Flow swirler

Abstract

A flow swirler comprising a first flow channel, defined by a first cylindrical wall, for first fluid flow, wherein a first end of the first cylindrical wall is arranged in the form of a swirl-inducing pattern, the swirl-inducing pattern comprising a plurality of bent-shaped swirl blades in a repeating pattern to induce swirling to the first fluid flow to generate swirl flow.

Description

PATENTAttorney Docket No.: 44024049W001FLOW SWIRLER TECHNICAL FIELDField

[0001] The present disclosure generally relates to mixing fluid flows. The disclosure relates particularly, though not exclusively, to flow swirlersBACKGROUND

[0002] This section illustrates useful background information without admission of any technique described herein representative of the state of the art.

[0003] For various applications, mixing of fluids, such as gases, is essential. Forming a swirling or rotating flow can be used to effectively mix fluids. High shear stress and turbulence in the swirl flow assure that the one or more fluid flows become effectively mixed.

[0004] Axial flow is typically converted to swirling flow by a mechanical device, a swirler. Swirl can also be formed by forcing fluid flow to follow a tangential path thus forming a circulating flow, for example, by a suitable flow channel geometry or fluid inlet positioning. In conventional swirlers, a mixing zone generated by the swirler, wherein the fluid(s) swirl and become mixed, may not be homogeneous and the mixing efficacy may vary within the mixing zone. Therefore, a need exists for improved flow swirlers.SUMMARY

[0005] It is an aim to solve or alleviate at least some of the problems related to prior art or at least provide an alternative. An aim is to provide an improved flow swirler. Another aim is to provide improved fluid mixing. Yet another aim is to provide a flow swirler capable of providing more uniform mixing zone.PATENTAttorney Docket No.: 44024049W001

[0006] The appended claims define the scope of protection. Any examples and technical descriptions of apparatuses, products and / or methods in the description and / or drawings not covered by the claims are presented not as embodiments of the invention but as background art or examples useful for understanding the invention.

[0007] According to a first example aspect there is provided a flow swirler comprising: a first flow channel, defined by a first cylindrical wall, for first fluid flow, wherein a first end of the first cylindrical wall is arranged in a form of a swirl-inducing pattern, the swirl-inducing pattern comprising a plurality of bentshaped swirl blades in a repeating pattern to induce swirling to the first fluid flow to generate swirl flow.

[0008] Advantageously, swirl flow may be effectively induced. Further, a compact flow swirler may be enabled.

[0009] In certain embodiments, the swirl blades are formed as (seamless) continuum of (the first end of) the fist cylindrical wall. In certain embodiments, the swirl blades are formed from the first end of the first cylindrical wall. That is, in certain embodiments, the swirl blades are formed by rearranging the first end of the first cylindrical wall. Advantageously, structural integrity and uniformity of the flow swirler may be improved. Further, seams and other structural inhomogeneities from joining parts to another may be reduced, thus, improving flow conditions.

[0010] In certain embodiments, the swirl inducing pattern comprises at least 2 swirl blades. In certain embodiments, the swirl inducing pattern comprises 2-12 swirl blades. Advantageously, swirl flow characteristics may be influenced by the number of swirl blades.

[0011] In certain embodiments, the swirl blades are identical. Advantageously, homogeneity of swirl flow may be improved.

[0012] In certain embodiments, the swirl blades have an inwards-bent shape. In certain embodiments, a first tip of each of the plurality of swirl bladesPATENTAttorney Docket No.: 44024049W001having the inwards-bent shape is arranged inwards (from the circumference of the first cylindrical wall) towards a predetermined point located on a central axis of the first flow channel. In certain embodiments, tip angle of the first tip of each of the plurality of swirl blades is 90 degrees of less. Advantageously, at least partially inwards directed swirl flow may be induced. Further, mixing efficacy close to central axis of mixing zone and mixing uniformity may be improved. Further, control over swirl magnitude and direction may be further improved.

[0013] In certain embodiments, the flow swirler comprises a second flow channel for a second fluid flow (between outside of the first cylindrical wall and inside of a second cylindrical wall coaxially surrounding the first cylindrical wall) coaxially surrounding the first flow channel. In certain embodiments, the second flow channel is defined as volume between outside of the first cylindrical wall and inside of a second cylindrical wall coaxially surrounding the first cylindrical wall.

[0014] In certain embodiments, the flow swirler is configured to combine the second fluid flow with the swirl flow downstream of the swirl-inducing pattern. Advantageously, the swirl flow of may induce swirling also to the second fluid flow. Further, mixing of the first fluid flow and second fluid flow may be improved. Further, the flow swirler may be kept simple as separate swirler for the second fluid flow may not be needed.

[0015] In certain embodiments, the second flow channel comprises a second channel outlet opening at first end of the second flow channel, wherein the diameter of the outlet opening is smaller than the diameter of the second cylindrical wall. In certain embodiments, (the first end of) the second flow channel is arranged to guide second fluid flow (at least partially) inwards towards the swirl flow generated by the swirl inducing pattern of the first flow channel. Advantageously, mixing of the first fluid flow and the second fluid flow may be further improved. Further, mixing efficacy and uniformity may be further improved by inwardly directed flow from the second flow channel. Further, fluid mixing close to central axis of mixing zone and mixing zone homogeneity may be further improved.PATENTAttorney Docket No.: 44024049W001

[0016] In certain embodiments, the second flow channel comprises a nozzle part (configured to guide the combined swirl flow) attached to the outlet opening. Advantageously, the flow characteristics of swirl flow and mixing zone properties may be further controlled.

[0017] In certain embodiments, the flow swirler (or at least the swirl-inducing pattern) is manufactured by additive manufacturing. In certain embodiments, the additive manufacturing is 3D printing. In certain embodiments, the swirlinducing pattern is manufactured by machining the first end of the first flow channel into the swirl inducing pattern. Advantageously, the flow swirler may be feasibly manufactured by different methods. Further, the flow swirler may be manufactured from various materials.

[0018] According to a second example aspect, there is provided use of the flow swirler in substrate processing. In certain embodiments, the substrate processing comprises atomic layer deposition, ALD, or chemical vapor deposition, CVD. In certain embodiments, the use comprises use of the flow swirler in an ALD system.

[0019] Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well.BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Some example embodiments will be described with reference to the accompanying figures, in which:

[0021] Fig. 1 schematically shows a side view of a flow swirler according to certain example embodiments;

[0022] Fig. 2 schematically shows a side-view of a first cylindrical wall according to certain example embodiments;PATENTAttorney Docket No.: 44024049W001

[0023] Fig. 3 schematically shows a straightened swirl blade according to certain example embodiments;

[0024] Fig. 4 schematically shows a side view of a bent-shaped swirl blade according to certain example embodiments;

[0025] Fig. 5 schematically shows a top view of a flow swirler according to certain example embodiments; and

[0026] Fig. 6 schematically shows a side view of a flow swirler according to certain further example embodiments.DETAILED DESCRIPTION

[0027] In the following description, like reference signs denote like elements or steps.

[0028] As used herein, the term fluid comprises both gases and liquids.

[0029] As used herein swirl flow (or swirling flow) refers to fluid flow having a tangential component of velocity about an axis which, when combined with an axial component of velocity of the propagating fluid flow, produces a helical or spiral flow.

[0030] It is provided a flow swirler 100. In certain embodiments, the flow swirler 100 comprises a first flow channel 110 for first fluid flow F1. In certain embodiments, the first flow channel 110 is defined by (inside of) a first cylindrical wall 115. In certain embodiments, the first cylindrical wall 115 comprises a first end 120. In certain embodiments, the first end 120 of the first cylindrical wall 115 is arranged in the form of a swirl-inducing pattern. In certain embodiments, the swirl-inducing pattern comprising a plurality of bent-shaped swirl blades 130. In certain embodiments, the plurality of bent-shaped swirl blades 130 are arranged in a repeating pattern, thus, forming the swirl-inducing pattern.PATENTAttorney Docket No.: 44024049W001

[0031] In certain embodiments, the first fluid flow F1 comprises gas. In certain embodiments, the first fluid flow F1 comprises liquid. Preferably, the first fluid flow F1 is a gas flow. In certain embodiments, the first fluid flow F1 is a mixture of two or more fluids.

[0032] Fig. 1 schematically shows a side view of a flow swirler 100 according to certain example embodiments. Fig. 2 shows a side-view of a first cylindrical wall 115 without swirl-inducing pattern according to certain example embodiments. Fig. 2 also depicts a schematical exemplary illustration how swirl blades 130 may be arranged from the first end 120 of the first cylindrical wall 115. Fig. 6 schematically shows a side view of a flow swirler 100 according to certain other example embodiments.

[0033] Dashed arrows in Figs. 1 and 6 schematically depict fluid flow propagation within and affected by the flow swirler 100.

[0034] The flow swirler 100 comprises the first cylindrical wall 115. The inside of the first cylindrical wall 115 defines the first flow channel 110. First fluid flow F1 propagates within the first flow channel 110.

[0035] The first cylindrical wall 115 comprises a first end 120 and a second end 125. The ends of the first cylindrical wall 115 are open to allow the first fluid flow F1 to enter and exit the first flow channel 110.

[0036] In certain embodiments, the first cylindrical wall 115 comprises the first end 120. In certain embodiments, the first end 120 of the first cylindrical wall 115 is open to allow the first fluid flow F1 to exit the first flow channel 110. In certain embodiments, the first fluid flow F1 is configured to exit the first flow channel 110 through the first end 120 of the first cylindrical wall 115 (i.e., the first end of the first flow channel 110).

[0037] In certain embodiments, the first cylindrical wall 115 comprises a second end 125 (distally located from the first end 120). In certain embodiments, the second end 125 of the first cylindrical wall 115 is open to allow the first fluid flow F1 to enter the first flow channel 110. In certainPATENTAttorney Docket No.: 44024049W001embodiments, the first fluid flow F1 is configured to enter the first flow channel 110 through the second end 125 of the first cylindrical wall 115 (i.e. , the second end 125 of the first flow channel 110). The second end 125 of the first cylindrical wall 115 may be coupled to a fluid inlet, fluid inlet line or a fluid source to provide the first fluid flow F1 to the first flow channel 110. In certain embodiments, the first flow channel 110 is branched 110 such that fluid flow from a plurality of sources may be provided to the first flow channel 110 simultaneously or sequentially.

[0038] In certain embodiments, a first end 120 of the first cylindrical wall 115 is arranged in the form of a swirl-inducing pattern. In certain embodiments, the first end 120 of the first cylindrical wall 115 comprises the swirl-inducing pattern.

[0039] In certain embodiments, the flow swirler 100 is manufactured by additive manufacturing. In certain embodiments, the additive manufacturing is 3D printing. In certain embodiments, the swirl-inducing pattern is manufactured by machining the first end 120 of the first cylindrical wall 115 into the swirl inducing pattern. In certain embodiments, the machining comprises cutting and bending the first end 120 of the first cylindrical wall 115.

[0040] The swirl-inducing pattern is arranged to convert the first fluid flow F1 to swirl flow Fs as the first fluid flow F1 exists the first flow channel 110. For instance, in certain exemplary embodiments, the first fluid flow F1 may be generally propagating substantially linearly (in a direction substantially parallel to central axis CA of the first flow channel 110) while flowing within the first flow channel 110. However, upon passing through the swirl-inducing pattern when exiting the first flow channel, tangential velocity component is induced to the first fluid flow by the swirl-inducing pattern, thus, resulting in the swirl flow Fs downstream of the swirl-inducing pattern. The magnitude and direction of the swirl flow Fs and its tangential velocity component are defined (at least partly) by the swirl inducing pattern. That is, the swirl inducing pattern defines characteristics of mixing zone 140, located immediately downstream of the flow swirler 100 and the swirl-inducing pattern.PATENTAttorney Docket No.: 44024049W001

[0041] The mixing zone 140 is depicted in Fig. 1 as an area between two inclined dashed lines. The mixing zone 140 is located (immediately) downstream of the flow swirler 100. The mixing zone 140 is the volume to which the swirl flow Fs arrives from the flow swirler 100 and wherein fluid mixing driven by the swirl occurs. In other words, the mixing zone 140 is the volume occupied and formed by the swirl flow Fs exiting the swirl-inducing pattern. Typically, general shape of the mixing zone is conical since the swirl flow Fs exiting the flow swirler 100 laterally expands after exiting the flow swirler 100, since it is no longer limited by the first cylindrical wall 115. However, in certain embodiments, in certain embodiments the dimensions of the mixing zone (downstream of the swirler 100) are limited (or defined) by a physical structure, such as another flow channel, processing chamber, or reaction cavity.

[0042] In certain embodiments, the swirl-inducing pattern comprises a plurality of bent-shaped swirl blades 130 in a repeating pattern. In certain embodiments, the swirl inducing pattern comprises at least 2 swirl blades. In certain embodiments, the swirl inducing pattern comprises 2-12 swirl blades. In certain embodiments, the plurality of swirl blades 130 are identical. In certain embodiments, the plurality of swirl blades have identical blade width 130w. In certain embodiments, the swirl-inducing pattern is rotation symmetric with respect to the central (axial) axis CA of the first flow channel 110.

[0043] In certain embodiments, (general) flow direction of the first flow F1 within the first flow channel is parallel to the central axis of the first flow channel 110. In certain embodiments, the swirl flow Fs, downstream of the swirlinducing pattern, also propagates in the general direction which is parallel to the central axis of the first flow channel 110, but the swirl flow Fs also comprises a tangential velocity component about the central axis CA.

[0044] Each of the plurality of swirl blades 130 comprises a base side 330. In certain embodiments, the base side 330 corresponds to an arc (with a predetermined length) of a circumference of the first flow channel 115. The base side 330 of the swirl blade 130 is the side of the swirl blade 130 through which the swirl blade 130 is joined (in connection) to the first cylindrical wallPATENTAttorney Docket No.: 44024049W001115. In certain embodiments, the transition from the first cylindrical wall to a swirl blade 130 is seamless. That is, in certain embodiments, the base side 330 is the border line at which the swirl blade 130 merges to (or emerges from) the first cylindrical wall 115.

[0045] In certain embodiments, the base side 330 of each of the plurality of swirl blades 130 has a certain width 130w (measured along the (curved) base side 330). In certain embodiments, the base sides 330 of the plurality of (adjacent) swirl blades 130 are configured to extend around the circumference of the first cylindrical wall 115. That is, in certain embodiments, the sum of widths 130w of the base sides 330 of the plurality of (adjacent) swirl blades 130 is (substantially) equal to the circumference of the first cylindrical wall 115. Furthermore, in certain embodiments, the length of circumference of (a cross section of) the first cylindrical wall 115 divided by blade width 130w (of an individual swirl blade 130) results in an integer. Accordingly, when having less blades 130, the swirl-inducing pattern may comprise wider swirl blades 130. On the other hand, the more swirl blades 130 the swirl-inducing pattern comprises, the narrower the swirl blades 130 are. Advantageously, the characteristics of the resulting swirl flow Fs may be controlled by selecting a swirler with a desired number and width of swirl blades 130.

[0046] In certain embodiments, a plane defined by the base sides of the plurality of swirl blades 130 extending around the circumference of the first cylindrical wall 115 is perpendicular to a central axis CA of the first flow channel 110.

[0047] In certain embodiments, (each of) the plurality of swirl blades 130 comprises a top side 340. In certain embodiments, the width of the top side 340 equals to the width 130w of the base side 330. In certain embodiments, (each of) the plurality of swirl blades 130 is shaped such that when arranged in an unbent shape (detached from the swirler 110 and flattened to a single plane), the base side 330 and top side 340 of the swirl blade are parallel to each other. In certain embodiments, (each of) the plurality of swirl blades 130 is shaped such that when arranged in an unbent shape, the swirl blade 130 forms aPATENTAttorney Docket No.: 44024049W001parallelogram. Such a flattened exemplary swirl blade 130 according to certain embodiments is depicted in Fig. 3

[0048] In certain embodiments, the plurality of swirl blades 130 is shaped such that if arranged to replicate and continue the curvature of the first cylindrical wall 115 and parallel to the first cylindrical wall 115, the plurality of swirl blades 130 at the first end 120 of the first cylindrical wall 115 is configured to form a (open-ended) cylindrical part with dimensions (radius and circumference) corresponding to the dimensions of the first cylindrical wall 115 (and first flow channel 110).

[0049] Fig. 2 schematically shows a side-view of a first cylindrical wall 115 without swirl-inducing pattern according to certain example embodiments. The plurality of swirl blades 130 may be arranged from the first cylindrical wall 115 by cutting the first cylindrical wall 115 along exemplary inclined dashed lines depicted in Fig. 2 from the first end of the first cylindrical wall 115 (the cuts having a predetermined spacing between adjacent cuts corresponding to blade width 130w, a predetermined cut angle (i.e., blade angle) 130a, and a predetermined blade height 130h) to separate the adjacent swirl blades 13 from each other, and then bending first tip 310 of each swirl blade 130 a predetermined distance towards a predetermined point located on the central axis CA of the first flow channel 110. Accordingly, the inclined dashed lines would define two side edges 350 of each of the plurality of swirl blades 130 extending from the base side 330 to the top side 240, and also the tip angle 31 Ot of the first tip (corresponding to blade angle 130a). The base side 330 of the plurality of swirl blades 130 would be located on the horizontal dashed line.

[0050] In certain embodiments, each swirl blade 130 comprises two blade tips, first blade tip 310 and second blade tip 320 distally located form the base side 330 of the swirl blade 130. In certain embodiments, the first tip 310 of each of the plurality of swirl blades 130 has a first tip angle 31 Ot. In certain embodiments, the tip angle 130t is equal to the blade angle 130a. In certain embodiments, the tip angle 31 Ot of the first tip 310 of each of the plurality of swirl blades 130 is 90 degrees of less. In certain embodiments, the tip anglePATENTAttorney Docket No.: 44024049W00131 Ot of first tip 310 of each of the plurality of swirl blades 130 is an acute angle. In certain embodiments, the sum of tip angles 31 Ot of the first tip 310 and second tip is 180 degrees.

[0051] Fig. 4 schematically shows a bent-shaped swirl blade 130 according to certain example embodiments.

[0052] In certain embodiments, the plurality of bent-shaped swirl blades 130 has their first tips 310 arranged inwards towards a predetermined point P1 (shown as black shaded circle in Fig. 4) located on the central axis CA of the first flow channel 110. Such a situation is depicted in Fig. 4. Fig. 4 also depicts alternative possible exemplary positions of the predetermined points P2, P3 (depicted as open unshaded circles) located on the central axis CA and corresponding alternative blade tip 310 positions of the bent-shaped swirl blade 130 which tips are drawn with dashed lines and extending towards the respective alternative predetermined points P2, P3. That is, the predetermined point P1 , P2, P3 may be located anywhere along the central axis CA of the first flow channel 110, also downstream of the first end 120 of the first cylindrical wall 115 and first cylindrical channel 110.

[0053] Advantageously, the inwards-bent shape of the plurality of the swirl blades 130 enables, in addition to inducing swirling, squishing of the swirl flow Fs towards the central rotational axis of the mixing zone 140. Therefore, swirl flow and fluid mixing in the center area of the mixing zone 140 may be improved. Also, immediate lateral spreading of the swirl flow Fs may be reduced. Consequently, more uniform mixing may be improved. In comparison, in conventional swirlers the tangential velocity component typically may tend to drive swirl flow laterally towards the periphery of mixing zone and away from the center, thus reducing mixing efficacy in the center of the mixing zone compared to the mixing zone periphery.

[0054] In certain embodiments, the first tip 310 (of each swirl blade 130 of the plurality of swirl blades 130) is arranged to reside a predetermined distance away from the central axis CA of the first flow channel 110 (that is, not in contactPATENTAttorney Docket No.: 44024049W001with the central axis CA). Top view of such a swirler 100 (viewed from the mixing zone 140 towards the swirler 100) is shown in Fig. 5. In certain embodiments, the first tip 310 of each swirl blade 130 is arranged to reside on the central axis CA of the first flow channel 110 (that is, in contact with the central axis CA).

[0055] In certain embodiments, the swirler 100 comprises a second flow channel 610 for a second fluid flow F2 coaxially surrounding the first flow channel 110. A non-limiting example of a swirler 100 comprising a second flow channel 610 is schematically shown in Fig. 6. In certain embodiments, the first flow channel 110 is comprised within the second flow channel 610.

[0056] In certain embodiments, the second fluid flow F2 comprises gas. In certain embodiments, the second fluid flow F2 comprises liquid. Preferably, the second fluid flow is a gas flow.

[0057] The second fluid flow F2 propagates within he second flow channel 610 essentially parallel to (and to the same direction with) the first fluid flow F1 within the first flow channel 110.

[0058] In certain embodiments, the second flow channel 610 is defined as the volume between the outside of the first cylindrical wall 115 and the inside of the second cylindrical wall 615. In certain embodiments, the second cylindrical wall 615 is coaxial to the first cylindrical wall 115.

[0059] In certain embodiments, the swirler 100 is configured to combine the second fluid flow F2 with the swirl flow Fs downstream of the swirl-inducing pattern. In certain embodiments, the first end 620 of the second flow channel is arranged to guide second fluid flow F2 inwards towards the swirl flow Fs generated by the swirl inducing pattern of the first flow channel 110. In certain embodiments, the first 620 end of (the second cylindrical flow channel 615 of) the second flow channel 610 is inwards tapered. In certain embodiments, the second flow channel 610 comprises a second channel outlet opening 630 at first end of the second flow channel 610, wherein the diameter of the second channel outlet opening 630 is smaller than the diameter of the secondPATENTAttorney Docket No.: 44024049W001cylindrical wall 615. Advantageously, the second fluid flow is effectively brough into contact with the swirl flow Fs. Further, the swirling motion of the swirl flow Fs may induce swirling also the second fluid flow F2 without requiring a separate swirler arrangement for the second fluid flow F2. Still further, the second fluid flow F2 may be effectively mixed with the swirl flow Fs generated from the first fluid flow F1. Still further, the combined swirling flow of swirl flow Fs and the second fluid flow may be effectively squished towards the central rotational axis of the mixing zone 140, thus, improving mixing uniformity particularly near the center of the mixing zone 140.

[0060] In certain embodiments, the second flow channel 610 comprises a nozzle part 640 attached to the outlet opening 630 of the second flow channel 610. In certain embodiments, the nozzle part 640 is configured to guide the combined swirl flow comprising swirl flow Fs and the second fluid flow F2. In certain embodiments, the nozzle part 640 is cylindrical. In certain embodiments, the nozzle part 640 is inwards tapered. In certain embodiments, the nozzle part 640 is outwards slanted (flared). Advantageously, characteristics and dimensions of swirl flow Fs mixed with the second fluid flow F2 and the mixing zone 140 may be further controlled and adjusted.

[0061] In certain embodiments, the swirler 100 is used in substrate processing. In certain embodiments, the swirler 100 is used in a substrate processing apparatus. In certain embodiments, the substrate processing comprises atomic layer deposition, ALD. In certain embodiments, the substrate processing is atomic layer deposition, ALD. In certain embodiments, the swirler 100 is used in an ALD system. In certain embodiments, the substrate processing comprises chemical vapor deposition, CVD. In certain embodiments, the substrate processing is chemical vapor deposition, CVD.

[0062] Without limiting the scope and interpretation of the appended claims, certain technical effects of one or more of the example embodiments disclosed herein are listed in the following. A technical effect is improved fluid mixing. A further technical effect is more uniform fluid mixing. A further technical effect isPATENTAttorney Docket No.: 44024049W001improved fluid in the center region of the mixing zone. A still further technical effect is mechanically robust flow swirler.

[0063] Various embodiments have been presented. It should be appreciated that in this document, words comprise, include, and contain are each used as open-ended expressions with no intended exclusivity.

[0064] The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

[0065] Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Claims

PATENTAttorney Docket No.: 44024049W001What is claimed is:

1. A flow swirler, comprising:a first flow channel, defined by a first cylindrical wall, for a first fluid flow, wherein a first end of the first cylindrical wall is arranged in a form of a swirlinducing pattern, the swirl-inducing pattern comprising a plurality of swirl blades in a repeating pattern to induce swirling to the first fluid flow to generate swirl flow.

2. The flow swirler of claim 1 , wherein the swirl blades are formed as a continuum of the first cylindrical wall.

3. The flow swirler of claim 1 , wherein the swirl-inducing pattern comprises at least two swirl blades.

4. The flow swirler of claim 3, wherein the plurality of swirl blades are identical.

5. The flow swirler of claim 3, wherein the plurality of swirl blades have an inwards-bent shape.

6. The flow swirler of claim 5, wherein a first tip of each of the plurality of swirl blades having the inwards-bent shape is arranged inwards towards a predetermined point located on a central axis (CA) of the first flow channel.

7. The flow swirler of claim 6, wherein a tip angle of the first tip of each of the plurality of swirl blades is 90 degrees of less.

8. The flow swirler of claim 1 , further comprising a second flow channel for a second fluid flow coaxially surrounding the first flow channel.

9. The flow swirler of claim 8, wherein the flow swirler is configured to combine the second fluid flow with the swirl flow downstream of the swirl-inducing pattern.

10. The flow swirler of claim 8, wherein a first end of the second flow channel is arranged to guide the second fluid flow inwards towards the swirl flow generated by the swirl-inducing pattern of the first flow channel.PATENTAttorney Docket No.: 44024049W00111. The flow swirler of claim 8, wherein the second flow channel comprises a second channel outlet opening at a first end of the second flow channel, wherein a diameter of the second channel outlet opening is smaller than a diameter of a second cylindrical wall.

12. The flow swirler of claim 11 , wherein the second flow channel comprises a nozzle part attached to the second channel outlet opening.

13. The flow swirler of claim 9, wherein the flow swirler is manufactured by additive manufacturing.

14. The flow swirler of claim 1, wherein the swirl-inducing pattern is manufactured by machining the first end of the first cylindrical wall to form the swirl-inducing pattern.

15. A method of operating a flow swirler comprising:rotating the flow swirler, the flow swirler comprising:a first flow channel, defined by a first cylindrical wall, wherein a first end of the first cylindrical wall is arranged in a form of a swirl-inducing pattern, the swirl-inducing pattern comprising a plurality of swirl blades in a repeating pattern;flowing a first fluid through the first flow channel; andflowing a second fluid through a second flow channel, the second flow channel coaxially surrounding the first flow channel and comprising a second channel outlet opening at a first end of the second flow channel, wherein a diameter of the second channel outlet opening is smaller than a diameter of a second cylindrical wall.

16. The method of claim 15, wherein the first fluid is different from the second fluid.

17. The method of claim 15, wherein the second flow channel comprises a nozzle part attached to the second channel outlet opening.

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