CN104006696A - Rectangular and circular channel mixed type contact-heat-resistance-free heat transfer element - Google Patents

Abstract

The invention designs a non-contact thermal resistance heat transfer element applied to various heat exchangers with a mixed rectangular and circular channel, which belongs to the category of thermodynamic mechanical devices. It is composed of rectangular and circular mixed heat transfer tube channels and corrugated heat dissipation fins. The corrugated heat dissipation fins and heat transfer tubes are integrally formed. The mixed combination of circular cross-section pipes and rectangular cross-section pipes not only has a high convective heat transfer coefficient, The water side flow resistance coefficient is lower than that of the circular channel, the gas side flow resistance coefficient is lower, the water side resistance coefficient is lower than the rectangular channel, and the bending resistance is enhanced compared with the rectangular channel, which improves the pressure resistance and deformation resistance of the assembled radiator. This kind of finned tube heat transfer element in the form of mixed pipes has better overall heat transfer performance, high space utilization rate, and compact structure, so it can be widely used in heat exchangers for various products such as air conditioners, refrigeration equipment, and vehicles.

Description

Rectangular and circular channel hybrid non-contact thermal resistance heat transfer element

technical field

The invention relates to a mixed non-contact thermal resistance heat transfer element of a rectangular channel and a circular channel used in various heat exchangers, belonging to the category of thermodynamic mechanical devices.

Background technique

The heat transfer elements used in existing air conditioners, vehicles, and refrigeration equipment heat exchangers are generally composed of copper tubes (or aluminum tubes) and aluminum fins, while the heat transfer tubes and cooling fins of the heat transfer elements used at this stage It is a split structure, usually connected by expansion tube or brazing, the manufacturing and processing technology is relatively complicated, the contact thermal resistance between the fin and the heat transfer tube is large; and the anti-vibration ability is poor, and in construction machinery The working environment of the heat exchanger is harsh, which often leads to local loosening or even fracture of the connection between the cooling fin and the heat transfer tube after a period of time, which will also increase the contact thermal resistance and cause a significant decline in its heat transfer performance . The heat transfer pipe channel is a single rectangular heat transfer element, which has poor bending resistance. Therefore, the overall pressure resistance and deformation resistance of the radiator assembled by the heat transfer element assembly is poor. If the rectangular channel is narrow, the flow resistance on the water side is large. If the rectangular channel is wide, the gas side flow resistance is large. In order to overcome the above defects, the present invention designs a non-contact thermal resistance heat transfer element with a mixture of rectangular and circular channels. The side flow resistance coefficient does not increase much, and at the same time, the pressure resistance and heat transfer performance of the entire heat transfer tube are improved. The element is an integral aluminum structure with compact structure and high heat transfer efficiency, which can greatly improve the heat transfer performance and structural strength of the heat exchanger. It is simple to process, saves materials, and reduces production costs.

Contents of the invention

The non-contact thermal resistance heat transfer element of the present invention is composed of a rectangular and a circular channel mixed type heat dissipation fin and a heat transfer tube. Corrugated, consisting of two straight lines and an arc, the straight lines are distributed on both sides of the arc and tangent to the arc. The radius of the arc is R, and the cross-sectional shape is two small rectangular pipes with a row of fins respectively. The wavelengths of these two rows of fins are both S ₁ and the wave height is H ₁ ; There is a row of fins respectively, the wavelength of these two rows of fins is S ₂ , and the wave height is H ₂ ; there is a row of fins on the pipe with a large rectangular cross section, the wavelength of this row of fins is S ₃ , and the wave height is H ₁ ; The radius of each arc is R. The corrugated fins are located on the upper and lower sides of the heat transfer tube, perpendicular to the heat transfer tube, the spacing between the fins is S _f , the thickness of the fins is δ, and the heights are H ₃ and H ₄ ; the cross-sectional shape is two small rectangles The heat transfer pipe whose section thickness is W ₁ and width is L ₁ ; the cross-sectional shape is two circular heat transfer pipes, whose cross-sectional thickness is diameter D, and the width is diameter D; the cross-sectional shape is a large rectangular heat transfer pipe , the section thickness is W ₁ and the width is L ₂ . The heat transfer pipes do not communicate with each other, and each pipe communicates with each other along the axial direction, and the distance between the channels is L ₃ .

Compared with the heat transfer elements of existing heat exchangers, the rectangular and circular channel hybrid non-contact thermal resistance heat transfer elements designed by the present invention have the following advantages:

(1) The heat transfer performance is significantly improved. The heat transfer pipe is a rectangular and circular non-contact thermal resistance heat transfer element, which improves the heat transfer coefficient. Due to the addition of the circular pipe, the heat transfer area and heat transfer space are greatly improved. The heat pipe adopts integral type, which eliminates the contact thermal resistance, so the heat transfer performance is good. Compared with the existing heat transfer elements, the heat transfer coefficient K of the heat transfer element of the rectangular and circular heat transfer pipe can be increased by 25-40 %.

(2) Under the condition of transferring the same amount of heat, the volume and weight of the hybrid heat transfer element can be reduced by 20-39%, saving a lot of materials and reducing production costs.

(3) Radiating fins and heat transfer tubes are integrated, no welding is required, and no pickling process is required, which simplifies the manufacturing process and does not pollute the environment.

(4) Due to the addition of circular pipes, its resistance coefficient is reduced by 5-10%, and its pressure resistance performance is improved at the same time.

(5) Compared with the non-contact thermal resistance heat transfer element of the rectangular and circular channel of the present invention, compared with a single rectangular channel, the bending resistance of the heat transfer element is significantly enhanced, the flow resistance coefficient of the water side is reduced, and the flow resistance coefficient of the air side is not increased. Large, the pressure resistance and heat transfer performance of the entire heat transfer tube are increased by 5-15%.

Concrete structure of the present invention is provided by accompanying drawing 1,2,3.

Description of drawings

Accompanying drawing 1 is the front view of the non-contact thermal resistance heat transfer element mixed with rectangular and circular channels;

Accompanying drawing 2 is the top view and detailed enlarged view of the non-contact thermal resistance heat transfer element mixed with rectangular and circular channels;

Accompanying drawing 3 is the left side view of the non-contact thermal resistance heat transfer element of the mixed rectangular and circular channel.

Detailed ways

As shown in Figures 1, 2, and 3, the rectangular and circular channel hybrid non-contact thermal resistance heat transfer element of the present invention is composed of heat dissipation fins 1 and heat transfer flat tubes 2, and the heat dissipation fins 1 and heat transfer flat tubes 2 are integrated. , the heat dissipation fins 1 are located on the upper and lower sides of the heat transfer flat tube 2, the heat dissipation fins 1 on the upper and lower sides are corrugated, the heat dissipation fins 1 are perpendicular to the heat transfer flat tube 2, and the distance between the heat dissipation fins 1 is S, the thickness of the cooling fin is δ, the height is H ₃ , H ₄ , the wavelength of the corrugated cooling fin is S ₁ , S ₂ , S ₃ , the wave height is H ₁ , H ₂ , H ₃ , the heat transfer flat tube 2 The section thickness is W and the width is L. Three rectangular and two circular passages are arranged in the heat transfer flat tube 2 along the axial direction, and they are not connected to each other (see Figure 1). W ₁ , the width is L ₁ , the section width of the circular channel 2 is the diameter D, the thickness is the diameter D, the section thickness of the rectangular channel 3 is W ₁ , the width is L ₂ , and the distance between the channels is L ₃ . When the heat transfer element is working, the fluid with high temperature (such as water or oil) flows in from one end of each channel in the heat transfer flat tube 2, and then flows out from the other end of the channel, while the air with a lower temperature sweeps across the heat transfer flat tube 2 outside the heat dissipation fins 1, so as to realize the heat exchange between the hot fluid in the heat transfer flat tube 2 and the cold air flowing through the heat dissipation fins 1.

Claims (2)

1. the hybrid contactless thermal resistance heat transfer element of rectangle and circular channel, comprises heat-transfer pipe and radiating fin, and wherein, heat-transfer pipe and radiating fin are aluminium matter monolithic construction, one machine-shaping.

2. heat-transfer pipe passage according to claim 1 is rectangle and circular hybrid heat transfer element, it is characterized in that: the axial location of heat-transfer pipe is uniform-distribution with heat-transfer pipe passage, heat-transfer pipe passage is formed by rectangular duct and circular pipe alternative arrangement, between each passage, spacing is identical, and each passage is not connected.