U.S. patent application number 12/441800 was filed with the patent office on 2009-12-24 for heat exchanger.
This patent application is currently assigned to HALLA CLIMATE CONTROL CORP.. Invention is credited to Young-Ha Jeon, Ki-Hong Kim, Jung-Jae Lee.
Application Number | 20090314475 12/441800 |
Document ID | / |
Family ID | 39200682 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090314475 |
Kind Code |
A1 |
Jeon; Young-Ha ; et
al. |
December 24, 2009 |
HEAT EXCHANGER
Abstract
A heat exchanger has plural tubes, an inlet tank, a fin, and an
outlet tank. Each tube has a dimple structure for inducing a
turbulent flow of heat exchange fluid flowing through each tube,
thereby increasing heat exchange performance. The dimples of each
tube satisfy the following formula: 8.80 < the sum A dimple of
the product of a width d and a depth h of each dimple a length L of
the tube .times. a height H of the tube .times. 100 < 13.60
##EQU00001##
Inventors: |
Jeon; Young-Ha; (Daejeon,
KR) ; Kim; Ki-Hong; (Daejeon, KR) ; Lee;
Jung-Jae; (Daejeon, KR) |
Correspondence
Address: |
LOWE HAUPTMAN HAM & BERNER, LLP
1700 DIAGONAL ROAD, SUITE 300
ALEXANDRIA
VA
22314
US
|
Assignee: |
HALLA CLIMATE CONTROL CORP.
Daejeon
KR
|
Family ID: |
39200682 |
Appl. No.: |
12/441800 |
Filed: |
September 18, 2007 |
PCT Filed: |
September 18, 2007 |
PCT NO: |
PCT/KR2007/004485 |
371 Date: |
March 18, 2009 |
Current U.S.
Class: |
165/109.1 |
Current CPC
Class: |
F28F 1/42 20130101; F28F
1/426 20130101; F28F 3/044 20130101; F28D 1/05366 20130101; F28D
1/0391 20130101 |
Class at
Publication: |
165/109.1 |
International
Class: |
F28F 13/12 20060101
F28F013/12 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 21, 2006 |
KR |
10-2006-0091660 |
Claims
1. A heat exchanger, comprising: a plurality of tubes 20 arranged
in parallel at regular distances so they in the same direction as a
ventilation direction through which a heat exchange medium is
adapted to flow; an inlet tank in which the heat exchange medium is
adapted to be introduced and then distributed to the plurality of
tubes; a fin interposed between the tubes so as to increase contact
surface with air passing between the tubes; and an outlet tank in
which the heat exchange medium flowing through the tubes is adapted
to be collected and then discharged, each of the tubes including a
dimple protruding from an inside surface of the tube, and when the
total sectional area A.sub.dimiple of the dimples of each tube is
expressed as the sum of the product of the width d and depth h of
each dimple and the cross sectional area of each tube is expressed
as the product of a length L and height H of each tube, the
following formula is satisfied: 8.80 < the sum A dimple of the
product of a width d and a depth h of each dimple a length L of the
tube .times. a height H of the tube .times. 100 < 13.60
##EQU00008##
2. The heat exchanger according to claim 1, wherein the depth h of
each dimple and the height H of each tube satisfy the following
formula: 0.25 < a depth h of the dimple a height H of the tube
< 0.4 ##EQU00009##
3. The heat exchanger according to claim 2, wherein a plurality of
the dimples are arranged in a transverse direction to form rows on
upper and lower surfaces of each tube, the upper dimple row and the
lower dimple row of each tube 20 being alternately arranged along
the length of each tube.
4. The heat exchanger according to claim 3, wherein the dimples of
the upper dimple row and lower dimple row are also arranged
alternately along the width of the tube so that the dimples of the
upper dimple row and lower dimple row are not aligned with each
other, and one of the dimples of the lower dimple row being
disposed between two adjacent dimples of the upper dimple row, and
one of the dimples of the upper dimple row being also disposed
between two adjacent dimples of the lower dimple row.
5. The heat exchanger according to claim 3, wherein the number of
dimples of the upper dimple row of each tube is the same as the
number of dimples of the lower dimple row of each tube.
6. The heat exchanger according to claim 1, wherein a plurality of
the dimples are arranged in a transverse direction to form rows on
upper and lower surfaces of each tube, and the upper dimple row and
the lower dimple row of each tube being alternately arranged along
the length of each tube.
7. The heat exchanger according to claim 6, wherein the dimples of
the upper dimple row and lower dimple row are also arranged
alternately along the width of the tube so that the dimples of the
upper dimple row and lower dimple row are not aligned with each
other, and one of the dimples of the lower dimple row being
disposed between two adjacent dimples of the upper dimple row, and
one of the dimples of the upper dimple row being also disposed
between two adjacent dimples of the lower dimple row.
8. The heat exchanger according to claim 7, wherein the number of
dimples of the upper dimple row of each tube is the same as the
number of dimples of the lower dimple row of each tube.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger, more
particularly, to a heat exchanger with a tube having a dimple
structure by which a turbulent flow is generated in the tube,
thereby increasing a heat exchanging performance.
BACKGROUND ART
[0002] FIG. 1 is a view showing a general cooling and heating
system of a vehicle. In a vehicle engine 1, high temperature and
high pressure gas is ignited and burned. Therefore, if leaving the
vehicle engine 1 as it is, it will be overheated and a metallic
material used in constructing the engine 1 is melted and thus a
cylinder, a piston and the like may be damaged seriously. To
prevent such damage, as shown in FIG. 1, a water jacket (not shown)
in which cooling water is stored is formed around the cylinder of
the vehicle engine 1 and the cooling water is circulated through a
radiator 2 or a heater core 3 by a water pump 5 so as to cool the
engine 1. The cooling water may be not passed through the heater
core 3, but directly returned to the water jacket through a bypass
circuit 6 according to the purpose of heating and cooling. At this
time, a thermostat 4 is provided in a passage for the cooling water
so as to function as a control device for preventing the
overheating of the engine 1 by controlling an opening/closing
degree of the passage on the basis of a temperature of the cooling
water.
[0003] The radiator 2 is a kind of heat exchanger for radiating
heat of the cooling water which is heated by heat of the engine 1
while being circulated in the engine 1. The radiator 2 is disposed
in an engine room of the vehicle and provided with a cooling fan at
a center portion thereof so as to cool a radiator core. Further,
the heater core 3 is a part of an air conditioner of the vehicle
and also functions as the kind of heat exchanger for supplying warm
air to an inside of the vehicle using the high temperature cooling
water which absorbs the heat generated from the engine 1 while
being circulated in the engine 1. In the heater core 3, the high
temperature cooling water which is heated by the heat of the engine
1 is passed through a fin and a tube of the heater core 3 so as to
transfer the heat to air supplied from the outside, thereby
providing the warm air to the inside of the vehicle.
[0004] In order to properly heat the inside of the vehicle, a heat
exchange performance of the heater core should be increased.
However, in case that the heat exchanger is installed in the
vehicle, it is difficult to change a basic structure of the heat
exchanger, like a size or a position of an inlet/outlet port for a
heat exchange medium due to problems of connection with other parts
as well as limitation of an inner space of the engine room. In
order to increase an amount of radiant heat without change of the
basic structure of the heat exchanger, typically, a design for
increasing a cross-sectional area of the tube in which the heat
exchange is substantially performed and thus increasing a flow rate
in the tube is employed. However, if the cross-sectional area of
the tube is increased, a laminar flow is generated at a low flow
rate condition, and thus there is a problem that the amount of
radiant heat is reduced. Japanese Laid-Open Publication No.
1996-136176 (hereinafter, called as "cited reference") had planed
to improve the heat radiation performance by numerically limiting
the tube and fin. In the cited reference, the laminar flow area is
always maintained at a running speed of 60 Km/h or less so as to
reduce a wide difference of the heating performance between when
the vehicle is running at 60 Km/h or more and when the vehicle is
in an idling state, thereby improving the heating performance.
However, since the laminar flow is generated at the low flow rate
condition, as described above, the heat exchange performance is
deteriorated.
DISCLOSURE
Technical Problem
[0005] An object of the present invention is to provide a heat
exchanger in which a turbulent flow is generated early at the low
flow rate condition, thereby securing an optimum heat exchange
performance.
[0006] Another object of the present invention is to provide an
optimum design range for each element constructing a heat exchanger
tube so as to satisfy the optimum heat exchange performance.
Technical Solution
[0007] In order to achieve the above objects, there is provided a
heat exchanger comprising a plurality of tubes 20 which are
arranged in parallel at regular distances to be parallel with a
ventilation direction and through which a heat exchange medium is
flowed; an inlet tank 11 in which the heat exchange medium is
introduced and then distributed to the plurality of tubes 20; a fin
30 which is interposed between the tubes 13 so as to increase a
contact surface with air passing between the tubes 20; and an
outlet tank 12 in which the heat exchange medium flowed through the
tubes 20 is collected and then discharged, wherein a dimple 21 is
formed in each of the tubes 20 so as to be protruded to an inside
of the tube 20, and when a total sectional area A.sub.dimiple of
the dimples 21 is expressed as sum of the product of a width d and
a depth h of each dimple 21 and a sectional area of the tube 20 is
expressed as the product of a length L and a height H of the tube
20, a following formula is satisfied:
8.80 < the sum A dimple of the product of a width d and a depth
h of each dimple a length L of the tube .times. a height H of the
tube .times. 100 < 13.60 ##EQU00002##
[0008] Preferably, the depth h of the dimple 21 and the height H of
the tube 20 satisfy a following formula:
0.25 < a depth h of the dimple a height H of the tube < 0.4
##EQU00003##
[0009] Preferably, the plurality of dimples which are arranged in a
transverse direction so as to form a row are formed at upper and
lower surfaces of the tube 20, and the upper dimple row and the
lower dimple row of the tube 20 are alternately arranged along the
length of the tube 20.
[0010] Preferably, the dimples 21 of the upper dimple row and lower
dimple row are also arranged alternately along the width of the
tube 20 so that the dimples 21 of the upper dimple row and lower
dimple row are not coincided with each other, and one of the
dimples 21 of the lower dimple row is disposed between two adjacent
dimples 21 of the upper dimple row, and one of the dimples 21 of
the upper dimple row is also disposed between two adjacent dimples
21 of the lower dimple row.
[0011] Preferably, the number of dimples 21 of the upper dimple row
of the tube 20 is the same as the number of dimples 21 of the lower
dimple row of the tube 20.
ADVANTAGEOUS EFFECTS
[0012] According to the present invention, since a turbulent flow
is generated early even when a flow rate condition of the heat
exchange medium in the heat exchanger tube is unfavorable, it is
possible to increase the heat exchange performance and also
optimize the heat exchange performance at all of the flow rate
conditions. Furthermore, it is possible to easily design a shape
and a dimension of the dimple for the optimal heat exchange
performance by regulating a flowing property of the fluid, thereby
saving labor, cost, time and the like.
DESCRIPTION OF DRAWINGS
[0013] The above and other objects, features and advantages of the
present invention will become apparent from the following
description of preferred embodiments given in conjunction with the
accompanying drawings, in which:
[0014] FIG. 1 is a view showing a general cooling and heating
system of a vehicle.
[0015] FIG. 2 is a perspective view of a heat exchanger.
[0016] FIG. 3 is a perspective view and cross-sectional views of a
tube having a dimple structure.
[0017] FIG. 4 is a view showing a fabricating method of the tube
having the dimple structure according to an embodiment of the
present invention.
[0018] FIG. 5 is a view showing dimensions of the dimple and
tube.
[0019] FIG. 6 is a view showing an effective area of the heat
exchanger.
[0020] FIG. 7 is a graph showing a heat exchange performance per
effective area with respect to each factor.
DETAILED DESCRIPTION OF MAIN ELEMENTS
TABLE-US-00001 [0021] 100: heat exchanger 10: tank 11: inlet tank
12: outlet tank 20: tube 30: fin 21: dimple 22: partition wall
Best Mode
[0022] Hereinafter, the embodiments of the present invention will
be described in detail with reference to accompanying drawings.
[0023] FIG. 2 is a perspective view of a heat exchanger 100. A heat
exchange medium is flown in the heat exchanger 100, and the heat
exchanger 100 includes a plurality of tubes 20 which are arranged
in parallel at regular distances to be parallel with a ventilation
direction, and tanks 10 which are respectively coupled to both ends
of the tubes 20. The tanks 10 are divided into an inlet tank 11 in
which the heat exchange medium is introduced and then distributed
to the plurality of tubes 20 and an outlet tank 12 in which the
heat exchange medium moved through the tubes 20 is collected and
then discharged. Fins 30 are provided between the tubes 20 so as to
increase a contact surface area with air flowing between the tubes
20. As described above, the heat exchange medium is introduced
through an inlet port of the inlet tank 11, collected in the outlet
tank 12 through the tubes 20 and then discharged through an outlet
port of the outlet tank 12. While the heat exchange medium is
flowed through the tubes 20, heat exchange is occurred between the
heat exchange medium received in the tubes 20 and the external air
through the tubes 20 and the fins 30 interposed between the tubes
20.
[0024] Hereinafter, the heat exchange phenomenon occurred in the
heat exchanger will be described briefly. First of all, the heat
exchange is occurred by convection between the heat exchange medium
in the tubes 20 and inner surfaces of the tubes 20, and the heat is
transferred from the inner surfaces of the tubes 20 to outer
surfaces of the tubes 20 and the fins 30. Finally, the heat
exchange is occurred between the outer surfaces of the tubes 20 and
the fins 30 and the external air by the convection. As described
above, the heat exchange phenomenon occurred in the heat exchanger
depends on the convective heat exchange, and a heat exchange amount
also depends on the contact surface area and flow rate.
Particularly, the heat exchange between the heat exchange medium
and the tubes 20 is performed more smoothly when the heat exchange
medium is under a turbulent flow condition. Therefore, it will be
easily understood that the heat exchange performance is increased
if the turbulent flow of the heat exchange medium is forcibly
generated in the tubes 20.
[0025] FIG. 3 is a perspective view and cross-sectional views of a
tube having a dimple structure. In the tube 20, there are formed a
dimple 21 which is protruded into the tube 20 and a partition wall
22 which partitions the inside of the tube 20 along a length of the
tube 20. As described above, the dimple 21 functions to form the
turbulent flow of the heat exchange medium received in the tube 20.
FIG. 3b is a cross-sectional view of the tube 20 taken along a line
A-A' of FIG. 3a, and FIG. 3c is a cross-sectional view of the tube
20 taken along a line B-B'. At upper and lower surfaces of the tube
20, there are formed the plurality of dimples which are arranged in
a transverse direction so as to form a row. The upper dimple row
and the lower dimple row are alternately arranged along the length
of the tube 20. Further, the dimples 21 of the upper dimple row and
lower dimple row are also arranged alternately as shown in FIGS. 3b
and 3c. In other words, one of the dimples 21 of the lower dimple
row is disposed between two adjacent dimples 21 of the upper dimple
row, and one of the dimples 21 of the upper dimple row is also
disposed between two adjacent dimples 21 of the lower dimple row so
that the dimples 21 of the upper dimple row and lower dimple row
are not coincided with each other. Preferably, the number of
dimples 21 of the upper dimple row is the same as the number of
dimples 21 of the lower dimple row. The turbulent flow can be
generated more smoothly by such structure.
[0026] FIG. 4 is a view showing a fabricating method of the tube
having the dimple structure and the partition wall according to an
embodiment of the present invention. As shown in FIG. 4a, the
dimples 21 are formed in a material (e.g., metal plate) of the tube
by a pressing process or other process. Referring to FIGS. 4a and
4b, A part becomes the lower surface of the tube 20, C1 and C2
parts are bent to form side surfaces thereof, B1 and B2 parts
become the upper surface thereof, and D1 and D2 are bent at a
boarder line between B1 and B2 so as to be protruded into the
inside of the tube 20 and thus form the partition wall 22. If the
tube 20 is fabricated by the bending process, the upper surface A
and the lower surface B1 and B2 are opposite to each other.
Therefore, when forming the dimples in the material of the tube 20,
all of the dimples 21 are formed to be protruded in the same
direction and thus directed to the inside of the tube 20. Of
course, the tube 20 having the dimples 21 or the dimples 21 and
partition wall 22 may be formed by other method.
[0027] FIG. 5 is a view showing dimensions of the dimple and tube.
Assuming that a width of the tube 20 is L, a height is H, a width
of the dimple 21 is d.sub.i and a height is h.sub.i, the sum of
sectional areas of the dimples 21 with respect to a section of a
specific position in the tube 20 having the plurality of dimples 21
is expressed as follows:
A dimple = i = 1 N d i h i [ Formula 1 ] ##EQU00004##
[0028] wherein A.sub.dimiple is an approximate sectional area value
of the total dimples 21, N is the number of dimples 21 per
sectional area, and d.sub.i and h.sub.i are a width and a depth of
the i-th dimple 21, respectively.
[0029] In the tube having the dimple structure, the dimensions of
the dimple and tube which directly affect to the heat exchange
performance and thus has a specific correlation with each other is
expressed as follows:
A dimple L .times. H , h H [ Formula 2 ] ##EQU00005##
[0030] Since the actual heat exchange is performed between the heat
exchange medium in the tube 20 and the external air while the
external air passes between the tubes 20, the heat exchange is
substantially performed at the surface area of the tube 20 and the
fin 30 perpendicular to a flowing direction of the external
air.
[0031] This surface area is the effective surface area S.sub.ff as
shown in FIG. 6. In order to express the heat exchange performance
regardless of a size of the heat exchanger, a valuation of the heat
exchange performance is obtained by only the effective surface area
S.sub.ff. Assuming that the heat exchange amount which is
substantially generated is Q, the heat exchange amount Q.sub.Ae per
effective surface area is expressed as follows:
Q Ae = Q S eff [ Formula 3 ] ##EQU00006##
[0032] Since the present invention provides a dimension
relationship between the tube 20 and the dimple 21 capable of
maximizing the heat exchange performance per effective surface
area, the heat exchange performance per effective surface area is
estimated on the basis of the heat exchange amount Q.sub.0 per
effective surface area which is a requirement in a vehicle. The
heat exchange performance .eta. per effective surface area is
expressed as follows:
.eta. = Q Ae Q 0 [ Formula 4 ] ##EQU00007##
[0033] FIG. 7 is a graph showing a heat exchange performance per
effective area with respect to each factor, wherein FIG. 7a shows a
change of .eta. with respect to A.sub.dimiple/L.times.H and FIG. 7b
shows a change of .eta. with respect to h/H. A large A.sub.dimiple
value means that many dimples are formed per sectional area of the
tube 20. The more the dimples are formed, the more the turbulent
flow is generated. However, if the dimples are formed excessively
and thus the A.sub.dimiple value approaches the sectional area
(L.times.H) of the tube, a sectional area of the passage for the
heat exchange medium is too small and thus the heat exchange medium
can not flow smoothly therethrough. As described above, in case
that a resistance is increased, a heat exchange coefficient is
reduced, thereby reducing the heat exchange performance. Therefore,
it will be understood that the A.sub.dimiple value should be
established at a proper ratio with respect to the sectional area
(L.times.H) of the tube. FIG. 7a shows that such tendency is
actually confirmed by experiment. Referring to FIG. 7a, when the
value of A.sub.dimiple/(L.times.H) is 8.80.about.13.60, the heat
exchange performance .eta. per effective surface area is optimized.
Therefore, from this it is possible to deduce the relationship
between the dimensions of the tube and dimple per sectional area so
as to optimize the heat exchange performance .eta. per effective
surface area.
[0034] FIG. 7b shows the change of the heat exchange performance
.eta. with respect to the relationship between the depth h and
height H of the dimple. According as the ration of h/H is increased
(i.e., the depth of the dimple is increased relatively), the heat
exchange performance is gradually increased and then reduced from a
peak point. Referring to FIG. 7b, when the value of h/H is
0.25.about.0.4, the heat exchange performance .eta. per effective
surface area is optimized. On the basis of the graphs of FIGS. 7a
and 7b, it is possible to design an optimal width and depth of the
dimple with respect to a width and height of a certain tube so as
to optimize the heat exchange performance .eta. per effective
surface area.
[0035] Those skilled in the art will appreciate that the
conceptions and specific embodiments disclosed in the foregoing
description may be readily utilized as a basis for modifying or
designing other embodiments for carrying out the same purposes of
the present invention. Those skilled in the art will also
appreciate that such equivalent embodiments do not depart from the
spirit and scope of the invention as set forth in the appended
claims.
INDUSTRIAL APPLICABILITY
[0036] According to the present invention, since a turbulent flow
is generated early even when a flow rate condition of the heat
exchange medium in the heat exchanger tube is unfavorable, it is
possible to increase the heat exchange performance and also
optimize the heat exchange performance at all of the flow rate
conditions. Furthermore, it is possible to easily design a shape
and a dimension of the dimple for the optimal heat exchange
performance by regulating a flowing property of the fluid, thereby
saving labor, cost, time and the like.
* * * * *