooth number shown in fig. 3 on the pressure drop with the impact weight of four impact factors of the tooth top angle, tooth height, spiral angle and tooth number shown in fig. 4 on the heat exchange coefficient, the impact weight of the tooth top angle on the pressure drop is third among the four impact factors, and the impact weight of the tooth number on the heat exchange performance is minimum. Therefore, the heat exchange performance of the heat exchange tube can be improved by reducing the tooth top angle, and the pressure drop lifting amount of R290 refrigerant is smaller.

The smaller the tooth crest angle alpha of the internal thread 200 of the heat exchange tube is, the heat exchange area of the internal surface of the heat exchange tube is increased, the thickness of a liquid film of a refrigerant is reduced, and the vaporization core of evaporation heat transfer is increased, so that the heat exchange performance of the heat exchange tube is improved. However, too small a tooth top angle causes too small expansion resistance of the heat exchange tube, so that the deformation of the tooth shape is increased, and the heat exchange performance of the heat exchange tube is reduced. Therefore, the tooth tip angle is preferably controlled within a certain range.

The tooth tip angle α of the heat exchange tube internal thread 200 according to the embodiment of the present utility model satisfies the following relational expression: alpha is more than or equal to 5 degrees and less than or equal to 18 degrees, the heat exchange performance of the heat exchange tube can be effectively improved, and the increment of pressure drop on R290 refrigerant is smaller.

Several specific examples of the heat exchange tube of the present utility model are described below with reference to tables 1 to 4.

TABLE 1

	Control group 1	Example 1
			Pipe diameter (mm)	5.5	5.5
Tooth height (mm)	0.13	0.13
			Helix angle (°)	25	0
Tooth tip angle (°)	25	5
			Tooth number (°)	40	60
In-tube Property (W/(m) ² ·K))	5673	6360
			Pressure drop ((Pa/m))	3466	3030

According to the pipe diameter D of the heat exchange pipe of example 1, the tooth height H of the internal thread 200 of the heat exchange pipe was 0.13mm, the helix angle beta of the internal thread 200 of the heat exchange pipe was 0 degrees, the tooth tip angle alpha of the internal thread 200 of the heat exchange pipe was 5 degrees, and the number N of the internal threads 200 of the heat exchange pipe was 60, as shown in Table 1.

Compared to the heat exchange tube of the control group 1, the tube diameter D of the heat exchange tube of example 1 and the tooth height H of the internal thread 200 were unchanged, the helix angle β of the internal thread 200 of example 1 was reduced, the tip angle α of the internal thread 200 of example 1 was reduced, and the number of internal threads 200 of example 1 was increased. Compared with the heat exchange tube of the control group 1, the heat exchange performance of the heat exchange tube of the embodiment 1 is obviously improved, the pressure drop of the R290 refrigerant flowing in the heat exchange tube is reduced, and the heat exchange effect of the heat exchange tube is improved.

TABLE 2

	Control group 2	Example 2
			Pipe diameter (mm)	6.35	6.35
Tooth height (mm)	0.14	0.14
			Helix angle (°)	30	10
Tooth tip angle (°)	25	10
			Tooth number (°)	52	70
In-tube Property (W/(m) ² ·K))	6536	7320
			Pressure drop ((Pa/m))	2990	2620

According to the pipe diameter D of the heat exchange pipe of example 2, shown in Table 2, was 6.35mm, the tooth height H of the internal thread 200 of the heat exchange pipe was 0.14mm, the helix angle beta of the internal thread 200 of the heat exchange pipe was 10 DEG, the tooth tip angle alpha of the internal thread 200 of the heat exchange pipe was 10 DEG, and the number N of the internal threads 200 of the heat exchange pipe was 70.

Compared to the heat exchange tube of the control group 2, the tube diameter D of the heat exchange tube of example 2 and the tooth height H of the internal thread 200 were unchanged, the helix angle β of the internal thread 200 of example 2 was reduced, the tip angle α of the internal thread 200 of example 2 was reduced, and the number of internal threads 200 of example 2 was increased. Compared with the heat exchange tube of the control group 2, the heat exchange performance of the heat exchange tube of the embodiment 2 is obviously improved, the pressure drop of the R290 refrigerant flowing in the heat exchange tube is obviously reduced, and the heat exchange effect of the heat exchange tube is improved.

TABLE 3 Table 3

	Control group 3	Example 3
			Pipe diameter (mm)	7	7
Tooth height (mm)	0.15	0.15
			Helix angle (°)	30	12
Tooth tip angle (°)	25	12
			Tooth number (°)	54	78
In-tube Property (W/(m) ² ·K))	7142	8004
			Pressure drop ((Pa/m))	2709	2435

According to the pipe diameter D of the heat exchange pipe of example 3, the tooth height H of the internal thread 200 of the heat exchange pipe was 0.15mm, the helix angle beta of the internal thread 200 of the heat exchange pipe was 12 degrees, the tooth tip angle alpha of the internal thread 200 of the heat exchange pipe was 12 degrees, and the number N of the internal threads 200 of the heat exchange pipe was 78, as shown in Table 3.

Compared to the heat exchange tube of the control group 3, the tube diameter D of the heat exchange tube of example 3 and the tooth height H of the female screw 200 were unchanged, the helix angle β of the female screw 200 of example 3 was reduced, the tip angle α of the female screw 200 of example 3 was reduced, and the number of female screws 200 of example 3 was increased. Compared with the heat exchange tube of the control group 3, the heat exchange performance of the heat exchange tube of the embodiment 3 is obviously improved, the pressure drop of the R290 refrigerant flowing in the heat exchange tube is obviously reduced, and the heat exchange effect of the heat exchange tube is improved.

TABLE 4 Table 4

	Control group 4	Example 4
			Pipe diameter (mm)	10	10
Tooth height (mm)	0.15	0.15
			Helix angle (°)	35	15
Tooth top angle(°)	25	15
			Tooth number (°)	60	80
In-tube Property (W/(m) ² ·K))	7352	8455
			Pressure drop ((Pa/m))	2530	2223

As shown in table 4, the pipe diameter D of the heat exchange pipe of example 4 was 10mm, the tooth height H of the internal thread 200 of the heat exchange pipe was 0.15mm, the helix angle β of the internal thread 200 of the heat exchange pipe was 15 °, the tooth tip angle α of the internal thread 200 of the heat exchange pipe was 15 °, and the number N of internal threads 200 of the heat exchange pipe was 80.

Compared to the heat exchange tube of the control group 4, the tube diameter D of the heat exchange tube of example 4 and the tooth height H of the internal thread 200 were unchanged, the helix angle β of the internal thread 200 of example 4 was reduced, the tip angle α of the internal thread 200 of example 4 was reduced, and the number of internal threads 200 of example 4 was increased. Compared with the heat exchange tube of the control group 4, the heat exchange performance of the heat exchange tube of the embodiment 4 is obviously improved, the pressure drop of the R290 refrigerant flowing in the heat exchange tube is obviously reduced, and the heat exchange effect of the heat exchange tube is improved.

Four specific examples of the heat exchange tube of the present utility model shown in tables 1 to 4 are combined, and the dimensions of the outer diameter D of the tube body 100 of the heat exchange tube of the present utility model satisfy: d is more than or equal to 5.5mm and less than or equal to 10mm, and the helix angle beta of the internal thread 200 of the heat exchange tube meets the following conditions: beta is more than or equal to 0 degree and less than or equal to 15 degrees, and the number N of the internal threads 200 of the heat exchange tube meets the following conditions: n is more than or equal to 60 and less than or equal to 80, and the tooth top angle alpha of the internal thread 200 of the heat exchange tube meets the following conditions: alpha is more than or equal to 5 degrees and less than or equal to 18 degrees, so that the heat exchange performance of the heat exchange tube is improved while the pressure drop of the refrigerant R290 is reduced. The pressure drop of the refrigerant R290 is reduced by more than 12%, and the heat exchange efficiency of the heat exchange tube flowing the refrigerant R290 is improved by more than 12%.

In some embodiments of the utility model, the size of the outer diameter D of the tubular body 100 is positively correlated with the internal thread 200 helix angle β, with the larger the size of the outer diameter D of the tubular body 100, the larger the internal thread 200 helix angle β.

In some embodiments of the present utility model, two adjacent internal threads 200 define a groove therebetween, and at least two portions of the groove have different directions of extension. The extending direction of the internal threads 200 defines the extending direction of the groove, that is, at least two internal threads 200 have different extending directions. Compared with the heat exchange tubes with the extending directions of the internal threads 200 being parallel to each other, the heat exchange tube with the internal threads 200 with different extending directions can enhance the disturbance of the refrigerant, thin the liquid film and improve the heat exchange performance.

In a first embodiment of the heat exchange tube of the present utility model, at least a portion of the grooves having different directions of extension are disposed to intersect to define a grid shape. The extending direction of the female screw 200 defines the extending direction of the groove, and at least part of the extending directions of the female screw 200 are disposed to intersect so that the groove has a mesh shape. Compared with the heat exchange tubes with the extending directions of all the internal threads 200 being parallel to each other, the heat exchange tube with the internal threads 200 with the extending directions being crossed with each other has the advantages that the grid-shaped grooves appear on the inner wall of the threaded tube, the disturbance of the refrigerant can be enhanced, the liquid film is thinned, and the heat exchange performance is improved.

In some embodiments of the first portion of the heat exchange tube of the present utility model, as shown in fig. 5, the extending directions of the first portion of the grooves in the heat exchange tube are the same, the extending directions of the second portion of the grooves in the heat exchange tube are the same, and the extending directions of the first portion of the grooves and the extending directions of the second portion of the grooves are intersected with each other, so that the plurality of grooves are intersected with each other to define a grid shape.

In the first partial embodiment of the heat exchange tube of the present utility model, the ratio of the length of the tube body 100 provided with the mesh shape to the entire length of the tube body 100 is not less than eighty percent. The ratio of the length of the pipe body 100 provided with the mesh shape to the entire length of the pipe body 100 is eighty percent or more, and the pipe body 100 provided with the mesh shape is a large part of the pipe body 100.

In the first embodiment of the heat exchange tube according to the present utility model, the pitch of the internal thread 200 corresponding to the plurality of grooves having the same extending direction is M, wherein the ratio of the pitch M to the pipe diameter D ranges from 3 to 5.

The effect of the pitch and the pipe diameter on the heat exchange pipe overall performance enhancement ratio will be briefly described below with reference to a schematic diagram of the effect of the ratio of the pitch to the pipe diameter on the heat exchange pipe overall performance enhancement ratio shown in fig. 6.

The integrated performance enhancement ratio PEC is an optimized parameter for evaluating the heat exchange performance and pressure drop of the heat exchange tube.

Wherein H is the heat exchange coefficient enhancement ratio of the heat exchange tube, and P is the pressure drop enhancement ratio of the refrigerant flowing in the heat exchange tube.

Wherein, under the condition that other parameters of the heat exchange tube are the same, h ₁ The heat exchange coefficient, h, of the heat exchange tube in the first part of the embodiment of the utility model ₀ The heat exchange coefficients of the heat exchange tubes are parallel to each other in the extending direction of the internal thread 200.

Wherein, when other parameters of the heat exchange tube are the same, the refrigerant is the same, p ₁ Is the pressure drop, p, of the refrigerant in the heat exchange tube in the first part of the embodiment of the utility model ₀ Is the pressure drop of the heat exchange tube in which the extending directions of the internal threads 200 are all parallel to each other.

The larger the values of the comprehensive performance enhancement ratio PEC and H can be obtained by bringing the formula 2 and the formula 3 into the formula 1, the better the heat exchange performance of the heat exchange tube in the first part of embodiments of the present utility model is, the smaller the value of P is, and the smaller the pressure drop of the refrigerant in the heat exchange tube in the first part of embodiments of the present utility model is.

It can be understood that the heat exchange tube aims at improving the heat exchange performance of the heat exchange tube while reducing the pressure drop of the refrigerant, so that the performance optimization of the heat exchange tube is described by adopting the comprehensive performance enhancement ratio PEC. The value of the comprehensive performance enhancement ratio PEC is larger than 1, which indicates that the heat exchange performance of the heat exchange tube is improved, the heat exchange tube has performance optimization, and the larger the value of the PEC, the larger the heat exchange performance of the heat exchange tube and the smaller the pressure drop.

When the ratio of the thread pitch M to the pipe diameter D is smaller, the helix angle β is larger, the movement resistance to the refrigerant is larger, the pressure drop is increased, and referring to fig. 6, when the ratio of the thread pitch M to the pipe diameter D is 2, the overall performance enhancement ratio PEC is smaller than 1. When the ratio of the thread pitch M to the pipe diameter D is large, the heat exchange coefficient is small, and referring to FIG. 6, when the ratio of the thread pitch M to the pipe diameter D is 6, the overall performance enhancement ratio PEC is smaller than 1. Therefore, the ratio of the thread pitch M to the pipe diameter D is optimal when the value range is 3-5, and the comprehensive performance enhancement ratio PEC is more than 1. Preferably, when the ratio of the thread pitch M to the pipe diameter D is 4, the comprehensive performance enhancement ratio PEC is the largest, and at the moment, the heat exchange performance of the heat exchange pipe is better and the pressure drop is smaller.

In the first embodiment of the heat exchange tube according to the present utility model, the ratio between the number N of the internal threads 200 and the outer diameter D of the tube body 100 is preferably 4 to 10, and the heat exchange performance of the heat exchange tube is better and the pressure drop is smaller.

In the second portion embodiment of the heat exchange tube of the present utility model, in the extending direction of the tube body 100, the tube body 100 includes a first portion and a second portion, and the spiral extending direction of the groove provided on the inner wall of the first portion is opposite to the spiral extending direction of the groove provided on the inner wall of the second portion. Compared with the heat exchange tubes with the extending directions of the internal threads 200 being parallel to each other, the heat exchange tube with the internal threads 200 with different extending directions can enhance the disturbance of the refrigerant, thin the liquid film and improve the heat exchange performance.

The direction of the helical extension of the grooves provided by the inner wall of the first portion is opposite to the direction of the helical extension of the grooves provided by the inner wall of the second portion, which in some embodiments may be understood as: the helix angle of the internal thread 200 of the first portion is in the opposite sense to the helix angle of the internal thread 200 of the second portion. In some embodiments, the helix angle of the internal threads 200 of the first portion is equal to the helix angle of the internal threads 200 of the second portion.

In a second portion embodiment of the heat exchange tube of the present utility model, the tube body 100 includes at least one first portion and includes at least one second portion. The first part and the second part can be a plurality of, and a plurality of first parts and second parts are mutually staggered to strengthen the refrigerant disturbance, attenuate the liquid film, promote the heat transfer performance of heat exchange tube.

In some embodiments of the second portion of the heat exchange tube of the present utility model, as shown in fig. 7, the tube body 100 includes a first portion and a second portion, and the spiral extension direction of the groove disposed on the inner wall of the first portion is opposite to the spiral extension direction of the groove disposed on the inner wall of the second portion.

In the second portion embodiment of the heat exchange tube of the present utility model, the ratio between the length L1 of the first portion and the outer diameter D of the tube body 100 satisfies the following relationship: l1/d=1.5 to 3.5; and/or the ratio between the length L2 of the second portion and the outer diameter D of the tubular body 100 satisfies the following relationship: l2/d=1.5 to 3.5.

The ratio between the length L1 of the first portion and the outer diameter D of the tube body 100, or the ratio between the length L2 of the second portion and the outer diameter D of the tube body 100, describes the ratio between the length of the tube body 100 having grooves in the same extending direction as the outer diameter of the heat exchange tube in the tube body 100 of the heat exchange tube in the embodiment of the second portion. The ratio L/D of the length L of the tube 100 to the outer diameter D of the tube 100 having the same extending direction grooves is thus used in fig. 8 and 9 to refer to the ratio between the length L1 of the first portion and the outer diameter D of the tube 100 and the ratio between the length L2 of the second portion and the outer diameter D of the tube 100.

The effect of the value of the length of the tube 100 and the tube diameter of the grooves in the same extending direction on the heat exchange tube comprehensive performance enhancement ratio will be briefly described below with reference to a schematic diagram of the effect of the ratio of the length of the tube with grooves in the same extending direction to the tube diameter on the heat exchange coefficient enhancement ratio and the pressure drop enhancement ratio shown in fig. 8, and a schematic diagram of the effect of the ratio of the length of the tube with grooves in the same extending direction to the tube diameter on the heat exchange tube comprehensive performance enhancement ratio shown in fig. 9.

Wherein, h2 is the heat exchange coefficient of the heat exchange tube in the second part of embodiments of the utility model, h under the condition that other parameters of the heat exchange tube are the same ₀ The heat exchange coefficients of the heat exchange tubes are parallel to each other in the extending direction of the internal thread 200.

Wherein, under the condition that other parameters of the heat exchange tube are the same, and the refrigerant is the same, p2 is the pressure drop of the refrigerant in the heat exchange tube in the second part of the embodiment of the utility model, p ₀ Is the pressure drop of the heat exchange tube in which the extending directions of the internal threads 200 are all parallel to each other.

The larger the values of the comprehensive performance enhancement ratio PEC and H can be obtained by introducing the formula 4 and the formula 5 into the formula 1, the better the heat exchange performance of the heat exchange tube in the second part of embodiments of the present utility model is, the smaller the value of P is, and the smaller the pressure drop of the refrigerant in the heat exchange tube in the second part of embodiments of the present utility model is.

Referring to fig. 8, when the value of L/D is small, the spiral angle β is large, the heat exchange coefficient enhancement ratio is large, but the movement resistance to the refrigerant is large, the pressure drop enhancement ratio is also large, and referring to fig. 9, when the value of L/D is 1, the overall performance enhancement ratio PEC is less than 1. Referring to fig. 8, the helix angle β is smaller when the value of L/D is larger, the same heat exchange coefficient is smaller although the pressure drop is smaller, and referring to fig. 9, the integrated performance enhancement ratio PEC is smaller than 1 when the value of L/D is 4.

Therefore, the value of L/D is preferably in the range of 1.5 to 3.5, and the overall performance enhancement ratio PEC is greater than 1 as shown in FIG. 8.

Preferably, the ratio between the length L1 of the first portion and the outer diameter D of the tube body 100 is 2.5, and the ratio between the length L2 of the second portion and the outer diameter D of the tube body 100 is 2.5, and the heat exchange performance of the heat exchange tube is better and the pressure drop is smaller.

The heat exchanger according to the embodiment of the utility model comprises the heat exchange tube of any one of the above.

Optionally, the heat exchanger of the embodiment of the utility model further comprises a plurality of fins, and the fins are connected with the heat exchange tube.

In some embodiments, the heat exchanger may be configured as an evaporator, and the heat exchanger may also be configured as a condenser.

According to the air conditioner provided by the embodiment of the utility model, the heat exchanger is arranged, so that the refrigerating and heating efficiency of the air conditioner is high, the use cleanliness of the air conditioner is good, and the environment-friendly performance is good.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., 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 utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the utility model, the scope of which is defined by the claims and their equivalents.

Claims

1. The utility model provides a heat exchange tube for heat exchanger, its characterized in that, the heat exchange tube is used for circulating R290 refrigerant, the heat exchange tube includes body and internal thread, the internal thread is many and every the internal thread is followed the inner wall spiral extension of body, the external diameter of body is D, every the helix angle of internal thread is beta, and wherein external diameter and helix angle satisfy following relation: d is more than or equal to 5.5mm and less than or equal to 10mm, and beta is more than or equal to 0 degree and less than or equal to 15 degrees.

2. The heat exchange tube for a heat exchanger according to claim 1, wherein the number N of the female screws satisfies the following relation: n is more than or equal to 60 and less than or equal to 80.

3. A heat exchange tube for a heat exchanger according to claim 1, wherein a tooth tip angle α of each of the internal threads satisfies the following relation: alpha is more than or equal to 5 degrees and less than or equal to 18 degrees.

4. A heat exchange tube for a heat exchanger according to any one of claims 1 to 3 wherein adjacent ones of the internal threads define a channel therebetween, at least two of the channels having different directions of extension.

5. A heat exchange tube for a heat exchanger according to claim 4 wherein at least a portion of the grooves having different directions of extension are disposed crosswise to define a grid shape.

6. The heat exchange tube for a heat exchanger according to claim 5, wherein a ratio of a length of the tube body provided with the mesh shape to an entire length of the tube body is not less than eighty percent.

7. The heat exchange tube for heat exchanger according to claim 5, wherein the pitch of the female screw corresponding to the plurality of grooves having the same extending direction is M, wherein the ratio of M to D ranges from 3 to 5.

8. The heat exchange tube for a heat exchanger according to claim 7, wherein a ratio between the number N of the internal threads and the outer diameter D of the tube body is 4 to 10.

9. The heat exchange tube for a heat exchanger according to claim 4, wherein in an extending direction of the tube body, the tube body includes a first portion and a second portion, and a spiral extending direction of the groove provided on an inner wall of the first portion is opposite to a spiral extending direction of the groove provided on an inner wall of the second portion.

10. A heat exchange tube for a heat exchanger according to claim 9, wherein the ratio between the length L1 of the first portion and the outer diameter D of the tube body satisfies the following relation: L1/D is less than or equal to 1.5 and less than or equal to 3.5; and/or

The ratio between the length L2 of the second portion and the outer diameter D of the tube body satisfies the following relation: L2/D is less than or equal to 1.5 and less than or equal to 3.5.

11. A heat exchanger comprising a heat exchange tube according to any one of claims 1-10.

12. An air conditioner comprising the heat exchanger according to claim 11.