BACKGROUND
[0001] The invention relates generally to a heat transfer device and, more particularly,
to a heat transfer enhancing system for improving the heat transfer characteristics
on various surfaces of the heat transfer device.
[0002] A heat transfer device, such as a heat exchanger, is a device that transmits thermal
energy between a hot fluid and a cold fluid. Heat flows from the hot fluid to the
cold fluid in the heat transfer device via a plurality of heat transfer surfaces such
as tubes or panels. Heat exchangers may be classified into different types such as
parallel flow type, counter flow type, cross flow type, single pass type, or multiple
pass type. Heat exchangers used in fluid processing plants, for example liquid natural
gas vaporizers or natural gas liquefiers, rely on several conventional heat transfer
techniques to enhance thermal effectiveness or to enhance other heat transfer characteristics
between a process fluid (e.g. liquid natural gas) side and a heat source or a heat
sink side of the heat exchanger.
[0003] One conventional technique to improve thermal effectiveness involves increasing the
surface area of the heat transfer surfaces. An increase in the surface area may be
achieved by providing a plurality of fins, protrusions, or recesses for example, to
the heat transfer surfaces, leading to an increase in the total heat flux per unit
area (base surface area) of the heat transfer device resulting in a decrease in size
and cost of the heat transfer device or an increase in total capacity of the device.
[0004] Another conventional technique to improve thermal effectiveness is to increase the
heat transfer coefficient by providing flow turbulators or baffles to the heat transfer
surfaces. However, provision of flow turbulators or baffles results in increased pressure
losses in the heat transfer device.
[0005] Accordingly, there is a need for a system and a method to increase thermal effectiveness
in a heat transfer device, while maintaining compact size and acceptable pressure
losses.
BRIEF DESCRIPTION
[0006] In accordance with one exemplary embodiment of the present invention, a heat transfer
device includes at least one heat transfer wall configured to separate a first fluid
and a second fluid. A heat transfer enhancing system is provided to at least one heat
transfer wall. The heat transfer enhancing system includes a plurality of micro turbulating
particles that are bonded to at least one heat transfer wall, or portions thereof,
using a binding medium. The heat transfer enhancing system includes a selected variation
in particle size, or particle distribution density, or particle region spacing, or
a combination thereof.
[0007] In accordance with another exemplary embodiment of the present invention, a natural
gas heat exchanger includes at least one heat transfer wall configured to separate
a first fluid and a second fluid, wherein the first fluid comprises a natural gas
process fluid. A plurality of micro turbulating particles is bonded to the at least
one heat transfer wall, or portions thereof, using a binding medium.
[0008] In accordance with another exemplary embodiment of the present invention, a method
for manufacturing a heat transfer device includes providing at least one heat transfer
wall configured to separate a first fluid and a second fluid. A heat transfer enhancing
system is provided to the at least one heat transfer wall. A plurality of micro turbulating
particles are bonded to the at least one heat transfer wall, or portions thereof,
using a binding medium.
DRAWINGS
[0009] These and other features, aspects, and advantages of the present invention will become
better understood when the following detailed description, provided by way of example
only, is read with reference to the accompanying drawings in which like characters
represent like parts throughout the drawings, wherein:
FIG. 1 is a diagrammatical view of a system having a heat transfer device, for example
a liquid natural gas heat exchanger, in accordance with an exemplary embodiment of
the present invention;
FIG. 2 is a perspective view of a heat exchanger tube having a heat transfer enhancing
system in accordance with aspects of the embodiment of FIG. 1;
FIG. 3 is a diagrammatical view of a heat transfer enhancing system in accordance
with an exemplary embodiment of the present invention;
FIG. 4 is a diagrammatical view of a heat transfer device provided with a plurality
of fins having a transfer enhancing system in accordance with an exemplary embodiment
of the present invention;
FIG. 5 is a perspective view of a heat transfer device having a corrugated panel provided
with a heat transfer enhancing system in accordance with an exemplary embodiment of
the present invention;
FIG. 6 is a diagrammatical view of a heat transfer enhancing system in accordance
with an exemplary embodiment of the present invention;
FIG. 7 is a diagrammatical view of a heat transfer enhancing system in accordance
with an exemplary embodiment of the present invention;
FIG. 8 is a diagrammatical view of a heat transfer enhancing system in accordance
with an exemplary embodiment of the present invention;
FIG. 9 is a diagrammatical view of a heat transfer enhancing system in accordance
with an exemplary embodiment of the present invention;
FIG. 10 is a graph representing variation of jet Reynolds number versus heat transfer
enhancement in accordance with an exemplary embodiment of the present invention;
FIG. 11 is a diagrammatical view of an exemplary technique used to provide a heat
transfer enhancing system to a heat transfer device, for example a heat exchanger,
in accordance with an exemplary embodiment of the present invention; and
FIG. 12 is a diagrammatical view of an exemplary technique used to provide a heat
transfer enhancing system to a heat transfer device, for example an intercooler, in
accordance with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION
[0010] As discussed in detail below, embodiments of the present invention provide a heat
transfer device having a plurality of heat transfer walls configured to separate a
first fluid and a second fluid. An exemplary heat transfer enhancing system in accordance
with the exemplary embodiments of the present invention is provided to one or more
heat transfer walls. The heat transfer enhancing system includes a plurality of micro
turbulating particles bonded to one or more heat transfer walls using a binding medium.
The micro turbulating particles may include spherical shaped particles, or particles
of different shapes depending on the requirement. Exemplary techniques in accordance
with the embodiments of the present invention are used to bond the micro turbulating
particles randomly or in a predetermined pattern to the heat transfer surfaces. The
heat transfer enhancing system utilizes micro turbulating particles to enhance thermal
effectiveness of heat transfer surfaces, such as for example, a plurality of tubes
or panels in a liquid natural gas heat exchanger. Particle size, distribution density,
spacing and pattern may be varied to achieve desired thermal enhancement. The "micro
turbulating particle distribution density" may be referred to as average increase
in wetted surface area due to the micro turbulating particles. In one example, an
average increase is 50%. The micro turbulating particles act to enhance heat transfer
between the first fluid and the second fluid via the heat transfer walls. Additional
pressure loss in the heat transfer device is minimal. Specific embodiments of the
present invention are discussed below referring generally to FIGS. 1-12.
[0011] Referring to FIG. 1, an exemplary system 10 (for example, a liquid natural gas (LNG)
system) is illustrated in accordance with an exemplary embodiment of the present invention.
In the illustrated embodiment, the system 10 is an open rack vaporizer system. The
illustrated system 10 includes an LNG pump 12 coupled to an LNG tank 14. The LNG pump
12 is also coupled via a pipe 16 to a panel (heat exchanger) 18.
[0012] The panel 18 includes a plurality of heat transfer tubes 20 arranged proximate to
each other. The LNG pump 12 is configured to supply a first fluid or a process liquid
19 (i.e. liquid natural gas) from the LNG tank 14 to the panel 18 via the pipe 16.
A valve 22 is provided to the pipe 16 and configured to control the amount of liquid
natural gas flowing through the pipe 16. The system 10 further includes another pump
24 coupled to an intake tank 26. The pump 24 is also coupled to a header 28 via a
pipe 30. The pump 24 is configured to supply a second liquid (i.e. sea water) 32 from
the intake tank 26 to the header 28 via the pipe 30. The header 28 is provided to
spray sea water 32 on the plurality of tubes 20 of the panel 18. Warm sea water flows
along external surfaces of the tubes 20, while liquid natural gas flows through the
tubes 20 and is evaporated.
[0013] The panel 18 includes an inlet side 34 configured to intake liquid natural gas 19
and an outlet side 36 configured to discharge natural gas via a supply pipe 38. The
inlet side 34 includes a vaporizing zone 40 and the outlet side 36 includes a heating
zone 42. The exemplary system 10 uses sea water 32 at atmospheric pressure as the
heating source for vaporizing or heating low-temperature fluids (liquid natural gas)
into gases at atmospheric temperatures. The liquid natural gas is vaporized using
sea water in the vaporizing zone 40 of the panel 18. The vaporized natural gas is
then further heated to a higher temperature in the heating zone 42 before discharging
through the supply pipe 38. In certain exemplary embodiments, an aluminum-zinc alloy
is thermal-sprayed on the panel 18 to protect the panel 18 against corrosion by seawater
32. A heat transfer enhancing system 44 in accordance with the exemplary embodiments
of the present invention is provided to a plurality of heat transfer walls 46 of the
plurality of tubes 20 of the panel 18. In certain exemplary embodiments, the heat
transfer enhancing system 44 includes a plurality of micro turbulating metallic particles
bonded to the one or more heat transfer walls 46 of the tubes 20 using a binding medium.
In accordance with the exemplary embodiments, a "micro turbulating particle" may be
referred to as a single micro turbulating particle or an agglomeration of one or more
single particles into one complex micro turbulating particle that does not allow liquid
flow to penetrate inside the agglomeration. It should also be noted that "micro turbulating
particle size" may be referred to as average height or diameter of a single or agglomerated
micro turbulating particle. "Particle spacing" may be referred to as the local or
regional average distance from one particle center to that of the adjacent particle
center, expressed as a ratio of the particle size.
[0014] In alternate exemplary embodiments, the panel 18 may include a plurality of panels
arranged in parallel arrays. Warm sea water flows along external surfaces of the panels,
while liquid natural gas flows through the panels and is evaporated. Although the
LNG vaporizer is illustrated, in certain other exemplary embodiments, the heat transfer
enhancing system 44 may also be applicable to liquefiers, intercoolers, electrical
and electronic thermal management devices, or the like where enhanced heat transfer
rates are required. Similarly, in certain other exemplary embodiments, the system
44 may be applicable to various types of heat exchangers such as parallel flow type,
counter flow type, crossed flow type, and combined flow type heat exchangers. Turbulation
in accordance with the exemplary embodiments of the present invention may be utilized
to treat a variety of components including combustor liners, combustor domes, vanes
or blades, or shrouds of gas turbines. The exemplary turbulation techniques may also
be used to treat shroud clearance control areas including flanges, casings, and rings.
[0015] The micro turbulating particles increase the surface area and the heat transfer coefficient
of the heat transfer walls 46 that results in increased heat transfer rates and reduced
relative pressure losses compared to other augmentation methods. Processing of the
heat transfer walls may be customized depending on the requirement and differing levels
of desired thermal enhancement. Specific embodiments of the present invention are
discussed below referring generally to FIGS. 1-12.
[0016] Referring to FIG. 2, the heat transfer tube 20 in accordance with the aspects of
FIG. 1 is illustrated. In the illustrated embodiment, the heat transfer enhancing
system 44 is provided to an exterior surface 41 and an interior surface 43 of the
heat transfer wall 46 of the tube 20. As described previously, the system 44 includes
a plurality of micro turbulating particles bonded to the surfaces 41, 43 of the tube
20 using a binding medium. In certain exemplary embodiments, the plurality of micro
turbulating particles may include nickel, cobalt, aluminum, silicon, or iron, or alloys
thereof, or a combination including any of the foregoing. The binding medium may include
epoxy, or metal foil, or solder, or braze material, or weld material, or a combination
thereof. It should be noted that the above-mentioned list of materials of the micro
turbulating particles and binding medium are not exhaustive and other metallic material
or metallic alloys suitable for enhancing heat transfer characteristics are also envisaged.
The amount and type of binder generally ensures sufficient adhesive strength of the
micro turbulating particles to the heat transfer wall in system 44.
[0017] In the illustrated embodiment, the micro turbulating particles are applied randomly
to the surfaces 41, 43 of the tube 20. In certain other embodiments, the micro turbulating
particles may be randomly or partially provided to the heat transfer walls of the
vaporizing zone and the heating zone of the panel. In certain other embodiments, the
micro turbulating particles are uniformly bonded to one or more heat transfer walls
of the tubes 20. In certain other embodiments, the micro turbulating particles are
bonded in a predetermined pattern to one or more heat transfer walls of the tubes
20. The provision of the micro turbulating particles may be varied in different zones
of the heat exchanger depending on the thermal potential of the zones. In accordance
with the exemplary embodiments of the present invention, the increase in heat transfer
is largely due to increased micro turbulated surface area of the tube. The micro turbulating
particles may also increase heat transfer by modifying fluid flow characteristics
such as from laminar flow to turbulent flow along the heat transfer surfaces. It should
noted that the fluid flow along the heat transfer surface having enhanced heat transfer
characteristics may include channel type fluid flow and impinging type fluid flow.
[0018] Referring to FIG. 3, the heat transfer enhancing system 44 in accordance with an
exemplary embodiment of the present invention is illustrated. The system 44 includes
a plurality of protuberances 48 provided in a predetermined pattern to a heat transfer
wall 46 of the heat transfer tube. The plurality of protuberances together defines
"turbulation", which appears as a roughened surface that is effective to increase
heat transfer through the heat transfer wall 46. Even though the protuberances are
shown approximately spherical shaped, other shapes may also be envisaged to meet the
desired roughness and surface area characteristics and thus obtain a desired heat
transfer enhancement. In the illustrated embodiment, the protuberances 48 are provided
along three rows 50, 52, 54 and four columns 56, 58, 60, and 62 to the heat transfer
wall 46. In certain exemplary examples, the height "h" of each protuberance 48 is
9 mils (0.009 inches). It should be noted that value of height "h" should not be construed
as a limiting value and may vary depending on the heat transfer requirement. Each
protuberance 48 includes one or more of micro turbulating particles packed closely
together. The protuberances 48 are bonded to the heat transfer surface 46 using the
binding medium. It should again be noted that the illustrated example is merely an
exemplary embodiment and that particle size, distribution density, spacing and pattern
may be varied to achieve desired thermal enhancement. Size of the particles is determined
based on the desired degree of surface roughness and surface area that will be provided
by the protuberances. The micro turbulating particles facilitate enhanced heat transfer
between the first fluid and the second fluid via the heat transfer wall 46. Additional
pressure loss in the heat transfer device is minimal relative to that without the
system 44.
[0019] In accordance with the exemplary embodiments, the pattern may include predetermined
limits on the relative size / spacing of the micro turbulating particles applied to
the heat transfer wall 46. In certain exemplary embodiments, if the average height
of the micro turbulating particle is characterized as "H", and the average micro turbulating
particle diameter is characterized as "D", then the spacing between mutually adjacent
micro turbulating particles may be in the range of 2 to 8 times the average diameter
(D). In certain examples, the micro turbulating particle height (H) may be in the
range of 1 to 6 times the average diameter (D) of the micro turbulating particle.
[0020] Referring to FIG. 4, an exemplary embodiment of an extruded heat transfer tube 64
of the open rack vaporizer is illustrated. In the illustrated embodiment, the heat
transfer tube 64 is an extruded tube having a plurality of fins 66 provided on an
exterior surface 68 of a heat transfer wall 70. The fins 66 may include plain type
fins, or perforate type fins, or herringbone type fins, or serrated type fins, or
a combination thereof. An exemplary heat transfer enhancing system 44 in accordance
with certain embodiments of the present invention is provided to the plurality of
fins 66 provided on the exterior surface 68 of the heat transfer wall 70. The heat
transfer enhancing system 44 includes a plurality of micro turbulating particles bonded
to the plurality of fins 66 using the binding medium. The micro turbulating particles
and the binding medium are applied to the fins 66 using techniques such as spraying,
or slurry painting, or flame spray, or dipping, or a combination thereof. In some
cases, the binder may be thermally matured to realize bond strength (e.g. solder,
braze). The micro turbulating particles increase the micro turbulated surface area
and heat transfer coefficient of the heat transfer wall 70 that results in enhanced
heat transfer rates and reduced relative pressure losses.
[0021] FIG. 5 is a perspective view of a heat transfer device 76 (heat exchanger) in accordance
with other aspects of the present invention. The heat transfer device 76 includes
a corrugated panel 78 in which the process fluid and heating/cooling fluid flows in
alternate channels 80, 82 respectively. The exemplary heat transfer enhancing system
44 in accordance with aspects of the present invention is provided and includes a
plurality of micro turbulating particles 79 bonded to one side or both sides of the
corrugated panel 78 using the binding medium. The micro turbulating particles 79 and
the binding medium are applied to the corrugated panel 78 using techniques such as
spraying, or slurry, or dipping, or sprinkling, or flame spray, or roll coating, or
a combination thereof and then heat treated to perform curing. The micro turbulating
particles 79 increase the micro turbulated surface area and heat transfer coefficient
of the corrugated panel 78 that results in enhanced heat transfer rates and reduced
relative pressure losses. Here again, it should be noted that the illustrated example
is merely an exemplary embodiment and that particle size, spacing and pattern may
be varied to achieve desired thermal enhancement.
[0022] Referring to FIG. 6, the heat transfer enhancing system 44 in accordance with an
exemplary embodiment of the present invention is illustrated. In the illustrated embodiment,
the direction of flow of the process fluid and/or the heating/cooling fluid is indicated
by the arrow 81 with respect to a flat heat transfer plate 83. The heat transfer plate
83 includes an inlet region 85, a middle region 89, and an exit region 93.
[0023] The system 44 includes the plurality of micro turbulating particles 79 bonded to
one side or both sides of the heat transfer plate 83 using the binding medium. In
the illustrated embodiment, the micro turbulating particle distribution is concentrated
in the inlet region 85 and the middle region 89. The exit region 93 of the plate 83
is maintained smooth. The micro turbulating particles 79 are closely packed together
in the inlet region 85 whereas spacing between the micro turbulating particles is
greater in the middle region 89. The micro turbulating particles 79 increase the micro
turbulated surface area and heat transfer coefficient of the heat transfer plate 83
that results in enhanced heat transfer rates and reduced relative pressure losses.
[0024] Referring to FIG. 7, the heat transfer enhancing system 44 in accordance with an
exemplary embodiment of the present invention is illustrated. As discussed in the
previous embodiment, the heat transfer plate 83 includes the inlet region 85, the
middle region 89, and the exit region 93. The system 44 includes the plurality of
micro turbulating particles 79 bonded to one side or both sides of the heat transfer
plate 83 using the binding medium. In the illustrated embodiment, the micro turbulating
particle distribution is concentrated in the inlet region 85 and the middle region
89. The exit region 93 of the plate 83 is maintained smooth. In the illustrated embodiment,
the size of micro turbulating particles 79 in the inlet region 85 is greater than
the size of particles in the middle region 89.
[0025] Referring to FIG. 8, the heat transfer enhancing system 44 in accordance with an
exemplary embodiment of the present invention is illustrated. In the illustrated embodiment,
the heat transfer plate 83 includes the inlet region 85, the middle region 89, and
the exit region 93. The system 44 includes the plurality of micro turbulating particles
79 bonded to one side or both sides of the heat transfer plate 83 using the binding
medium. In the illustrated embodiment, the micro turbulating particle distribution
is concentrated in the inlet region 85 and the exit region 93. The middle region 87
is maintained smooth. In the illustrated embodiment, the size of micro turbulating
particles 79 in the inlet region 85 is greater than the size of particles in the exit
region 93. The particle distribution density in the exit region 93 is greater than
the distribution density in the inlet region 85 (i.e. the micro turbulating particles
79 are closely packed in the exit region 93 whereas spacing between the micro turbulating
particles in the inlet region 85 is greater). The particle distribution density is
also characterized by the particle shaping, or agglomeration sizes, or size, or a
combination thereof and creation of wetted surface area/flow turbulation.
[0026] Referring to FIG. 9, the heat transfer enhancing system 44 in accordance with an
exemplary embodiment of the present invention is illustrated. In the illustrated embodiment,
the heat transfer plate 83 includes a top region 95, an intermediate region 97, and
a lower region 99. The system 44 includes the plurality of micro turbulating particles
79 bonded to one side or both sides of the heat transfer plate 83 using the binding
medium. In the illustrated embodiment, the micro turbulating particle distribution
is concentrated in the top region 85 and the lower region 99. The intermediate region
97 is maintained smooth. In the illustrated embodiment, the size of micro turbulating
particles 79 in the inlet region 85 is greater than the size of particles in the exit
region 93. It should be noted that in the illustrated embodiment and previous embodiments,
although flat shaped heat transfer plate 83 is illustrated, the system 44 is also
suitable for other surfaces including three dimensional, curved, concave, convex,
multiply curved, intersections, or a combination thereof. It should be noted that
the above described embodiments may be selected depending on the type of heat transfer
device used and also the thermodynamic distribution.
[0027] Referring to FIG. 10, a graph representing variation of fluid jet Reynolds number
(x-axis) versus heat transfer enhancement (y-axis) for impinging type fluid flow in
accordance with an exemplary embodiment of the present invention is illustrated. As
known to those skilled in the art, the Reynolds number is the ratio of inertial forces
to viscous forces and is used for determining whether a flow will be laminar or turbulent.
Heat transfer enhancement is the ratio of heat transfer coefficient for a micro turbulated
surface to the heat transfer coefficient for a smooth surface.
[0028] The illustrated graph shows variation of jet Reynolds number versus heat transfer
enhancement for two heat transfer walls having different surface roughnesses. Curve
84 represents variation of jet Reynolds number versus heat transfer enhancement for
a heat transfer wall having an average surface roughness (Ra) equal to 0.35 mils (i.e.0.00035
inches). Curve 86 represents variation of jet Reynolds number versus heat transfer
enhancement for a heat transfer wall having an average surface roughness (Ra) equal
to 1.14 mils (0.00114 inches). It may be observed that heat transfer rates across
the heat transfer walls increases with increase in average surface roughness. The
illustrated graph is merely an exemplary embodiment and the variation of jet Reynolds
number versus heat transfer enhancement may vary depending on the particle size, spacing
and pattern applied to achieve desired thermal enhancement. In certain exemplary embodiments,
the average surface roughness values are typically 7 to 12 times less than the actual
particle size for random surfaces, and depend on particle spacing for non-random surfaces.
[0029] Referring to FIG. 11, an exemplary technique used to provide a heat transfer enhancing
system to a heat transfer device, for example a heat exchanger, in accordance with
an exemplary embodiment of the present invention. The illustrated exemplary technique
involves spraying a binding medium to a heat transfer tube 88 of a heat exchanger.
The binding medium may include epoxy, or metal foil, or solder, or braze material,
or weld material, or a combination thereof. The micro turbulating particles 87 are
dusted over the binding medium applied to the heat transfer tube 88. It should be
noted that other exemplary techniques for applying micro turbulating particles over
the binding medium applied to the heat transfer tube 88 are also envisaged. The micro
turbulating particles 87 are bonded randomly or in a predetermined pattern to the
heat transfer surface of the heat transfer tube 88. The plurality of micro turbulating
particles may include nickel, or cobalt, or aluminum, or silicon, or iron, or copper,
or a combination thereof. The particle size, spacing and pattern may also be varied
to achieve desired thermal enhancement. In certain exemplary embodiments, the heat
transfer tube 88 may be rotated for applying micro turbulating particles 87 over the
binding medium applied to the heat transfer tube 88. In certain other exemplary embodiments,
the micro turbulating particles 87 may be applied from different angles over the binding
medium applied to the heat transfer tube 88. The heat transfer tube 88 is then passed
through an oven 90 for thermal heat treatment to cure the micro turbulating particles
87.
[0030] FIG. 12 illustrates an exemplary technique used to provide a heat transfer enhancing
system to a heat transfer device 94, for example an intercooler, in accordance with
an exemplary embodiment of the present invention. The exemplary technique involves
spraying or applying a binding medium 91 such as a film of high conductivity epoxy
to a heat transfer surface 92 of an intercooler 94. As described in previous embodiments,
a plurality of micro turbulating particles 96 are sprayed randomly or in predetermined
pattern over the binding medium applied to the heat transfer surface 92 of the intercooler
94. The micro turbulating particles 96 may be then heat treated for curing. In certain
other exemplary embodiments, a binding medium such as aluminum foil or solder foil
are applied to the heat transfer surface 92 of the intercooler. Then the plurality
of micro turbulating particles 96 are sprayed randomly or in predetermined pattern
over the aluminum foil or solder foil applied to the heat transfer surface 92. The
foil and the particles are then heat treated to bond the particles to the heat transfer
surface 92. In certain other exemplary embodiments, a binding medium such as a braze
alloy may be dip coated to the heat transfer surface 92 of the intercooler 94. Then
the plurality of micro turbulating particles 96 are sprayed randomly or in predetermined
pattern over the braze alloy applied to the heat transfer surface 92. The braze alloy
and the particles are then heat treated to bond the particles to the heat transfer
surface 92.
[0031] In certain exemplary embodiments of the exemplary technique, the binding medium and
the micro turbulating particles are applied simultaneously to the heat transfer surface
92 and then heat treated to bond the binding medium and the particles to the heat
transfer surface. The application of binding medium and the micro turbulating particles
may be done by techniques such as spraying, or screen printing, or roll coating, or
a combination thereof. The patterning of the binding medium on the heat transfer surface
may be performed through patterned masking, or screen printing, or roll printing,
or a combination thereof. In certain exemplary embodiments, the micro turbulating
particles are patterned to the heat transfer surface 92 through a screen by a screen
printing technique. Alternately or additionally, the binding medium is applied through
the screen to the heat transfer surface. Removal of the screen results in the predetermined
pattern formed on the heat transfer surface. A pattern in accordance with aspects
of the present invention may be defined as plurality of "clusters" of particles (one
or more particles), wherein the clusters are generally spaced apart from each other
by a pitch corresponding to the spacing of openings in the screen. The excess particles
are removed resulting in the desired pattern of the particles. The binding medium
may be applied using sprayers, or brushes, or squeegee, or trowel, or as sheets, or
a combination thereof. In certain exemplary embodiments, the micro turbulating particles
may also be patterned to the heat transfer surface by screen printing. The binding
medium and the particles may be cured by thermal heat treatment, or ultra violet rays,
or spray activator, or a combination thereof. In certain other exemplary embodiments,
a pre-turbulated sheet having micro turbulating particles and binding medium may be
bonded to the heat transfer surface.
[0032] While only certain features of the invention have been illustrated and described
herein, many modifications and changes will occur to those skilled in the art. It
is, therefore, to be understood that the appended claims are intended to cover all
such modifications and changes as fall within the true spirit of the invention.
1. A heat transfer device (18), comprising:
at least one heat transfer wall (46) configured to separate a first fluid (19) and
a second fluid (32); and
a heat transfer enhancing system (44) provided to the at least one heat transfer wall
(46), and comprising a plurality of micro turbulating particles (48) bonded to the
at least one heat transfer wall (46), or portions thereof, using a binding medium;
wherein the heat transfer enhancing system (44) comprises a selected variation in
particle size, or particle distribution density, or particle region spacing, or a
combination thereof.
2. The heat transfer device (18) of claim 1, wherein the plurality of micro turbulating
particles (48) comprises nickel, cobalt, aluminum, silicon, or iron, or copper, or
alloys thereof, or a combination including any of the foregoing.
3. The heat transfer device (18) of claim 1, wherein the binding medium comprises epoxy,
or metal foil, or solder, or braze material, or weld material, or a combination thereof.
4. The heat transfer device (18) of claim 1, wherein the plurality of micro turbulating
particles (48) are randomly or uniformly bonded to the at least one heat transfer
wall (46) using the binding medium.
5. The heat transfer device (18) of claim 1, wherein the plurality of micro turbulating
particles (48) are bonded in a predetermined pattern to the at least one heat transfer
wall (46), or portions thereof, using the binding medium.
6. The heat transfer device (18) of claim 1, wherein the plurality of micro turbulating
particles (48) are provided partially to the at least one heat transfer wall (46)
using the binding medium.
7. The heat transfer device (18) of claim 1, wherein the plurality of micro turbulating
particles (48) are bonded to a plurality of fins or protrusions (66) on the at least
one heat transfer wall (46) using the binding medium.
8. A method for manufacturing a heat transfer device (18), comprising:
providing at least one heat transfer wall (46) configured to separate a first fluid
(19) and a second fluid (32); and
providing a heat transfer enhancing system (44) to the at least one heat transfer
wall (46) comprising bonding a plurality of micro turbulating particles (48) to the
at least one heat transfer wall (46), or portions thereof, using a binding medium.
9. The method of claim 8, comprising bonding the plurality of micro turbulating particles
(48) in a predetermined pattern to the at least one heat transfer wall (46), or portions
thereof, using the binding medium.
10. The method of claim 8, comprising bonding the plurality of micro turbulating particles
(48) partially to the at least one heat transfer wall (46) using the binding medium.