JPS6166092A - Heat exchanger for air cooling - Google Patents

Abstract

PURPOSE:To reduce noises due to the coolant injection energy generating in the air cooling heat exchanger by providing a means for scattering a coolant jet. CONSTITUTION:The top end of a flat coolant tube 1 of the air cooling exchanger is brazed to a coolant collective tube in the state of being inserted into the latter. To scatter the coolant jet, the top end 1a of the coolant tube is cut aslant in the direction of the flat part of the tube. As a result, the flow of the coolant gas in the tube becomes asymmetric right and left in the cross direction so that the flow of the coolant is disturbed and the generation of sounds resulting from a resonance phenomenon of the gas column in the tube liable to take place when the gas flows within the tube in a high-speed rectified condition is prevented. Further, the coolant collective tube 2 is attached to the coolant tube 1 at an angle of inclination with respect to the direction of the width of the top end surface of the tube 1. Therefore, the coolant gas flowing through the tube 2 becomes turbulent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a heat exchanger used in a cooling device, and particularly to an evaporator built into a vehicle cooling unit.

[Prior Art] One of the basic principles when designing a vehicle, especially a passenger car, is to increase the static/T1 degree inside the vehicle cabin as much as possible. There are many sources of noise, but in the case of heating and cooling equipment, the jet noise of refrigerant generated from the cooling evaporator installed in front of the driver's seat reaches a level that is difficult to celebrate. Since the mechanism by which this occurs has not been fully elucidated, effective countermeasures have not yet been developed.

By the way, a conventional evaporator has an appearance as shown in FIG. 10, and as can be understood from the partially cutaway view in FIG. 11, it is wide and flat, and has many partition walls 1b inside.
The porous refrigerant tube 1 provided with the refrigerant tube 1 is bent in a meandering manner to form a panel-like or block-like body, and both ends of the refrigerant tube 1 are inserted into the refrigerant collecting pipe 2, and these three parts are joined by brazing. I was letting it happen. 3 is a fin for increasing the heat transfer area inserted between the parallel tubes.

As shown in FIG. 12, which shows the A-A section of FIG. I am trying to improve my overall strength.

In order to operate the evaporator with the above configuration, when liquefied cold 1 is sent into one of the refrigerant collecting pipes, it exchanges heat with warm air while passing through the tube, evaporates, and gradually increases the vapor pressure while moving the tube. It reaches the outlet end and is ejected as a high-velocity gas stream in the other refrigerant manifold. It is understood that the kinetic energy of this ejected gas causes resonance vibrations in the air column within the refrigerant manifold pipe, which causes refrigerant passage noise.

[Problems to be Solved by the Invention] The present inventors aimed to elucidate the mechanism of noise generation from evaporators used in automobile cooling systems (in the process of conducting a series of experiments, a They discovered that the distance between the tip of the refrigerant tube and the opposing refrigerant aggregate color/inner wall surface is closely related to the level of noise generated. As explained in , in the evaporator having the structure of the refrigerant collecting pipe as shown in the cross-sectional view of FIG. We found that when the distance is within the range, noise above the audible level is generated, but even if the distance decreases beyond this numerical range, or conversely increases, the G-sound level decreases to below the audible level. It was.

In the graph of FIG. 13, the horizontal axis represents distance and the vertical axis represents the level of noise level. When the level B is exceeded, Hta becomes audible to the ears. Therefore, in this experimental example, audible noise is generated only in the refrigerant collecting pipe whose distance is set in the range of A1-A2 shown in the figure. The present invention
Based on the knowledge obtained through a series of experiments as described above, the present invention aims to provide a supplementary heat exchanger that can eliminate or significantly reduce the noise derived from the jet energy of the refrigerant generated in the air cooling heat exchanger. purpose.

[Means for Solving the Problems] The air cooling heat exchanger of the present invention is a heat exchanger having a configuration in which a flat refrigerant tube is bent in a meandering manner, and refrigerant collecting pipes are assembled at both ends of the tube. The refrigerant jet is dispersed onto at least one of the tip of the refrigerant tube protruding into the refrigerant manifold and the refrigerant manifold so as to minimize the refrigerant jet noise generated in the manifold. A means is provided for this purpose.

[Operation and Effect 1 of the Invention] The air cooling heat exchanger of the present invention has a conventional homogeneous heat exchanger in at least one of the tip of the refrigerant tube that is fitted into the refrigerant collecting pipe and protrudes into the pipe, and the refrigerant collecting pipe. It is generated due to the high kinetic energy possessed by the gaseous refrigerant that is discharged from the tip of the refrigerant tube into the refrigerant collecting pipe without a jet shape due to the shape being somewhat different from that of the refrigerant tube or by giving +Ma. , it is possible to suppress the level of refrigerant passing noise to below or to the lowest level, and it is possible to reduce the noise level of refrigerant passing from the 5-cycle evaporator, which was often audible in a quiet living room or a passenger car. The resulting noise problem can be solved with almost no increase in the manufacturing cost of the device.

[Example] The air cooling heat exchanger of the present invention will be described below based on an example shown in the accompanying drawings.

Fig. 1 is a cross-sectional view showing the assembly of a refrigerant tube and a refrigerant collecting pipe in an embodiment in which a specific shape is given to the end surface of the refrigerant tube in order to disperse the refrigerant jet; Refrigerant tubes 2 are refrigerant collecting pipes, both of which are made of aluminum or aluminum alloy. The insulator is made of a copper-based alloy, and the distal end of the refrigerant tube 1 is inserted into a blowing hole previously provided in the refrigerant manifold 2, and the refrigerant tubes 1 are joined together by brazing. 1a is an end face obtained by cutting the tip of the refrigerant tube 1 obliquely in the flat direction of the tube.

10 and 11 are a perspective view and a sectional view taken along the line B-B' of a conventional air cooling heat exchanger as an evaporator incorporated in an air conditioner for an automobile, and the Oi flat refrigerant tube 1 is Bent in a serpentine shape! The entire structure has a panel or block shape, and corrugated fins 3 for increasing the heat transfer area are fitted into the gaps between the refrigerant tubes 1 that are adjacent to each other in parallel. are joined by. Further, as shown in FIG. 11, the refrigerant tube 1 has a porous reinforcing structure in which the inner space is divided into partition walls 1b in the width direction. 1G
is the part of the hole. The cooling 1s collecting pipe 2 is provided with a hole 2a for fitting the refrigerant tube 1, and the tip of the refrigerant duplex 1 is inserted into the collecting pipe in a state that protrudes to some extent into the refrigerant collecting pipe 2 in order to ensure assembly strength. 2 is joined by brazing. 4 is a joint for connection to a refrigerant pipe, and 5 is a stopper.

Next, to explain the characteristics of the air cooling heat exchanger shown in this embodiment, the tip surface of the refrigerant tube of a conventional heat exchanger is In contrast to the case where the end face extends vertically, the end face 1a of the present invention has an end face 1a extending in an oblique direction. For this reason, the refrigerant gas discharged from the refrigerant tube 1 is divided evenly to the left and right in the cross-sectional direction within the refrigerant collecting pipe 2, and then proceeds longitudinally within the pipe toward its terminal outlet. While the latter exhibits a smooth flow state, the latter is deflected to the left in the figure and ejected due to the shape of the oblique end surface 1a of the refrigerant tube 1.
The flow of refrigerant gas is asymmetrical in the cross-sectional direction within the refrigerant collecting pipe, and as a result, the flow of refrigerant gas within the refrigerant collecting pipe is in a disturbed state, unlike the former.
This has the effect of preventing the generation of sound due to the resonance phenomenon of the air column within the pipe, which generally occurs when gas flows through the pipe with high-speed rectification. The length of the refrigerant tube 1 projected into the refrigerant collecting pipe 2 and the inclination angle of the obliquely cut end surface 1a of the refrigerant tube 1 can only be determined empirically, but in this case, the inclination angle was set to about 456.

[Other Embodiments] In the embodiment shown in FIG. 2, the distal end surface of the refrigerant tube 1 in the refrigerant collecting pipe is mounted at a certain inclination angle α with respect to the width direction. By taking such measures, the distance Nt from the tip of the refrigerant tube 1 to the inner wall surface of the refrigerant collecting pipe 2 is not uniform in the inside direction of the refrigerant tube 1. Turbulent conditions are created in the refrigerant gas.

It's cold again in Figure 3! I! ! ! In the third embodiment shown as a side view of the collecting pipe section, instead of installing the refrigerant collecting pipe 2 at an angle with respect to the refrigerant duplex 1 as in the embodiment shown in FIG. By cutting in a state in which each β is slightly inclined in the `` direction, the effect of reducing the refrigerant jet J9ii sound according to the second embodiment can be obtained more easily.

Next, in the fourth embodiment shown as a cross-sectional view of the refrigerant collecting pipe portion in FIG. By providing this, the effect of causing turbulence in the refrigerant gas flow discharged into the refrigerant collecting pipe 2 is increased.

As mentioned above, the inventors of the present application first explained the reason why the level of refrigerant passage noise inside the pipe is reduced by providing the so-called pupil "object 2b" in the J: sea urchin refrigerant collecting pipe 2. The discovered fact about the relationship between the internal shape of the refrigerant collecting pipe 2 and the refrigerant passage noise generated inside the pipe, that is, the distance between the tip end of the refrigerant tube 1 and the inner wall surface of the refrigerant collecting pipe 2 is The combination structure of the refrigerant collecting pipe and the refrigerant tube can be considered in conjunction with experimental data that the noise level is weakened below the audible level within a certain range. Then, by providing the pipe obstruction 2b in the refrigerant collecting pipe 2, the above-mentioned distance falls within the above-mentioned specific range, and therefore, the refrigerant gas discharged from the tip of the refrigerant tube 1 hits the inner wall surface of the refrigerant collecting pipe. It is understood that a situation is brought about in which turbulence is most likely to occur before the collision occurs, and therefore resonance phenomena in the air column within the tube are less likely to occur.

The fifth fruit 11+[! of the present invention shown in FIG. i example J
3, the refrigerant collecting pipe 6 is an obstacle in the refrigerant collecting pipe.
A band-shaped rib 6a is formed integrally with the tube on the top surface thereof in the longitudinal direction of the tube.

FIG. 6 is a diagram of a sixth embodiment as a modification of the embodiment depicted in FIG. It is fixed.

FIG. 7 shows a seventh embodiment, in which the top 9a of the refrigerant collecting pipe 9 is flattened into a crowned shape, and functions as an obstacle to the refrigerant discharge port of the refrigerant duplex 1.

FIG. 8 is a view of the eighth embodiment, in which an obstacle 10 having a U-shaped cross section is fitted into the upper part of the refrigerant collecting pipe 2.

In the ninth embodiment shown in FIG. 9, the refrigerant collecting pipe 11 has a somewhat elongated elliptical shape. By doing this, the distance between the tip of the refrigerant tube 1 and the inner wall surface of the refrigerant manifold 11 is maintained while keeping the length that the refrigerant duplex 1 protrudes into the refrigerant manifold 11 to the required length for the assembly strength of both. The effect of making it easier to set a state in which refrigerant passage noise is less likely to occur as described above can be obtained.

The air cooling heat exchanger of the present invention relates to a method for reducing the jet noise of refrigerant gas flowing at high speed in a pipe, and the mechanism of generation of this type of noise has not yet been numerically clarified. Therefore, it is extremely difficult to uniquely express the shape and structure of a heat exchanger to achieve the object of the present invention based on the idea of the present invention, and the above embodiments are only a few representative examples. However, various partial design changes are possible.

[Brief explanation of drawings]

FIG. 1 and FIGS. 4 to 9 are cross-sectional views of the joints between cold tJX collector pipes and refrigerant tubes in seven embodiments of the air cooling heat exchanger according to the present invention, and FIG. and FIG. 3 are transparent side views of similar joints for two other embodiments, and FIGS. 10 to 12 are external views of a conventional heat exchanger, perspective views of partial section B-E3'. figure,
FIG. 13 is a graph showing the correlation between the distance between the end surface of the refrigerant tube and the inner wall surface of the refrigerant collecting pipe and the level of refrigerant jet noise generated in the refrigerant collecting pipe.

Claims (1)

[Scope of Claims] 1) In a heat exchanger having a structure in which a flat refrigerant tube is bent in a meandering manner and refrigerant collecting pipes are assembled at both ends of the tube, the refrigerant tube protrudes into the refrigerant collecting pipe. and at least one of the refrigerant collecting pipe is provided with a means for dispersing the refrigerant jet so as to minimize the refrigerant jet noise generated in the collecting pipe. exchanger. 2) The air cooling heat exchanger according to claim 1, wherein the means is a diagonal cut surface formed at the tip of the tube in the width direction or thickness direction of the flat tube. vessel. 3) The air cooling heat exchanger according to claim 1, wherein the means is formed by attaching the collecting pipe obliquely in the width direction of the tube. 4) The air cooling device according to claim 1, wherein the means is a protrusion-like body provided in the longitudinal direction of the tube at a portion of the inner wall surface of the collecting tube opposite to the tip end surface of the tube. Heat exchanger. 5) The air cooling heat exchanger according to claim 1, wherein the means is an ellipse, a quasi-semicircle, or any other irregular cross-sectional shape given to the collecting pipe.