JPH03137498A - Heat exchanger with liquid flowing means - Google Patents

Abstract

PURPOSE:To prevent builtup of water droplets on the flat surface of a flat pipe horizontally disposed, an increase in ventilation resistance and a decrease in heat exchanging efficiency by providing liquid flowing means for connecting between pipes on the side face of the fluid pipes in a laminated tube at the downstream side of an air flow. CONSTITUTION:A plurality of pin fins 2 are disposed in parallel at a predetermined interval between fluid pipes 1 in a tube adjacent to a fluid pipe 2 in the tube, and respectively secured to the flat parts of the pipes 1. The sectional shape of a U-shaped bend 3 is not particularly limited, but in order to reduce the pressure loss of the fluid in the tube, a circular shape is desirable. As liquid flowing means 4, metal, ceramics, resin, etc., which do not vary in shape according to its temperature is employed, and a rodlike or sheetlike material is employed. The sectional shape of the rodlike material is not particularly limited, but in order to reduce its ventilation resistance, a circular shape is desirable. The drainage of condensed water is further improved by providing water droplet guiding means 6 communicating with the means 4 from the vicinity of the pin fins of the frontmost row at the downstream side of an air flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat exchanger. More specifically, the present invention relates to a heat exchanger with high heat exchange efficiency.

[Prior art and problems to be solved by the invention] The shape of the heat exchanger mainly used at present has a plate on the outer periphery of the pipe for the fluid inside the pipe in order to increase the heat exchange efficiency between the fluid inside the pipe and the fluid outside the pipe. The above fins are attached, and various types of fin shapes have been proposed depending on the purpose and conditions of use, and a heat exchanger with higher heat exchange efficiency is desired. Under these circumstances, pin-fin type heat exchangers have recently been considered to be one of the most promising.

The configuration of the fluid pipes in the pin-fin type heat exchanger is similar to that of the plate-fin type heat exchanger, and the pipes are arranged parallel to each other in a stepped manner and at equal intervals. However, the pipe is a flat pipe, and the pin fins are arranged perpendicularly to the flat plane of the flat pipe adjacent to the flat pipe. Pin-fin heat exchangers have better heat exchange efficiency than plate-fin heat exchangers in applications such as condensers and radiators, so they can be made more compact. However, in applications such as evaporators and water-cooled heat exchangers, the surface temperature of the pin fins is below the dew point of the atmosphere, causing water droplets to condense on the surface of the pin fins. By accumulating on the top, ventilation resistance increases and heat exchange efficiency decreases significantly. This phenomenon is particularly noticeable in pin-fin type heat exchangers in which the fin pitch is narrowed in order to improve the performance and make the heat exchanger more compact. The present invention aims to overcome these drawbacks and provide a heat exchanger with excellent heat exchange efficiency.

[Means for solving problems]

The present invention is a heat exchanger in which pin fins are arranged between the pipes for fluid in the pipes, and is characterized in that a water flow means for connecting the pipes is provided on the downstream side of the air flow of the stacked pipes for fluid in the pipes. .

The invention will now be described with reference to the accompanying drawings, which illustrate an example of the invention.

1 and 2 show an embodiment of the heat exchanger of the present invention. 1
are a plurality of pipes for fluid in a pipe provided at equal intervals, and a plurality of pin fins 2 are arranged in parallel with each other at a predetermined distance between the pipes for fluid in a pipe 1 and the pipes for fluid in a pipe adjacent to each other. arranged, respectively, pipes for fluid in the pipes l
It is fixed to the flat part of.

Here, the linear thermal conductor used for the internal fluid pipe 1 and the pin fin 2 is a pure metal or alloy such as silver, copper, aluminum, or a metal with good thermal conductivity, such as a metal that has been soldered or tin-plated. Non-limiting materials can be used.

The internal fluid pipe 1 may have a serpentine type, a header type, or a combination of each type.

As shown in Figure 1, the serpentine type is made by bending straight flat pipes into an S-shape, or connecting straight pipes and both ends of adjacent straight pipes alternately with U-shaped bends 3. It refers to the structure that Although the cross-sectional shape of the U-shaped bend 3 is not particularly limited, it is preferable to use a circular shape in order to reduce the pressure loss of the fluid within the pipe.

The header type refers to a structure in which both ends of a plurality of straight pipes are open-connected to a pair of manifolds 5, as shown in FIG.

The fluid pipe 1 and pin fin 2 are joined by brazing, but the brazing material used for this brazing differs depending on the material of the pipe and pin fin. For example, if copper is used, solder containing lead-tin as the main component may Preferably, the material may be appropriately selected depending on the material used, or a resin with good thermal conductivity may be used.

The water flowing means 4 may be made of metal, ceramic, resin, or the like that does not change its shape due to temperature, but preferably has a hydrophilic surface or one whose surface has been imparted with hydrophilic properties in order to improve drainage.

Furthermore, in order to allow the water flow means 4 to exchange heat, the water flow means 4 may be made of the same material as the pin fin.

As the water flowing means 4, a rod-like object or a sheet-like object is used.

The cross-sectional shape of the bar is not particularly limited, but it is preferable to use a circular bar in order to reduce ventilation resistance. The sheet-like material used is a woven fabric, knitted fabric, non-woven fabric, or film with holes, but in order to reduce ventilation resistance, the area occupation rate of the voids in the sheet-like material should be 70% or more, preferably 90% or more. .

The water flowing means is fixed to the downstream side of the air flow of the pipe for internal fluid by adhesive, soldering, brazing, thermal bonding, or ultrasonic bonding as shown in Figure 3 (A) and Figure 3 (B). be done. Adhesives, solders, and brazing materials preferably have hydrophilic properties or have been imparted with hydrophilic properties in order to improve drainage.

FIG. 3(C) shows a structure in which a water drop guiding means 6 is provided which communicates with the water flowing means 4 from the vicinity of the pin fin in the front row on the downstream side of the air flow, thereby further improving the drainage performance of condensed water.

The water droplet guiding means 6 may be made of metal, ceramic, resin, or the like that does not change its shape due to temperature, but preferably has a surface that is hydrophilic or has been imparted with hydrophilicity in order to improve drainage. Further, the water droplet guiding means 6 may be made of the same metal as the pin fin in order to cause heat exchange to occur in the water droplet guiding means 6 as well.

Further, as the water drop guiding means 6, a notch may be made in the pipe from the vicinity of the pin fin toward the water flowing means.

The pin-fin type heat exchanger provided with the water flowing means and the water droplet guiding means configured as described above has better drainage of condensed water than the conventional pin-fin type heat exchanger, so that the ventilation resistance can be lowered.

〔Example〕

Next, examples of the heat exchanger according to the present invention will be shown, and the heat exchange performance when using a heat exchanger of a comparative example will also be shown.

Example 1 A pin fin heat exchanger shown in FIG. 1 was made under the conditions shown below.

・Heat exchanger type Serpentine type ・Pin fin conditions Material Copper Cross-sectional shape Circular wire Diameter 200/1mφ Pin height
h = 15m Tairi Robin pitch Pfx = 1.0 mark depth pin pitch Pfz = 0.5 mm / Straight pipe for fluid in pipe, conditions for U-shaped bend Materials
Copper cross-sectional shape Flat length Diameter 18.0mm Minor diameter
5. , Width of Om field flat part 12
．． 0mm Length of pipe 200.0mm Number of stages of vibrator 15 stages / Conditions of fluid in the pipe Cold water (5℃) / Conditions of fluid means Material Copper Shape Rod with circular cross section Diameter 1mmφ Number of pipes
40 pieces pitch 5mm Mounting method Mount parallel to the bottle on the downstream side of the heat exchanger Adhesion method Epoxy resin adhesive Example 2 A structure in which the heat exchanger of Example 1 is provided with a water droplet guiding means under the conditions shown below. This was referred to as Example 2.

Water droplet guide material Material: Copper Shape: Rod with circular cross section Diameter: 1mmφ pitch
5mm Adhesion method Comparative example of epoxy resin adhesive A heat exchanger having the structure shown in FIGS. 4(A) to 4(D) is made. The heat exchanger of this comparative example was obtained by removing the water flow means from the heat exchanger of Example 1, and the other conditions were the same as those of Example 1.

The heat transfer rate and ventilation resistance of the heat exchangers of the Examples and Comparative Examples were measured.

The device used for the measurement is a suction type wind tunnel device shown in FIG. 5, and the cross section of the flow path of the heat exchanger 101 to be measured is 3001111.
There are 11X 3001+1111. The volume of air flowing in the direction of arrow 106 is measured using hot wire anemometer 104 (@Hiyoshi 11
The wind speed was measured using a YBRIDAN εMOMETER DP70C) and determined from the flow path cross section and the wind speed value, and the ventilation resistance of the heat exchanger was measured by measuring the static pressure difference before and after the heat exchanger as a pressure loss using a manometer 105. Cold water is flowed from the heat exchanger population 102 into the pipe fluid vibe of the heat exchanger,
The cold water that has undergone heat exchange with the air flow in the heat exchanger is discharged from the heat exchanger outlet 103 and returns to the water temperature controller via the flow meter.

The water side heat exchange amount Qw was determined from the cold water flow rate, the cold water temperature at the inlet of the heat exchanger, and the cold water temperature at the outlet, and the heat transfer rate K was determined using the following formula.

K=Qw/(A・ΔQ) Here, Qw is the water side heat exchange amount, A is the total heat transfer area of the heat exchanger,
ΔQ is the average temperature difference between the air side and the cold water side. The wind speed of the air flow (25℃, 60%RH) is 1 (m/5ec
) was measured.

The results obtained are shown in Table 1.

Table 1 proves that by using the heat exchanger according to the present invention, ventilation resistance can be suppressed and heat transfer performance can be improved.

Table 1 [Effects of the Invention] In the heat exchanger according to the present invention, the ventilation resistance caused by condensed water droplets in conventional heat exchangers is significantly reduced, and extremely high heat exchange efficiency is obtained, resulting in heat exchange The device can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the heat exchanger of the present invention,
2 is a perspective view of another embodiment of the heat exchanger of the present invention, FIG. 3(A) is a front view of the heat exchanger of FIG. 1, and FIG. 3(B) is a perspective view of the heat exchanger of the present invention. FIG. 3(C) is a cross-sectional view taken along line AA' of the heat exchanger in FIG. Fig. 4(A) is a perspective view of an embodiment of a conventional pin fin heat exchanger, and Fig. 4(B) is a sectional view of Fig. 4(A).
Fig. 4(C) is a front view of the heat exchanger of Fig. 4(B).
4(D) is a sectional view taken along line BB' of the heat exchanger in FIG. 4(B), and FIG. 5 is a sectional view taken along line BB' of the heat exchanger in FIG. FIG. 2 is a front view showing a device for measuring the heat transfer rate of a heat exchanger. DESCRIPTION OF SYMBOLS 1... Pipe for internal fluid, 3... U-shaped bend, 5... Manifold, 2... Pin fin, 4... Water flow means, 6... Water drop guiding means. Patent applicant Asahi Kasei Industries Co., Ltd. Patent application agent

Claims (1)

[Claims] A heat exchanger in which pin fins are arranged between the pipes for fluid in the pipes, characterized in that a water flow means for connecting the pipes is provided on the downstream side of the air flow of the stacked pipes for fluid in the pipes. Heat exchanger.