Fluid machine and method for producing fluid-medium-conducting component of fluid machine

Abstract

The invention relates to a turbomachine, in particular a turbomachine, preferably a fan, having at least one flowing-medium-conducting component, for example an impeller blade, an outlet guide blade, a hub ring, a top ring, a base plate, a nozzle or a housing part / component, said flowing-medium-conducting component being made of plastic by a casting process, preferably an injection process, flow ribs are formed on and / or on and / or in the surface of the component in the flow-around region at least in some regions. The invention also relates to a method for producing a flowing medium-conducting component.

Description

Field of the Invention

[0001] The present invention relates to a fluid machine, in particular a turbine, preferably a fan, having at least one component for guiding a flowing medium, such as the blades of an impeller, outlet guide vanes, hub rings, top rings, bottom plates, nozzles or housing parts / components, etc.

[0002] The present invention also relates to a method for manufacturing a component for guiding a flowing medium of a fluid machine. Background Art

[0003] Fluid machines of the type described herein are well known in practice. For this purpose, only fans and their components are cited by way of example. In such fluid machines, wall friction poses problems both in terms of the noise level during operation and in terms of power consumption or efficiency. Therefore, measures must be taken to reduce wall friction.

[0004] It is known in practice that wall friction is reduced by means of riblets on the flow-around surface, thereby reducing frictional losses and additional load torques. This particularly also relates to fluid machines, such as turbines or fans. It is worth noting here that such riblets can be provided for both stationary components and components that rotate or move during operation.

[0005] Riblets refer to elongated structures protruding from the flow-around surface, the length of which is advantageously oriented substantially in the direction of the relative flow-around velocity in the surface area. In order to obtain the effect of reducing wall friction, special requirements are imposed on the cross-section of the riblets according to the relative flow velocity. In particular, the dimensions of the riblets in the cross-section should be small. For example, the width of the riblets, the spacing between adjacent riblets and the height of the riblets are advantageously in the range of 1 μm to 100 μm.

[0006] It is usually necessary to arrange a large number of riblets side by side to cover the flow-around surface. Therefore, there is no known method in the prior art suitable for high-volume production with a high output per unit time. Known manufacturing methods are to apply, such as by pasting, a film provided with riblets, or to machine riblets on a prefabricated component by laser machining, cutting machining or other subsequent surface modification processes. Summary of the Invention

[0007] The object of the present invention is based on: providing a fluid machine, in particular a turbine, preferably a fan, and its components, in which riblets for reducing wall friction can be realized at low cost. The riblets should be able to be applied to the fluid machine at low cost. In particular, the manufacturing of the corresponding components in the fluid machine should be simply and cost-effectively realized according to the relative flow velocity. In addition, the fluid machine according to the present invention should be distinguishable from market competitors.

[0008] In the case of a fluid machine according to the invention, the object is achieved by the features of claim 1. Accordingly, the relevant components guiding the fluid are made of plastic by means of a casting process, preferably an injection molding process. At least partially, flow ribs are constructed at or on and / or in the surface in the wetted and thus critical area of the component, and these flow ribs are simply integrated into the component by the casting process employed.

[0009] Advantageously, the flow ribs are constructed in areas of the respective component where the flow losses are higher, i.e., where the wall friction losses are greater and / or noise is generated. By this measure, the flow ribs serve to reduce the wall friction in the critical areas.

[0010] The flow ribs are constructed as elongate, preferably protruding structures that are substantially parallel to the overflow direction. They can be designed to be straight or curved. In addition, a plurality of flow ribs are arranged as a layout unit side by side, at least largely parallel to one another, depending on the specific component, and in necessary cases, there are a plurality of such layout units. When there are multiple rows of such side-by-side arranged flow ribs, they can be arranged equidistantly from one another.

[0011] It is also conceivable that the layout unit of the flow ribs depicts an arc or an involute curve. Otherwise, the layout unit of the flow ribs can be curved, where the individual flow ribs are arranged side by side. In necessary cases, two or more such layout units are advantageously constructed substantially parallel to one another.

[0012] It is also advantageous that all or at least almost all of the flow ribs are designed without interference with respect to the demolding direction of the mold. Further advantageously, there is a demolding slope of at least 1°, advantageously at least 3°.

[0013] In particular, the flow ribs can be constructed with side surfaces that are asymmetric with respect to the local normal on the imaginary base plane of the respective component, thereby facilitating the removal of the mold in a demolding direction that is specifically adapted to or required by the geometry of the component.

[0014] The corresponding component together with the flow ribs can be demolded from the casting mold in one piece without interference, i.e., based on the specific shape of the flow ribs.

[0015] In addition, it is conceivable that at least the area of the flow ribs is made of a preferably fiber-reinforced thermoplastic. This is advantageous for stability. Wear is reduced.

[0016] In terms of the method according to the present invention, the object of the type described at the beginning is achieved by the features of dependent claim 11, wherein the component guiding the flowing medium is at least partially equipped with flow ribs. Here, casting technology manufacturing is also an essential element, especially manufacturing the component by injection molding technology with the aid of a molding die. The concave profile of the flow rib is machined into the die. In view of the association between the method according to the present invention and the fluid machine according to the present invention, the relevant features are also incorporated into the method according to the present invention.

[0017] Advantageously, before machining the flow rib hub, the surface of the die into which the concave profile of the flow rib is machined is surface-treated to obtain a small roughness, specifically a roughness of less than 10 μm, preferably less than 4 μm. The surface can in particular be ground or honed.

[0018] It is also conceivable to machine the flow rib profile into the die in a subsequent process, especially into a die that has already been put into production operation. Thus, subsequent processing of the existing die in terms of flow ribs can be carried out.

[0019] Advantageously, the die is designed such that during manufacturing, an elevated die wall temperature is set in the region provided with flow ribs, for example, at least 5 Kelvin higher than other regions of the die surface. For example, this can be achieved by an independent cooling circuit with an increased initial flow temperature, or by other targeted measures involving the die cooling system. Thereby, a better molding effect of the flow ribs is achieved because the light plastic material can flow into the small-scale concave depths forming the flow ribs, otherwise there is a risk that these concave depths are not filled with the plastic material.

[0020] The flow ribs are designed in cross-section to ensure the effect of reducing wall friction, while the stability of the flow ribs on the component and the durability of the die against erosion or other wear phenomena are also relatively high. In particular, it has non-interfering demolding properties. Description of the Drawings

[0021] There are various possibilities for usefully designing and improving the teachings of the present invention. For this purpose, on the one hand, reference can be made to the dependent claims of claim 1 and, in terms of the method, to the dependent claims of claim 11, and on the other hand, reference can be made to the following illustration of a preferred embodiment of the fan according to the present invention by means of the drawings. In combination with the illustration of the preferred embodiment of the present invention by means of the drawings, generally preferred design solutions and improvement solutions of the teachings are also illustrated. In the drawings:

[0022] Figure 1 A perspective view of the impeller of an axial fan as seen from the flow-in side is shown, wherein the extension of the flow ribs on the air guiding surface is schematically shown;

[0023] Figure 2 schematically shows a cross-sectional view on a plane that is locally substantially perpendicular to the air guiding surface or its base surface and substantially perpendicular to the longitudinal extension of the flow ribs, and partial detailed views of the flow ribs on the air guiding surface of a component of a fluid machine in the prior art and a related forming die;

[0024] Figure 3 Shows a view similar to Figure 2, in which an improved flow rib geometry is configured according to the present invention for interference-free demolding;

[0025] Figure 4 Shows a plan view of the impeller of a radial flow fan as viewed from the flow-in side, in which the extension of the flow ribs on the air guiding surface is schematically shown;

[0026] Figure 5 Shows a plan view of the impeller of a radial flow fan as viewed from the flow-out side, in which the extension of the flow ribs on the air guiding surface is schematically shown;

[0027] Figure 6 Shows a perspective view of the housing of an axial flow fan as viewed from the flow-in side, in which the extension of the flow ribs on the air guiding surface is schematically shown. Detailed Description

[0028] Figure 1 Shows a perspective view of the impeller 19 of an axial flow fan as viewed from the flow-in side. The impeller 19 is a rotating component of a fan (not fully shown), i.e., a fluid machine and especially a vortex machine, and is driven by a motor (the impeller is fastened to the motor) in the assembled fan in order to convey a flowing medium. The impeller mainly includes a hub ring 21 and blades 22 fastened thereto. The impeller 19 is a flow-around component 1 of a fluid machine, especially a vortex machine and especially a fan, which has an air guiding surface 13 especially on the surfaces of the blades 22 on the suction side and the pressure side, but also on the hub ring 21.

[0029] During operation, wall shear stresses are generated by the relative velocity of the conveyed medium relative to the flow-around surface 13, and these wall shear stresses cause the drive power to increase and / or the conveyed volume flow to decrease. Therefore, a reduction in the wall shear stress at comparable operating points and comparable relative flow velocities will result in a reduction in the drive power and / or an increase in the conveyed volume flow and thus an increase in efficiency. Noise generation can also be reduced by reducing the wall shear stress.

[0030] With reference to Figure 2 and Figure 3 describe the cross-sectional shape of the flow ribs. In accordance with Figure 1In the impeller 19 of the fluid machine, flow ribs 14 are now formed on the gas-guiding surface 13 of the blade 22. The longitudinal extension of some of the flow ribs 14 is schematically shown here. In fact, a large number of parallel flow ribs 14 extending side by side at a small distance are formed. For the sake of clarity, only the extension of a smaller number of flow ribs 14 is outlined here. The flow ribs 14 extend substantially parallel to the relative flow on the flow-around surface 13 of the blade 22 from the oncoming flow edge 27 to the outflow edge 28. It is also conceivable that the flow ribs 14 extend only on a part of the blade 22 in their length, or only cover a part of the blade 22, for example, in areas with particularly higher flow losses or noise generation due to wall shear stress. It is also conceivable that flow ribs are formed on the flow-around surface 13 of the hub ring 21, but this is not provided here.

[0031] In order to economically manufacture the impeller 19 of the component 1 of the fluid machine, the component 1, 19 including the flow ribs 14 is manufactured in one piece by a casting process, advantageously by an injection molding process according to the present invention. Thereby, mass production can be achieved. Therefore, the concave profile of the flow ribs 14 is machined in the corresponding forming surface of the casting mold in a suitable manner (see FIGS. 2 and Figure 3 description). Figure 1 The impeller 19 in is manufactured using a mold that particularly includes two main forming parts.

[0032] When the component is demolded, one of the forming parts moves substantially to the left away from the component 1 along the demolding direction 12. This forming part is mainly used to form the impeller surface facing the oncoming flow side that is visible in the view. The other forming part of the casting mold moves along another demolding direction 12a, substantially to the right away from the component 1 during the demolding process. This other forming part is mainly used to form the impeller surface facing the outflow side that is not visible in the view. Since the component 1 has a complex geometry with three-dimensional twisted blades 22, these demolding directions are largely predetermined by this basic geometry.

[0033] In such a component, the demolding direction cannot or can only be very difficultly adjusted according to the interference that may be caused by the flow ribs 14, and it is costly. In particular, the demolding directions 12, 12a are usually not parallel to the local wall normal direction of the flow-around surface 13, as is the case with the oncoming flow side and the outflow side of the impeller 22 here. Therefore, such a component 1 could not be formed in one casting before. Although in the prior art, the flow ribs can be realized by applying them to the component with a special film with flow ribs or by laser processing the component. However, these techniques cannot achieve short manufacturing times or low-cost manufacturing, nor can they achieve mass manufacturing.

[0034] To illustrate the demolding problem of the flow ribs integrated into the casting, FIG. 2 shows, in a sectional view on a plane that is locally approximately perpendicular to the air guiding surface 13a or its base surface 23a and approximately perpendicular to the longitudinal extension of the flow rib 14a, the flow rib 14a on the air guiding surface 13a of the component 1a of the prior art fluid machine and the associated molding die part 17a. The demolding direction 12 of the die part 17a relative to the component 1a, i.e., the air guiding component 1a, is marked in the figure. This demolding direction 12 can be regarded as the projection on the drawing plane, and the actual demolding direction may also have a component perpendicular to the drawing plane in three dimensions.

[0035] According to the prior art, the flow ribs 14a are each configured to be approximately symmetric about the imaginary local normal of the air guiding surface 13a or its base surface 24a when observed in cross-section. This base surface 24a corresponds to the contour of the imaginary air guiding surface 13a without flow ribs. The flow ribs 14a each have a lateral spacing (measured transversely to their longitudinal extension direction), i.e., a pitch, relative to the adjacent flow ribs 14a and a height above the base surface at the center of their cross-section. Advantageously, the height above the base surface is 15% - 70% of the pitch. In particular, each flow rib 14a has two side surfaces 18a that are not parallel to each other but form a wedge angle relative to each other, and the wedge angle is advantageously 10° - 50°.

[0036] In the prior art shown, interference occurs on the side surface 18a (the upper side surface 18a in the figure) of the flow rib 14a, as can be clearly identified by the hatching extending parallel to the demolding direction 12 pre-given by the component in the die part 17a. This is because the demolding direction 12 pre-given by the component 1a significantly deviates from the local wall normal direction of the flow surface 13a. This is common in complex three-dimensional streamlined components of fluid machines, such as axial or radial impellers, inlet nozzles, casings, or outlet guide devices. If demolding is forced in the demolding direction 12 shown here, the flow rib 14a will be damaged during the demolding process. Because for the good hydrodynamic function of the flow rib 14a, it is crucial that the side surface 18a and the base surface area 23 of the flow rib 14a are well-formed, especially to achieve the ratio of the height of the flow rib 14a to the pitch between the adjacent flow ribs 14a of 15% - 70%.

[0037] Figure 3 An embodiment of the flow surface 13 provided with flow ribs 14 of the component 1 of the fluid machine is shown in a view similar to FIG. 2, and this embodiment is adapted to the manufacturing method or the demolding process according to the present invention. Figure 3The component 1 of the fluid machine, the flow-around component 1 with flow ribs 14 on the air-guiding surface 13, and the associated molding die part 17 are shown in a sectional view on a plane that is locally approximately perpendicular to the air-guiding surface 13 or its base surface 23 and approximately perpendicular to the longitudinal extension of the flow rib 14a by a local detail schematic diagram. The demolding direction 12 of the die part 17 relative to the component 1, i.e., the air-guiding component 1, is marked in the figure. This demolding direction 12 can be regarded as the projection on the drawing plane, and the actual demolding direction may also have a component perpendicular to the drawing plane in three dimensions.

[0038] For interference-free demolding, the flow rib geometry is improved compared to the prior art shown in Figure 2, but it basically has the function of reducing wall friction during the operation of the fluid machine. The flow rib 14, especially its cross-section, is now improvedly constructed considering the demolding direction 12 pre-given by the component 1. Therefore, the flow rib 14 is constructed such that, for example, in the cross-section as Figure 3 shown, it is not symmetric about the imaginary local normal of the air-guiding surface 13 or its base surface 23. The two side surfaces 18 of the corresponding flow rib 14 are accordingly no longer symmetric about the imaginary local normal of the air-guiding surface 13 or its base surface 23. The two outer angles of the two side surfaces 18 of a flow rib 14 relative to the base surface 23 are significantly different from each other in the region where the demolding direction 12 significantly deviates from the imaginary local normal of the base surface 23 of the air-guiding surface 13, for example, deviates by more than 25°, for example, the difference > 10°. The molding die part 17 has the concave profile of the component 1 provided with the flow rib, i.e., the flow-around component 1, whereby the above structural features of the flow rib 14 are synchronously reflected on the die part 17.

[0039] The profile of the side surface 18 in the cross-section is adapted to the demolding direction 12 as follows, i.e., the flow rib 14 can be demolded basically without interference along the demolding direction 12, and advantageously also as Figure 3 shown, the demolding slope relative to the demolding direction 12 is at least 1°, advantageously 3°. The interference-free demolding property can be well verified by the hatching lines of the sectional plane of the die part 17 in Figure 3 , which is designed to be parallel to the (projected) demolding direction 12. In this embodiment, the flow rib 14 is not damaged or destroyed during the demolding process.

[0040] However, in order to achieve the function of reducing the wall shear stress, the main structural features of the flow ribs 14 have been taken into account. The flow ribs 14 have a lateral spacing (measured transversely to their longitudinal extension direction), i.e., a pitch, and a height above the base surface, respectively measured at the center of their cross-section relative to adjacent flow ribs 14. Advantageously, the height above the base surface is 15%-70% of the pitch. In particular, the flow ribs 14 each have two side surfaces 18 that are not parallel to each other but have a wedge angle relative to each other, and the wedge angle is advantageously 10° to 50°. In the present embodiment, upper end surfaces 24 are constructed in the flow ribs 14, which are beneficial to the stability and durability of the flow ribs 14. Advantageously, the width of the end surface 24 of the flow rib 14 is in the range of approximately 30%-200% of the height of the relevant flow rib 14 as observed in the cross-section. Embodiments without the end surface 24 can also be considered, for example, the flow ribs or their side surfaces transition into each other at an acute angle or with a rounded corner at their outer ends.

[0041] In the present embodiment, a sharp outer edge 20 is designed at the transition between the side surface 18 and the end surface 24. Here, it can also be advantageously considered that in other embodiments, the outer edge 20 can be rounded with a small transition radius.

[0042] Also in the present embodiment, a sharp inner edge 29 is designed at the transition between the side surface 18 and the base surface 23. Here, it can also be advantageously considered that in other embodiments, the inner edge 29 can be rounded with a small transition radius. By rounding, the stability of the component 1 or the flow ribs 14 thereon and the forming die member 17 is correspondingly improved, and the wear during the manufacture of the fluid machine with the air guiding component 1 having the flow ribs 14 and during its operation is reduced. The radius of curvature in the possible rounding of the outer edge 20 or the inner edge 19 is advantageously in the range of at most 30% of the height of the corresponding flow rib 14.

[0043] Particularly advantageously, the region of the inner edge 29 can be rounded imitating the trunk of a tree with a variable radius of curvature. Here, the radius of curvature at the transition to the base surface 23 is smaller than the radius of curvature at the transition to the side surface 18, advantageously at least 1.4 times smaller.

[0044] In the shown embodiment, the flow-around component 1 together with the flow ribs 14 can be demolded from the casting mold in one piece without interference. The flow ribs 14 are not damaged or destroyed during the demolding process. The component 1 can be mass-produced at low cost. In order to fully fill the flow rib profile of the die member 17 with the casting material, appropriate parameters and materials need to be selected when injecting with a thermoplastic plastic (which may also be provided with reinforcing fibers). Advantageously, a material with good fluidity and a sufficiently heated die surface are used in the region of the turbulence ribs 14. The holding time should be longer and the holding pressure should be higher. In particular, the die region forming the flow ribs is advantageously at least partially at a temperature increase of at least 10 K higher than other die regions where the flow ribs are not locally formed during the injection molding process.

[0045] Figure 3 The demoulding direction 12 shown is to be understood as a projection into the drawing plane. The actual three-dimensional demoulding direction can therefore also have a component perpendicular to the drawing plane. However, this component extending perpendicular to the drawing plane will be parallel to the longitudinal extension direction of the flow rib 14. As far as possible interference is concerned, the directional component of the demoulding direction extending perpendicular to the drawing plane has no substantial effect. Special measures on the flow rib 14 to ensure interference-free demoulding, in particular the asymmetrical shaping of the two side surfaces 18 of the flow rib 14 relative to each other, are necessary in particular in the following situations or areas of the flow surface 13 of the flow component 1, namely, Figure 3 When the angle between the demoulding direction 12 projected onto the drawing plane and the local wall normal of the base surface 23 is greater than 20°, especially greater than 45°, that is, the projected demoulding direction is not parallel to the local wall normal of the base surface 23. This generally occurs in most areas of the flow guide surface 13 of the flow-around component 1 provided with flow ribs 14, for example, more than 25% or 50% of the flow-around surface.

[0046] Figure 4 A plan view of an impeller 19 of a radial fan is shown from the upstream side, wherein the extension of the flow ribs 14 on the air guide surface 13 is schematically shown. The impeller 19 in the embodiment has a radial structure and in particular comprises a hub ring 21 (also called a base plate in a radial impeller), a top ring 16 and blades 22 extending therebetween.

[0047] The impeller 19 rotates about the central axis of symmetry during radial fan operation and simultaneously conveys the conveying medium in the conveying direction approximately from the inflow edge 27 of the blade 22 to the outflow edge 28 (see Figure 5 ). The conveying medium enters the impeller 19 through the central opening of the top ring 16 and is conveyed radially outward. The impeller 19 is in any case a flow-around component 1 of a fluid machine (here a fan). The flow ribs 14 on the flow-around surface 13 are used to reduce the wall shear stress to reduce the driving torque and / or increase the conveying volume flow and thereby improve the efficiency / performance coefficient. The noise generation during operation can also be reduced thereby. In this embodiment, the flow ribs 14 are schematically installed on multiple guide surfaces 13 as an example.

[0048] like Figure 1 1, only a few of the flow ribs 14 are shown, in practice a large number of flow ribs 14 extend side by side on the flow surface 13 at small intervals. Here, the flow surface 13 is obtained by way of example on the visible outer side of the top ring 16, where the relative flow velocity extends approximately in the circumferential direction, and therefore the flow ribs 14 extend in the circumferential direction. The relative demolding direction of the mold parts for demolding the outer side of the top ring 16 is usually approximately perpendicular to the drawing plane. Due to the three-dimensional contour of the top ring 16, the demolding direction is not perpendicular to the base surface of the outer side of the top ring 16 at all locations, so that the flow ribs 14 can be arranged according to the invention according to the invention as necessary. Figure 4The local design is carried out in the manner shown to avoid interference. On the Figure 4 visible inner side surface of the hub ring 21 (which is also the flow-around surface 13), flow ribs 14 are also arranged, which point in the direction of the expected relative overflow at this position.

[0049] The hub ring 21, or rather its base surface, is usually not flat and not parallel to the drawing plane either, but is designed as a conical rotating body, for example. Therefore, here, the expected demolding direction of the molding die part is usually neither perpendicular to the flow-around base surface nor parallel to the extension direction of the flow ribs 14. Therefore, it is necessary to adjust the geometry of the flow ribs 14 according to the Figure 4 description to avoid interference. The flow ribs 14 provided on the flow-around surface 13 of the blade 22 also follow exactly the same treatment principle.

[0050] It is not necessary to provide flow ribs 14 on all the gas-guiding surfaces 13 of the component 1. Depending on the influence of local wall friction, some gas-guiding surfaces 13 may be provided with flow ribs only partially or not at all. The design of the flow ribs 14 depends on the demolding direction of the die part relative to the flow-around surface 13 of the component 1 and the longitudinal orientation of the flow ribs 14 on site. If it is not necessary to modify the flow ribs 14 locally to achieve interference-free demolding, then this modification can naturally be omitted advantageously.

[0051] For the sake of completeness, it still needs to be mentioned here: It is also feasible to adopt a structure of an annular top ring for the impeller of the axial-flow fan, and this top ring connects the radially outer blade ends to each other circumferentially. It is also beneficial to arrange flow ribs on such a top ring.

[0052] Figure 5 And Figure 4 Similarly, a plan view of the impeller 19 of the flow-around component 1 as a radial-flow fan is shown as viewed from the outflow side. The rear edge 28 of the blade 22 can be seen, which is roughly located in the area where the air flow discharges during the operation of the fan. Flow ribs 14 are arranged on the visible outer side surface of the hub ring 21, that is, on the flow-around surface 13. The hub ring 21, or rather its base surface, is advantageously not flat. The flow ribs 14 extend roughly circumferentially on the outer side surface of the hub ring 21. The flow ribs 14 are designed according to the Figure 4 design to avoid interference during the demolding process (the relative demolding direction of the die part for the flow-around surface 13 points towards the observer roughly perpendicular to the drawing plane, and the flow-around surface is constituted by the outer side surface of the hub ring 21).

[0053] The impeller 19 is a component that rotates and transmits power during operation. The reduction of the circumferential wall shear stress of the impeller 19 leads to the reduction of the loss torque. In a fluid machine where power is transmitted from the impeller to the fluid, the required driving torque can be reduced accordingly, thereby reducing the required driving power. In a fluid machine where power is transmitted from the fluid to the impeller, the effective driving torque transmitted to the impeller and the transmitted driving power can be increased by reducing the loss torque.

[0054] Figure 6 The housing 2 of an axial fan is viewed from the flow side in a perspective view, wherein the extension of the flow ribs on the air guide surface 13 is schematically shown. The housing is a fixed, non-driven component, and the wall shear stress has no effect on the drive torque or drive power. However, reducing the wall shear stress still helps to increase the conveying volume flow, thereby improving efficiency, and also improves the acoustic properties. In any case, the housing 2 is a flow-around component 1 of the fluid machine.

[0055] The housing comprises an outer ring 4, which in particular comprises an integrated inlet nozzle 9, a running area for an impeller (not shown) and a diffusion area, in which an integrated outlet guide device 15 is arranged. The outlet guide device 15 comprises an outer bracing element 3a, an annular intermediate ring 5, an inner guide element 3 and a hub ring 10. The motor (not shown) and the impeller of the fan can be fastened to the hub ring, and the guide device 15 connects the outer ring 4 of the housing 2 with the hub ring 10, thereby fixing the motor and the impeller relative to the outer ring 4, on which the housing 2 can be fastened to the upper system.

[0056] In the assembled blower (not shown in full), the impeller runs inside the housing 2 or its outer ring 4 on the flow-incoming side of the guide device 15 and is driven by a motor to convey the conveying medium approximately from left to right in the conveying direction, which enters the housing 2 at the inlet nozzle 9 and exits the housing 2 again after passing through the guide device 15. In any case, there are a plurality of flow surfaces 13 on the housing 2, as shown. In particular, the inner side of the inlet nozzle 9, the surface of the bracing element 3a, the surface of the guide element 3, the surface of the intermediate ring 5 and the surface of the hub ring 10 are all flow surfaces. Wall friction and thus flow losses can be minimized everywhere by installing flow ribs 14 with suitable geometry, which helps to increase efficiency and reduce noise emissions.

[0057] Flow rib 14 according to Figure 4 The design shown in the figure and its cross section are adjusted when necessary to ensure that there is no interference in demoulding. Figure 6 The flow ribs 14 shown by way of example are shown in a few examples, which are advantageously selected to always be approximately parallel to the local relative flow velocity with respect to the flow surface 13. In the example of the flow components 1, 2 (similar to Figure 1 In the component shown in the figure, the relative demoulding direction of the molding mold parts is mainly parallel to the central axis of the component.

[0058] For the sake of completeness, it should be mentioned that the flow ribs 14 on the inner contour of the inlet nozzle 9 have no circumferential component in their longitudinal extension, which corresponds to the intended overflow direction of the corresponding flow surface 13 there. It is therefore possible and advantageous to achieve a flow rib cross section that is symmetrical with respect to the local wall normal without interfering with the demoulding of the housing 2 in a demoulding direction parallel to the housing axis. This is because according toFigure 4 In a sectional plane that is perpendicular to the longitudinal extension direction of the flow rib 14 and perpendicular to the local base plane of the flow guiding surface 13 there, no interference occurs between the (projected) demolding direction and the flow rib 14.

[0059] Advantageously, the component 1, i.e., the flow-around component 1, has a flow rib cross-section that is symmetric with respect to the local wall normal when observed in cross-section, provided that local non-interference can be achieved while maintaining the effective flow rib cross-section based on the demolding direction. In regions where non-interference demolding needs to be ensured due to the demolding direction, it has an asymmetric flow rib cross-section.

[0060] There are numerous other conceivable flow-around components 1 of fluid machines, and these flow-around components can advantageously be provided with flow ribs in the manner described. In particular, it should be noted that for the spiral housing of a radial or diagonal flow fan, flow ribs having the cross-sectional geometry described can be beneficially arranged substantially circumferentially along the installed impeller on its flow-guiding inner contour. Through the manufacturing method of integrating the flow ribs into the component in the casting process, the corresponding component can be mass-produced economically and efficiently.

[0061] Regarding further advantageous improvement solutions of the fluid machine according to the present invention, to avoid repetition, reference can be made to the general part of the specification and the appended claims.

[0062] Finally, it should be particularly noted that the foregoing embodiments of the fluid machine according to the present invention are only used to illustrate the claimed claims, but this does not limit these embodiments.

[0063] List of reference numerals

[0064] 1, 1a Flow-around component

[0065] 2 Housing

[0066] 3 Flow guiding element, flow guiding vane

[0067] 3a Diagonal bracing element

[0068] 4 Outer ring of the housing

[0069] 5 Intermediate ring of the flow guiding device

[0070] 6 Outer flow-through region

[0071] 7 Inner flow-through region

[0072] 8 Accommodation region inside the hub ring

[0073] 9 Inlet nozzle

[0074] 10 Hub ring of the flow guiding device

[0075] 11 Inner contour of the housing

[0076] 12. Demolding direction of the die parts 12 and 12a relative to the component

[0077] 13. Air guiding surfaces 13 and 13a, flow around surfaces

[0078] 14. Flow ribs 14 and 14a

[0079] 15. Flow guiding element

[0080] 16. Annular top ring of the impeller

[0081] 17. Molding die parts 17 and 17a

[0082] 18. Side surfaces of the flow ribs 18 and 18a

[0083] 19. Impeller

[0084] 20. Outer edges of the flow ribs 20 and 20a

[0085] 21. Hub ring of the impeller

[0086] 22. Blades of the impeller

[0087] 23. Base surface of the air guiding surface

[0088] 24. Top surfaces of the flow ribs 24 and 24a

[0089] 25. Outlet side edge of the housing

[0090] 26. Axis of the fan

[0091] 27. Oncoming flow edge

[0092] 28. Outlet edge

[0093] 29. Inner edge at the transition part between the flow rib and the base surface

Claims

1. A fluid machine, in particular a turbine, preferably a fan, having at least one component for guiding a flowing medium, such as an impeller blade, an outlet guide vane, a hub ring, a crown ring, a base plate, a nozzle or a housing part / component, wherein the component for guiding the flowing medium is made of plastic by a casting process, preferably an injection process, and in this case at least locally structured with flow ribs at and / or on and / or in the surface of the component in the flow-around area.

2. The fluid machine according to claim 1, characterized in that, The flow ribs are structured in areas of the respective component with high flow losses and / or where noise is generated.

3. The fluid machine according to claim 1 or 2, characterized in that, The flow ribs are structured as elongated, preferably protruding structures running substantially parallel to the overflow direction.

4. The fluid machine according to any one of claims 1 to 3, characterized in that The flow ribs are designed to be straight or curved.

5. The fluid machine according to any one of claims 1 to 4, characterized in that A plurality of flow ribs are linearly arranged side by side as an arrangement unit according to the specific component, and if necessary, at least two such flow rib arrangement units are arranged at least largely parallel to each other, preferably equidistantly from each other.

6. The fluid machine according to any one of claims 1 to 5, characterized in that, The flow ribs are arranged side by side as an arrangement unit in an arc shape, an involute curve shape or other curved forms according to the specific component, and if necessary, two such flow rib arrangement units are arranged parallel to each other.

7. The fluid machine according to any one of claims 1 to 6, characterized in that, The flow ribs are designed to be free of interference with respect to the demolding direction of the mold for all or at least almost all, and advantageously have a demolding taper of at least 1°, advantageously at least 3°.

8. The fluid machine according to any one of claims 1 to 7, characterized in that, The flow ribs are in particular locally structured in cross-section with sides that are asymmetric with respect to the local normal on the surface of the component, and the local normal is not parallel to the demolding direction.

9. The fluid machine according to any one of claims 1 to 8, characterized in that The component together with the flow ribs can be demolded from the casting mold in one piece without interference.

10. The fluid machine according to any one of claims 1 to 9, characterized in that, At least the area of the flow ribs is made of a fiber-reinforced thermoplastic.

11. A method for manufacturing a component for guiding a flowing medium in a fluid machine according to one of claims 1 to 10, wherein, The component for guiding the flowing medium is at least locally equipped with flow ribs, characterized by a casting technology manufacturing, in particular by using a forming mold by injection molding technology, wherein the concave profile of the flow ribs is machined into the mold.

12. The method according to claim 11, wherein The surface of the mold into which the concave profile of the flow ribs is machined is surface-treated, in particular ground or honed, to obtain a small roughness, i.e., a roughness of less than 10 μm, preferably less than 4 μm.

13. The method according to claim 11 or 12, characterized in that, The profile of the flow ribs is machined into the mold in a subsequent process, in particular into a mold that has already been put into production operation.

14. The method according to any one of claims 11 to 13, characterized in that, During production operation, the temperature of at least some areas of the formed flow ribs in the injection mold is at least 10 Kelvin higher than other areas without formed flow ribs.

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