Heat exchanger

Abstract

In a heat exchanger having a flat square plate with offset fins attached thereto and having refrigerant inlet and outlet ports arranged at diagonal positions, deviation in flow distribution in the width direction of the offset fins is suppressed. In a heat exchanger having a length-to-width ratio b / a of 0.12 to 0.33 between the refrigerant inlet and outlet ports arranged at the diagonal positions, the fin pitch Pf is set to 2 mm to 5 mm and the slot length SL is set to 1 to 3 mm.

Description

TECHNICAL FIELD

[0001] The present application relates to a heat exchanger which is stacked with a plurality of disk-shaped plates and in which first flow paths and second flow paths are alternately arranged in a stacking direction, and in which bias fins are fitted in the first flow paths, and particularly to a heat exchanger most suitable for heat exchange of an evaporator or a condenser. BACKGROUND

[0002] As an example, a plate-stacked heat exchanger is known in which first flow paths and second flow paths are formed between square disk-shaped plates stacked, in which inner fins are fitted in the first flow paths, and in which inlets and outlets of the flow paths are provided at diagonal positions of the plates.

[0003] An example of the inner fin is a bias type inner fin in which a fluid passes through a gap of a bias portion and also diffuses in a width direction of the fin, but in a case where the passing and diffusing are insufficient, a flow rate distribution can be deviated, and thus a pressure loss increases. SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] At present, it is desired to uniformize a flow rate distribution of a fluid passing in a heat exchanger having the bias type inner fin and to reduce a pressure loss.

[0006] Therefore, an object of the present application is to provide a heat exchanger having a bias type inner fin which can uniformize a flow rate distribution of a fluid and reduce a pressure loss.

[0007] MEANS FOR SOLVING THE PROBLEMS

[0008] The present application described in Technical Solution 1 is a heat exchanger having a plurality of plates 3a, 3b which have a pair of long sides L and a pair of short sides M opposite each other in an outer periphery and are formed in a disk shape in a plane in which a pair of first medium passing holes 1 are arranged at first diagonal positions of the plane and second medium passing holes 2 are arranged at a pair of second diagonal positions, the heat exchanger being stacked with the plates 3a, 3b and alternately formed with first flow paths 4 of a first medium and second flow paths 5 of a second medium in a stacking direction, bias fins 6 being fitted in the first flow paths 4, the plates being liquid-tightly joined to each other, and heat being exchanged between the two media,

[0009] The heat exchanger is characterized in that

[0010] The bias fins 6 are formed by bending a metal plate into a plurality of wave shapes 6a which run in the short side M direction, each wave shape 6a which is adjacent in the long side L direction being positionally offset from each other in the short side M direction, and a ridge line 6b of each wave shape being arranged in parallel with the long side L direction,

[0011] The aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium of each plate 3a, 3b and the offset fin 6 is 0.12 ≤ b / a ≤ 0.33,

[0012] The fin pitch Pf of each wave form 6a of the offset fin 6 is 2 mm ≤ Pf ≤ 5 mm,

[0013] The slot length SL of each wave form 6a of the offset fin 6 is 1 mm ≤ SL ≤ 3 mm.

[0014] The application described in Technical Solution 2 is based on the application described in Technical Solution 1,

[0015] The heat exchanger is an evaporator,

[0016] The fin pitch Pf is 3 mm ≤ Pf ≤ 5 mm.

[0017] The application described in Technical Solution 3 is based on the application described in Technical Solution 1,

[0018] The heat exchanger is a condenser,

[0019] The fin pitch Pf is 2 mm ≤ Pf ≤ 3 mm.

[0020] Inventive Effects

[0021] The application of the heat exchanger described in Technical Solution 1 is characterized in that, in a heat exchanger in which the aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium is 0.12 ≤ b / a ≤ 0.33, the fin pitch Pf of each wave form 6a of the offset fin 6 is 2 mm ≤ Pf ≤ 5 mm, and the slot length SL of each wave form 6a of the offset fin 6 is 1 mm ≤ SL ≤ 3 mm.

[0022] As a result, the flow path (gap) of the offset portion and the reinforcing effect by the inner fin are ensured, and the deviation of the flow distribution in the width direction orthogonal to the ridge line direction of the wave is suppressed, thereby enabling the flow distribution of the fluid of the heat exchanger to be uniformized.

[0023] The application of the heat exchanger described in Technical Solution 2 is characterized in that, in an evaporator in which the aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium is 0.12 ≤ b / a ≤ 0.33, the fin pitch Pf of each wave form of the offset fin is 3 mm ≤ Pf ≤ 5 mm, and the slot length SL of each wave form 6a is 1 mm ≤ SL ≤ 3 mm.

[0024] As a result, in the evaporator, the deviation of the flow distribution in the width direction orthogonal to the ridge line direction of the wave can be suppressed, and sufficient heat exchange amount is ensured.

[0025] The invention of the heat exchanger described in technical solution 3 is characterized in that, in a condenser with an aspect ratio b / a (size ratio) of 0.12≤b / a≤0.33 between the inlet and outlet of the first medium, the fin pitch Pf of each waveform of the biased fins is 2mm≤Pf≤3mm, and the groove length SL of each waveform 6a is 1mm≤SL≤3mm.

[0026] Therefore, in the condenser, deviations in the flow distribution in the width direction orthogonal to the direction of the wave ridge can be suppressed, and sufficient heat exchange can be ensured. Attached Figure Description

[0027] Figure 1 (A) is a top view of the main part of the heat exchanger of the present invention. Figure 1 (B) is a perspective view of the main part of the bias fin 6 of the heat exchanger of the present invention. Figure 1 (C) is Figure 1 (B) CC view.

[0028] Figure 2 This is an exploded three-dimensional view of the heat exchanger.

[0029] Figure 3 yes Figure 1 (A) is a simplified sectional view of the III-III direction.

[0030] Figure 4 This is a graph showing the pressure drop ratio of the heat exchanger of the present invention. Figure 4 (A) shows the characteristic curves of the evaporator for each fin pitch Pf and slot length SL. Figure 4 (B) is a characteristic curve showing the pressure drop ratio of the condenser.

[0031] Figure 5 This is a graph showing the heat exchange ratio of the heat exchanger, and it contains characteristic curves for each fin pitch Pf and each slot length SL. Figure 5 (A) is the characteristic curve of the evaporator. Figure 5 (B) is the characteristic curve of the condenser. Detailed Implementation

[0032] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0033] The heat exchanger of the present invention has offset fins in the flow path for fluid flow and is suitable for use as an evaporator or condenser.

[0034] Figure 1 (A) is a top view of the heat exchanger plates 3a and 3b, and the offset fins 6 clamped between the plates 3a and 3b. Furthermore, Figure 1(B) is an enlarged perspective view of the offset fin 6, Figure 1 (C) is Figure 1 (C) is a C-C view of (B). In addition, Figure 2 is an exploded perspective view of the heat exchanger. Figure 3 is Figure 1 is a III-III sectional view of (A).

[0035] As shown in Figure 2 , Figure 3 the core of the heat exchanger includes a stack of plates 3a, 3b, a first flow path 4 and a second flow path 5 are formed every other plate, and an offset fin 6 is sandwiched in the first flow path 4. The plates 3a, 3b are formed in a disc shape in a substantially square planar shape, and a pair of first medium flow-through holes 1 are formed at first diagonal positions, and a pair of second medium flow-through holes 2 are formed at second diagonal positions. On the plate 3a side, a ring-shaped bulging portion 9 is provided protruding from a hole edge portion of the second medium flow-through hole 2, and on the plate 3b side, a ring-shaped bulging portion 9 is provided protruding from a hole edge portion of the first medium flow-through hole 1. The offset fin 6 sandwiched in the first flow path 4 is provided with an opening 10 penetrating in a manner matching the first medium flow-through hole 1 and the second medium flow-through hole 2 of each plate. Also, when they are stacked, the offset fin 6 forms a communication hole between adjacent plates.

[0036] As shown in Figure 2 , the upper end in the stacking direction of the core of the heat exchanger is covered by a top plate 12 via an end plate 15, and a pipe 13 is provided to the top plate 12. Also, they are arranged on a base plate 11, and the components are brazed and fixed as one body.

[0037] Also, the first medium 7 flows through each first flow path 4 from one first medium pipe 13, and flows out from the other first medium pipe 13. In addition, the second medium 8 flows through each second flow path 5 from one second medium pipe 13, and flows out from the other second medium pipe 13.

[0038] In this example, a refrigerant that changes phase to gas and liquid is supplied as the first medium 7, and cooling water is supplied as the second medium 8, and heat exchange is performed between the two media.

[0039] The offset fin 6 sandwiched in the first flow path 4 can be formed of aluminum material (alloy including aluminum) or the like, and as shown in Figure 1 (B) and (C), the offset fin 6 is bent in a manner that a wave travels in the direction of the short side M of the plate 3a at a constant fin pitch Pf, and a wave shape 6a is formed. The phase of the ridge line 6b of the wave shape 6a is shifted in position by several pitches with respect to the direction of the long side L, and thereby an offset gap is formed. The interval of the offset gap can be set to about ¼ of the fin pitch Pf, for example.

[0040] Further, the height H of the wave 6a can be set to about 1 / 2 of the fin pitch Pf, and the plate thickness of the offset fin 6 can be set to 0.1 mm to 0.3 mm, for example.

[0041] The present inventors found that the conditions of the aspect ratio (size ratio) b / a between the inlet and outlet of the heat exchanger, the fin pitch Pf of the offset fin 6, and the slit length SL of the offset fin 6 affect the flow resistance (pressure loss ratio, pressure loss) of the refrigerant flowing through the offset fin 6 of the first flow path 4 and the heat exchange amount (exchange heat).

[0042] Here, a of the size ratio b / a is the distance between the centers of the inlet and outlet measured in parallel with the long side L of each plate 3 in (A), and b is the distance between the centers of the inlet and outlet measured in parallel with the short side M in (B). The slit length SL refers to the length of the ridge line 6b of each wave 6a in (B). Figure 1 Figure 1

[0043] The experimental conditions of the heat exchanger having the offset fin 6 are described below.

[0044] The size ratio (b / a) was set to the range of 0.12 ≤ b / a ≤ 0.33, the fin pitch Pf was set to the range of 2 mm, 3 mm, 4 mm, and 5 mm, and the slit length SL was set to the range of 1 mm to 7 mm.

[0045] The first medium 7 flowing through the first flow path 4 is a fluorocarbon refrigerant, and the second medium 8 flowing through the second flow path 5 is cooling water.

[0046] The pressure loss when the heat exchanger is used as an evaporator and the pressure loss when the heat exchanger is used as a condenser were measured for each offset fin 6. Further, the exchange heat when the heat exchanger is used as an evaporator and the exchange heat when the heat exchanger is used as a condenser were measured.

[0047] Note that the minimum value (lower limit) of the slit length SL was set to 1 mm based on the limit of the punching process of the offset fin.

[0048] Further, the lower limit of the fin pitch Pf was set to 2 mm in consideration of the minimum limit of the offset gap of the offset fin. The upper limit of the fin pitch Pf was set to 5 mm because, if the Pf of the offset fin is too large, the pressure resistance of the inner fin between the plates of the heat exchanger cannot be sufficiently obtained.

[0049] As a result, the following was clarified.

[0050] Figure 4 ​​Figure (A) shows the pressure loss ratio when used as an evaporator. The vertical axis represents the pressure loss ratio, and the horizontal axis represents the slot length SL. Here, the pressure loss is based on a fin pitch Pf = 2 mm and a slot length SL = 2 mm (100%). Additionally, Figure 4 (B) shows the pressure loss ratio when used as a condenser. The method of choosing the vertical axis, horizontal axis, and reference is the same as... Figure 4 The same as Figure (A).

[0051] exist Figure 4 (A) Figure 4 In any of the cases in (B), the pressure loss ratio decreases within the range of shorter tank lengths (SL is in the range of 1mm to 3mm).

[0052] This is because, basically, the shorter the tank length, the more refrigerant is distributed in the width direction ( Figure 1 The more uniform the flow velocity distribution on the (A)M), the better. That is, this is because, corresponding to a shorter tank length, the refrigerant passing through the tank flows not only more easily along the long side of the plate but also more easily along the width, thus reducing pressure loss. This trend is also the same when the aspect ratio (size ratio) between the inlet and outlet is b / a = 0.12 and 0.33.

[0053] Next, Figure 5 (A) shows the heat exchange ratio when used as an evaporator. The vertical axis represents the heat exchange ratio, and the horizontal axis represents the trough length SL. The heat exchange ratio is based on a fin pitch Pf = 2 mm and a trough length SL = 2 mm (100%).

[0054] When used as an evaporator, the optimal range for heat exchange ratio is the shaded area (Pf = 3mm to 5mm). The larger the fin pitch Pf, the greater the heat exchange capacity.

[0055] This is because the refrigerant's operating pressure in the evaporator is as low as around 200 kPaG, and the saturation temperature changes significantly due to pressure loss. Furthermore, the lower the pressure loss, the smaller the change in saturation temperature, the greater the temperature difference with the cooling water, and the greater the heat exchange.

[0056] Next, Figure 5 (B) shows the heat exchange ratio when used as a condenser. The vertical axis, horizontal axis, and reference point are determined in the same way as... Figure 5 (A) is the same.

[0057] The optimal range for heat exchange ratio when used as a condenser is the shaded area (Pf = 2mm to 3mm). For condensers, the smaller the fin pitch, the greater the heat exchange capacity.

[0058] This is because, since the working pressure of the condenser is as high as about 2000 KPaG, the change in the saturation temperature due to the pressure loss is small. In addition, unlike the evaporator, for the condenser, the proportion of the gas phase state in the heat exchanger is large. Therefore, the more the fin pitch Pf is reduced and the heat exchange area is increased, the more the heat exchange of the gas phase progresses, and the more the overall heat exchange amount increases.

[0059] According to the above, in the case where the heat exchanger having the offset fins is used as an evaporator, it is optimal that the aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium is set to the range of 0.12 ≤ b / a ≤ 0.33, the groove length SL of the offset fins 6 is set to the range of 1 mm ≤ SL ≤ 3 mm, and the fin pitch Pf of the offset fins 6 is set to the range of 3 mm ≤ Pf ≤ 5 mm.

[0060] Next, in the case where the heat exchanger is used as a condenser, it is optimal that the aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium is set to the range of 0.12 ≤ b / a ≤ 0.33, the groove length SL of the offset fins 6 is set to the range of 1 mm ≤ SL ≤ 3 mm, and the fin pitch Pf of the offset fins 6 is set to the range of 2 mm ≤ Pf ≤ 3 mm.

[0061] Note that, in the case where the plate-stacked heat exchanger having the offset fins is used as a heat exchanger other than an evaporator such as an oil cooler (the first medium is oil) and a condenser, the aspect ratio b / a (dimensional ratio) between the inlet and outlet of the first medium can be set to the range of 0.12 ≤ b / a ≤ 0.33, the groove length SL of the offset fins 6 can be set to the range of 1 mm ≤ SL ≤ 3 mm, and the fin pitch Pf of the offset fins 6 can be set to the range of 2 mm ≤ Pf ≤ 5 mm.

[0062] Explanation of Reference Numerals

[0063] 1 First medium flow-through hole

[0064] 2 Second medium flow-through hole

[0065] 3a, 3b Plate

[0066] 4 First flow path

[0067] 5 Second flow path

[0068] 6 Offset fin

[0069] 6a Wave shape

[0070] 6b Ruled line

[0071] 7 First medium

[0072] 8 Second medium

[0073] 9 annular bulge

[0074] 10 opening

[0075] 11 substrate

[0076] 12 top plate

[0077] 13 tube

[0078] 14 recess

[0079] 15 end plate

[0080] b / a aspect ratio (size ratio) between inlet and outlet

[0081] Pf fin pitch

[0082] SL slot length

[0083] L long side

[0084] M short side

[0085] H height

Claims

1. A heat exchanger having a plurality of plates having a pair of opposing long sides (L) and a pair of opposing short sides (M) on their outer periphery, and forming a square disk shape in plan, wherein a pair of first medium flow holes (1) are arranged at a first diagonal position and a pair of second medium flow holes (2) are arranged at a second diagonal position, wherein the heat exchanger stacks the plates and alternately forms a first flow path (4) for a first medium and a second flow path (5) for a second medium in the stacking direction, wherein bias fins (6) are installed in the first flow path (4), and openings (10) are provided through the bias fins (6) in a manner matching the first medium flow holes (1) formed in each plate, wherein the plates are liquid-tightly joined together to perform heat exchange between the two media. The heat exchanger is characterized in that... The offset fin (6) is formed by bending a metal plate into multiple waveforms (6a) that travel in the direction of the short side (M). The waveforms (6a) that are separately adjacent in the direction of the long side (L) are offset relative to each other in the direction of the short side (M). The edges (6b) of each waveform are arranged parallel to the direction of the long side (L). The aspect ratio b / a, i.e., the size ratio, between the inlet and outlet of the first medium of each plate and the bias fin (6) is 0.12≤b / a≤0.

33. In the aspect ratio b / a, 'a' is the center-to-center distance between entrances and exits measured parallel to the long side (L) of each plate, and 'b' is the center-to-center distance between entrances and exits measured parallel to the short side (M). The fin pitch Pf of each waveform (6a) of the offset fin (6) is 2mm≤Pf≤5mm. The slot length SL of each waveform (6a) of the bias fin (6) is 1mm≤SL≤3mm. The height H of each waveform (6a) of the offset fin (6) is about 1 / 2 of the fin pitch Pf.

2. The heat exchanger according to claim 1, characterized in that, The heat exchanger is an evaporator. The fin pitch Pf is 3mm≤Pf≤5mm.

3. The heat exchanger according to claim 1, characterized in that, A heat exchanger is a condenser. The fin pitch Pf is 2mm≤Pf≤3mm.

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