JP5655477B2 - Extruded tube, heat exchanger using the extruded tube, and refrigeration apparatus using the heat exchanger - Google Patents

Description

  The present invention relates to an extruded tube, and more particularly to an extruded tube constituting a double tube heat exchanger used in a refrigeration apparatus.

  Conventionally, as a double-pipe heat exchanger used in a refrigeration apparatus, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2002-181466), an inner first flow path and its first flow 2. Description of the Related Art An exchanger composed of an extruded tube that allows fluid to flow through a multi-hole flow path that surrounds a channel to exchange heat with each other is widely used. In such a double pipe heat exchanger, it is desirable that the plurality of walls partitioning the first flow path and the multi-hole flow path satisfy the required pressure resistance and be formed with the smallest possible thickness.

  However, in general, although each wall satisfies the required pressure resistance strength, the method of designing the optimum value of the thickness has not been established, so the thickness dimension tends to be set larger, which is reduced in weight and size. This is a factor that hinders cost reduction and cost reduction.

  An object of the present invention is to provide a small, lightweight, and low-cost extruded tube in which the thickness of a plurality of walls that partition each flow path is set to an optimum value or a value in the vicinity thereof.

An extruded tube according to a first aspect of the present invention is an extruded tube made of aluminum that forms an inner first flow path and an outer multi-hole flow path, and includes an inner cylindrical portion, an outer cylindrical portion, and a plurality of And a beam portion. The outer cylindrical portion surrounds the outer peripheral surface of the inner cylindrical portion. The plurality of beam portions extend in the radial direction and connect the inner cylindrical portion and the outer cylindrical portion. The first flow path is a space surrounded by the inner cylindrical portion. The multi-hole channel is a space surrounded by the inner cylindrical portion, the outer cylindrical portion, and the beam portion. Also,
The inner diameter Di of the inner cylindrical portion is 3 mm to 8 mm,
The outer diameter Do of the outer cylindrical portion is 15 mm to 26 mm,
Der is,
A dimensionless parameter a ^* determined by the circumferential width a of the beam portion, the thickness b of the inner cylindrical portion, the thickness c of the outer cylindrical portion, the inner diameter Di, the outer diameter Do, the tensile strength σs of the material, and the required pressure strength Pb ^. , B ^* , c ^* are
a ^* = a.sigma.s.62 / {(1/2). (Do-Di) .157.Pb}
b ^* = b · σs · 62 / {(Di / 2) · (Do / 18) · 157 · Pb}
c ^* = c · σs · 62 / {(Do / 2) · (Di / 6) · 157 · Pb}
Represented by
The total number N is 8 to 16 der multiwell channel is,
The relationship between the coefficients C1, C2, C3, C4 set by the total number N and the dimensionless parameters a ^* , b ^* , c ^* is
b ^* / (a ^* ) ^C2 = C1,
(C ^* −C4) / b ^* = C3,
C1 = 0.17697N + 0.72687,
C2 = 0.00241N + 0.86991,
C3 = −0.00960N−0.21260,
C4 = 0.00180N + 0.36960,
It is.

  In this extruded tube, the optimum wall thickness of each of the inner cylindrical portion, the outer cylindrical portion, and the beam portion can be calculated relatively easily by the above formula, so that reduction in the amount of extruded tube material used is promoted.

The extruded tube according to the second aspect of the present invention is an extruded tube according to the first aspect,
Tensile strength σs is 100 N / mm ^{2 to} 200 N / mm ² ,
The required pressure strength Pb is 30 MPa or more,
It is.

  In this extruded tube, since the range of applicable tensile strength is wide, when selecting an aluminum material, the flexibility of the material selection is great.

An extruded tube according to a third aspect of the present invention is an extruded tube according to the first aspect or the second aspect, and includes an inner cylindrical portion-side circumferential surface and an outer cylindrical portion-side circumferential surface of the multi-hole channel. Is concentric.

  In this extruded tube, for example, the inner cylindrical part-side circumferential surface of the multi-hole flow path is concentric with the inner cylindrical part, so that the thickness b of the inner cylindrical part is constant in the region facing the multi-hole flow path. Therefore, the pressure strength is stabilized. Similarly, since the outer cylindrical part side circumferential surface of the multi-hole flow path is concentric with the outer cylindrical part, the thickness c of the outer cylindrical part becomes a constant dimension in the region facing the multi-hole flow path. Stable pressure strength.

An extruded tube according to a fourth aspect of the present invention is the extruded tube according to any one of the first to third aspects, wherein the virtual plane that divides the width a of the beam portion into two equals the central axis of the inner cylindrical portion. The plane including the width a of the beam portion is parallel to the virtual plane.

  In this extruded tube, since the width a of the beam portion is the same from the inner cylindrical portion to the outer cylindrical portion, the compressive strength is stabilized over the entire length of the beam portion (direction perpendicular to the width a).

The heat exchanger which concerns on the 5th viewpoint of this invention is a heat exchanger using the extruded tube which concerns on a 1st viewpoint to a 4th viewpoint, Comprising: A refrigerant | coolant distribute | circulates to a 1st flow path and a multihole flow path.

  This heat exchanger is used, for example, as a supercooling heat exchanger that cools the refrigerant from the radiator outlet of the air conditioner toward the expansion valve, and therefore, the refrigerating capacity of the air conditioner equipped with the supercooling heat exchanger is It can contribute to improvement and cost reduction.

A heat exchanger according to a sixth aspect of the present invention is a heat exchanger using an extruded tube according to the first to fourth aspects, wherein water flows through one of the first flow path and the multi-hole flow path. The refrigerant circulates on the other side.

  Since this heat exchanger is used as, for example, a water-refrigerant / heat exchanger of a heat pump type hot water heater, it can contribute to the improvement of the capacity of the heat pump type hot water heater and cost reduction.

A refrigeration apparatus according to a seventh aspect of the present invention is a refrigeration apparatus including the heat exchanger according to the fifth aspect or the sixth aspect . When the heat exchanger is used as a supercooling heat exchanger or as a water-refrigerant / heat exchanger, the capacity of the refrigeration apparatus is improved and the cost is reduced.

  In the extruded tube according to the first aspect of the present invention, the optimum wall thickness of each of the inner cylindrical portion, the outer cylindrical portion, and the beam portion is relatively easily calculated by the mathematical formula, so that the usage amount of the extruded tube material can be reduced. Promoted.

In the extruded tube according to the second aspect of the present invention, since the range of applicable tensile strength is wide, when selecting an aluminum material, the degree of freedom in selecting the material is great.

In the extruded tube according to the third aspect of the present invention, since the thickness b of the inner cylindrical portion and the thickness c of the outer cylindrical portion are constant in the region facing the multi-hole flow path, the pressure resistance is stable.

In the extruded tube according to the fourth aspect of the present invention, since the width a of the beam portion is the same from the inner cylindrical portion to the outer cylindrical portion, the pressure strength is stabilized over the entire length of the beam portion (direction perpendicular to the width a). .

Since the heat exchanger which concerns on the 5th viewpoint of this invention is utilized as a supercooling heat exchanger which cools the refrigerant | coolant which goes to the expansion valve from the radiator outlet of an air conditioning apparatus, for example, a supercooling heat exchanger is mounted. It can contribute to the improvement of the refrigerating capacity and cost reduction of the air conditioner.

Since the heat exchanger according to the sixth aspect of the present invention is used as, for example, a water-refrigerant / heat exchanger of a heat pump type hot water heater, it can contribute to improvement of the capacity of the heat pump type hot water heater and cost reduction. it can.

In the refrigeration apparatus according to the seventh aspect of the present invention, the capacity of the refrigeration apparatus is improved and the cost is also reduced.

The block diagram of the freezing apparatus which uses the supercooling heat exchanger which consists of an extrusion pipe concerning one embodiment of the present invention. Sectional drawing of an extrusion pipe. The graph which shows the relationship of the dimensionless parameters a ^* , b ^* , and c ^* concerning a, b, and c which satisfy | fill target pressure-resistant intensity | strength. The graph which showed the relationship between the thickness b of an inner cylindrical part, and an outer side channel cross-sectional area for every width a of a beam part. The table | surface which showed the optimum value and tolerance | permissible_range of the thickness b of an inner cylindrical part and the thickness c of an outer cylindrical part for every width a of a beam part. The stress distribution diagram when the width a of the beam portion, the thickness b of the inner cylindrical portion, and the thickness c of the outer cylindrical portion are simultaneously broken.

  Embodiments of the present invention will be described below with reference to the drawings. The following embodiments are specific examples of the present invention and do not limit the technical scope of the present invention.

(1) Air Conditioner (1-1) Overall Configuration FIG. 1 is a configuration diagram of a refrigeration apparatus that uses a supercooling heat exchanger composed of an extruded tube according to an embodiment of the present invention. In FIG. 1, a refrigeration apparatus 1 is an air conditioner capable of cooling operation and heating operation, and a liquid refrigerant communication pipe for connecting an outdoor unit 3, an indoor unit 5, and the outdoor unit 3 and the indoor unit 5. 7 and a gas refrigerant communication pipe 9.

(1-2) Indoor Unit The indoor unit 5 includes an indoor heat exchanger 51 and an indoor fan 53. In the indoor heat exchanger 51, the refrigerant flowing inside is evaporated or radiated by heat exchange with the room air, and the room air is cooled or heated. The indoor fan 53 takes in room air by rotating and blows it to the indoor heat exchanger 51 to promote heat exchange between the indoor heat exchanger 51 and room air.

(1-3) Outdoor unit The outdoor unit 3 mainly includes a compressor 21, a four-way switching valve 23, an outdoor heat exchanger 25, an expansion valve 29, a liquid side closing valve 37, a gas side closing valve 39, an accumulator 31, A bypass path 33 and a supercooling heat exchanger 83 are provided. Furthermore, the outdoor unit 3 also has an outdoor fan 41.

(1-3-1) Compressor, four-way switching valve, and accumulator The compressor 21 sucks and compresses the gas refrigerant. An accumulator 31 is arranged in front of the suction port of the compressor 21 so that liquid refrigerant is not directly sucked into the compressor 21.

  The four-way switching valve 23 switches the direction of the refrigerant flow when switching between the cooling operation and the heating operation. During the cooling operation, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 25 and connects the suction side of the compressor 21 and the gas side closing valve 39. That is, this is the state indicated by the solid line in the four-way selector valve 23 in FIG.

  During the heating operation, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side shut-off valve 39 and connects the suction side of the compressor 21 and the gas side of the outdoor heat exchanger 25. That is, this is the state indicated by the dotted line in the four-way selector valve 23 of FIG.

(1-3-2) Outdoor heat exchanger In the outdoor heat exchanger 25, the refrigerant flowing inside is radiated or evaporated by heat exchange with outdoor air. Note that the chamber outside the fan 41 is disposed so as to face this outdoor heat exchanger 25, and blown to the outdoor heat exchanger 25 takes in outdoor air by rotating the outdoor heat exchanger 25 and the outdoor air Promote heat exchange with.

(1-3-3) Expansion Valve The expansion valve 29 is connected to a pipe between the outdoor heat exchanger 25 and the liquid side shut-off valve 37 in order to adjust the refrigerant pressure and the refrigerant flow rate. It has a function of expanding the refrigerant at any time during operation.

(1-3-4) Bypass path and flow rate adjustment valve A branch point 271 is provided between the outdoor heat exchanger 25 and the expansion valve 29 to branch a part of the refrigerant toward the bypass path 33. Yes. A flow rate adjustment valve 35 is connected in the middle of the bypass path 33. In the present embodiment, the flow rate adjustment valve 35 is an electric expansion valve.

(1-3-5) Closing valve and refrigerant communication pipe The liquid side closing valve 37 and the gas side closing valve 39 are connected to the liquid refrigerant communication pipe 7 and the gas refrigerant communication pipe 9, respectively. The liquid refrigerant communication pipe 7 connects between the liquid side of the indoor heat exchanger 51 of the indoor unit 5 and the liquid side closing valve 37 of the outdoor unit 3. The gas refrigerant communication pipe 9 connects between the gas side of the indoor heat exchanger 51 of the indoor unit 5 and the gas side closing valve 39 of the outdoor unit 3.

  As a result, the refrigerant flows in the order of the compressor 21, the outdoor heat exchanger 25, the expansion valve 29, and the indoor heat exchanger 51 during the cooling operation, and the compressor 21, the indoor heat exchanger 51, the expansion valve 29, and the outdoor heat during the heating operation. The refrigeration circuit 11 in which the refrigerant flows in the order of the exchanger 25 is formed.

(1-3-6) Supercooling Heat Exchanger The supercooling heat exchanger 83 flows through the bypass (33) and the refrigerant (hereinafter referred to as main refrigerant) flowing between the outdoor heat exchanger 25 and the expansion valve 29. Heat is exchanged with the refrigerant (hereinafter referred to as bypass refrigerant). The supercooling heat exchanger 83 of this embodiment is a double-pipe heat exchanger composed of an aluminum extruded tube that forms an inner channel and an outer channel.

(2) Extruded tube FIG. 2 is a cross-sectional view of the extruded tube. In FIG. 2, the extruded tube 81 has an inner cylindrical portion 71, an outer cylindrical portion 73, and a plurality of beam portions 75. The outer cylindrical portion 73 surrounds the outer peripheral surface of the inner cylindrical portion 71. Further, the inner cylindrical portion 71 and the outer cylindrical portion 73 are concentric.

  The beam portion 75 extends in the radial direction and connects the inner cylindrical portion 71 and the outer cylindrical portion 73. The inner cylindrical portion 71 forms a first flow path 61. The inner cylindrical portion 71, the outer cylindrical portion 73, and the plurality of beam portions 75 form a multi-hole flow channel 63 as a second flow channel.

  In the present embodiment, the inner cylindrical portion 71 side circumferential surface of the multi-hole flow channel 63 is concentric with the inner cylindrical portion 71, and the thickness b of the inner cylindrical portion 71 faces the multi-hole flow channel 63. Since the dimensions are constant in the region, the pressure strength is stable. Similarly, the outer cylindrical portion 73 side circumferential surface of the multi-hole flow channel 63 is concentric with the outer cylindrical portion 73, and the thickness c of the outer cylindrical portion 73 faces the multi-hole flow channel 63. Since the dimensions are constant, the pressure resistance is stable.

  As shown in FIG. 1, the refrigerant (hereinafter referred to as main refrigerant) from the outdoor heat exchanger 25 toward the expansion valve 29 passes through the first flow path 61 of the supercooling heat exchanger 83 (extruded pipe 81). Further, a part of the refrigerant that has exited the outdoor heat exchanger 25 becomes a refrigerant that flows from the branch point 271 to the bypass passage 33 (hereinafter referred to as a bypass refrigerant), and is depressurized by the flow rate adjustment valve 35, and then the supercooling heat. It goes to the suction side of the compressor 21 through the multi-hole channel 63 of the exchanger 83 (extruded tube 81). For this reason, in the supercooling heat exchanger 83, when the bypass refrigerant passing through the multi-hole flow path 63 evaporates, a part of the heat amount of the main refrigerant passing through the first flow path 61 is deprived, so that the main refrigerant is cooled. It becomes a supercooled refrigerant.

(3) Heating Operation and Cooling Operation With regard to the refrigeration apparatus configured as described above, the refrigerant flow in each of the heating operation and the cooling operation will be described below.

(3-1) Flow of Refrigerant During Heating Operation In FIG. 1, during the heating operation, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side shut-off valve 39 and at the suction side of the compressor 21. And the gas side of the outdoor heat exchanger 25 are connected. In addition, the opening of the expansion valve 29 is reduced. As a result, the outdoor heat exchanger 25 functions as a refrigerant evaporator, and the indoor heat exchanger 51 functions as a refrigerant radiator.

  In the refrigeration circuit 11 in such a state, the low-pressure refrigerant is sucked into the compressor 21 and is discharged after being compressed to a high pressure. The high-pressure refrigerant discharged from the compressor 21 enters the indoor heat exchanger 51 through the four-way switching valve 23, the gas side closing valve 39 and the gas refrigerant communication pipe 9. The high-pressure refrigerant that has entered the indoor heat exchanger 51 exchanges heat with the indoor air and radiates heat. Thereby, indoor air is heated.

  The high-pressure refrigerant radiated by the indoor heat exchanger 51 reaches the expansion valve 29 through the liquid refrigerant communication pipe 7 and the liquid side closing valve 37. The refrigerant is decompressed to a low pressure by the expansion valve 29 and then enters the outdoor heat exchanger 25 through the first flow path 61 of the supercooling heat exchanger 83.

  A branch point 271 leading to the bypass path 33 is provided between the supercooling heat exchanger 83 and the outdoor heat exchanger 25. However, during the heating operation, the flow rate adjustment valve 35 in the middle of the bypass passage 33 is closed, so that the refrigerant does not flow into the bypass passage 33. Therefore, heat exchange in the supercooling heat exchanger 83 is not performed.

  The refrigerant that has entered the outdoor heat exchanger 25 evaporates by exchanging heat with the outdoor air supplied by the outdoor fan 41. The low-pressure refrigerant evaporated in the outdoor heat exchanger 25 is again sucked into the compressor 21 through the four-way switching valve 23.

(3-2) Refrigerant Flow During Cooling Operation In FIG. 1, during the cooling operation, the four-way switching valve 23 connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 25 and the compressor 21. Are connected to the gas side closing valve 39. In addition, the opening of the expansion valve 29 is reduced. As a result, the outdoor heat exchanger 25 functions as a refrigerant radiator, and the indoor heat exchanger 51 functions as a refrigerant evaporator.

  In the refrigerant circuit in such a state, the low-pressure refrigerant is sucked into the compressor 21, compressed to a high pressure, and discharged. The high-pressure refrigerant discharged from the compressor 21 is sent to the outdoor heat exchanger 25 through the four-way switching valve 23.

  The high-pressure refrigerant sent to the outdoor heat exchanger 25 exchanges heat with outdoor air and radiates heat. The high-pressure refrigerant that has radiated heat in the outdoor heat exchanger 25 passes through the first flow path 61 of the supercooling heat exchanger 83 toward the expansion valve 29.

  On the other hand, a part of the refrigerant flows from the branch point 271 in front of the supercooling heat exchanger 83 to the bypass passage 33 and is decompressed by the flow rate adjusting valve 35 on the way, and then passes through the multi-hole flow passage 63 of the supercooling heat exchanger 83. Pass through to the suction side of the compressor 21. For this reason, in the supercooling heat exchanger 83, when the refrigerant passing through the multi-hole flow path 63 evaporates, a part of the heat quantity of the main refrigerant passing through the first flow path 61 is taken away, so that the main refrigerant is cooled and superheated. It becomes a cooling refrigerant.

  The supercooled refrigerant is sent to the expansion valve 29 and depressurized to a low pressure. The low-pressure refrigerant depressurized by the expansion valve 29 enters the indoor heat exchanger 51 through the liquid side closing valve 37 and the liquid refrigerant communication pipe 7.

  The low-pressure refrigerant that has entered the indoor heat exchanger 51 evaporates by exchanging heat with the indoor air. Thereby, indoor air is cooled. The low-pressure refrigerant evaporated in the indoor heat exchanger 51 passes through the gas refrigerant communication pipe 9, the gas side shut-off valve 39 and the four-way switching valve 23 and is again sucked into the compressor 21.

(4) Design of extruded tube In this embodiment, in order to reduce the weight, size and cost of the extruded tube 81, the thickness b of the inner cylindrical portion 71, the thickness c of the outer cylindrical portion 73, and the beam portion 75 The width a in the circumferential direction is set to a value that simultaneously destroys when the same predetermined pressure is applied to each of the first channel 61 and the multi-hole channel 63.

  The basis for this is that if all the walls of the extruded tube 81 are formed with optimum dimensions with reduced excess thickness, all the walls will be removed when the pressure acting on each flow path is increased until the wall breaks. This is because it is estimated that they will break at almost the same pressure at almost the same pressure. Hereinafter, a design method of the thickness b of the inner cylindrical portion 71, the thickness c of the outer cylindrical portion 73, and the width a of the beam portion 75 will be described.

(4-1) Procedure 1
First, the inner diameter Di of the inner cylindrical portion 71, the outer diameter Do of the outer cylindrical portion 73, and the total number N of the multi-hole flow paths 63, which are basic shapes, are determined. At this time, the inner diameter Di is 3 mm to 8 mm, the outer diameter Do is 15 mm to 26 mm, and the total number N is 8 to 16.

  Here, Di = 6 mm, Do = 18 mm, and N = 16.

(4-2) Procedure 2
Next, the tensile strength σs of the material and the target pressure strength are determined. At this time, the tensile strength σs is 100 N / mm ^{2 to} 200 N / mm ² and the required pressure strength Pb is 30 MPa or more.

Here, σs = 157 N / mm ² and Pb = 62 MPa.

(4-3) Procedure 3
Next, the width a of the beam portion 75 is arbitrarily determined within a manufacturable range from the inner diameter Di, the outer diameter Do, and the total number N determined in the procedure 1.

  Here, a = 0.9.

(4-4) Procedure 4
Next, the dimensionless parameter a ^* related to the width a is calculated from the following equation from the width a, the inner diameter Di, the outer diameter Do, the tensile strength σs, and the required pressure strength Pb of the beam portion 75 determined in the procedure 3.

a ^* = a.sigma.s.62 / {(1/2). (Do-Di) .157.Pb}
As a result of the calculation, a ^* = 0.15.

(4-5) Procedure 5
Next, the dimensionless parameter a ^* calculated in the procedure 4 is substituted into the following equation to derive the dimensionless parameters b ^* and c ^* related to the thickness b and the thickness c.

b ^* / (a ^* ) ^C2 = C1,
(C ^* −C4) / b ^* = C3,
C1 = 0.17697N + 0.72687,
C2 = 0.00241N + 0.86991,
C3 = −0.00960N−0.21260,
C4 = 0.00180N + 0.36960,
As a result of the calculation, b ^* = 0.64 and c ^* = 0.16.

(4-6) Procedure 6
Next, the dimensionless parameters b ^* and c ^* derived in the procedure 5 are substituted into the following equations, and the thickness b and the thickness c are calculated backward.

b ^* = b · σs · 62 / {(Di / 2) · (Do / 18) · 157 · Pb}
c ^* = c · σs · 62 / {(Do / 2) · (Di / 6) · 157 · Pb}
As a result of the calculation, b = 1.9 and c = 1.5.

(4-7) Modification 1 of Procedure 4-6
It should be noted that, based on the formula of the above procedure 4-6, formulas for directly calculating the thickness b and the thickness c from the dimensionless parameter a ^* may be created. The specific calculation formula is
a ^* = a · σs · 62 / {(1/2) · (Do-Di) · 157 · Pb},
b = C1 · (a ^* ) ^C2 · (Di / 2) · (Do / 18) · 157 · Pb / (σs · 62) ± 0.2,
c = {C1 · C3 · (a ^* ) ^C2 + C4} · (Do / 2) · (Di / 6) · 157 · Pb / (σs · 62) ± 0.2,
C1 = 0.17697N + 0.72687,
C2 = 0.00241N + 0.86991,
C3 = −0.00960N−0.21260,
C4 = 0.00180N + 0.36960,
It is.

(4-8) Modification 2 of procedure 4-6
Further, assuming that the tensile strength σs of the material and the target pressure strength are constant, a graph showing the relationship between the dimensionless parameters a ^* , b ^* , and c ^* is created for each total number N of the multi-hole flow paths 63, and b ^* , And c ^* may be obtained from the graph.

FIG. 3 is a graph showing the relationship between the dimensionless parameters a ^* , b ^* , and c ^* related to a, b, and c that satisfy the target withstand pressure strength. The horizontal axis represents b ^* and the vertical axis represents c ^* .

When the preconditions are σs = 157 N / mm ² , Pb = 62 MPa, N = 16, according to the FEM analysis, the dimensionless parameter a ^* relating to each of the width a, the thickness b, and the thickness c satisfying the target pressure strength, The combination of b ^* and c ^* is in the upper region of each curve shown in FIG. 3 (for example, the shaded portion at a ^* = 0.1), and the inflection point of each curve is the beam portion 75 and the inner cylindrical portion. 71 and a combination of dimensionless parameters a ^* , b ^* , and c ^* such that the walls of the outer cylindrical portion 73 are destroyed at the same time. There is no waste of material at the inflection point, the hole cross-sectional area of the multi-hole flow path 63 is maximum, and the heat exchanger performance is maximum.

For example, when the width a = 0.6, a ^* = 0.1 is obtained according to the equation of procedure 4. From the inflection point of the curve at a ^* = 0.1 in FIG. 3, b ^* = 0.44 and c ^* = 0.24 can be read.

Substituting b ^* = 0.42 and c ^* = 0.24 into the expression of procedure 6 to calculate the thickness b and the thickness c in reverse. As a result, b = 1.3 and c = 2.1 are obtained.

(5) Thickness of the inner cylindrical portion, allowable range of the thickness of the outer cylindrical portion Even if the optimum values of the width a of the beam portion 75, the thickness b of the inner cylindrical portion 71, and the thickness c of the outer cylindrical portion 73 are determined, The finished dimensions of width a, thickness b and thickness c of the manufactured extruded tube 81 may deviate from the optimum values. Here, an allowable range of the thickness b of the inner cylindrical portion 71 and the thickness c of the outer cylindrical portion 73 when the width a of the beam portion 75 is constant will be described.

FIG. 4 is a graph showing the relationship between the thickness b of the inner cylindrical portion and the cross-sectional area of the outer flow path for each width a of the beam portion. The preconditions are Di = 6 mm, Do = 18 mm, σs = 157 N / mm ² , and Pb = 62 MPa.

  In FIG. 4, the horizontal axis indicates the thickness b of the inner cylindrical portion, and the vertical axis indicates the outer channel cross-sectional area ratio. In the outer channel cross-sectional area ratio, the outer channel cross-sectional area when the thickness b with respect to the width a is an optimum value is 1. That is, when the thickness b and the thickness c with respect to the width a are the optimum values, the outer channel cross-sectional area becomes the maximum, and the outer channel even if the thickness b and the thickness c deviate from the optimum values to either the plus side or the minus side. The cross-sectional area decreases, and the outer channel cross-sectional area ratio becomes less than 1.

  As shown in FIG. 4, the optimum value of the thickness b at the width a = 0.5 is 1.13, and the outer channel cross-sectional area ratio is 1. In general, since the flow path cross-sectional area is allowed to decrease from the maximum value to 5%, the allowable range of the thickness b is between the intersections of the curve at the width a = 0.5 and the horizontal line at the ratio 0.95. From FIG. 4, the allowable range of the thickness b at the width a = 0.5 is 0.95 to 1.28 (the optimum value is 1.13).

  Similarly, the optimum value of the thickness b at the width a = 0.7 is 1.54, and the allowable range is 1.38 to 1.71. The optimum value of the thickness b at the width a = 0.9 is 1.93, and the allowable range is 1.77 to 2.10.

  FIG. 5 is a table showing optimum values and allowable ranges of the thickness b of the inner cylindrical portion and the thickness c of the outer cylindrical portion for each width a of the beam portion. In FIG. 5, the thickness c is calculated from the width a and the thickness b. When the thickness b is the maximum value in the allowable range, the thickness c is the minimum value in the allowable range. [A] in the bottom column is the value of the width a calculated backward from the thickness b.

  As an example, the result of inspecting the manufacturing rod of the extruded tube 81 that is optimally designed with (width a, thickness b, thickness c) = (0.50, 1.13, 2.34) is (width a, thickness b, thickness c) = (0.41 to 0.57, 0.95 to 1.28, 2.54 to 2.18).

  FIG. 6 is a stress distribution diagram when the width a of the beam portion, the thickness b of the inner cylindrical portion, and the thickness c of the outer cylindrical portion are simultaneously broken. As shown in FIG. 6, in the beam portion 75, the stress is concentrated substantially at the center of the section from the inner cylindrical portion 71 to the outer cylindrical portion 73. In the present embodiment, the virtual plane P that bisects the width a of the beam portion 75 includes the central axis of the inner cylindrical portion 71, and the plane that sandwiches the width a of the beam portion 75 is parallel to the virtual plane P. In other words, by setting the width of the beam portion 75 to the same dimension from the inner cylindrical portion 71 to the outer cylindrical portion 73, the stress is concentrated at substantially the center of the section from the inner cylindrical portion 71 to the outer cylindrical portion 73. The pressure strength is stable over the entire length of the portion 75.

(6) Features (6-1)
In the extruded tube 81, the thickness b of the inner cylindrical portion 71, the thickness c of the outer cylindrical portion 73, and the circumferential width a of the beam portion 75 are the same predetermined pressure in each of the first flow path 61 and the multi-hole flow path 63. Is set to a value that destroys at the same time. The basis for this is that if all the walls of the extruded tube 81 are formed with optimum dimensions with reduced excess thickness, all the walls will be removed when the pressure acting on each flow path is increased until the wall breaks. This is because it is estimated that they will break at almost the same pressure at almost the same pressure.

Specifically, the relationship between the width a, the thickness b, the thickness c, the inner diameter Di, the outer diameter Do, the total number N, the tensile strength σs of the material, and the required pressure strength Pb is
a ^* = a · σs · 62 / {(1/2) · (Do-Di) · 157 · Pb},
b = C1 · (a ^* ) ^C2 · (Di / 2) · (Do / 18) · 157 · Pb / (σs · 62) ± 0.2,
c = {C1 · C3 · (a ^* ) ^C2 + C4} · (Do / 2) · (Di / 6) · 157 · Pb / (σs · 62) ± 0.2,
C1 = 0.17697N + 0.72687,
C2 = 0.00241N + 0.86991,
C3 = −0.00960N−0.21260,
C4 = 0.00180N + 0.36960,
Is set to a value that satisfies the expression represented by.

  Therefore, in the extruded tube 81, the amount of material used to satisfy pressure resistance can be reduced to the lower limit or the vicinity thereof. As a result, the cross-sectional area of the flow path can be increased, reduced in weight, and reduced in size.

(6-2)
The inner cylindrical portion 71 side circumferential surface of the multi-hole flow channel 63 is concentric with the inner cylindrical portion 71, and the thickness b of the inner cylindrical portion 71 is constant in a region corresponding to the multi-hole flow channel 63. As a result, the pressure strength is stabilized. Similarly, the outer cylindrical portion 73 side circumferential surface of the multi-hole flow channel 63 is concentric with the outer cylindrical portion 73, and the thickness c of the outer cylindrical portion 73 is a region corresponding to the multi-hole flow channel 63. Since the dimensions are constant, the pressure strength is stable.

(6-3)
In the extruded tube 81, a virtual plane P that bisects the width a of the beam portion 75 includes the central axis of the inner cylindrical portion 71, and a plane that sandwiches the width a of the beam portion 75 is parallel to the virtual plane P. In other words, by setting the width of the beam portion 75 to the same dimension from the inner cylindrical portion 71 to the outer cylindrical portion 73, the stress is concentrated at substantially the center of the section from the inner cylindrical portion 71 to the outer cylindrical portion 73. The pressure strength is stable over the entire length of the portion 75.

(6-4)
In the heat exchanger composed of the extruded tube 81, the refrigerant flowing through the first flow path 61 is cooled by the refrigerant flowing through the multi-hole flow path 63. Therefore, it is suitable for a supercooling heat exchanger.

(6-5)
In the heat exchanger using the extruded tube 81, the water flowing through the first flow path 61 is heated by the refrigerant flowing through the multi-hole flow path 63. Therefore, it is suitable for water-refrigerant / heat exchangers.

  As described above, according to the present invention, waste of material is suppressed, and the cross-sectional area of the flow path becomes a maximum value or a value in the vicinity thereof, so that a double tube type heat composed of an extruded tube having high heat exchanger performance is obtained. An exchange is realized. Therefore, it is useful not only for an air conditioner but also for a heat pump type water heater.

61 1st flow path 63 Multi-hole flow path 71 Inner cylindrical part 73 Outer cylindrical part 75 Beam part 81 Extrusion pipe 83 Heat exchanger 85 Refrigeration apparatus

JP 2002-181466 A

Claims (7)

An aluminum extruded tube that forms an inner first channel (61) and an outer multi-hole channel (63),
An inner cylindrical portion (71);
An outer cylindrical portion (73) surrounding an outer peripheral surface of the inner cylindrical portion (71);
A plurality of beam portions (75) extending in a radial direction and connecting the inner cylindrical portion (71) and the outer cylindrical portion (73);
Have
The first flow path (61) is a space surrounded by the inner cylindrical portion (71),
The multi-hole channel (63) is a space surrounded by the inner cylindrical portion (71), the outer cylindrical portion (73), and the beam portion (75),
An inner diameter (Di) of the inner cylindrical portion (71) is 3 mm to 8 mm,
An outer diameter (Do) of the outer cylindrical portion of 15 mm to 26 mm,
Der is,
The circumferential width (a) of the beam portion (75), the thickness (b) of the inner cylindrical portion (71), the thickness (c) of the outer cylindrical portion (73), the inner diameter (Di), and the outer The dimensionless parameters a ^* , b ^* , c ^* determined by the diameter (Do), the tensile strength (σs) of the material, and the required pressure strength (Pb) are:
a ^* = a.sigma.s.62 / {(1/2). (Do-Di) .157.Pb}
b ^* = b · σs · 62 / {(Di / 2) · (Do / 18) · 157 · Pb}
c ^* = c · σs · 62 / {(Do / 2) · (Di / 6) · 157 · Pb}
Represented by
The total number of multiwell channel (63) (N) is Ri 8 to 16 der,
The relationship between the coefficients C1, C2, C3, C4 set by the total number (N) and the dimensionless parameters a ^* , b ^* , c ^* is as follows:
b ^* / (a ^* ) ^C2 = C1,
(C ^* −C4) / b ^* = C3,
C1 = 0.17697N + 0.72687,
C2 = 0.00241N + 0.86991,
C3 = −0.00960N−0.21260,
C4 = 0.00180N + 0.36960,
Is,
Extrusion tube (81). The tensile strength (σs) is 100 N / mm ^{2 to} 200 N / mm ² ,
The required pressure strength (Pb) is 30 MPa or more,
Is,
The extruded tube (81) according to claim 1. Of the multi-hole flow path (63), the inner cylindrical part (71) side circumferential surface and the outer cylindrical part (73) side circumferential surface form a concentric shape,
The extruded tube (81) according to claim 1 or claim 2 . The virtual plane that bisects the width (a) of the beam portion (75) includes the central axis of the inner cylindrical portion (71),
The surface sandwiching the width (a) of the beam portion (75) is parallel to the virtual surface,
The extruded tube (81) according to any one of claims 1 to 3 . A heat exchanger using the extruded tube according to any one of claims 1 to 4 ,
A refrigerant flows through the first channel (61) and the multi-hole channel (63).
Heat exchanger (83). A heat exchanger using the extruded tube according to any one of claims 1 to 4 ,
Water flows through one of the first flow path (61) and the multi-hole flow path (63), and a refrigerant flows through the other.
Heat exchanger (83). The heat exchanger according to claim 5 or claim 6 is provided.
Refrigeration equipment (1).

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