Impeller for hydrogen circulating pump

Abstract

The present application provides an impeller for a hydrogen circulation pump, the impeller having opposite first and second sides, the first side comprising: a first end of a hub portion located in the center of the first side; and a flow channel portion extending in a radial direction from the first end and having a plurality of flow channels separated by separators, the second side including: a second end of the hub portion centrally located opposite the first end; a bottom surface recessed from the second end in the axial direction; the drum surface is located on the outermost portion of the second side in the radial direction, the second side further comprises a transition surface located between the bottom surface and the drum surface, and the transition surface is a smooth transition curved surface. According to the impeller, the transition surface which is formed into the smooth transition curved surface is arranged between the bottom surface and the drum surface, so that the overall rigidity of the impeller is improved, and the deformation of the impeller in the axial direction during high-speed rotation is reduced. This allows the impeller to be arranged closer to the housing of the hydrogen circulation pump, increasing the efficiency of the hydrogen circulation pump, and increasing reliability.

Description

Technical Field

[0001] The utility model relates to an impeller, in particular to an impeller used for a hydrogen circulation pump. Background Art

[0002] Fuel cell systems that generate electricity by electrochemical reactions between fuel and oxidant are increasingly being used to provide electricity. Proton exchange membrane fuel cell (PEMFC) systems are a widely used fuel cell system that usually uses hydrogen as fuel. During the operation of PEMFC, hydrogen as fuel is supplied to the anode of the PEMFC stack and adsorbed by the catalyst to be ionized into hydrogen ions and electrons. The hydrogen ions are transferred to the cathode via the proton exchange membrane, and the electrons flow to the cathode through the external circuit to form an electric current to the outside.

[0003] In order to enable PEMFC to provide stable output power, it is common practice to supply excess hydrogen on the anode side of the fuel cell system to cope with possible fluctuations in hydrogen demand. Therefore, a hydrogen circulation pump is also provided in the fuel cell system to circulate hydrogen at the anode end of the fuel cell. Its function is to pressurize and transport the unreacted hydrogen at the outlet of the stack to the inlet of the stack for recovery, so as to fully reuse the hydrogen. Usually, the hydrogen circulation pump has a motor and an impeller, and the motor is connected to the impeller through the shaft of the motor, so that the rotation of the motor shaft drives the impeller to rotate, thereby circulating the hydrogen.

[0004] However, in the existing hydrogen circulation pump, due to the insufficient rigidity of the impeller, the impeller may deform in the axial direction of the motor shaft when it is driven by the motor to rotate at high speed or work under high load conditions. When such deformation exceeds the gap between the impeller and the housing of the hydrogen circulation pump, the impeller will scratch the housing, and in more serious cases, it may even cause damage to the impeller, thereby causing the hydrogen circulation pump to fail. Although setting a larger gap can solve this defect, such a setting method increases the leakage of hydrogen between the impeller and the housing of the hydrogen circulation pump, and the efficiency of the hydrogen circulation pump will be significantly reduced.

[0005] Therefore, it is necessary to improve the existing impeller structure design to increase the rigidity of the impeller so as to adapt to the existing or smaller gap width to improve the efficiency of the hydrogen circulation pump. Utility Model Content

[0006] The purpose of the present application is to provide an impeller for a hydrogen circulation pump to solve at least one problem existing in the prior art.

[0007] According to one aspect of the present application, an impeller for a hydrogen circulation pump is provided, the impeller having a first side and a second side in opposite directions, the first side comprising: a first end of a hub portion, which is located at the center of the first side; and a flow channel portion, which extends from the first end in a radial direction and has a plurality of flow channels separated by a partition, the second side comprising: a second end of the hub portion, which is located at the center of the second side and opposite to the first end; a bottom surface, which is recessed from the second end of the hub portion in an axial direction; and a drum surface, which is located at the outermost portion of the second side in a radial direction, wherein the second side also comprises a transition surface between the bottom surface and the drum surface, and the transition surface is a smooth transition curved surface.

[0008] According to an embodiment of the present application, in a cross section of the rotating shaft including the impeller, the contour of the smooth transition curved surface is an arc, and the central angle of the arc is less than ninety degrees.

[0009] According to an embodiment of the present application, the central angle is thirty degrees.

[0010] According to an embodiment of the present application, in the axial direction of the impeller, the axial top end of the drum surface is flush with the second end of the hub portion.

[0011] According to an embodiment of the present application, in the axial direction, the distance between the bottom surface and the axial top end of the drum surface is less than four elevenths of the maximum axial thickness of the impeller.

[0012] According to an embodiment of the present application, on the first side of the impeller, the first end includes a mounting portion and a recessed portion formed on the radially outer side of the mounting portion, and the recessed portion is located between the mounting portion and the flow channel portion.

[0013] According to an embodiment of the present application, the concave portion is formed by a smooth transition curved surface.

[0014] According to an embodiment of the present application, in the radial direction, a radial length of a portion of the recess corresponding to the bottom surface is less than one quarter of the diameter of the impeller.

[0015] According to an embodiment of the present application, in the radial direction, the minimum axial thickness of a portion of the recess corresponding to the bottom surface is greater than one third of the maximum axial thickness of the impeller.

[0016] According to an embodiment of the present application, the radial length of the flow channel portion is greater than one third of the diameter of the impeller.

[0017] By providing a transition surface formed as a smooth transition curved surface between the bottom surface and the drum surface on the second side of the impeller, the thickness of the impeller at the transition surface is increased. With this structure, the rigidity of the impeller as a whole is increased, so that the deformation of the impeller in the axial direction when the impeller rotates at high speed is reduced, thereby allowing the impeller to be arranged closer to the housing of the hydrogen circulation pump. This improves the efficiency of the hydrogen circulation pump and increases the reliability of the hydrogen circulation pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the embodiments described below are only used to explain the present application, rather than to limit the scope of the present application. In the accompanying drawings:

[0019] Figure 1 schematically shows a cross-sectional view of a hydrogen circulation pump in which an impeller is installed;

[0020] Figure 2 A cross-sectional view showing an impeller for a hydrogen circulation pump according to an exemplary embodiment of the present application;

[0021] Figure 3 A perspective view showing a first side of an impeller for a hydrogen circulation pump according to an exemplary embodiment of the present application;

[0022] Figure 4 A perspective view showing a second side of an impeller for a hydrogen circulation pump according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present application are described in detail below in conjunction with examples. In the embodiments of the present application, the present application is described by taking the impeller for a hydrogen circulation pump as an example. However, it should be understood by those skilled in the art that these exemplary embodiments do not mean that any limitation is formed on the present application. In addition, the features in the embodiments of the present application can be combined with each other in the absence of conflict. In different drawings, the same parts are represented by the same reference numerals, and for the sake of brevity, other parts are omitted, but this does not mean that the impeller of the present application cannot include other parts. It should be understood that the size, proportional relationship and number of parts of the various parts in the drawings are not used as limitations on the present application.

[0024] It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of this application.

[0025] Figure 1 A cross-sectional view of a hydrogen circulation pump in which an impeller 100 is installed is schematically shown.

[0026] According to an exemplary embodiment of the present application, an impeller 100 for a hydrogen circulation pump is provided. As described above, the hydrogen circulation pump is generally used in the fuel subsystem of a PEMFC to redirect unreacted (excess) hydrogen to the anode of the fuel cell stack of the fuel cell system, thereby increasing the use efficiency of hydrogen. The impeller 100 includes a hub portion 101, which is located at the center of the impeller 100 and has a through hole 102 (see FIG. 1 ) that penetrates the impeller 100. Figure 2 ). The shaft 310 of the motor 300 is configured to be inserted into the through hole 210 and connected to the hub portion 101, so as to drive the hub portion 101 and the entire impeller 100. The impeller 100 has a first side 110 and a second side 120 opposite to each other, wherein the second side 120 is installed to face the body 320 of the motor 300, and the first side 110 is correspondingly installed to face the direction away from the body 320 of the motor 300 (i.e., toward the flowing hydrogen). Figure 1 As shown, there is a gap between the end (outermost part) of the first side 110 in the radial direction and the housing 200, and the control of this gap is crucial to the efficiency of the hydrogen circulation pump, as described above. It should be noted that Figure 1 The purpose is only to show the arrangement of the components in the hydrogen circulation pump, but not to show that the components can only be arranged in the manner shown or designed in the shape shown, which is illustrative rather than restrictive. At the same time, since the impeller 100 is symmetrical, unless otherwise specified, the description of the elements on one side of the symmetry axis is also valid for the elements on the other side.

[0027] Figure 2 A cross-sectional view of an impeller 100 for a hydrogen circulation pump according to an exemplary embodiment of the present application is shown. Figure 3 A perspective view of a first side 110 of an impeller 100 for a hydrogen circulation pump according to an exemplary embodiment of the present application is shown.

[0028] like Figure 2 and Figure 3 As shown, the first side 110 includes a first end (front end) 111 of the hub portion 101 and a flow channel portion 112, wherein the first end 111 is located in the center of the entire first side 110, and the flow channel portion 112 extends from the first end 111 in the radial direction to all sides and has a plurality of flow channels 112a separated by partitions (the flow channels 112a are formed by the drum surface 123 and separated by the partitions, which will be described below in conjunction with Figure 4Explanation). For example, the partition may be a partition, but is not limited thereto. Opposite to the first side 110, at least two openings (not shown) are provided on the housing 200 of the hydrogen circulation pump, one of which is configured as a fluid inlet to direct excess hydrogen to the flow channel of the impeller driven to rotate by the motor and pressurized, and the other is configured as a fluid outlet, so that the pressurized hydrogen flows out from the fluid outlet. The hub portion 101 and the flow channel portion 112 may be of an integral design, for example, processed from one material, or molded in one step. When a metal material is used, it may be integrally molded using a mold, and when a material such as a resin is used, it may be made by injection molding, or it may be made by insert molding using both metal and resin materials. Alternatively, the hub portion 101 and the flow channel portion 112 may also be made into separate components, and then connected using means known in the prior art (such as welding, etc.).

[0029] Figure 4 A perspective view of a second side 120 of an impeller 100 for a hydrogen circulation pump according to an exemplary embodiment of the present application is shown.

[0030] like Figure 2 and Figure 4 As shown, the second side 120 includes the second end (rear end) 121 of the hub portion 101. Since the hub portion 101 is located at the center of the impeller 100, the second end 121 of the hub portion 101 is also located at the center of the second side 120, and the second end 121 is opposite to the first end 111 (the hub portion 101 penetrates the impeller 100, and thus has the first end 111 on the first side 110 and the second end 121 on the second side 120). The second side 120 also includes a bottom surface 122 and a drum surface 123. The bottom surface 122 is concave relative to the second end 121 of the hub portion 101 in the axial direction, and the drum surface 123 is located at the outermost portion of the second side 120 in the radial direction and forms the outer contour of the flow channel 112a (that is, the flow channel 112a is formed by the drum surface 123 bulging from the first side 110 to the second side 120 and separated by the partition). If the direction of the first side 110 of the impeller 100 is the front and the direction of the second side 120 is the rear in the axial direction as a reference, then the so-called bottom surface 122 is the part that is more forward relative to the second end 121 of the hub 101 and the drum surface 123 (that is, the bottom surface 122 is the most forward part of all parts of the second side 120). Preferably, the bottom surface 122 extends perpendicular to the axial direction, but is not limited thereto.

[0031] In addition, according to an exemplary embodiment of the present application, the second side 120 of the impeller 100 further includes a transition surface 124 between the bottom surface 122 and the drum surface 123, and the transition surface 124 is a smooth transition curved surface. The smooth transition curved surface means that the entire transition surface 124 is continuously differentiable, and its Jacobian determinant is not zero at the same time. In this way, on the second side 120, from the second end 121 of the hub portion 101 to the outermost portion of the second side 120, the second side 120 is a continuous curved surface as a whole, thereby avoiding stress concentration caused by the ridge line, thereby enhancing the reliability of the impeller 100. Moreover, the provision of a transition surface (smooth transition curved surface) between the bottom surface 122 and the drum surface 123 significantly increases the thickness of the impeller 100 in the axial direction compared with not providing the transition surface 124 (i.e., the bottom surface 122 is directly connected to the drum surface 123), thereby significantly enhancing the rigidity of the impeller 100. In this way, when the impeller 100 rotates at a high speed, the deformation of the impeller 100 in the axial direction can be reduced, so that the impeller 100 and the housing 200 of the hydrogen circulation pump can be arranged more compactly. By making the impeller adopt the impeller structure according to the present application, the impeller and the housing are arranged more closely, thereby improving the working efficiency of the hydrogen circulation pump.

[0032] According to an exemplary embodiment of the present application, in a cross section of the rotating shaft of the impeller 100, the profile of the smooth transition curved surface is an arc, and the central angle α corresponding to the arc is less than ninety degrees, that is, the sector corresponding to the arc (by Figure 2 In this way, the transition surface 124 can extend a sufficient length (surface area) in the radial direction on the second side 120, so that the impeller 100 can have an increased thickness over a sufficiently long distance in the radial direction, further improving the rigidity of the impeller 100, thereby improving the working efficiency of the hydrogen circulation pump. At the same time, the structure is also easy to manufacture, reducing the manufacturing cost.

[0033] As the thickness of the impeller 100 increases, the weight of the impeller 100 will also increase, so the force on the motor 300 driving the impeller 100 and the impeller 100 itself will also increase accordingly. This requires appropriate weight reduction of the impeller 100 to increase the service life of the impeller 100, the motor 300 and even the hydrogen circulation pump. Therefore, preferably, the central angle α is set to thirty degrees. In this way, the transition surface 124 will neither extend too long in the radial direction to significantly increase the weight of the impeller 100 (significantly reduce the service life of the hydrogen circulation pump), nor extend only a short distance to make the stiffness of the impeller 100 not significantly enhanced, thereby achieving a balance between the service life and working efficiency of the impeller 100.

[0034] According to an exemplary embodiment of the present application, in the axial direction of the impeller 100, the axial top end of the drum surface 123 is flush with the second end 121 of the hub portion 101, that is, there is no front-to-back relationship between the second end 121 and the axial top end of the drum surface 123 in the axial direction. With such a structural design, the structure of the impeller 100 can be more compact, which helps to reduce the axial force on the portion corresponding to the bottom surface 122, thereby reducing the axial deformation of the impeller 100 during rotation.

[0035] Based on the same reasons as above, more preferably, in the axial direction, the distance between the bottom surface 122 and the top end of the drum surface 123 is less than four elevenths of the maximum axial thickness of the impeller 100 .

[0036] In the embodiments described above, the first end 111 of the hub portion 101 may include a mounting portion 111a perpendicular to the axial direction (the mounting portion 111a is used to engage with the shaft of the motor 300) and a connecting portion (not shown), and the flow channel portion 112 extends from the connecting portion. In these embodiments, the connecting portion is located in front of the mounting portion 111a in the axial direction. However, in other embodiments, the first end 111 may also include a recessed portion 111b located in the radial direction outside and behind the mounting portion 111a in the axial direction (this can be understood as the connecting portion being cut off from some parts, thereby being recessed from the connecting portion located in front of the mounting portion 111a to form a recessed portion 111b located behind the mounting portion 111a). Similar to the aforementioned embodiment, although the provision of the recess 111b will reduce the thickness of the impeller 100 at the recess 111b (which means a reduction in the stiffness of the impeller 100), the thickness will still increase compared to the existing impeller, thereby being able to obtain improved stiffness compared to the existing impeller and greatly reducing the mass of the impeller, thereby extending the service life of the impeller.

[0037] Preferably, the thickness of the impeller 100 at the recess 111 b can be obtained by computer simulation.

[0038] Preferably, the recess 111b is located between the mounting portion 111a and the flow channel portion 112 of the first end 111, and the connecting portion is omitted. In such an embodiment, the recess 111b extends from the mounting portion 111a, and the flow channel portion 112 extends from the recess 111b, thereby forming the first side 110 of the impeller 100 together.

[0039] According to an exemplary embodiment of the present application, similar to the transition surface 124, the recess 111b is also formed by a smooth transition curved surface, for example, formed by an arc corresponding to a sector of a part of a circle. Similarly, this avoids stress concentration caused by the ridge line, thereby enhancing the reliability of the impeller 100. However, this is not restrictive, and the recess 111b may also not be formed by a smooth transition curved surface, for example, Figure 2As shown, there is a vertex at the connection between the mounting portion 111a and the recess 111b. In addition, embodiments of the recess 111b arranged in other shapes are also envisioned. In one embodiment, the recess 111b can be formed in a ring shape, which is perpendicular to the axial direction, that is, the straight line representing the recess 111b in the cross-sectional view is perpendicular to the axial direction. In another embodiment, the recess 111b can be formed as a part of a cone whose bottom surface is perpendicular to the axial direction, that is, the straight line representing the recess 111b in the cross-sectional view is not perpendicular to the axial direction, but is not limited thereto.

[0040] Typically, at least a portion of the recess 111b of the first side 110 of the impeller 100 is spatially corresponding (opposite) to the bottom surface 122 of the second side 120 of the impeller 100. However, such a corresponding arrangement reduces the thickness of the impeller 100 at the portion where the recess 111b corresponds to the bottom surface 122. For example, Figure 2 As shown, such a corresponding part can be the part 130 defined by the dotted line. It can be seen that, compared with the part 130, the axial thickness of the impeller parts on both sides of the part 130 in the radial direction is significantly increased, that is, the part 130 is a part of the impeller 100 with a thinner thickness. Therefore, it is necessary to limit the size of the part 130 so that the impeller 100 can still have sufficient rigidity. Therefore, according to another exemplary embodiment of the present application, in the radial direction, the radial length of the part 130 corresponding to the recess 111b and the bottom surface 122 is less than one-fourth of the diameter of the impeller 100. In this way, from the overall point of view, the proportion of the part of the impeller 100 with a thinner radial thickness will not exceed 20% of the total impeller 100. At the same time, the minimum axial thickness of the part 130 corresponding to the recess 111b and the bottom surface 122 is greater than one-third of the maximum axial thickness of the impeller 100, thereby ensuring sufficient thickness. The above restrictions together guarantee the rigidity of the impeller 100 , thereby ensuring that the impeller 100 does not generate excessive axial deformation when rotating at high speed.

[0041] In order to ensure that the working efficiency of the impeller 100 is sufficiently high, according to an exemplary embodiment of the present application, the axial length of the flow channel portion 112 is greater than one third of the diameter of the impeller. Since the portion corresponding to the flow channel portion 112 is a thicker portion of the impeller 100, providing a sufficiently large flow channel portion 112 can not only improve the working efficiency of the impeller 100, but also have a positive impact on its rigidity.

[0042] The above-mentioned embodiment of the present application provides an impeller for a hydrogen circulation pump. According to the technical solution of the present application, a transition surface formed as a smooth transition curved surface is provided between the bottom surface of the second side of the impeller and the drum surface, so that the thickness of the impeller at the transition surface is significantly increased, and its stress distribution is significantly improved, thereby improving both the rigidity of the impeller and the reliability of the impeller. In this way, when the impeller rotates at a high speed, the size of the axial deformation of the impeller in the axial direction is reduced, so that the impeller can be arranged closer to the housing of the hydrogen circulation pump, thereby improving the working efficiency of the hydrogen circulation pump.

[0043] The present application has been described in detail above in conjunction with specific embodiments. Obviously, the above description and the embodiments shown in the accompanying drawings should be understood as exemplary and do not constitute a limitation to the present application. For those skilled in the art, various modifications or changes can be made to the present application without departing from the spirit of the present application, and these modifications or changes do not depart from the scope of the present application.

Claims

1. An impeller (100) for a hydrogen circulation pump, the impeller (100) having a first side (110) and a second side (120) opposite to each other, in, The first side (110) includes: a first end (111) of the hub portion (101), which is located at the center of the first side (110); and a flow channel portion (112), which extends from the first end (111) in a radial direction and has a plurality of flow channels (112a) separated by a partition. The second side (120) includes: a second end (121) of the hub portion (101), which is located at the center of the second side (120) and opposite to the first end (111); a bottom surface (122), which is concave relative to the second end (121) of the hub portion (101) in the axial direction; and a drum surface (123), which is located at the outermost portion of the second side (120) in the radial direction. It is characterized in that the second side (120) further comprises a transition surface (124) located between the bottom surface (122) and the drum surface (123), and the transition surface (124) is a smooth transition curved surface.

2. The impeller (100) for a hydrogen circulation pump according to claim 1, characterized in that: In a cross section including the rotating shaft of the impeller (100), the profile of the smooth transition curved surface is a circular arc, and a center angle (α) corresponding to the circular arc is less than ninety degrees.

3. The impeller (100) for a hydrogen circulation pump according to claim 2, characterized in that: The central angle (α) is thirty degrees.

4. The impeller (100) for a hydrogen circulation pump according to any one of claims 1 to 3, characterized in that: In the axial direction of the impeller (100), the axial top end of the drum surface (123) is flush with the second end (121) of the hub portion (101).

5. The impeller (100) for a hydrogen circulation pump according to claim 4, characterized in that: In the axial direction, the distance between the bottom surface (122) and the axial top end of the drum surface (123) is less than four elevenths of the maximum axial thickness of the impeller (100).

6. The impeller (100) for a hydrogen circulation pump according to claim 5, characterized in that: On the first side (110) of the impeller (100), the first end (111) includes a mounting portion (111a) and a recessed portion (111b) formed radially outside the mounting portion (111a), wherein the recessed portion (111b) is located between the mounting portion (111a) and the flow channel portion (112).

7. The impeller (100) for a hydrogen circulation pump according to claim 6, characterized in that: The concave portion (111b) is formed by a smooth transition curved surface.

8. The impeller (100) for a hydrogen circulation pump according to claim 6 or 7, characterized in that: In the radial direction, a radial length of a portion (130) of the recess (111b) corresponding to the bottom surface (122) is less than one quarter of the diameter of the impeller (100).

9. The impeller (100) for a hydrogen circulation pump according to claim 8, characterized in that: In the radial direction, the minimum axial thickness of the portion (130) of the recess (111b) corresponding to the bottom surface (122) is greater than one third of the maximum axial thickness of the impeller (100).

10. The impeller (100) for a hydrogen circulation pump according to claim 9, characterized in that: The radial length of the flow channel portion (112) is greater than one third of the diameter of the impeller (100).

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