JP4256515B2 - Multi-tube heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multitubular heat exchanger used for heat exchange of fluid, and more particularly to a multitubular heat exchanger in which a baffle plate for guiding a trunk side fluid is provided at right angles to a heat transfer tube.
[0002]
[Prior art]
Multi-tube heat exchangers are used for heat exchange of fluids in a wide range of fields, for example to cool hydraulic oil in motors and cylinders, and have a circular cutout on a part of a disk as a baffle plate , And the notch is alternately positioned on the opposite side and provided perpendicularly to the heat transfer tube so that the cylinder side fluid can flow smoothly across the heat transfer tube.
[0003]
In this type of multi-tube heat exchanger, the body side fluid is guided to adjust the flow velocity, and the entire heat transfer surface is utilized to increase the overall heat transfer coefficient and reduce the pressure loss. It is a well-known fact that many studies have been made on the number and arrangement of heat transfer tubes, the distance between baffle plates, the size and shape of notches, and so on.
[0004]
[Problems to be solved by the invention]
However, there is a limit to the improvement under the restriction of providing an arcuate notch in a part of the disk, and no further performance improvement can be measured. Also, instead of the baffle plate with a bow-shaped notch, two types of baffle plates consisting of a large-diameter perforated disc and a small-diameter disc are alternately arranged, and a baffle plate that penetrates the heat transfer tube with a large gap is used. , One using a blade-shaped baffle plate, one using a continuous baffle plate in a spiral shape is known, but these are disadvantageous in price, only a gas can be used as a trunk side fluid, a small one It has at least one of the problems that it can only be applied to, and is currently not used much.
[0005]
The present invention has been made in the background of such a situation, and provides an even better performance than a multi-tube heat exchanger using a baffle plate with an arc-shaped notch that is most frequently used at present. The purpose is to do.
[0006]
[Means for Solving the Problems]
The present invention is unsatisfactory in terms of performance with a multi-tube heat exchanger in which a large number of baffle plates through which a large number of heat transfer tubes penetrate inside the fuselage and in which a baffle side fluid is guided are installed at right angles to the heat transfer tubes In order to improve
[0007]
In other words, two types of baffle plates are used: a baffle plate with two centrally symmetric notches on the outer peripheral edge, and a confluence baffle plate with an elongated through hole extending in the diameter direction at the center. It is arranged in.
[0008]
The trunk side fluid is divided into two before the shunt baffle, passes through the notch, gathers in the center before the next confluence baffle, passes through the through hole, and further cuts out the next shunt baffle The flow is divided into two toward the bottom, and flows from the entrance at one end of the body to the exit at the other end. Therefore, the stagnation of the trunk side fluid in the peripheral part of the trunk center axis is eliminated, the overall heat transfer coefficient is increased, and the pressure loss is reduced because the shunt is diverted in two directions toward the respective shunt baffle plates.
[0009]
Further, in order to maximize the performance in the present invention, the notch and the through hole are made parallel to each other, and the total actual opening area of the two notches and the actual opening area of the through hole are It is preferable that they are substantially equal to each other, or consist of two groups arranged with the through hole of the heat transfer tube interposed therebetween, and an inlet and an outlet of the trunk side fluid are opened at the interval portion. However, even if the notch and the through hole are arranged so as to be orthogonal to each other, or if the through hole is arranged in parallel with the one arranged in parallel with the notch, the diversion and the merging are also performed. The stagnation can be resolved by repeating.
[0010]
Next, in the present invention, at least a part of the above-described confluence baffle plates is replaced with one provided with an elongated cross-shaped through hole.
[0011]
This allows the trunk side fluid to perform various diversions and merging, and the stagnation is more reliably eliminated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, fixed tube plates 4 and 5 are attached in a liquid-tight or air-tight manner to a cylindrical body 1 with both ends closed. A bonnet 6 having an inlet 7 and an outlet 8 for the tube-side fluid is attached to the outside of the tube 4, and a bonnet 9 for making a U-turn of the tube-side fluid is attached to the outside of the other fixed tube plate 5. A large number of heat transfer tubes 10 are inserted into and supported by fixed tube plates 4 and 5 at both ends, and are inserted through the inside of the body 1 in the direction of the central axis thereof. A plane passing through the central axis of the body 1, a horizontal plane in the illustrated embodiment. The group of the heat transfer tubes 10 arranged on the upper side with the gap interposed therebetween communicates with the inlet 7, and the group of the heat transfer tubes 10 arranged on the lower side communicates with the outlet 8.
[0013]
The group of the upper heat transfer tubes 10 and the group of the lower heat transfer tubes 10 are arranged with a large gap across the plane. The trunk-side fluid inlet 2 and outlet 3 open to the lateral side of the trunk 1 toward this distance.
[0014]
The baffle plate installed in the body 1 perpendicular to the heat transfer tube 10 is composed of the shunt baffle plate 11 shown in FIG. 2 (A) and the confluence baffle plate 13 shown in FIG. 2 (B), which are alternately arranged. Has been.
[0015]
The diversion baffle plate 11 has two arcuate cutouts 12 that are symmetrical with respect to the outer peripheral edge, and the confluence baffle plate 13 has an elongated through hole 14 that extends in the diameter direction at the center. The shunt baffle plate 11 is installed so that the edge of the notch 12 is parallel to the plane, and the confluence baffle plate 13 is installed so that the through hole 14 is parallel to the plane. The baffle plates 11 and 13 are located at both ends of the baffle plate 11 as a shunt baffle plate 11, and the trunk side fluid flowing into the gap portion from the inlet 2 is immediately divided into two parts, and the notches 12 are formed. The pipe-side fluid flowing through the heat transfer tube 10 by repeating the operation of passing through, then gathering toward the center, passing through the through-hole 14, and then again dividing into two and passing through the notch 12. Perform heat exchange. The trunk side fluid that has passed through the notch 12 of the final diverting baffle plate 11 gathers toward the outlet 3, thereby performing heat exchange also in this portion.
[0016]
In this way, the trunk side fluid repeats the diversion and merging from immediately after flowing into the trunk 1 to immediately before flowing out, so that it uniformly contacts the heat transfer tube 10 and eliminates the stagnation that tends to occur particularly in the central portion. The overall heat transfer coefficient increases. Further, the pressure loss is reduced by diverting the trunk side fluid in two directions.
[0017]
In the illustrated embodiment, the inlet 2 and the outlet 3 are opened at the space portion so that the heat transfer tube 10 does not cross the front face of the heat transfer tube 10, thereby reducing the pressure loss. In addition, the heat transfer tube 10 is prevented from passing through the notch 12 and the through hole 14, so that the stagnation of the trunk side fluid near the notch 12 and the through hole 14 can be almost eliminated. However, even if a part of the heat transfer tube 10 protrudes from the edge of the notch 12 or the through hole 14, there is no practical problem.
[0018]
In addition, the actual opening areas through which the cylinder side fluids of the two notches 12 of the diverting baffle plate 11 and the through hole 14 of the converging baffle plate 13 pass are made substantially equal to each other. Helps to resolve.
[0019]
According to the illustrated embodiment, as described above, the overall heat transfer coefficient is improved and the pressure loss is reduced, thereby reducing the number of heat transfer tubes 10 used and reducing the distance between the baffle plates 11 and 13. This makes it possible to reduce the size. Alternatively, it is possible to improve the heat exchange efficiency by increasing the flow rate of the trunk side fluid.
[0020]
Next, the present invention repeats the splitting and merging of the cylinder side fluid to perform efficient heat exchange. For this purpose, the merging baffle plate 13 is replaced with the one shown in FIGS. 3 (A) and 3 (B). Something like that can be used. That is, the confluence baffle plate 15 shown in (A) is provided with an elongated through hole 16 orthogonal to the notch 12 of the diversion baffle plate 11 at the center. Further, the confluence baffle plate 17 shown in (B) is provided with an elongated hole portion extending in a direction parallel to the notch 12 and a cross-shaped through hole 18 composed of an elongated hole portion orthogonal to the center.
[0021]
These junction baffles 15 and 17 can be installed without allowing the heat transfer tubes 10 to pass through the through holes 16 and 18 by reducing the number of heat transfer tubes 10 used as described above, and FIG. By using together with or instead of the confluence baffle plate 13 shown in B), the overall heat transfer coefficient can be increased by performing various diversions and confluences.
[0022]
【Example】
Next, performance comparison test results between the product of the present invention and the conventional product will be described. Both products have a fuselage inner diameter (84.1 mm), length (550 mm), heat transfer tube outer diameter (8 mm) and wall thickness (1.2 mm), number of baffle plates (15) and spacing (25 mm), cutting The actual opening area of the notch and the through hole (25% of the total area of the baffle plate), the trunk side fluid (equivalent to ISO VG-32) and the pipe side fluid (cooling water) are the same conditions, and the number of heat transfer tubes is the present invention. There were 36 and 46 conventional products. The product of the present invention has the form shown in FIG. 1, and the conventional product uses the baffle plate having the previously described notch.
[0023]
For both products, the pipe side fluid inlet temperature (30 ° C) and flow rate (20 l / min) are constant, and the trunk side fluid is subjected to heat exchange by changing the flow rate and inlet temperature so that the outlet temperature (50 ° C) is constant. The quantity, overall heat transfer coefficient, and pressure loss were measured. As a result, the heat exchange amount with respect to the flow rate of the trunk side fluid is shown in FIG. 4, the overall heat transfer coefficient is shown in FIG. 5, and the pressure loss is shown in FIG. Note that the flow rate of the trunk side fluid was set to a constant outlet temperature by, for example, 20 l / min at an inlet temperature of 68 ° C. and 100 l / min at 55 ° C.
[0024]
According to this result, the product of the present invention reduces the number of heat transfer tubes used and reduces the heat transfer area by about 22% compared to the conventional product. For example, at a pressure loss of 1 kg / cm ² shown in FIG. At a certain cylinder side fluid flow rate of about 130 l / min, as can be seen from FIG. 4, the heat exchange amount is about 6% less than that of the conventional product. However, as can be seen from FIG. 5, the overall heat transfer coefficient is about 16% higher than that of the conventional product, and as can be seen from FIG. 6, the pressure loss is reduced to about 57% of the conventional product. Further, when the product of the present invention may have the same overall heat transfer coefficient and pressure loss as the conventional product, the capacity can be improved by increasing the flow rate of the trunk side fluid.
[0025]
【The invention's effect】
As described above, according to the present invention, an excellent performance that the overall heat transfer coefficient is large and the pressure loss is low is an extremely simple means that the baffle plate is formed so that the trunk side fluid flows while repeatedly dividing and joining. It is possible to provide an appropriate one according to the type of fluid and the place of use, such as miniaturization and improvement in capacity.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
2A is an enlarged cross-sectional view taken along line AA in FIG. 1, and FIG. 2B is an enlarged cross-sectional view taken along line BB in FIG.
FIGS. 3A and 3B are front views showing different embodiments of a confluence baffle plate, respectively.
FIG. 4 is a graph showing a test result of the heat exchange amount.
FIG. 5 is a graph showing the overall heat transfer coefficient test results.
FIG. 6 is a graph showing test results of pressure loss.
[Explanation of symbols]
1 fuselage, 10 heat transfer tube, 11 minutes flow baffle, 12 notches, 13, 15, 17 merge baffle, 14, 16, 18 through holes

Claims (2)

A large number of baffle plates through which a large number of heat transfer tubes pass through the fuselage and guide the trunk side fluid are provided at right angles to the heat transfer tubes. In the multi-tube heat exchanger in which the diversion baffle plate and the confluence baffle plate are alternately arranged, and a diversion baffle plate provided with an elongated through hole extending in the diameter direction in the center portion The heat transfer pipe is composed of two groups arranged with a large gap across the through hole, and a trunk-side fluid inlet and outlet are open toward the gap. Type heat exchanger. The at least part of the confluence baffle plate is provided with a cross-shaped through-hole including an elongated hole portion extending in a diameter direction of a central portion and an elongated hole portion orthogonal to the center. The multitubular heat exchanger according to 1.

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