JP2007010180A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger having a louver structure dispensing with reduction of fin pitches of corrugate fins when louvers are refined to increase heat exchange quantity. <P>SOLUTION: A center portion 25 positioned at a center of each group of louvers is composed of a flat portion free from flanging, a flanging angle of an end portion at a center side of the group of louvers of the louvers inside of the group of louvers positioned between an upstream-side flanging portion 21 positioned at an most upstream of each group of louvers and the center portion 25 is larger than a flanging angle of an end portion at an upstream side of the group of louvers, and the flanging angles of the upstream-side flanging portion and the end portion at the center side of the group of louvers of the louvers inside of the group of louvers are determined within a range of 50°-80°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat exchanger, and more particularly to a heat exchanger in which heat exchange efficiency is improved using a louver that has been miniaturized without causing an increase in corrugated fin weight or an increase in ventilation resistance.

  In a heat exchanger, when heat exchange is performed between a first thermal refrigerant (water, a refrigerant for air conditioning, etc.) that is a liquid and a second thermal refrigerant (such as air, hereinafter, air) that is a gas, Is limited by the heat transfer performance of the second thermal refrigerant on the gas side. Accordingly, the first thermal refrigerant is caused to flow into the heat transfer tube, which is a tube, and the second thermal refrigerant is caused to flow between the fins provided outside thereof. In the heat exchanger for automobiles, corrugated fins provided with louver fins (louvers) for increasing the heat transfer area on the second thermal refrigerant side and increasing the heat exchange amount are used.

  An air heat exchanger provided with a conventional corrugated fin serving as the basis of the present invention will be described with reference to FIGS. As shown in FIG. 1A, the air heat exchanger 1 is in communication between the upper and lower headers 3A and 3B in which refrigerant is introduced and led out and the upper and lower headers 3A and 3B, and the longitudinal length of the upper and lower headers. And a plurality of flat heat transfer tubes 2, 2... Arranged in parallel with each other at a predetermined interval, and a substantially S-shape in the vertical direction between the plurality of flat heat transfer tubes 2, 2. The corrugated fins 4 are arranged in a bent state and are thermally welded to the flat heat transfer surfaces of the adjacent flat heat transfer tubes 2, 2. Has been.

  The flat heat transfer tubes 2, 2... Allow the refrigerant introduced and distributed from the outside via the upper header 3A to uniformly flow into the respective refrigerant circulation holes, and are wide via the corrugated fins 4, 4,. The heat transfer area is configured to exchange heat between the internal refrigerant and the external air.

  In addition, as shown in FIG. 1B, the corrugated fins 4, 4... Are flat flat portions excluding bent portions (folded portions), and are centered on a flat flat surface 4c portion formed in the processing. The louvers 4a, 4a,..., Which are a plurality of raised and raised pieces for improving the heat transfer efficiency with the air in each of the upstream portion and the downstream portion of the air flow, are symmetrical with respect to the center. It is formed so that the heat exchange performance between the refrigerant and the air is enhanced by the louvers 4a, 4a.

  In this air heat exchanger, the amount of heat exchange is increased by suppressing the development of the boundary layer on the fin wall surface by the louver 4a (hereinafter referred to as the leading edge effect). If the louver 4a is refined and the leading edge effect is increased, the heat exchange amount increases. Therefore, as the length of the louver (louver pitch FL of the louver) shown in FIGS. 1C and 1D is decreased, the leading edge effect is increased and the heat exchange amount is increased.

  Conventionally, a heat exchanger has been proposed in which the louver pitch is set to 0.5 to 0.9 mm and the louver inclination angle is set to 25 ° to 40 ° (Patent Document 1).

  Further, in a louver fin in which fins are formed by roller processing of a thin plate material, the cross-sectional shape of the fins is a rectangle. For this reason, for the purpose of improving heat transfer performance, a louver fin has been proposed in which the louver fin is bent at the center of the fin and the louver angles of the front edge and the rear edge of the fin are changed (Patent Document 2).

  However, not only the louver pitch and the inclination angle but also the vertical pitch of the corrugated fin (fin pitch Fp) has a great influence on the performance of the louver fin. For this reason, based on the geometrical relationship, an equation for determining the optimum values of the three specifications of the fin pitch Fp, the louver pitch FL, and the louver inclination angle θ has been proposed (Patent Document 3).

  FIG. 2 shows the relationship between the fin specifications of a conventional corrugated louver fin and the flow in the louver. As shown in FIG. 2A, when the louver pitch is reduced and at the same time the fin pitch is reduced, the flow 15 passes between the louvers and the amount of heat exchange increases. On the other hand, when the fin pitch is not reduced and only the louver pitch is reduced as shown in FIG. 2B, a flow 16 that passes between the louvers is generated without passing between the louvers, and the amount of heat exchange is reduced. That is, in order to increase the heat exchange amount by miniaturizing the louver, it is necessary to reduce the fin pitch.

  FIG. 3 shows a comparison between fin pitch and heat transfer performance when the louver is miniaturized. The horizontal axis represents the fin pitch, and the vertical axis represents the ventilation resistance, the weight of the fin portion, and the heat exchange amount. The vertical axis is dimensionless with the performance of fin pitch 1.25 mm, and is represented by the ventilation resistance ratio, the weight ratio of the fin portion, and the heat exchange amount ratio. The louver pitch FL is 0.9 mm, the louver angle θ is constant, the fin pitch Fp is changed, and the ventilation resistance and the heat exchange amount of each specification are as follows. The heat transfer coefficient was evaluated using an arrangement formula.

As understood from the figure, the heat exchange amount increases as the fin pitch is reduced. However, if the fin pitch is reduced, the air-side flow path area is reduced, and as a result, the ventilation resistance is increased more than the increase in the heat exchange amount. Furthermore, if the fin pitch is reduced while the volume of the heat exchanger is kept constant, the number of times the corrugated fin is bent increases, so that the weight of the fin portion increases.
Japanese Patent Laid-Open No. 2000-154989 JP 2005-69679 A JP-A-1-263498 A generalized friction correlation for lover fin geometry, Yu-Juei Chang, International Journal of Heat and Mass Transfer, 2000, Vol. 43, P2237-2243 A generalized heat transfer correlation for lover fin geometry, Yu-Juei Chang, International Journal of Heat and Mass Trust, 1997, Vol. 40, P533-2243

  As described above, in order to increase the heat exchange amount of an automobile heat exchanger or the like equipped with a louver, the louver is refined to expand the leading edge effect, and a flow along the louver is generated inside the louver group. It is necessary to reconcile these two points. In order to make the two compatible, it is necessary to reduce the louver pitch FL of the louver and simultaneously reduce the fin pitch Fp of the corrugated fin.

  However, if the fin pitch Fp of the corrugated fins is reduced, the number of times the corrugated fins are bent increases, which causes a problem that the weight of the fin portion increases. Moreover, since the air side flow path area decreases, the problem that the air side ventilation resistance increases also arises.

  The present invention has been made in order to solve the above-described problems. When the louver is miniaturized for the purpose of increasing the amount of heat exchange, it is not necessary to reduce the fin pitch of the corrugated fins, that is, the flow. It is an object of the present invention to provide a heat exchanger having a louver structure that induces a flow passing between louvers adjacent in a direction.

  In order to achieve the above object, the present invention includes a tube in which a first thermal refrigerant flows and a plurality of louver groups in which a plurality of fine louvers are arranged so as to be symmetrical with respect to the center. And a corrugated fin for exchanging heat between the first thermal refrigerant and the second thermal refrigerant flowing outside the tube, the center of each louver group The center portion located at the center is a flat portion that does not cut, and a cut-and-raised portion is formed on the upstream side of the most upstream louver located at the uppermost stream of each louver group, and the cut-and-raised portion and the center A cut-and-raised angle of an end portion on the louver group center side of the louver group inside the louver group located between the louver group and a cut-and-raised angle of the end portion on the upstream side of the louver group, The louver angle in the louver group is in the range of 55 ° to 80 °. It is characterized by an angle.

  Since the plurality of fine louvers of the present invention are arranged so that their positions and shapes are symmetric with respect to the central portion, other cutouts are provided downstream of the most downstream louver located at the most downstream of each louver group. The raised angle of the end of the louver group center side of the louver inside the louver group located between the other cut-and-raised part and the central part is the end of the louver group downstream side. The cut-and-raised angle of the louver within the louver group and the other cut-and-raised part is set to an angle in the range of 55 ° to 80 °.

  The cut-and-raised angle is set to 55 ° to 80 ° so that the flow between the louvers is induced in the louver group regardless of the angle less than 55 ° or the angle exceeding 80 °. This is because the effect is not obtained and the ventilation resistance increases and the heat exchange amount decreases.

  The upstream cut-and-raised part of the present invention is preferably cut and raised at an angle close to 80 ° or 80 °, whereby the flow of the second thermal refrigerant to the cut-and-raised part of the cut and raised part. When a collision occurs, a contracted flow that induces the flow of the second thermal refrigerant is generated between the louvers in the louver group. As a result, the louvers inside the louver group are, for example, horizontally oriented from the lower louver group to the upper louver group on the upstream side from the center, and from the upper louver group to the lower louver group on the downstream side from the central part. A flow is induced passing between adjacent louvers. This flow promotes heat exchange between the second thermal refrigerant near the fin and the second thermal refrigerant away from the fin.

  The induction of the flow between the louvers of the present invention utilizes the contracted flow effect generated in the upstream cut and raised portion. Therefore, it is not necessary to reduce the pitch of the corrugated fins as in the prior art for miniaturizing the louver.

  In the present invention, in the louver within the louver group, the cut-and-raised angle at the end on the central side of the louver group, or the cut-and-raised angle and the cut-and-raised height are Or an end portion on the downstream side of the louver group). Thereby, a flow along the louver is generated on the bottom surface of the louver, and a high heat transfer coefficient can be obtained due to the leading edge effect of the fine louver. Moreover, in the front edge part of an upstream louver, a high heat transfer rate is obtained by the collision with the louver front edge part of the flow between louvers. Furthermore, a high heat transfer coefficient can be obtained at the upper part of the louver by reattaching the flow between the louvers. Since there is a region where such a high heat transfer coefficient can be obtained, there is no need to form a flow along the fin surface unlike the conventional louver fin. As a result, even if the louver is miniaturized, it is not necessary to reduce the pitch of the corrugated fins, so that there is an effect that the fin weight is not increased and the ventilation resistance is not increased.

  The fine louver can be processed from a thin member by roller molding or press molding. In order to consider the elongation of the material during processing, the position and shape of each louver in the louver group are formed symmetrically with respect to the central part of the louver group.

  Moreover, the cut-and-raised height of the end of the louver inside the louver group on the center side of the louver group can be reduced as it goes from the upstream side toward the center of the louver group.

  Moreover, it is preferable to form a circular arc part in the corner | angular part of the louver bending part formed by the louver inside a louver group, and the cut-and-raised part. The cut-and-raised part and the cut-and-raised height of the louver inside the louver group can be lowered from the upstream side toward the center part of the louver group, and at least at the center part of the louver group inside the louver group. The cutting angle of the near louver can be reduced from the upstream side toward the center of the louver group.

  And you may arrange | position the auxiliary | assistant fin which induces the flow which passes between the several louvers adjacent to the flow direction of a said 2nd thermal refrigerant | coolant between the said louver groups.

  Further, the present invention provides a plurality of tubes in which the first thermal refrigerant flows, and the second thermal refrigerant and the first heat that are alternately arranged with the tubes and flow in a space between the tubes. In the heat exchanger having a corrugated fin that promotes heat exchange with the refrigerant, the flat end surface of the fin has a flat central portion of the width of the fin in the passage direction of the second thermal refrigerant. And is formed to be cut and raised on both sides of the flat part in the direction of passage of the second thermal refrigerant, and to be symmetrical with respect to the flat part. Can be provided with a plurality of louvers cut and raised so as to be in the range of 55 ° to 80 °.

  In this case, among the plurality of louvers, at an angle of 80 ° with respect to the flat surface, upstream of the louver disposed on the most upstream side of the second thermal refrigerant flow, upstream of the second thermal refrigerant flow. A cut and raised portion that is cut and raised can be formed.

  As described above, according to the heat exchanger provided with the fine louver of the present invention, the louver length corresponding to the louver pitch can be shortened without reducing the corrugated fin pitch. Even if it refines | miniaturizes, it has the effect that it can prevent an increase in a fin weight and an increase in ventilation resistance.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
FIG. 4 shows a cross-sectional shape of the corrugated fin according to the first embodiment. As shown in the drawing, a number of fine louvers 20 are provided on the flat portion 4d (see FIG. 1B) of the corrugated fin according to the present embodiment.

  The position and shape of the louver 20 are formed so as to be symmetric with respect to the center of the louver group.

  An upstream cut-and-raised portion 21 and a downstream cut-and-raised portion are provided on the upstream and downstream sides of the louvers at both ends of the louver group, that is, on the upstream side and the downstream side of the most upstream louver and the most downstream louver. 22 is formed. In each of the upstream cut-and-raised part 21 and the downstream cut-and-raised part 22, the louver ends 21a and 22a on the center side of the louver group are cut and raised at an angle close to 80 ° or 80 °. On the other hand, the louver end on the louver group end side (the upstream end 21b in the upstream cut-and-raised part 21 and the downstream end 22b in the downstream cut-and-raised part 22) has a cut-and-raised angle (inclination angle). Corresponding) is formed flat at 0 °.

  FIG. 5 shows the cross-sectional shape of the louvers in the louver group and the flow in the vicinity of these louvers. Each of the louvers 20 inside the louver group, excluding the louver 25 at the center of the louver group, has a louver end 51 on the louver group center side (in the upstream louver upstream of the louver group center, downstream of the louver, downstream from the louver group center). The side louver corresponds to the front edge of the louver.Hereinafter, the cut-up angle of the center-side louver end is close to the fin ends (upstream cut-up portion 21 and downstream cut-up portion 22 side). The louver end 50 is formed larger than the louver front edge in the louver upstream from the louver group center, and the louver rear edge in the louver downstream from the louver group center. That is, in the present embodiment, the central louver end 51 is cut and raised at an angle of 80 ° or close to 80 °, and the inclination angle of the both ends louver end 52 is 0 ° and is formed flat. In the present embodiment, the louvers in the louver group are cut and raised at the center of each louver so that the center fin end portions and the end fin end portions are made the same.

  Also, the louver 25 at the center of the louver group is formed flat without being cut out at all.

  In this embodiment, the corrugated fin has a fin pitch of 1.25 mm, a louver length (corresponding to the louver pitch of the louver) of 0.45 mm, and the length of the cut-and-raised portion of each louver is half the louver length. It was.

  In the case of louver fins, when the fin pitch is 1.25 mm and the louver pitch is 0.45 mm, the air flow does not pass between the louvers as shown in FIG. In the present embodiment, even when the fin pitch is 1.25 mm and the louver length is 0.45 mm, the air flow passes between the louvers.

  The reason why it is not necessary to reduce the fin pitch of the corrugated fins although it is a fine louver will be described with reference to FIGS. FIG. 6 is a schematic diagram showing the air flow in the louver group upstream of the louver group center. The flow 14 in front of the fins collides with the front edge of the upstream cut-and-raised part 21, and then branches into a flow 34 at the upper part of the louver group and a flow 35 at the lower part of the louver group.

  In the flow 34 above the louver group, the flow path area decreases due to the presence of the upstream cut and raised portion 21. As a result, the contracted flow 30 is generated when passing the upper part of the upstream cut and raised portion 21. On the other hand, no contraction occurs in the flow 35 below the louver group.

  In the contracted portion, a pressure drop occurs as the flow velocity increases, and the pressure of the flow 34 at the upper part of the louver group is lower than the pressure of the flow 35 at the lower part of the louver group. As a result, as shown in FIG. 5, a flow 31 is generated that passes between the louvers adjacent in the horizontal direction from the lower louver group 28 to the lower louver group 29. That is, when the air flow collides with the upstream cut and raised portion 21, a contracted flow that induces the flow 31 passing between the louvers adjacent in the horizontal direction is generated.

  Four effects of the inter-louver flow 31 will be described with reference to FIG. As a first effect, the inter-louver flow 31 transports the air in the louver group lower portion 28 having a large temperature difference from the wall temperature of the fine louver 20 between the louvers. As a result, heat exchange between the air and the louver is promoted. As a second effect, the inter-louver flow 31 collides with the louver leading edge 50 when passing between the louvers. A high heat transfer coefficient is obtained by the collision of the flow with the louver leading edge. As a third effect, a high heat transfer coefficient is obtained at the louver bottom surface 52 due to the leading edge effect of the fine louver 20. Further, the flow passing near the louver bottom surface 52 is pressed against the louver bottom surface 52 by the flow 57 passing between the louvers on the downstream side. As a result, as a fourth effect, the flow 57 causes the louver bottom boundary layer 58 to be thinned. Due to the thinning of the boundary layer 58, the temperature gradient on the wall surface increases and the heat transfer coefficient increases.

  With the above mechanism, the fine louver 20 having high heat transfer performance can be realized. In the vicinity of the louver, a stagnation region 59 having a small flow velocity is generated. In the louver fin, when a stagnation region occurs in the vicinity of the louver, the performance deteriorates. In the present embodiment, because of the above four effects, a high heat transfer coefficient can be obtained. Therefore, even if a stagnation region occurs in the vicinity of the louver, the performance does not deteriorate. That is, in the present embodiment, unlike the conventional louver, there is no need to generate a flow along the louver wall surface around the louver, so the degree of freedom of the louver shape is expanded.

  Further, in order to achieve the effect of the present embodiment, it is sufficient that a contracted flow is generated by the upstream cut-and-raised portion 21, and at the same time as the louver is refined, the fin of the corrugated fin is used. There is no need to reduce the pitch. That is, it is possible to realize a fine louver that does not require the pitch of the corrugated fins to be reduced. As a result, it is possible to realize a fine louver that does not cause an increase in air-side ventilation resistance and an increase in the weight of the fin portion.

  Moreover, in the louver fin of a prior art, it is necessary to make the flow in a louver group follow the fin surface. As a result, the rear edge of the upstream cut-and-raised part is cut and raised at the same angle as the louver inclination angle inside the louver group. Since the louver has an inclination angle of about 40 ° at the maximum, the cut-up angle of the upstream cut-and-raised portion is also around 40 °. At this angle, the louver is contracted so as to induce the flow between the louvers. The flow effect is not obtained.

  The effect of the flow between louvers in the downstream louver group will be described with reference to FIG. The louver 25 at the center of the louver group is a flat portion that is not cut and raised. Since the louver 25 is composed of a flat portion, the inter-louver flow 33 passing through the upper portion of the louver 25 flows in a horizontal direction, unlike the inter-louver flow 31 of the upstream louver upstream from the louver group center.

  In the upstream louver 26 upstream from the center of the louver group, the flow 34 passing through the upper part of the louver group is pushed upward by the flow 31 passing between the louvers as described in FIG. However, since the louver flow 33 of the louver 25 at the center of the louver group flows in the horizontal direction, the force that pushes the flow passing through the upper part of the louver group upward is weakened. Therefore, in the upper part of the louver 25, the flow passing through the upper part of the louver group descends and a descending flow 36 is generated. The descending amount of the descending flow 36 is increased in proportion to the horizontal distance from the louver 25 at the center of the louver group. When the descending amount is increased, the flow is the side surface 43 of the louver front edge portion of the louver downstream from the louver group center. Collide with.

  As a result, a flow 32 is generated from the louver group upper part 29 toward the louver group lower part 28 and passing between the louvers downstream from the center of the louver group adjacent in the horizontal direction. This flow 32 transports air between the fine louvers 20 and the louver group upper portion 29 having a large temperature difference between the louvers, and promotes heat exchange between the louvers and the air. Furthermore, a high heat transfer coefficient is obtained by the collision of the flow 32 passing between the louvers on the downstream side against the louver side surface 43.

In the above, the angle at the center louver end of the louver in the louver group is made larger than the angle at the end of both ends louver, and the amount of protrusion at the end of the center louver and the end of both ends louver Although the example in which the cut-and-raised amount of the part is made the same has been described, both the cut-and-raised angle and the cut-and-raised amount of the center louver end are determined by the cut-and-raised angle and the cut-and-raised amount of both ends of the louver It may be made larger.
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the louver group central louver end 51 of the louver group internal louver is cut at an angle of 80 ° or close to 80 °, and the flow rate between the louvers is increased at both ends of the louver end 50. It is made to incline in the direction to do. That is, in the louver upstream from the center, the flow passing through the lower part of the louver flows along the louver bottom after colliding with the louver front edge. When the front edge side end of the upstream louver is inclined downward from the horizontal direction from the center, the flow along the louver bottom flows in the direction between the louvers, not in the horizontal direction.

  As a result, the flow rate of the flow passing between the louvers increases as compared with the case where the front edge side end of the upstream louver is horizontal from the center. When the flow rate of the flow passing between the louvers increases, heat exchange between the air in the vicinity of the louvers and the air away from the louvers is promoted, and the amount of heat exchange is greater than when the ends 50 on both ends of the louver group are horizontal. Will increase.

  The louver shape of the second embodiment is shown in FIG. In the second embodiment, in the inner louver 24 of the louver group, the end portion 51 on the center side of the louver group is cut at an angle of 80 ° or an angle close to 80 °, and the end portions 50 on both ends of the louver group are inclined by the inclination angle θb. Is cut and raised so as to be in the range of 5 to 15 ° downward from the horizontal direction.

  The optimum range of the tilt angle was determined by heat flow analysis. In the present embodiment, the fin pitch of the corrugated fins is 1.25 mm, and the louver length corresponding to the louver pitch of the louver is 0.45 mm. FIG. 9 shows a flow velocity vector of a flow passing between louvers in the second embodiment, which is obtained by heat flow analysis.

  In the upstream louver upstream from the center of the louver group, the flow 35 passing through the fin lower portion flows along the louver bottom surface 52 after colliding with the louver front edge 50. When the louver ends 50 at both ends of the louver in the louver group are inclined, the flow along the louver bottom surface 52 flows in the direction between the louvers, not in the horizontal direction. As a result, the flow rate of the flow passing between the louvers increases as compared with the case where the both end side louver ends 50 are horizontal.

  When the flow rate of the flow passing between the louvers increases, heat exchange between the air in the vicinity of the louvers and the air away from the louvers is promoted, and the amount of heat exchange increases compared to the case where the louver ends 50 at both ends are horizontal. To do.

  FIG. 10 illustrates the relationship between the bottom surface inclination angle θb and the heat exchange amount. The heat exchange amount was made dimensionless by the heat exchange amount when the bottom surface inclination angle was 0 °. As understood from FIG. 10, when the bottom surface inclination angle is increased from 0 ° to 20 °, the amount of heat exchange increases. However, since the draft resistance also increases at the same time, the optimum value of the inclination angle cannot be determined from this result. Therefore, the performance of the fine louver is calculated using the louver performance organizing formula proposed in Non-Patent Document 1 and Non-Patent Document 2, and the performance of the fine louver is estimated using heat flow analysis. By comparing the performance, the optimum value of the tilt angle was determined. The physical quantities compared are the heat exchange amount, the ventilation resistance, and the weight of the fin portion.

  The specifications of the louver fin were such that the louver pitch and the louver angle were constant, and the fin pitch of the corrugated fin was changed from 1.25 mm to 0.45 mm. A comparison of the performance of the louver fin and the fine louver is shown in FIG. FIG. 11 shows a case where the louver pitch is 0.9 mm. The horizontal axis represents the heat exchange amount, and the vertical axis represents the weight of the corrugated fin part and the ventilation resistance. Both the horizontal axis and the vertical axis are made dimensionless by the amount of heat exchange when the fin pitch of the corrugated fins is 1.25 mm, and are shown as ratios.

  In the case of the louver fin, the leftmost data on the horizontal axis is when the corrugated fin pitch is 1.25 mm, and the rightmost data is when the corrugated fin pitch is 0.45 mm. In the fine louver with the louver bottom inclined, the data on the leftmost side is when the bottom surface inclination angle is 0 °, and the data on the right side is when the bottom surface inclination angle is 30 °. In the louver fin, it is necessary to reduce the pitch of the corrugated fins in order to increase the heat exchange amount. Therefore, if the heat exchange amount is increased by 20%, the fin portion weight is 1.7 times. In the fine louver, it is not necessary to reduce the fin pitch of the corrugated fins. By setting the louver length to 0.45 mm, the leading edge effect is expanded, and the heat exchange amount increases due to the effect of promoting the heat exchange of the flow between the louvers. As a result, when the heat exchange amount is increased by 20%, the fin portion weight of the fine louver is 60% of the louver fin.

From FIG. 11, the optimal range of the inclination angle θb is preferably in the range of 5 to 15 °.
[Third embodiment]
Next, a third embodiment will be described. The louver shape of the third embodiment is shown in FIG. In the present embodiment, the bottom surface of the louver (both end side louver end portion 50) and the louver side surface (center side louver end portion 51) in the louver group are inclined in the direction in which the flow between the louvers increases. The louver ends 50 at both ends of the present embodiment are the same as the louver shape of the second embodiment, but the inclination angle of the center louver end 51 is smaller than 80 ° or an angle close to 80 °. It has been cut up. The stagnation area generated between the louvers is reduced and the ventilation resistance is reduced as compared with the case where the center louver end 51 is cut and raised at an angle close to 80 ° or 80 °.

  FIG. 13 shows the result of heat flow analysis performed to determine the optimum range of the side surface inclination angle θs under the same conditions as in FIG. When the inclination angle θs is 55 ° to 80 °, the ventilation resistance is equal to or less and the heat exchange amount is equal to or more than that when the inclination angle θs is 90 °. The inclination angle θs is preferably in the range of 55 ° to 80 °.

  In the present embodiment, the example in which each of the end portions on both ends of the louver inside the louver group is inclined has been described. However, it may not be inclined as in the first embodiment.

In the third embodiment described above, the embodiment in which the cut-and-raised portion 21 is cut and raised at an angle of 80 ° or 80 ° with respect to the plane portion has been described. After the collision, the angle may be such that the flow branches up and down the louver.
[Fourth embodiment]
Next, a fourth embodiment will be described. This embodiment is a bent portion generated when the upstream cut-and-raised portion and the downstream cut-and-raised portion are cut and raised, and a corner portion of the louver bent portion that is generated when the louver is cut and raised in the first embodiment. A circular arc portion is provided on the outer side of the.

  FIG. 14 shows the louver shape of the fourth embodiment. As shown in FIG. 14, in the present embodiment, arc portions 65 are formed at the corners of the louver bent portion. FIG. 15 shows a flow velocity vector of a flow passing between louvers in the fourth embodiment, which is obtained by heat flow analysis.

  The flow 35 passing through the lower part of the louver flows along the louver bottom surface 52 after colliding with the front edge 50 of the louver. When the arc portion 65 is provided in the bent portion, the flow along the louver bottom surface 52 flows not in the horizontal direction but in the direction between the louvers. As a result, the flow rate of the flow passing between the louvers is increased as compared with the case where it is bent at a right angle. When the flow rate of the flow passing between the louvers increases, heat exchange between the air in the vicinity of the louvers and the air away from the louvers is promoted, and higher heat transfer performance is obtained than when bent at right angles.

  The optimum range of the radius R of the arc portion 65 was determined by heat flow analysis. The corrugated fin has a fin pitch of 1.25 mm, and the louver length corresponding to the louver pitch of the louver fin is 0.45 mm.

  FIG. 16 illustrates the relationship between the radius R of the arc portion 65 and the heat exchange amount. In the horizontal axis, the radius R of the arc portion 65 is made dimensionless by the horizontal portion louver length Lb when the louver is bent at a right angle. When R / Lb is increased from 0 to 0.9, the amount of heat exchange increases. However, since the ventilation resistance also increases at the same time, the optimum value of the radius of the arc portion cannot be determined from this result. Therefore, the performance of the fine louver is estimated using the louver performance prearrangement formula proposed in Non-Patent Document 1 and Non-Patent Document 2, and the performance of the fine louver is estimated using heat flow analysis. The optimum value of the radius of the arc portion was determined by comparing the performance of both. The physical quantities compared are the heat exchange amount, the ventilation resistance, and the weight of the fin portion.

  The specifications of the louver fin were such that the louver pitch and the louver angle were constant, and the fin pitch of the corrugated fin was changed from 1.25 mm to 0.45 mm. A comparison of the performance of the louver fin and the fine louver is shown in FIG. The figure shows a case where the louver pitch is 0.9 mm. The horizontal axis represents the heat exchange amount, and the vertical axis represents the weight of the corrugated fin part and the ventilation resistance. Both the horizontal axis and the vertical axis are shown dimensionlessly by the heat exchange amount when the fin pitch of the corrugated fin is 1.25 mm.

  In the case of the louver fin, the leftmost data on the horizontal axis is when the corrugated fin pitch is 1.25 mm, and the rightmost data is when 0.45 mm. When the louver bent portion has an arc portion, the leftmost data is when there is no arc portion, and the right data is when the radius of the arc portion is 0.2 mm. In the louver fin, it is necessary to reduce the pitch of the corrugated fins in order to increase the heat exchange amount. Therefore, if the heat exchange amount is increased by 15%, the weight of the fin portion becomes 1.4 times. In the fine louver, it is not necessary to reduce the fin pitch of the corrugated fins. By setting the louver length to 0.45 mm, the leading edge effect is expanded, and the heat exchange amount increases due to the effect of promoting the heat exchange of the flow between the louvers. As a result, when the heat exchange amount is increased by 15%, the fin portion weight of the fine louver is 72% of the louver fin.

  From FIG. 17, the optimal range of the ratio of the horizontal portion louver length Lb when the radius R of the arc portion 65 and the louver are bent at right angles is preferably 0.2 to 0.9.

  In the present embodiment, the example in which the arc portion is provided on the outer side portion of the corner portion of the louver bent portion generated when the louver is cut and raised in the first embodiment has been described. However, the second embodiment or the second embodiment In the third embodiment as well, an arc portion can be provided in the outer portion of the corner portion of the louver bent portion that is generated when it is similarly cut and raised.

[Fifth embodiment]
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the amount by which the center side louver end portion 51 of each louver is cut from the both ends of the louver group toward the center of the louver group is gradually reduced. Further, both end portions 50 of the upstream cut and raised portion 21 and the downstream cut and raised portion 22 are flattened, and the both end portions 50 of each louver 20 in the louver group are as described with reference to FIG. It is tilted horizontally downward.

  The louver shape of the fifth embodiment is shown in FIG. In the fifth embodiment, the cut-and-raised height of the louver side surface portion 43 that is the center-side louver end portion 51 of each louver, that is, the cut-and-raised amount of each louver is the upstream-side cut and raised located at both ends of the louver group. The length is gradually shortened from each of the ridge portion 21 and the downstream cut-and-raised portion 22 toward the center of the louver group.

  Air in the louver group lower part 28 is transported to the louver group upper part 29 of the upstream louver 26 upstream of the louver group center by the inter-louver flow 31. As a result, the flow rate of the flow passing through the louver group upper portion 29 of the upstream louver 26 increases as the distance from the upstream cut-and-raised portion 21 increases. Therefore, as the distance from the upstream cut-and-raised portion 21 becomes longer, the cut-and-raised height 70 of the louver side surface 43 is lowered and the flow path area 72 is expanded. As a result, it is possible to reduce the ventilation resistance compared to the case where all the louvers are cut and raised and the height is constant.

  In the downstream louver 27 downstream of the louver group center, the air in the louver group upper part 29 is transported to the louver group lower part 28 by the flow 32 between louvers. In the fifth embodiment, the cut-and-raised height 71 of the louver side surface 43 of the downstream louver is formed so as to gradually increase from the central portion of the louver group toward the downstream cut-and-raised portion 22. As a result, the air at a higher position is transported to the lower louver group 28 as the distance from the center of the louver group becomes longer. The further away from the louver group, the greater the temperature difference between the air and the louver. Air having a large temperature difference from the louver wall surface is transported to the vicinity of the louver by the inter-louver flow 32. As a result, the amount of heat exchange increases.

FIG. 19 shows a flow velocity vector of a flow passing between louvers in the fifth embodiment, which is obtained by heat flow analysis. The cut-and-raised height 70 of the side faces 43 of the cut-and-raised parts 21 and 22 on both ends of the louver group was 0.2 mm, and the cut-and-raised height 71 of the louver on the center side of the louver group was 0.1 mm. FIG. 20 shows the effect. The amount of heat exchange was equal to or greater than that in the case where the cutting height was fixed, and the ventilation resistance was reduced by 22%.
[Sixth embodiment]
Next, a sixth embodiment of the present invention will be described. In the present embodiment, the inclination angle of the louver side face 43, which is the central louver end 51 of each louver, is changed so as to gradually decrease toward the louver group center.

  FIG. 21 shows a louver shape according to the sixth embodiment. In the sixth embodiment, the louver side surface 43 has a cut-and-raised angle θs that is gradually reduced from the cut-and-raised portions 21 and 22 on both ends of the louver group toward the center of the louver group. The effect similar to that of the embodiment is produced. Note that both end portions 50 of the upstream cut-and-raised portion 21 and the downstream cut-and-raised portion 22 are flattened, and each end portion 50 of each louver 20 in the louver group is as described with reference to FIG. It is tilted horizontally downward.

  FIG. 22 shows the effect of the sixth embodiment obtained by heat flow analysis. The cut-and-raised angle θs ′ of the side surfaces 43 of the cut-and-raised parts 21 and 22 was 80 °, and the louver cut-and-raised angle θs on the louver group center side was 45 °. Compared with the case where the cut-and-raised height angle is constant, the amount of heat exchange is equal to or greater, and the ventilation resistance is reduced by 14%.

In the sixth embodiment, the same effect as that of the fifth embodiment is obtained by reducing the cut-up angle of the side surface of the louver from the louver on the side of the raised portion toward the louver in the central portion of the louver group. Have.
[Seventh embodiment]
Next, a seventh embodiment of the present invention will be described. This embodiment is provided with auxiliary fins for inducing a strong inter-louver flow in the second embodiment.

  The louver shape of the seventh embodiment is shown in FIG. In the seventh embodiment, auxiliary fins 80 for inducing a flow between louvers are provided between louver groups. The auxiliary fin 80 is formed such that the vertical distance 81 between the auxiliary fin and the louver bottom surface 52 gradually decreases from both ends of the louver group toward the center of the louver group. In the louver group lower part 28, since the flow area on the air side decreases, the flow rate of the flow 31 passing between the fins increases. As a result, the amount of heat exchange increases.

  In addition, although the example which provides an auxiliary fin in 2nd Embodiment was demonstrated above, you may make it provide an auxiliary fin in 1st, 3rd-6th embodiment.

(A) is the schematic of the heat exchanger provided with the conventional corrugated louver fin, (b) is a top view of a corrugated fin, (c) is the sectional view on the AA line of FIG.1 (b), (d) is It is the elements on larger scale of FIG.1 (c). It is explanatory drawing explaining the flow between the fin item of a prior art, and a louver fin. It is a diagram which shows the relationship between the pitch of a corrugated fin of a prior art, and ventilation resistance ratio, the weight ratio of a fin, and the ratio of heat exchange amount. It is explanatory drawing which shows the flow between the louvers of the fine louver of 1st Embodiment. It is explanatory drawing explaining the flow of the air of the inside louver vicinity of the louver group of the said 1st Embodiment. It is explanatory drawing for demonstrating generation | occurrence | production of the flow between louvers in the upstream louver group of the said 1st Embodiment. It is explanatory drawing for demonstrating generation | occurrence | production of the flow between louvers in the downstream louver group of the said 1st Embodiment. It is the schematic which shows the bottom face inclination louver of 2nd Embodiment. It is a figure which shows the flow-velocity vector of the flow between louvers of the bottom face inclination louver of the said 2nd Embodiment. It is a diagram which shows the relationship between the bottom face inclination | tilt angle (theta) b of the said 2nd Embodiment, and the amount of heat exchange. It is a diagram which shows the ratio of the louver weight with respect to the ratio of the heat exchange amount of the said 2nd Embodiment, and the ratio of ventilation resistance. It is the schematic which shows the bottom face and inclination louver of 3rd Embodiment. It is a diagram which shows the relationship between side surface inclination-angle (theta) s of the said 3rd Embodiment, and the ratio of ventilation resistance ratio and heat exchange amount. It is the schematic which shows the louver by which the circular arc part was formed in the corner | angular part of the fin bending part of 4th Embodiment. It is a figure which shows the flow velocity vector of the flow between louvers of the bottom face inclination louver of the said 4th Embodiment. It is a diagram which shows the relationship between the radius of a circular arc part, and the amount of heat exchange. It is a diagram which shows the ratio of the fin weight with respect to the ratio of the heat exchange amount of the said 4th Embodiment, and the ratio of ventilation resistance. It is the schematic which shows the louver of 5th Embodiment. It is a figure which shows the flow velocity vector of the flow which passes between louvers calculated | required by the heat flow analysis in the said 5th Embodiment. It is a diagram which shows the performance ratio of the ventilation resistance and heat exchange amount in the said 5th Embodiment. It is the schematic which shows the louver of 6th Embodiment. It is a diagram which shows the performance ratio of the ventilation resistance and heat exchange amount in the said 6th Embodiment. It is the schematic which shows the louver of 7th Embodiment.

Explanation of symbols

4,4 Corrugated fin 4a Louver 10 Louver fin 21 Upstream cut and raised part 22 Downstream cut and raised part 25 Louver 28 Louver group lower part 29 Louver group upper part 30 Contracted flow

Claims (8)

A tube through which the first thermal refrigerant flows, and a plurality of louver groups in which a plurality of fine louvers are arranged so as to be symmetrical with respect to the center, and the first thermal refrigerant and the In a heat exchanger comprising a corrugated fin for performing heat exchange with a second thermal refrigerant flowing outside the tube,
A central portion located at the center of each louver group is a flat portion that is not cut, and a cut-and-raised portion is formed upstream of the most upstream louver located at the most upstream of each louver group. A cutting angle at the end of the louver group center side of the louver located inside the louver group located between the center part and the center part is larger than the cutting angle at the end part on the upstream side of the louver group. A heat exchanger characterized in that the cut-up angle of the louver in the raising portion and the louver group is an angle in the range of 55 ° to 80 °.   2. The heat exchanger according to claim 1, wherein a cut-and-raised height of an end of the louver inside the louver group on the center side is made smaller from the upstream side toward the center.   The heat exchanger according to any one of claims 1 and 2, wherein an arc portion is formed at a corner portion of a bent portion formed by cutting and raising the louver inside the louver group and the louver group.   The heat exchanger according to any one of claims 1 to 3, wherein a cut-and-raised height of the louver in the cut-and-raised part and the louver group is lowered from the upstream side toward the central part.   The heat exchanger according to any one of claims 1 to 4, wherein a cut-and-raft angle of a louver close to at least the central portion of the louvers in the louver group is reduced from the upstream side toward the central portion.   The heat exchanger according to any one of claims 1 to 5, wherein auxiliary fins for inducing a flow passing between louvers adjacent in the flow direction of the second thermal refrigerant are arranged between the louver groups. A plurality of tubes through which the first thermal refrigerant flows;
A heat exchanger provided with a corrugated fin that is arranged alternately with the tubes and that promotes heat exchange between the second heat refrigerant flowing in the space between the tubes and the first heat refrigerant. In
On the flat end surface of the fin,
A center part of the width of the fin in the passing direction of the second thermal refrigerant is a flat part,
In the passing direction of the second thermal refrigerant, it is formed to be cut and raised on both sides of the flat portion, and is formed to be symmetric with respect to the flat portion, and the cut and raised angle with respect to the flat portion is 55 °. A heat exchanger comprising a plurality of louvers cut and raised to be -80 °. Of the plurality of louvers, the louver disposed upstream of the second thermal refrigerant flow is upstream of the second thermal refrigerant flow and is cut and raised at 80 ° with respect to the flat surface. The heat exchanger according to claim 7, wherein a cut and raised portion is formed.

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