HEAT EXCHANGER AND METHODS OF FORMING FINS IN A HEAT EXCHANGER

Abstract

A method of forming fins in a heat exchanger having a metal body by skiving the metal body to form a first fin in a first orientation, and skiving the metal body again to form a second fin in a second orientation while straightening the first fin into a third orientation.

Description

BACKGROUND OF THE INVENTION

Skiving may be generally used to produce a series of very fine integrated shavings on a metal body and the shavings may all have generally the same shape and size. For example, a heat exchanger manufacturer may use the skiving technique to create metal fins where the fin of the heat exchanger then provides a way to transfer heat. Integral fins formed from the parent material have a significantly higher heat transfer coefficient versus fins which may be brazed or otherwise attached to the metal body.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present disclosure relates to a method of forming fins in a heat exchanger including providing a metal body including fluid cooling passages, skiving the metal body to form a first fin extending from a first surface of the metal body, with the first fin having a body terminating in a tip and where the body is at a first orientation with respect to the first surface, and skiving the metal body to form a second fin extending from the first surface of the metal body, with the second fin having a body terminating in a tip, and where the body of the second fin is at a second orientation with respect to the first surface, and simultaneously shaping the first fin to orient the body of the first fin in a third orientation with respect to the first surface.

In another aspect, the present disclosure relates to a heat exchanger including a metal body having an upper surface, a set of fluid passages extending through at least a portion of a depth of the metal body where the set of fluid passages is formed along at least a portion of a width of the metal body, and a set of fins skived from the upper surface, with each of the set of fins having a body with a length and a laterally extending tip, and where the body extends substantially along the width of the metal body.

In yet another aspect, the present disclosure relates to an annular surface cooler for an aircraft including a surface cooler metal body having a first surface configured to confront a peripheral wall of an annular fan casing and a second surface spaced from the first surface, a set of fluid passages extending through the metal body where the set of fluid passages is formed along at least a portion of a width of the metal body, and a set of fins skived from the first surface, with each of the set of fins having a body and a laterally extending tip and where the body extends substantially along the width of the surface cooler metal body.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 illustrates a partially cutaway view of a turbine engine assembly with a surface cooler in accordance with various aspects described herein.

FIG. 2 is a perspective view of an aft portion of a fan casing in the turbine engine assembly of FIG. 1.

FIG. 3 is an exploded perspective view of the fan casing of FIG. 2.

FIG. 4 is an exemplary cross-sectional view of the surface cooler of the fan casing of FIG. 3.

FIG. 5 is a perspective view of a metal body in the surface cooler of FIG. 4 before and after the creation of a set of fins.

FIG. 6 is an axial cross-section view of the metal body of FIG. 5 during formation of a first fin.

FIG. 7 is an axial cross-section view of the metal body of FIG. 6 after formation of the first fin.

FIG. 8 is an axial cross-section view of the metal body of FIG. 5 during formation of a second fin.

FIG. 9 is an axial cross-section view of the metal body of FIG. 8 after formation of the second fin.

FIG. 10 is an axial cross-section view of the metal body of FIG. 5 with fins formed in accordance with one embodiment of the disclosure.

FIG. 11 is an axial cross-section view of the metal body of FIG. 5 with fins formed in accordance with a second embodiment of the disclosure.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Aspects disclosed herein relate to surface coolers in an engine such as an aircraft engine. The exemplary surface coolers can be used for providing efficient cooling. Further, the term “surface coolers” as used herein can be used interchangeably with the term “heat exchangers.” As used herein, the surface coolers are applicable to various types of applications such as, but not limited to, turbojets, turbo fans, turbo propulsion engines, aircraft engines, gas turbines, steam turbines, wind turbines, water turbines, and any environment where a heat exchanger may be desired.

FIG. 1 illustrates an exemplary turbine engine assembly 10 having a longitudinal axis 12. A turbine engine 16, a fan assembly 18, and a nacelle 20 can be included in the turbine engine assembly 10. The turbine engine 16 can include an engine core 22 having at least one compressor 24, a combustion section 26, at least one turbine 28, and an exhaust 30. An inner cowl 32 radially surrounds the engine core 22.

Portions of the nacelle 20 have been cut away for clarity. The nacelle 20 surrounds the turbine engine 16 including the inner cowl 32. In this manner, the nacelle 20 forms an outer cowl 34 radially surrounding the inner cowl 32. The outer cowl 34 is spaced from the inner cowl 32 to form an annular passage 36 between the inner cowl 32 and the outer cowl 34. The annular passage 36 characterizes, forms, or otherwise defines a nozzle and a generally forward-to-aft bypass airflow path. A fan casing assembly 37 having an annular forward casing 38 and an annular aft casing 52 can form a portion of the outer cowl 34 formed by the nacelle 20 or can be suspended from portions of the nacelle 20 via struts (not shown).

In operation, air flows through the fan assembly 18 and a first portion 40 of the airflow is channeled through compressor(s) 24 wherein the airflow is further compressed and delivered to the combustion section 26. Hot products of combustion (not shown) from the combustion section 26 are utilized to drive turbine(s) 28 and thus produce engine thrust. The annular passage 36 is utilized to bypass a second portion 42 of the airflow discharged from fan assembly 18 around engine core 22.

The turbine engine assembly 10 can pose unique thermal management challenges and a heat exchanger or surface cooler, illustrated herein as an annular surface cooler 50, can be attached to the turbine engine assembly 10 to aid in the dissipation of heat.

FIG. 2 illustrates an aft casing 52 of the fan casing assembly 37 from FIG. 1. The annular surface cooler 50 can be operably coupled to a peripheral wall 54 (FIG. 3) of the annular aft casing 52 and can include, but is not limited to, an air-cooled heat exchanger that is positioned within the annular passage 36. While the surface cooler 50 has been illustrated as being downstream of the fan assembly 18 it is also contemplated that the surface cooler 50 can alternatively be upstream from fan assembly 18. As such, it will be understood that the surface cooler 50 can be positioned anywhere along the axial length of the annular passage 36.

A partially exploded view of the aft casing 52 from FIG. 2 is shown in FIG. 3. The surface cooler 50 can include a circumferential and axial profile that is substantially similar to the circumferential and axial profile of the peripheral wall 54, and can cover any portion of the circumference of the peripheral wall 54. The annular surface cooler 50 can also include a metal body 60 having an upper surface 62 and a lower surface 64, as well as a set of fins 80 spaced circumferentially along the metal body 60. It will be understood that a set of surface coolers 50 can be utilized to cool a single turbine engine assembly 10, and also that “a set” as used herein can include any number including only one.

A circumferential cross-sectional view of the surface cooler 50, taken along the line 4-4, is shown in FIG. 4. The metal body 60 of the surface cooler 50 can further include an axial width 68, and the lower surface 64 can be spaced apart a depth 66 from the upper surface 62 as shown. A fin 80 of the surface cooler 50 can have a body 84 that extends radially from the first surface 62 and terminates in a tip 86 which is unattached from the bulk of the surface cooler 50. The body 84 of the fin 80 can have a length 88 that extends substantially along the width 68 of the metal body 60 as shown.

The surface cooler 50 further includes a set of circumferential internal fluid cooling passages 70 having an inlet 71 and an outlet 73, and also extending through at least a portion of the depth 66 of the metal body 60. The fluid cooling passages 70 also have a width 72 along at least a portion of the width 68 of the metal body 60, wherein the width 72 of the set of cooling passages 70 is defined as the combined width of all individual cooling passages 70 and can be smaller than the length 88 of the fin 80 as shown. In addition, the surface cooler 50 can be constructed such that a side 90 of a fin in the set of fins 80 can form a side angle 91 with a vertical reference line 92 as shown. It is also contemplated that either side of a fin in the set of fins 80 can form such an angle with respect to a vertical direction, and further, that the angles may be different between the two sides as desired. In addition, the surface cooler 50 can be constructed to create a different side angle for different fins in the set of fins 80.

Arrows 56 (FIG. 2) illustrate exemplary fluid flow through the surface cooler 50 and arrows 58 illustrate airflow that interacts with fins 80 during operation. Heat can be transferred from the fluid within through conduction to the remainder of the surface cooler 50 including the fins 80. Heat can then be dispersed via convection to the airflow 58.

A method of forming the fins 80 is illustrated in FIGS. 5-9. In FIG. 5, the metal body 60 is shown before and after the creation of the set of fins 80, and the metal body 60 is illustrated with a depth 66 and width 68 as shown. The depth 66 and width 68 can be any suitable depth and width depending on the configuration of the surface cooler 50. While the metal body 60 has been illustrated as straight and rectangular it will be understood that this is for clarity purposes only and that the metal body 60 can be curved and contain any of the features used for mounting of the surface cooler 50.

In one non-limiting example, the metal body 60 and fluid cooling passages 70 can be formed by an extrusion process. In such an instance an additional metal portion 75 can also be extruded onto the upper surface 62 of the metal body 60. It is contemplated that the metal body 60 and additional metal portion 75 can include an aluminum-based alloy such as 1100 aluminum alloy; however, this example is not intended to be limiting, and any material suitable for the fan casing environment is contemplated for the metal body 60 and additional portion 75. It is further contemplated that the metal body 60 and additional metal portion 75 may be made from the same material, or the metal body 60 may be made from a different material from the additional metal portion 75, having different hardnesses or thermal properties suited for the intended location of the surface cooler 50.

A skiving machine 300 having a skiving blade 302 and fin straightener 306 can be used to create the fins 80 as shown in FIG. 6, which is an axial cross-sectional view taken along the line 6-6 (FIG. 3). The skiving blade 302 may be operably coupled to a cutter backing block or other machine which may apply a driving pressure to the skiving blade 302. It is contemplated that a driving pressure may be applied in any suitable manner that may exert a force on the skiving blade 302. The skiving blade 302 may be advanced into the metal body 60 thereby producing a first fin 81, which is formed at a leading edge 304 of the skiving blade 302.

The advancement of the skiving blade 302 may be stopped while the first fin 81 is attached to the metal body 60 in a first orientation A as shown in FIG. 6. After forming the first fin 81, the skiving blade 302 may be retreated from the metal body while the first fin 81 remains attached in the first orientation A as shown in FIG. 7; in this orientation, the body 84 of the first fin 81 forms an acute first angle 100 with the first surface 62. The skiving blade 302 may then be advanced again into the metal body 60 to produce a second fin 82 in a second orientation B, similar to the first orientation A having an acute first angle 100 with the first surface 62 as shown in FIG. 8. During creation of the second fin 82, the fin straightener 306 can contact any point along the body 84 of the first fin 81 and move it into a third orientation C in which the body 84 of the first fin 81 forms a second angle 200 with the first surface, preferably 90 degrees as shown in FIG. 9. Continuing in this manner, it can be appreciated that successive advances of the skiving blade 302 can simultaneously produce one fin in the first or second orientations A, B while straightening a previously-skived fin into the third orientation C, and the last fin in the set of fins 80 may be straightened by the fin straightener 306 without skiving any additional fins with the blade 302. It will be understood that while the first and second orientations are illustrated as being at the same at the same acute angle that this need not be the case. Further, while the third orientation has been described as being at 90 degrees it will be understood that the “straightened” orientation can merely be straighter when compared to the first orientation.

In FIG. 10, a completed set of fins 80 is shown in accordance with a first embodiment of the disclosure. The body 84 of a fin 80 creates a 90-degree angle with the first surface 62 of the metal body 60, extending radially inward when assembled on the annular aft casing 52.

In FIG. 11, a completed set of fins 80 is shown in accordance with a second embodiment of the disclosure. The second embodiment is similar to the first embodiment; therefore, like parts will be identified with like numerals increased by 100, with it being understood that the description of the like parts of the first embodiment applies to the second embodiment, unless otherwise noted. It is contemplated that a similar skiving machine having a skiving blade and a straightener may form a set of fins 180 out of an upper surface 162 of a metal body 160, where the fins 180 can have an arcuate cross-section as shown.

During operation, of the surface cooler 50 (FIG. 1) a hot fluid such as oil can be passed through the fluid cooling passages 70, proximal to the upper surface 62. Heat from the fluid may be conducted through the metal body 60 and can be dissipated through the set of fins 80 to a cooling fluid passing by the fins 80. The cooling fluid can include, but is not limited to, cooling air passing through the annular passage 36, which by way of a non-limiting example can be a bypass duct of the turbine engine 10.

The above described embodiments provide for a variety of benefits including that fins may be created at a faster rate than traditional skiving methods; in one example, the present method could create 250 fins per minute while moving them into the second orientation B. Additionally, the use of skiving methods can allow for less material to be used during formation of the fins 80 compared to other manufacturing methods such as machining, which can reduce the material costs of the surface cooler 50. The present method also allows for the skiving of fins from an extruded material containing pre-formed fluid cooling passages 70, which can improve the thermal performance of the surface cooler 50 due to fluid movement within the cooling passages 70.

In addition, the fins 80 created by skiving can be durable enough to be adjusted in position or shape using standard tools such as circular saws or other abrasive means, including reshaping the fins 80 into arcuate or conical profiles based on the desired position of the surface cooler 50 within the engine 10. The durability of the fins 80 can also improve resistance to impact damage from various sources such as foreign object debris.

It should also be appreciated that surface coolers having fins integrally formed from parent material such as the metal body can have a higher heat transfer coefficient compared to surface coolers having fins coupled to the parent material by various known attachment mechanisms, and the embodiments described above can provide for the more efficient manufacture of surface coolers having integrally-formed fins with better cooling ability. Further, the above described embodiments may be more affordable, repeatable, and more reliable which allows for predictable fin geometry at predictable spacing.

To the extent not already described, the different features and structures of the various aspects can be used in combination with others as desired. That one feature cannot be illustrated in all of the aspects is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly described. Combinations or permutations of features described herein are covered by this disclosure.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A method of forming fins in a heat exchanger, the method comprising:

providing a metal body including fluid cooling passages;

skiving the metal body to form a first fin extending from a first surface of the metal body, with the first fin having a body terminating in a tip and where the body is at a first orientation with respect to the first surface; and

skiving the metal body to form a second fin extending from the first surface of the metal body, with the second fin having a body terminating in a tip and where the body of the second fin is at a second orientation with respect to the first surface and simultaneously shaping the first fin to orient the body of the first fin in a third orientation with respect to the first surface.

2. The method of claim 1 wherein the first fin comprises a fin that extends substantially along a width of the metal body.

3. The method of claim 1 wherein the body of the first fin in the third orientation includes an arcuate cross section.

4. The method of claim 1 wherein skiving the metal body to form the second fin and simultaneously shaping the first fin is accomplished via a single advancing motion of a skiving machine along a lengthwise direction of the metal body.

5. The method of claim 4 wherein the skiving machine comprises a skiving blade and an operably coupled fin mover.

6. The method of claim 1 wherein skiving the metal body to form the first fin comprises creating of a straight fin at an angle less than 90 degrees from the first surface.

7. The method of claim 6 wherein shaping the first fin to orient the body in a third orientation comprises lifting the tip of the first fin away from the first surface.

8. The method of claim 7 wherein shaping the first fin to orient the body in a third orientation comprises straightening the fin to a more vertical position.

9. The method of claim 8 wherein shaping the first fin to orient the body in a third orientation comprises moving the fin to a 90 degree angle with respect to the first surface.

10. The method of claim 1 wherein providing a metal body including fluid cooling passages comprises extruding the metal body.

11. The method of claim 10 wherein the metal body is formed from an aluminum-based alloy.

12. The method of claim 1, further comprising shaping the second fin to orient the body of the second fin in the third orientation with respect to the first surface.

13. The method of claim 12 wherein the metal body includes a predetermined angled surface that forms a leading edge of the first fin.

14. A heat exchanger comprising:

a metal body having an upper surface;

a set of fluid passages extending through at least a portion of a depth of the metal body, where the set of fluid passages is formed along at least a portion of a width of the metal body; and

a set of fins skived from the upper surface, with each of the set of fins having a body with a length and a laterally extending tip and where the length of the body extends substantially along the width of the metal body.

15. The heat exchanger of claim 14 wherein the length of a fin of the set of fins is greater than a width of the set of fluid passages.

16. The heat exchanger of claim 14 wherein the body includes an arcuate cross section.

17. An annular surface cooler for an aircraft, comprising:

a surface cooler metal body having a first surface and a second surface spaced from the first surface and configured to confront a peripheral wall of an annular fan casing;

a set of fluid passages extending through the metal body, where the set of fluid passages is formed along at least a portion of a width of the metal body; and

a set of fins skived from the first surface, with each of the set of fins having a body and a laterally extending tip and where the body extends substantially along the width of the surface cooler metal body.

18. The annular surface cooler of claim 17 wherein the body includes an arcuate cross section.

19. The annular surface cooler of claim 17 wherein the width of the body is greater than a width of the set of fluid passages.

20. The annular surface cooler of claim 17 wherein the metal body comprises an aluminum-based alloy body.