Inline Cross Flow Heat Exchangers

Apparatus and methods provide for the exchange of heat in a cross flow heat exchanger having heat exchanger sub-chambers in an inline configuration. According to embodiments described herein, the heat exchanger sub-chambers may be arranged in an inline configuration, where two or more of the sub-chambers are positioned generally along a linear axis. In further configurations, to accommodate the linear configuration of two or more sub-chambers, inlet fluid flows to subsequent or downstream sub-chambers are directed to the sub-chambers using bypasses around the upstream or prior sub-chambers. Various configurations may reduce or minimize pressure losses of one or more of the fluids moving through the heat exchanger.

BACKGROUND

Heat exchangers in aircraft transfer heat energy across an energy boundary from a fluid at a higher temperature to a fluid at lower temperature. Heat exchangers are typically categorized based on the relationship between the relative directions of the flow paths of the fluids moving through the heat exchanger. Examples of heat exchangers include concurrent flow (fluids move in relatively the same direction), counter flow (fluids move in opposing directions) and cross flow (one fluid flow direction is perpendicular to another fluid flow direction). The choice of heat exchanger is based on design considerations within the system, with each type providing various advantages and suffering from various deficiencies.

Along with design considerations, the location and/or use of a heat exchanger can modify the engineering of the heat exchanger. For example, the choice and configuration of a heat exchanger used in a land-based power plant may have different factors than the choice and configuration of a heat exchanger used in an aircraft. In the land-based power plant, weight, size and other physical considerations may only be economic factors, whereas in an aircraft, weight, size and other physical considerations may be both economic and critical design factors. Economical operation of an aircraft relies on the costs to build and operate the aircraft. The costs to operate the aircraft increase as the size and weight of the mechanical components of the aircraft increase.

SUMMARY

According to one aspect of the disclosure herein, an aircraft heat exchanger is provided. The heat exchanger may include a cold fluid input and a first partition. The first partition may split the cold fluid input into a first cold fluid input and a second cold fluid input. The aircraft heat exchanger may also include a hot fluid input and a second partition. The second partition may split the hot fluid input into a first hot fluid input and a second hot fluid input. The aircraft heat exchanger may further include a first heat exchanger sub-chamber that exchanges heat energy in a cross flow configuration between the first cold fluid input and the first hot fluid input. The aircraft heat exchanger may also include a second heat exchanger sub-chamber inline to the first heat exchanger sub-chamber. The second heat exchanger sub-chamber may exchange heat energy in a cross flow configuration between the second cold fluid input and the second hot fluid input. A bypass may direct the second cold fluid input around the first heat exchanger sub-chamber.

According to another aspect, a method for exchanging heat between aircraft components is provided. The method may include receiving a cold fluid input, partitioning the cold fluid input into a first cold fluid input and a second cold fluid input, receiving a hot fluid input, partitioning the hot fluid input into a first hot fluid input and a second hot fluid input, exchanging heat energy in a first heat exchanger sub-chamber in a cross flow configuration between the first cold fluid input and the first hot fluid input, exchanging heat energy in a second heat exchanger sub-chamber inline to the first heat exchanger sub-chamber in a cross flow configuration between the second cold fluid input and the second hot fluid input, and directing the second cold fluid input around the first heat exchanger sub-chamber in a bypass.

According to yet another embodiment, an aircraft is provided. The aircraft may include an engine having a precooler fan air supply as a cold fluid supply, an engine bleed air supply as a hot air supply and a cross flow heat exchanger. The cross flow heat exchanger may include a cold fluid input for receiving the precooler fan air supply, a first partition for splitting the cold fluid input into a first cold fluid input and a second cold fluid input. The cross flow heat exchanger may also include a hot fluid input, a second partition for splitting the hot fluid input into a first hot fluid input and a second hot fluid input. The cross flow heat exchanger may include a first heat exchanger sub-chamber for exchanging heat energy in a cross flow configuration between the first cold fluid input and the first hot fluid input, a second heat exchanger sub-chamber inline to the first heat exchanger sub-chamber for exchanging heat energy in a cross flow configuration between the second cold fluid input and the second hot fluid input. A bypass may direct the second cold fluid input around the first heat exchanger sub-chamber.

DETAILED DESCRIPTION

The following detailed description provides for an aircraft cross flow heat exchanger having an inline arrangement. As discussed briefly above, aircraft commonly use heat exchangers to cool various aircraft components, including some parts of the aircraft engine. Because weight and size can be factors when selecting and designing aircraft components, the type of heat exchanger used can be limited. Because of those limitations, the efficiency or effectiveness of conventional heat exchangers used on aircraft may be limited, diminishing the capacity of the heat exchanger to adequately reduce the temperature, or in the alternative, increase the temperature, of certain fluids in the aircraft. For example, a conventional cross flow heat exchanger used to reduce the temperature of engine bleed air may be limited in its ability to reduce the temperature to a desired temperature because of design limitations such as size and weight. Other limitations of conventional aircraft heat exchangers may be present as well.

Utilizing the concepts described herein, an aircraft cross flow heat exchanger is provided that, in some configurations, can achieve an increased efficiency over conventional aircraft cross flow heat exchangers. In some configurations, the concepts described herein can provide for a smaller heat exchanger that can achieve the same level of cooling as a larger conventional aircraft cross flow heat exchanger. In one configuration, concepts and technologies described herein provide for an aircraft cross flow heat exchanger having more than one cross flow heat exchange chamber in an inline arrangement. An inlet fluid flow, such as cold air from an engine, may enter an aircraft heat exchanger. The inlet fluid flow can be partitioned into several sub-inlet fluid flows. The sub-inlet fluid flows are directed into one or more heat exchanger sub-chambers that are arranged in an inline pattern. As used herein, “inline” means that the central axes of one or more sub-chambers of heat exchanger lie generally in a straight line along an axis. The sub-inlet fluid flows exchange heat energy with a cross flowing fluid in their respective heat exchanger sub-chambers. The sub-inlet fluid flows thereafter exit their respective heat exchanger sub-chambers and are recombined to exit the aircraft heat exchanger as an outlet fluid flow.

As will be described below, the inline arrangement can increase the efficiency of an aircraft heat exchanger. In some configurations, by partitioning the inlet fluid flow into sub-inlet fluid flows, with each being directed to a sub-heat exchanger chamber, the pressure drop experienced in one or both of the chambers may be reduced. By reducing or minimizing the pressure drop across any one particular component of the aircraft heat exchanger, the heat exchanger can be designed using less robust materials. In some configurations, this may result in possible weight, size and/or cost gains.

In the following detailed description, references are made to the accompanying drawings that form a part hereof, and which are shown by way of illustration, specific embodiments, or examples. Referring now to the drawings, in which like numerals represent like elements through the several FIGs., an aircraft cross flow heat exchanger having an inline arrangement will be described.

Turning toFIG. 1, a perspective view of a conventional cross flow, fin-plate heat exchanger100is shown. The heat exchanger100has two fluid inlets, illustrated as T1(COLD) and T2(HOT), and two fluid outlets, illustrated as T1(HOT) and T2(COLD). The T1fluid, which may be a gas or liquid, flows in stream102, while the T2fluid, which may also be a gas or liquid, flows in stream104in the heat exchanger chamber100. It should be noted that the concepts and technologies described herein are not limited to any specific cold or hot fluid flows. Further, the use of a fin-plate heat exchanger100is merely illustrative. For example, other configurations considered to be within the scope of the present disclosure may include configurations in which the T1fluid is a hot fluid when compared to the T2fluid.

As described above, fluids in a cross flow heat exchanger move generally normal to each other. In a similar manner, the T1fluid flows generally parallel to axis XY, whereas the T2fluid flows generally normal to axis XY. As the T1fluid moves from inlet106to outlet108, heat energy is exchanged with the T2fluid, which is at a higher temperature than the T1fluid. Thus, the T1fluid exits the heat exchanger100at a higher temperature than when it entered the heat exchanger100. In a similar manner, the T2fluid, because of the transfer of heat energy from the T2fluid to the T1fluid, leaves the heat exchanger100at a lower temperature than when it entered the heat exchanger100.

FIG. 2Ais an illustration of an inline heat exchanger200having inline heat exchanger sub-chambers, according to various embodiments. In some configurations, the inline heat exchanger200can provide for increased efficiency, reduced sized, reduced pressure drops, or other possible design advantages. The inline heat exchanger200receives as an input T1(COLD) as the lower temperature input fluid and T2(HOT) as the higher temperature input fluid. In the configuration illustrated inFIG. 2A, the T1(COLD) may be precooler fan air from an engine and the T2(HOT) may be precooler bleed air. It should be appreciated that the concepts and technologies described herein are not limited to any particular fluid source and may be equally applicable to other fluid sources without departing from the scope of this disclosure and the accompanying claims.

The inline heat exchanger200has two cross flow, heat exchanger sub-chambers, sub-chamber204A and sub-chamber204B. It should be appreciated that the concepts and technologies described herein are not limited to any particular number of sub-chambers. Various configurations of the concepts and technologies described herein are illustrated in terms of two sub-chambers, though more may be used and are considered to be within the scope of this disclosure. In one configuration, the heat exchange duty is shared by both sub-chamber204A and sub-chamber204B. It should be appreciated that the concepts and technologies described herein are not limited to any particular division of the heat exchange duty. For example, the heat exchange duty division between the sub-chambers204A and204B may be equal or one sub-chamber may be configured to handle more heat transfer load than the other sub-chamber.

To divide the heat exchange duties between sub-chamber204A and sub-chamber204B, T1(COLD) inlet flow is partitioned into two fluid flows, illustrated as T1A (COLD) and T1B (COLD). There may be various ways in which the T1(COLD) inlet fluid is partitioned into the T1A (COLD) and T1B (COLD) fluid flows. For example, valve212may be configured to partition the T1(COLD) inlet flow into the T1A (COLD) and T1B (COLD) fluid flows. The value212may be further configured to vary the amount of fluid flow in the T1A (COLD) and T1B (COLD) fluid flows in relation to the heat exchange duty of sub-chamber204A and sub-chamber204B.

Another configuration for partitioning the T1(COLD) inlet fluid into the T1A (COLD) and T1B (COLD) fluid flows may be to use a barrier214. The barrier214may be a fixed or movable divider between fluid inlet chamber216, going to sub-chamber204A, and fluid inlet chamber218, going to sub-chamber204B. In some configurations in which the division of the T1(COLD) inlet fluid is fixed, the barrier214may be a fixed divider. In some configurations in which the division of the T1(COLD) inlet fluid is variable, the barrier214may be configured to be movable to increase or decrease the amount of fluid entering fluid inlet chamber216and fluid inlet chamber218.

It should be understood that the valve212and the barrier214, or other fluid flow divider technologies, may be used separately or in various combinations. For example, the heat exchanger200includes both the valve212and the barrier214. T2(HOT) inlet fluid can be split into T2A (HOT) fluid flow and T2B (HOT) fluid flow. T2A (HOT) fluid flow can be directed to sub-chamber204A, while T2B (HOT) fluid flow can be directed to sub-chamber204B. In the cross-flow configuration of the heat exchanger200, the T2A (HOT) fluid flow and the T2B (HOT) fluid flow can flow generally normal in sub-chambers204A and204B to the T1A (COLD) fluid flow and the T1B (COLD) fluid flow, respectively. Upon exiting their respective sub-chambers, T1A (HOT) and T1B (HOT), as well as, T2A (COLD) and T2B (COLD), can thereafter be recombined into a single fluid flow, illustrated as T1(HOT) and T2(COLD), respectively.

As described above, the heat exchanger200is in an inline configuration. As illustrated inFIG. 2A, the sub-chamber204A is generally inline to the sub-chamber204B along axis AB. It should be appreciated that the concepts and technologies described herein are not limited to any specific degree of linearity between the sub-chamber204A and the sub-chamber204B, as various configurations may depart somewhat from a perfectly linear configuration and are still considered to be within the scope of the present disclosure.

In order to accommodate the cross flow pattern and the linearity of the sub-chambers204A and204B, the heat exchanger200uses a fluid flow bypass system to direct fluids around various components. InFIG. 2A, fluid bypass220directs the T1A (COLD) fluid flow around sub-chamber204A and into sub-chamber204B. Fluid bypass222directs the T1B (HOT) fluid exiting sub-chamber204A around sub-chamber204B. Thus, by using fluid bypass220and fluid bypass222, the linearity of the sub-chamber204A and204B may be achieved. Although the fluid bypass220and the fluid bypass222are shown as having generally flat or planar sidewalls, it should be understood that the fluid bypass220and the fluid bypass222may be formed using various shapes, including circular, all of which are considered to be within the scope of the present disclosure. The use of planar or rectangular components in the heat exchanger200is for purposes of illustration only and does not limit the scope of the present disclosure or the accompanying claims to a heat exchanger using that particular shape.

FIG. 2Bis a perspective exploded view of the heat exchanger200illustrating an exemplary fluid flow configuration. InFIG. 2B, the heat exchanger200has been separated into the portions associated with the sub-chamber204A and the sub-chamber204B. In one implementation, the design of the sub-chambers204A and204B and their associated components may resemble a chair. The wall of the fluid bypass222may resemble the back of a chair, which may be “offset” from the sub-chamber204A and the area330that may resemble the legs, base, or support structure. In a similar manner, the wall of the fluid bypass220may be “offset” from the sub-chamber204B and the area332.

In some configurations, the “chair” design of the heat exchanger200may provide for various benefits. For example, the chair design of the heat exchanger200may allow for the inline of the sub-chambers204A and204B while maintaining a relatively compact size. The bypasses220and222may extend and be offset to either side along the length of the sub-chambers204A and204B. By placing the bypasses220and222along the outer walls of the sub-chambers204A and204B, the sub-chambers204A and204B may be placed closer together and in an inline configuration than what may be possible if the bypasses220and222were placed in another location, such as between the sub-chambers204A and204B.

The shape of the bypasses220and222may also provide additional benefits. For example, the offset configuration of the bypasses220and222may reduce the heat exchange of fluids while the fluids are in the bypasses220and222. For example, if the fluid moving in the bypass220is a hot fluid, a reduction in the temperature of the fluid will reduce the difference in temperature between the hot fluid and the cold fluid in the sub-chamber204B, thus reducing the amount of heat exchanged with the cold fluid. This results in a decreased efficiency of the heat exchanger200. In a different manner, using the configuration ofFIGS. 2A and 2B, because the offset bypasses220and222are adjacent to the sub-chambers204A and204B, the fluids moving in the bypasses220and222may act as insulators for the sub-chambers204A and204B. For example, hot air moving through the bypass220may keep colder, outside air from interacting with the sub-chamber204A. This may help maintain the efficiency of the sub-chamber204A, while reducing the amount of insulation needed for the sub-chamber204A. This may allow for a smaller size of the heat exchanger200for a certain efficiency or heat exchange capacity.

In some configurations, the shape of the heat exchanger200may also provide for various fluid movement capabilities. For example, a divider334and a divider336, which forms part of the bypasses220and222, may be shaped to increase or decrease the velocity of fluids moving through the heat exchanger200. In one implementation, the divider334may be shaped to cause a Venturi effect. In that implementation, the divider334may be shaped to cause a constriction in the bypass220, the bypass222, or both. The increased speed of the fluids may increase the heat transferred in the sub-chamber204A,204B, or both, an effect that may be analogous to forced convention. In some configurations, the divider334may be configured to cause a desired pressure drop in the fluids moving through the divider334. The divider336may be configured to provide benefits similar to those described in regard to the divider334. In some configurations, the divider334and the divider336may be integral parts of the bypasses220and222and not separate structures.

In further configurations, the shape of the components of the heat exchanger200may provide for a modular design. As illustrated inFIG. 2B, the portions associated with the sub-chamber204A may be similar in size, shape and functionality to the portions of the heat exchanger200associated with the sub-chamber204B. This may allow one portion of the heat exchanger200to be interchangeable with another portion of the heat exchanger200. The modular design and interchangeable nature of the configuration illustrated inFIG. 2Bmay reduce construction and assembly costs of the heat exchanger200. For example, instead of requiring the design and manufacturing of different portions of the heat exchanger200, a single portion may be designed and manufactured. Further, because of the similarity of designs, the assembly of the various portions of the heat exchanger200may be better facilitated because the portions are interchangeable, obviating any errors from installing the incorrect portion.

In some configurations, the modular components may be modified to provide additional benefits. For example, the divider334is shown inFIG. 2Bas having a section338, which is indicated by a dotted line. The section338may have a wall340, which may fluidically enclose the bypass222. The wall340may be used as the enclosing wall in lieu of the side342of the sub-chamber204B. In this configuration, the dividers334and336may be abutted to provide for the heat exchanger200with the two sub-chambers204A and204B. Additionally, because the bypasses220and222are enclosed by the section338, there may not be a need to seal the structure when assembled, as the section338may provide the fluidic barrier. A section344of the bypass336may also be similarly configured as the section338of the bypass334.

FIG. 3is a top-down view illustrating fluid flows in a configuration of the presently disclosed subject matter. It should be noted that the T2(HOT) inlet fluid and the T2(COLD) outlet fluid ofFIG. 2Aare not illustrated inFIG. 3. As illustrated, the T1(COLD) inlet fluid is partitioned into the T1A (COLD) fluid flow and the T1B (COLD) fluid flow. The T1A (COLD) fluid flow is directed to the fluid inlet chamber218and the T1B (COLD) fluid flow is directed to the fluid inlet chamber216. In order to accommodate a linear sub-chamber configuration, the T1A (COLD) fluid flow is directed around the sub-chamber204A by using fluid bypass220, which directs the T1A (COLD) fluid flow through the fluid inlet chamber218into sub-chamber204B. In a similar manner, the T1B (HOT) fluid flow exiting the sub-chamber204A is directed around the sub-chamber204B using fluid bypass222. By using the fluid bypass220and the fluid bypass222, the sub-chamber204A and the sub-chamber204B can be placed generally linear along axis AB.

FIG. 4is a side view illustrating an exemplary heat exchanger mounting system400. Shown inFIG. 4is a jet engine424. Although the presently disclosed subject matter may be described in terms of a jet engine, it should be appreciated that the technology described herein is not limited to jet engines, as the technology may be used with other types of engines, motors, or heat sources in general. Jet engine424has precooler fan air supply426as a fluid input to the sub-chamber204A and204B. The precooler fan air supply426is a cool fluid input, similar to T1(COLD) illustrated inFIG. 2A, above.

The mounting system400also includes a precooler bleed air supply428as a second fluid input the sub-chamber204A and204B. The precooler bleed air supply428is a hot fluid input, similar to T2(HOT) illustrated inFIG. 2A. The precooler fan air supply426is heated in the sub-chambers204A and204B and output as fluid440. The precooler bleed air supply428is cooled in the sub-chambers204A and204B and output as fluid442. In some configurations, the fluid442can be bleed air supply to the airframe and power plant. Depending on their size, the sub-chambers204A and204B can be mounted close to the engine424. InFIG. 4, the sub-chambers204A and204B are mounted proximate to an engine strut444and an aft engine mount446. In some configurations, the sub-chambers204A and204B are mounted to the engine strut444.

FIG. 5is a system diagram illustrating an exemplary heat exchange system for precooling fluid for use in an aircraft. In one exemplary use of precooling for an aircraft can include an environment system for an aircraft. In some configurations, the precooler takes bleed air from the engine, such as from a compressor stage, and supplies that air to the cabin and flight deck. The bleed air is typically high pressure air at a high temperature. Prior to supplying various components in the aircraft, the high pressure/high temperature bleed air may need to be precooled.FIG. 5illustrates an exemplary heat exchanger system500in which bleed air502from an aircraft engine504is cooled for use within an aircraft. The bleed air502travels from the aircraft engine504into a wing506of the aircraft. The wing506has a top outer surface508and a bottom outer surface510.

As described above, components in an aircraft may be limited in size and/or weight based on their use in an aircraft, as illustrated by way of example, inFIG. 5. A cross flow heat exchanger512is placed within structure components514and516of the wing506. In some configurations, the structure components514and/or516may be wing spars that provide structure rigidity to the wing506. In some configurations, it may be desirable or necessary to be able to place an aircraft component in the space within various structure components, such as the structure components514and516. Although the concepts and technologies are not limited to any reason for doing so, in some configurations, by placing the cross flow heat exchanger512in the space between the structure components514and516, the integrity, and thus strength, of the structure components514and516may be maintained. It should be noted that the cross flow heat exchanger512may be placed in locations other than the wing506. For example, the cross flow heat exchanger512may be placed in the fuselage of the aircraft. The concepts and technologies described herein are not limited to any one location of placement of the cross flow heat exchanger512.

The bleed air502, which is at a high temperature and pressure, enters the cross flow heat exchanger512and is split for entry into heat exchanger sub-chambers518and520. As described herein, the heat exchanger sub-chambers518and520are inline. In some configurations, the inline configuration may provide for the ability of the cross flow heat exchanger512to be placed in certain locations in the aircraft, such as between the structure components514and516. A portion of the bleed air502is bypassed around the heat exchanger sub-chamber518and is directed to heat exchanger sub-chamber520in a manner illustrated, by way of example, inFIGS. 2-3. Fan air522, which is at a lower temperature than bleed air502, is directed into the heat exchanger sub-chambers518and520and exchanges heat with the bleed air502in their respective heat exchanger sub-chambers518and520. The fan air522leaves the heat exchanger sub-chambers518and520as heated fan air524and may be recycled or used for other purposes. The precooled bleed air502leaves the heat exchanger sub-chambers518and520as cooled bleed air526for various uses such as an environmental system for the aircraft. In some configurations, the cross flow heat exchanger512may minimize the pressure loss of the bleed air502as it is cooled.

Turning now toFIG. 6, an illustrative routine600for cooling an aircraft component is described in detail. Unless otherwise indicated, it should be appreciated that more or fewer operations may be performed than shown in the figures and described herein. Additionally, unless otherwise indicated, these operations may also be performed in a different order than those described herein.

Routine600begins at operation602, where a cold fluid input and a hot fluid input are received at a heat exchanger. The cold fluid input can be from various sources, including precooler fan air. The hot fluid input can be from various sources, including precooler bleed air. It should be appreciated that the terms “cold” and “hot” are used only in their relative sense and do not connote a specific temperature or temperature range. The heat exchanger can be an inline heat exchanger in accordance with various embodiments disclosed herein.

Routine600continues from operation602to operations604and606, where the cold and hot fluids are partitioned into a plurality of fluid inputs. In one configuration, at operation606, the cold fluid input is partitioned into a first cold fluid input and a second cold fluid input. In a similar manner, at operation604, the hot fluid input is partitioned into a first hot fluid input and a second hot fluid input. It should be appreciated that the number of fluid inputs the cold and/or the hot fluid inputs are partitioned into may vary depending on the configuration of the particular system. For example, a heat exchanger may have two inline sub-chambers, and therefore, the cold and the hot fluid inputs may be partitioned into a first and second fluid input. In another example, a heat exchanger may have n-number of inline sub-chambers, and therefore, the cold and hot fluid inputs may be partitioned into n-number of fluid inputs.

Routine600continues from operation606to operation614, where the first cold fluid input is directed into a first heat exchanger sub-chamber and the second cold fluid input is directed into a second heat exchanger sub-chamber through a bypass around the first heat exchanger sub-chamber. In some configurations, the bypass allows for the movement of fluid around one or more of the sub-chambers while providing an inline configuration of the sub-chambers. In some configurations, providing an inline configuration may provide for a smaller heat exchanger.

Routine600continues from operation614to operation616, where the first cold fluid input and the second cold fluid input are combined upon exit from their respective sub-chambers. It should be appreciated that concepts and technologies described herein are not limited to requiring the combination of the fluids upon exit from their respective chambers. For example, the fluids may be further partitioned and/or may be maintained in a separate fluid configuration. Routine600continues from operation616to operation612, where the routine600ends.

In parallel to operation614, the routine600continues from operation604to operation608, where the first hot fluid input is directed into a first heat exchanger sub-chamber and the second hot fluid input is directed into a second heat exchanger sub-chamber. The routine600continues from operation608to operation610, where the first hot fluid input and the second hot fluid input are combined upon exit from their respective chambers. It should be appreciated that concepts and technologies described herein are not limited to requiring the combination of the fluids upon exit from their respective chambers. Routine600continues from operation610to operation612, wherein the routine600ends.

Based on the foregoing, it should be appreciated that technologies for exchanging heat in an aircraft cross flow heat exchanger having inline heat exchanger sub-chambers have been presented herein. The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes may be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the present disclosure, which is set forth in the following claims.