BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present disclosure relates to heat exchangers, and more particularly to plate-stack
heat exchangers.
2. Description of Related Art
[0002] Heat exchangers such as, for example, tube-shell heat exchangers, are typically used
in aerospace turbine engines. These heat exchangers are used to transfer thermal energy
between two fluids without direct contact between the two fluids. In particular, a
primary fluid is typically directed through a fluid passageway of the heat exchanger,
while a cooling or heating fluid is brought into external contact with the fluid passageway.
In this manner, heat may be conducted through walls of the fluid passageway to thereby
transfer energy between the two fluids. One typical application of a heat exchanger
is related to an engine and involves the cooling of air drawn into the engine and/or
exhausted from the engine.
[0003] However, typical tube shell design heat exchangers have structural issues when their
cantilevered tube bundles are exposed to typical aerospace vibration environments.
In addition, there can be significant bypass of flow around the tubes on the low pressure
side of the heat exchanger, resulting in reduced thermal effectiveness as well as
other adverse system impacts such as excessive low pressure flow. Subsequently, the
heat exchangers either fail, or are heavy, expensive, and difficult to manufacture.
[0004] Such conventional methods and systems have generally been considered satisfactory
for their intended purpose. However, there is still a need in the art for improved
heat exchangers. The present disclosure provides a solution for this need.
SUMMARY OF THE INVENTION
[0005] A heat exchange device includes a first section and a second section. Each of the
first and second sections includes flow passages configured for heat exchange between
heat exchange fluid within the flow passages and fluid external of the flow passages.
A center manifold is disposed between the first and second sections. Heat exchange
fluid enters the manifold at one end, passes through the first and second sections
and exits the manifold at the opposing end.
[0006] Each of the flow passages can have a bend at an outer edge of the heat exchange device
configured to return high pressure fluid to the center manifold. Each of the bends
can be equal in radius to allow for uniform distribution of fluid flow. Each of the
flow passages can be dimensionally the same to create uniform flow throughout each
of the first and second sections. Each of the flow passages can define an external
air inlet and an external air outlet.
[0007] The center manifold can include a first plenum at one end configured to allow air
to enter the center manifold and a second plenum on the opposing side configured to
allow air to exit the center manifold. Fluid can flow through the first plenum into
an air inlet of a respective flow passage within the first and second sections and
enter the center manifold through and air outlet of the respective flow passage. The
fluid can exit the center manifold through the second plenum.
[0008] Each of the first and second sections can include plate-fin core sections in a stacked
arrangement. Each of the flow passages can include structures such as fins, pins or
vanes within the flow passage extending from the passage configured to act as secondary
heat transfer and structural elements. The secondary heat transfer and structural
elements can form a solid matrix configured to limit wear of the device due to relative
motion within the device. The device can further include a housing surrounding the
heat exchange device to provide a tight seal and configured to prevent air from flowing
around the flow passages. The first and second sections and the center manifold can
be created through the use of additive manufacturing.
[0009] These and other features of the systems and methods of the subject disclosure will
become more readily apparent to those skilled in the art from the following detailed
description of the preferred embodiments taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that those skilled in the art to which the subject disclosure appertains will
readily understand how to make and use the devices and methods of the subject disclosure
without undue experimentation, preferred embodiments thereof will be described by
way of example only in detail herein below with reference to certain figures, wherein:
Fig. 1 is a perspective view of an exemplary embodiment of a heat exchange device
constructed in accordance with the present disclosure, showing first and section sections
and a center manifold;
Fig. 2 is a detailed cross-sectional perspective view of the flow passage of each
of the first and second sections of Fig. 1, showing hot and cold fins running in directions
perpendicular to one another;
Fig. 3 is a detailed perspective view of the flow passage of each of the first and
section sections of Fig. 1, showing angled separators and the flow direction for hot
fluid through the flow passages;
Fig. 4a is a cross-sectional view of the center manifold of Fig. 1, showing a plurality
of sheets spanning the width of the center manifold, structurally connecting inner
loops of the first and second sections and separating the flows at flow passage inlet
and outlet; and
Fig. 4b is an alternate cross-sectional view of the center manifold of Fig. 1, showing
a plurality of sheets spanning the width of the center manifold connecting outer sheets
of the flow passages of the first and second section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] Reference will now be made to the drawings wherein like reference numerals identify
similar structural features or aspects of the subject disclosure. For purposes of
explanation and illustration, and not limitation, a partial view of an exemplary embodiment
of a heat exchange device in accordance with the disclosure is shown in Fig. 1 and
is designated generally by reference character 100. Other embodiments of the heat
exchange device in accordance with the disclosure, or aspects thereof, are provided
in Fig. 2-4b, as will be described. The systems and methods described herein can be
used in turbine engines exposed to high pressure and high temperatures, for example
in aerospace application.
[0012] With reference to Fig. 1, a heat exchange device 100 in accordance with the present
disclosure is shown. The device includes a first section 102 and a second section
104. The first and second sections 102, 104 are two identical plate-fin core sections
each made up of flow passages 110 configured for heat exchange between heat exchange
fluid within the flow passages 110 and fluid external of the fluid passages 110. The
first and second sections 102, 104 are separated by a center manifold 106 configured
to allow high pressure fluid to enter the manifold 106 at one end 112, pass into the
flow passages 102, 104 on either side of the manifold 106, and return to the manifold
106 to exit the manifold 106 at the opposite end 114. More specifically, the center
manifold 106 includes a first plenum 112a at one end and a second plenum 114a on an
opposing end. Each of the flow passages 110 includes an air inlet 120 and a separate
air outlet 122 (see Fig. 2) leading to and from the center manifold 106, respectively.
Fluid flows into the first plenum 112a of the center manifold 106, passes through
a respective air inlet 120 of a flow passage 110, follows a bend/loop 130 of the flow
passage 110, enters the center manifold 106 again through the air outlet 122 and then
exits the center manifold 106 through the second plenum 114a. The design for the first
and second sections 102, 104 and the center manifold 106 facilitates installation
of the proposed heat exchange device 100 in place of an existing tube-shell unit.
[0013] With continued reference to Figs. 1 and 2, each of the flow passages 110 includes
a bend or loop 130 at the outer edges of the device 100 to return the fluid to the
center manifold 106. The bulk of the heat transfer occurs within the flow passages
110 of the first and section sections 102, 104. The bends 130 of each flow passage
110 are equal in radius and each flow passage 110 is dimensionally the same to achieve
uniform distribution of fluid flow within the first and second sections 102, 104 and
achieve optimal thermal effectiveness. This similarity in structure also facilitates
quick and accurate prediction of thermal performance. In further embodiment, the flow
passages may vary in length so as to fit into designated spaces with opposing sides
that are not perpendicular to one another.
[0014] The flow passages 110 are in stacked arrangement such that the air flow direction
loops back to the center manifold 106. In one embodiment, heat transfer elements,
such as fins 132, 134 (see Fig. 2a) are included within each of the flow passages
110. The fins 132, 134 can be either hot fins 132 or cold fins 134 that form a solid
matrix to provide thermal and structural connection. Fins 132 can run parallel to
fins 134 when the fins 132 have openings to allow flow through the flow passage. Therefore,
the device 100 does not have fretting or other wear issues associated with relative
motion between tubes and supporting structure of typical tube-shell heat exchange
designs.
[0015] As shown in Fig. 3, a cross-sectional view of the center manifold 100 illustrating
angled center manifold plates 138. The flow rate of the hot fluid flowing (illustrated
with arrows) within the center manifold 106 varies as a function of a distance along
a flow length of the manifold in both the inlet and outlet sections of the center
manifold 106. The cross-sectional area increases with increased flow in regions of
both the inlet and outlet manifolds to reduce pressure drop as well as to achieve
a more uniform static pressure distribution along the flow length of the manifold
106 that helps to achieve more uniform distribution of flow among each flow passage
bend 130. This in turn improves the overall thermal effectiveness of the device relative
to a manifold configuration with nearly uniform manifold inlet and outlet cross-sectional
flow areas.
[0016] Figs. 4a and 4b illustrate two embodiments of a cross-section of the center manifold
106. In both embodiments continuous sheets 124 span across the center manifold. In
both embodiments shown in Fig. 4a and 4b, the sheets provide load paths to react against
pressure forces pulling the first and second core sections 102 and 104 apart. The
sheets also separate the hot inlet and outlet flows. In Fig. 4a, the sheets extend
from inner loops of cold fluid between the first and second sections 102 and 104.
In Fig. 4b the sheets extend straight across from outer sheets of the flow passages.
The tight radius of each flow passage 110 at the outer edges of the heat exchanger
100 reduces hoop stress, reducing the amount of material required to contain the high
pressure fluid compared to traditional heat exchanger fluid turning methods such as
external headers or internal miter sections with thick closure bars.
[0017] The device 100 as a whole is stiffer than a typical tube-shell heat exchanger, which
typically drives critical mode frequencies above regions of concern, due to the fins
130 and 132 and parting sheets forming a solid matrix. In further embodiments, a housing
can be included which tightly surrounds the device to provide a tight seal and prevent
air from flowing around or outside of the air passages. In this embodiment, bends/loops
of the flow passages can be modified to tightly align with the housing. In addition,
the secondary heat transfer and structural elements can extend from the outermost
flow passages to the housing containing the low pressure fluid to create the tight
seal around the heat exchange device. The bends and loops are created during manufacturing
therefore the tightness of the loops or exact shapes can be modified as needed. The
first and section sections 102, 104 and the center manifold 106 as shown and described
can be formed using the techniques of additive manufacturing.
[0018] The methods and systems of the present disclosure, as described above and shown in
the drawings, provide for a heat exchange device with superior properties including
a center manifold to provide improved structural integrity. While the apparatus and
methods of the subject disclosure have been shown and described with reference to
preferred embodiments, those skilled in the art will readily appreciate that changes
and/or modifications may be made thereto without departing from the scope of the subject
disclosure.
1. A heat exchange device (100), comprising:
a first section (102) and a second section (104), each of the first and second sections
(102, 104) including flow passages (110) configured for heat exchange between fluid
within the flow passages (110) and fluid external of the flow passages (110); and
a center manifold (106) disposed between the first and second sections (102, 104),
wherein fluid enters the manifold (106) at one end (112), passes through the first
and second sections (102, 104) and exits the manifold (106) at an opposing end.
2. The heat exchange device of claim 1, wherein each of the flow passages has a bend
at an outer edge of the heat exchange device configured to return high pressure fluid
to the center manifold.
3. The heat exchange device of claim 2, wherein each of the bends are equal in radius
to allow for uniform distribution of fluid flow.
4. The heat exchange device of claim 1, wherein each of the flow passages are dimensionally
the same to create uniform flow throughout each of the first and second sections.
5. The heat exchange device of claim 1, wherein each of the flow passages defines a fluid
inlet and a fluid outlet.
6. The heat exchange device of claim 1, wherein the center manifold includes a first
plenum at one end configured to allow fluid to enter the center manifold and a second
plenum at the opposing side configured to allow fluid to exit the center manifold.
7. The heat exchange device of claim 6, wherein fluid enters through the first plenum
into a fluid inlet of a respective flow passage within the first and second sections,
enters the center manifold through a fluid outlet of the respective flow passage,
and exits the center manifold through the second plenum.
8. The heat exchange device of claim 1, wherein each of the first and second sections
include plate-fin core sections in a stacked arrangement.
9. The heat exchange device of claim 8, wherein each of the flow passages includes secondary
heat transfer and structural elements within the flow passage.
10. The heat exchange device of claim 8, wherein each of the flow passages includes secondary
heat transfer and structural elements extending from the passage in a direction perpendicular
to the flow passage configured to structurally and physically connect adjacent flow
passages.
11. The heat exchange device of claim 8, wherein the secondary heat transfer and structural
elements and flow passages form a solid matrix configured to limit wear of the device
due to relative motion with the device.
12. The heat exchange device of claim 1, further comprising a housing surrounding the
heat exchange device to provide a tight seal and configured to prevent fluid from
flowing around the flow passages.
13. The heat exchange device of claim 1, wherein the first and second sections and the
center manifold are created through the use of additive manufacturing.
14. The heat exchange device of claim 1, wherein the first and second sections are connected
to one another by one or more plates or structural elements passing continuously through
the center manifold configured to segregate inlet and outlet flow and counteract the
forces created by high pressure acting in opposite directions on the first and second
sections.
15. The heat exchange device of claim 1, wherein some or all of the flow passages are
of different length to allow the device to fit within an envelope with sides that
are not perpendicular to each other.