DIMPLE CHILLER WITH SECONDARY DIMPLES
A heat exchanger with at least one plate includes main dimples between which secondary dimples are formed which are flatter and/or smaller with respect to their dimensions as seen in a plan view. A depth of the secondary dimples may be at most 0.5 times a channel height and/or at most 0.5 times the depth of the main dimples.
This patent application is a United States nation phase patent application based on PCT/KR2021/001305 filed on Feb. 1, 2021, which claims the benefit of German Patent Application No. DE 10 2020 201 344.6 filed on Feb. 4, 2020 and German Patent Application No. DE 10 2020 212 900.2 filed on Oct. 13, 2020, the entire disclosures of which are hereby incorporated herein by reference.
TECHNICAL FIELDDimple plates in heat exchanger (HEX) applications often suffer from low specific heat exchange rates due to low velocities of the heat-exchanging fluids.
PRIOR ARTOne known solution is the increase of dimple size to increase local velocities and change the flow directions in the fluid.
However, an increase of dimple size directly leads to a reduced surface for the heat exchange and to an increase of pressure drop in the channel. Therefore, a solution must be found to increase heat exchange rates with a minimal increase in pressure drop in the fluid at an accelerated rate and taking away from the surface of heat exchange.
DESCRIPTION OF THE INVENTIONThe above problem is solved by the subject matter as shown and described herein.
The invention can be regarded as being a plate of a heat exchanger or a heat exchanger having at least one plate which is preferably rectangular and comprises main dimples, between which secondary dimples are formed that are flatter and/or smaller with respect to their dimensions as seen in a plan view.
The plate thus has main dimples, depressions, bumps and/or protrusions or bulges which are preferably arranged in rows preferably extending obliquely to the edges of the preferably rectangular plate. According to the invention, secondary dimples are formed between the main dimples, which can alternatively be designated as the main dimples as above. The rows are thereby seen in those directions in which the dimples are lined up one behind the other with minimal spacing. These rows can extend at any angle to the edges, as well as perpendicular to the one edges and therefore parallel to the other edges.
As a result of the secondary dimples, the present invention leads to increased heat exchange rates in a dimple heat exchanger, in particular a cooler plate, while the active surface for heat exchange is not reduced. In fact, the surface of heat exchange is increased without changing the use of material. In addition, the velocities of the fluids around the secondary dimples are increased, which results in an increased heat exchange. The invention further leads to a change in flow directions not only in the horizontal plane, but also perpendicular thereto, thus leading to a mixing of temperature layers in the channels between the dimple heat exchanger plates.
Preferred further developments are described herein.
The depth of the secondary dimples is set to a maximum of 0.5 times the channel height and/or 0.5 times the depth of the main dimples. The depth of the main dimples can be set to a maximum corresponding to the channel height.
The distance between the main and secondary dimples in an x direction (a first diagonal direction) can be varied between 1.9 and 2.5 mm and in they direction (a second diagonal direction) between 1.9 and 2.5 mm.
In each case one secondary dimple can be formed between two main dimples. Preferably at least one, preferably precisely one, secondary dimple is formed in each case on the entire plate between two main dimples, or several, preferably four, and preferably spaced apart by 90 degrees, secondary dimples are formed in the vicinity of each main dimple.
At least some, preferably all, of the secondary dimples can be arranged on the lines or rows that are described by the main dimples.
The main dimples are preferably arranged in rows which preferably extend obliquely to the edges of the preferably rectangular plate. The rows are designated above as diagonals; however, they do not have to correspond to the diagonals of the rectangular plate, but can extend at an angle thereto. The rows can be formed in two directions extending at an angle to each other, wherein the angle can be equal or not equal to 90 degrees. For all of the above-mentioned embodiments, favorable properties could be determined in initial tests and simulations.
The sheet thickness of the plate can thereby be less in the area of the main and/or secondary dimples than between the dimples.
The main and/or secondary dimples can be circular, elliptical, or oval in plan view. The main axes of elliptical or oval main dimples can extend parallel to a plate edge, in particular parallel to the longer edge of a rectangular plate. The main axes of elliptical or oval secondary dimples can extend at an angle to the plate edges of a rectangular plate. The main axes of several elliptical or oval secondary dimples can extend parallel to each other and at an angle to the main axes of several other secondary dimples.
Further details of the invention can be seen from the drawings.
As can be seen in
In the plate 10 of a heat exchanger according to the invention according to
According to the invention, one secondary dimple 14 is formed in each case between every two main dimples 12, which in this case in plan view is both smaller and, not visible in plan view, flatter. In particular, precisely one secondary dimple 14 is formed in each case between two main dimples 12, and therefore four secondary dimples are formed in the vicinity of every main dimple. As is also preferred, the secondary dimples are located on those lines or rows that are described by the main dimples. In the case shown, the main dimples 12 are oval when viewed from the top, with their longer axis extending parallel to the longer edge of the rectangular plate 10, and the secondary dimples are circular when viewed from the top.
As is revealed in
In contrast, a plate 10 according to the invention according to
The shape and alignment of the main dimples 12 and the secondary dimples 14 can be seen more clearly in the detailed view of
As is apparent from
Claims
1.-10. (canceled)
11. A heat exchanger with at least one plate having main dimples, between which secondary dimples are formed which are flatter and/or smaller with respect to their dimensions as seen in a plan view.
12. The heat exchanger according to claim 11, wherein a depth of the secondary dimples is at most 0.5 times a channel height and/or at most 0.5 times a depth of the main dimples.
13. The heat exchanger according to claim 11, wherein a distance between the main dimples and the secondary dimples in at least one direction is 1.9 to 2.5 mm.
14. The heat exchanger according to claim 11, wherein one of the secondary dimples is formed in each case between two of the main dimples.
15. The heat exchanger according to claim 11, wherein the main dimples are arranged in rows, and the secondary dimples are arranged on the rows of main dimples.
16. The heat exchanger according to claim 15, wherein the rows of the main dimples are formed obliquely to at least one edge of the at least one plate.
17. The heat exchanger according to claim 11, wherein a sheet thickness of the at least one plate in an area of the main dimples and/or the secondary dimples is less than between the dimples.
18. The heat exchanger according to claim 11, wherein the main dimples and/or the secondary dimples have a circular, an elliptical, or an oval shape in plan view.
19. The heat exchanger according to claim 18, wherein a main axis of the main dimples having the elliptical or the oval shape are parallel to an edge of the at least one plate, in particular a longer edge of a rectangular plate.
20. The heat exchanger according to claim 18, wherein a main axis of the secondary dimples having the elliptical or the oval shape extend at an angle with respect to edges of a rectangular plate.
Type: Application
Filed: Feb 1, 2021
Publication Date: Mar 2, 2023
Inventors: Gero Lapp (Köln), Julian Neukirchen (Köln), Felix Girmscheid (Köln), Jihoon Choi (Sejong-si), Florian Bieregger (München), Matthias Herpers (Jülich)
Application Number: 17/756,781