EP3730891A1 - Échangeur de chaleur pour fluides à nombre de prandtl élevé - Google Patents

Échangeur de chaleur pour fluides à nombre de prandtl élevé Download PDF

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Publication number
EP3730891A1
EP3730891A1 EP19212330.5A EP19212330A EP3730891A1 EP 3730891 A1 EP3730891 A1 EP 3730891A1 EP 19212330 A EP19212330 A EP 19212330A EP 3730891 A1 EP3730891 A1 EP 3730891A1
Authority
EP
European Patent Office
Prior art keywords
fluid
segment
flow
heat exchanger
channel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19212330.5A
Other languages
German (de)
English (en)
Inventor
Abbas A. Alahyari
John H. Whiton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hamilton Sundstrand Corp
Original Assignee
Hamilton Sundstrand Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hamilton Sundstrand Corp filed Critical Hamilton Sundstrand Corp
Publication of EP3730891A1 publication Critical patent/EP3730891A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
    • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
    • F28F3/025—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being corrugated, plate-like elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
    • F28F13/12—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media by creating turbulence, e.g. by stirring, by increasing the force of circulation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/02—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by influencing fluid boundary
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
    • F28F13/08—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media by varying the cross-section of the flow channels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
    • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations
    • F28F3/04—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element
    • F28F3/048—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations the means being integral with the element in the form of ribs integral with the element or local variations in thickness of the element, e.g. grooves, microchannels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0098—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for viscous or semi-liquid materials, e.g. for processing sludge

Definitions

  • the present disclosure relates to a heat exchanger, and more particularly to a heat exchanger for a high Prandtl number fluid.
  • a fluid heat exchanger includes a channel for passing a first fluid therethrough arranged along a primary axis including at least two segments of a first flow pattern, wherein at least one segment of the at least two segments defines a length greater than five times a hydraulic diameter of the channel, and a first pattern flow disruptor interspersed between each of the segments of the first flow pattern configured to reduce a pressure loss of the fluid flow along the channel, and a second series of channels for passing a second fluid therethrough for transferring energy to the first fluid.
  • a first segment of the at least two segments can define a length different from a length of a second segment of the at least two segments.
  • the length of the first segment can be defined by the equation 5 D h ⁇ L ⁇ 4D h P r wherein L is the length of the first segment, D h is the hydraulic diameter of the first segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the first segment.
  • the length of the second segment can be defined by the equation 5 D h ⁇ L ⁇ 4 D h Pr wherein L is the length of the second segment, D h is the hydraulic diameter of the second segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the second segment.
  • the segments of the first flow pattern can be aligned in the same direction.
  • the segments of the first flow pattern can be straight.
  • the first pattern flow disruptor can narrow the flow channel.
  • the first pattern flow disruptor can change a direction of flow of the first fluid.
  • the first pattern flow disruptor can include multiple disruptors, wherein at least one of the flow disruptors includes a longer length than another disruptor.
  • a method of transferring heat between fluids includes directing a fluid through a heat exchanger channel and developing a thermal boundary layer between the fluid and a surface of the channel and a momentum boundary layer between the fluid and the surface of the channel, wherein the thermal boundary layer of the fluid includes a different thickness than a thickness of the momentum boundary layer, and directing a second fluid through a second channel adjacent to the first channel and transferring heat from the first fluid to the second fluid.
  • the fluid includes a Pradntl number greater than 1, or preferably a Prandtl number greater than 7.
  • the thermal boundary layer of the fluid is thinner than the momentum boundary layer.
  • a ratio of thermal boundary thickness to momentum boundary layer thickness can decrease along a flow direction of the fluid and the ratio of thermal boundary thickness to momentum boundary layer thickness can be greater than 1.
  • FIG. 1 a partial view of an exemplary embodiment of a heat exchanger channel in accordance with the invention is shown in Fig. 1 and is designated generally by reference character 100.
  • the methods and systems of the invention can be used to improve heat transfer using fluids with a high Prandtl number.
  • the heat exchanger 100 includes a hot fluid inlet 102, a cold fluid inlet 104, and a header 106.
  • the disclosure focuses on the structure of the individual channels for the hot fluid and the cold fluid.
  • a channel 108 for passing a first fluid therethrough is arranged along a primary axis 110 including at least two segments 112, 114 of a first flow pattern.
  • a first segment 112 defines a length L1 that may be different from a length L2 of a second segment 114, and a first pattern flow disruptor 116 is interspersed between each of the segments of the first flow pattern to enhance heat transfer of the fluid flow along the channel 108.
  • the channel 108 can include multiple segments of the first flow pattern, and multiple disruptors 116.
  • the length of the first segment L1 is defined by the equation 5 D h ⁇ L1 ⁇ 4D h Pr wherein L1 is the length of the first segment, D h is the hydraulic diameter of the first segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the first segment 112, and the length of the second segment is defined by the equation 5 D h ⁇ L2 ⁇ 4D h Pr wherein L2 is the length of the second segment, D h is the hydraulic diameter of the second segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the second segment 114.
  • the Prandtl number can be calculated at the midpoint of each segment.
  • Prandtl number is a dimensionless number defined as the ratio of momentum diffusivity to thermal diffusivity.
  • momentum diffusion rate is dependent of the dynamic viscosity and density of the fluid along a heat exchange channel
  • thermal diffusivity is dependent of the thermal conductivity and density of the fluid, which again varies along the flow path.
  • the segments 112, 114 of the first flow pattern are aligned in the same direction.
  • the segments 112, 114 of the first flow pattern can be straight.
  • the flow disruptor 116 can be a sinusoidal path attached to the straight first flow pattern.
  • the flow disruptor 116 can be straight flow and set-off from the first flow pattern.
  • the first pattern flow disruptor 116 can narrow the flow channel or change a direction of flow of the first fluid.
  • the first pattern flow disruptor 116 can include multiple disruptors between each of the first flow pattern portions 112, 114.
  • the disruptors can be of various shapes and sizes.
  • the disruptors can include various lengths along the same path, which can be beneficial for channels for larger changes in Pr.
  • a method of transferring heat between fluids using a heat exchanger includes directing a first fluid through a heat exchanger channel and developing a thermal boundary layer between the first fluid and a surface of the channel and a momentum boundary layer between the first fluid and the surface of the channel, wherein the thermal boundary layer of the first fluid includes a different thickness than a thickness of the momentum boundary layer.
  • the first fluid includes a Pradntl number greater than 1, or more specifically a Prandtl number greater than 7.
  • the thermal boundary layer of the first fluid is thinner than the momentum boundary layer.
  • a ratio of thermal boundary thickness to momentum boundary layer thickness decreases along with the flow of the fluid and the ratio is always greater than 1.
  • the method described above is leveraged to augment heat transfer while reducing pressure drop penalty by intermittently disturbing the flow at desired intervals, where the momentum profile is allowed to recover while the thermal profile remains augmented.
  • the flow through the first segement (L1) result in lower pressure drop with little degradation to the enhancement in heat transfer caused by the disruptor.
  • the optimal length the disruptors can be selected based on expected steady state conditions and fluid properties. The implementation of this method has shown an improvement of approximately 30% more heat transfer with respect to conventional methods, while keeping the pressure drop penalty unchanged.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
EP19212330.5A 2019-04-26 2019-11-28 Échangeur de chaleur pour fluides à nombre de prandtl élevé Withdrawn EP3730891A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US16/396,124 US20200340765A1 (en) 2019-04-26 2019-04-26 Heat exchanger for high prandtl number fluids

Publications (1)

Publication Number Publication Date
EP3730891A1 true EP3730891A1 (fr) 2020-10-28

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ID=68732784

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19212330.5A Withdrawn EP3730891A1 (fr) 2019-04-26 2019-11-28 Échangeur de chaleur pour fluides à nombre de prandtl élevé

Country Status (2)

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US (1) US20200340765A1 (fr)
EP (1) EP3730891A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111982A (en) * 1958-05-24 1963-11-26 Gutehoffnungshuette Sterkrade Corrugated heat exchange structures
DE3521914A1 (de) * 1984-06-20 1986-01-02 Showa Aluminum Corp., Sakai, Osaka Waermetauscher in fluegelplattenbauweise
CA2290230A1 (fr) * 1998-11-20 2000-05-20 Eberhard Paul Plaques de transfert de chaleur et methode de fabrication
US20160327346A1 (en) * 2015-05-06 2016-11-10 Halla Visteon Climate Control Corp. Heat exchanger with mechanically offset tubes and method of manufacturing

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4230179A (en) * 1979-07-09 1980-10-28 Haruo Uehara Plate type condensers
FR2695326B1 (fr) * 1992-09-08 1994-12-02 Strasbourg Ecole Nale Sup Arts Matrice métallique de réacteur catalytique pour le traitement des gaz de combustion.
JP3665810B2 (ja) * 1995-12-13 2005-06-29 エコキャット オサケユイチア 触媒コンバータにおける乱流誘発装置
DE19922356C2 (de) * 1999-05-14 2001-06-13 Helmut Swars Wabenkörper
KR101534497B1 (ko) * 2013-10-17 2015-07-09 한국원자력연구원 증기발생기용 열교환기 및 이를 구비하는 증기발생기

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3111982A (en) * 1958-05-24 1963-11-26 Gutehoffnungshuette Sterkrade Corrugated heat exchange structures
DE3521914A1 (de) * 1984-06-20 1986-01-02 Showa Aluminum Corp., Sakai, Osaka Waermetauscher in fluegelplattenbauweise
CA2290230A1 (fr) * 1998-11-20 2000-05-20 Eberhard Paul Plaques de transfert de chaleur et methode de fabrication
US20160327346A1 (en) * 2015-05-06 2016-11-10 Halla Visteon Climate Control Corp. Heat exchanger with mechanically offset tubes and method of manufacturing

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US20200340765A1 (en) 2020-10-29

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