CN216974931U - Turbine blade, turbine and turbocharger for fuel cell system - Google Patents

Abstract

The present application provides a turbine blade for a turbine of a fuel cell system, the turbine configured for connection on a cathode exhaust gas line of the fuel cell system to be driven by cathode exhaust gas. The turbine blade includes a radially outermost leading end, a radially innermost trailing end, and a body extending between the leading end and the trailing end. The front end has a rounded convex profile. The present application further provides a turbine for a turbine of a fuel cell system, the turbine comprising the aforementioned turbine blade. The radially outermost portion of the leading end of the turbine blade is radially inwardly set back a predetermined distance relative to a radially outer edge of a disk of the turbine to form a buffer space between the leading end and the radially outer edge. The present application further provides a turbocharger comprising the aforementioned turbine. According to the application, the impact of water drops in the cathode waste gas on the front ends of the turbine blades can be effectively reduced, so that the erosion of the water drops on the front ends is reduced.

Description

Turbine blade, turbine and turbocharger for fuel cell system

Technical Field

The present application relates to the field of fuel cell systems, and in particular, to turbine blades and turbines for turbochargers of fuel cell systems, and turbochargers including such turbines.

Background

In a fuel cell system such as a Proton Exchange Membrane Fuel Cell (PEMFC), a turbocharger is generally used to recover energy from cathode off-gas for compressing air, thereby improving the operating efficiency of the fuel cell system. A turbocharger includes at least a turbine and an air compressor at least partially driven by the turbine. The turbine is connected to a cathode exhaust line of a stack of the fuel cell system to be driven by cathode exhaust gas, and the air compressor is connected to a cathode air supply line of the stack to supply air to the stack. During operation of the turbocharger, the cathode exhaust gas in the cathode exhaust line impacts the turbine blades of the turbine to rotate the turbine, and the rotating turbine rotates the impeller of the air compressor through the transmission mechanism. The rotating impeller in turn pressurizes air in the cathode air supply line to supply air to the stack.

Fig. 1 schematically shows a conventional turbine 1 for a turbocharger of a fuel cell system. Referring to the portions circled by the dashed boxes a and B in fig. 1, the front end portion 5 (alternatively referred to as the "inlet tip") of the turbine blade 3 of a conventional turbine 1 typically has a sharp profile. The cathode exhaust gas carries water droplets due to its high moisture content. Such a sharp profile of the leading end portion 5 of the turbine blade 3 is easily eroded when being impacted by water droplets (commonly referred to as "water droplet erosion") when the cathode off-gas impacts the turbine blade 3. The water droplet erosion causes the surface of the leading end portion 5 to be roughened, increasing the resistance of the leading end portion 5, resulting in a decrease in turbocharger efficiency. Furthermore, water droplet erosion also increases the risk of the turbine blades 3 breaking and reduces the useful life of the turbine.

Accordingly, there is a need for improvements to existing turbochargers for fuel cell systems.

SUMMERY OF THE UTILITY MODEL

The present application aims to overcome the above-mentioned drawbacks by providing a turbine blade for a turbine of a turbocharger of a fuel cell system.

According to an aspect of the present application, there is provided a turbine blade for a turbine of a fuel cell system, the turbine configured to be connected to a cathode exhaust line of the fuel cell system to be driven by cathode exhaust gas, the turbine blade including a leading end outermost in a radial direction, a trailing end innermost in the radial direction, and a body extending between the leading end and the trailing end, wherein the leading end has a rounded convex profile.

Preferably, the body comprises a pressure surface and a suction surface disposed on an opposite side of the pressure surface, the front end comprises a rounded front head, and a front end surface of the front end gradually expands from the front head to connect the pressure surface and the suction surface by the front end surface.

Preferably, a cross section of the leading end in the radial direction is a round curved surface.

Preferably, the cross-section is semi-circular.

Preferably, the turbine blade includes a water droplet erosion resistant coating applied to the leading end.

Preferably, the turbine blade includes a protection against erosion by water droplets that is fixed to the leading end and conforms in shape to the shape of the leading end.

According to another aspect of the present application, there is provided a turbine for a turbine of a fuel cell system, the turbine being configured for connection on a cathode exhaust line of the fuel cell system to be driven by cathode exhaust gas, the turbine comprising: a wheel disc; and the aforementioned turbine blades fixedly coupled to or integrally formed with the disk and uniformly arranged on the disk along a circumferential direction of the turbine, a leading end of each two adjacent turbine blades defining an inlet for the cathode off-gas.

Preferably, the disk includes a radially outer edge extending in a circumferential direction of the turbine wheel, and a radially outermost portion of the forward end is recessed inward in the radial direction by a predetermined distance relative to the radially outer edge to form a buffer space between the forward end and the radially outer edge.

Preferably, the predetermined distance is 2% to 5% of the diameter of the wheel disc.

According to yet another aspect of the present application, there is provided a turbocharger for a fuel cell system, the turbocharger including: a turbine that includes the foregoing turbine wheel and is connected on a cathode exhaust line of the fuel cell system to be driven by cathode off-gas; and an air compressor configured to be at least partially driven by the turbine, the air compressor being connected to a cathode air supply line of the fuel cell system to supply air to the fuel cell system.

According to the application, the impact of water drops in the cathode waste gas on the front ends of the turbine blades can be effectively reduced, so that the erosion of the water drops on the front ends is reduced. This can reduce the risk of the turbine blade breaking, improve the reliability of the turbine blade and prolong its service life. In addition, this can also effectively delay the efficiency of turbochargers that use such turbine blades from decreasing with use.

Drawings

The above-described and other aspects of the present application will be more fully understood and appreciated in view of the accompanying drawings. It should be noted that the figures are merely schematic and are not drawn to scale. In the drawings:

FIG. 1 schematically illustrates a conventional turbine for a turbocharger of a fuel cell system;

FIG. 2 schematically illustrates an exemplary fuel cell system to which a turbocharger according to a preferred embodiment of the present application can be applied;

FIG. 3 is a schematic perspective view of a turbine of the turbocharger shown in FIG. 2;

FIG. 4 is another schematic perspective view of the turbine shown in FIG. 3;

FIG. 5 is a schematic side view of the turbine shown in FIG. 3;

FIG. 6 is an enlarged view of the dashed area C in FIG. 3;

FIG. 7 is a radial cross-sectional view of the turbine shown in FIG. 3 along line I-I in FIG. 5; and

FIG. 8 is a radial cross-sectional view of the turbine shown in FIG. 3 along line II-II in FIG. 5.

List of reference numerals

100 fuel cell system

101 electric pile

103 anode

105 cathode

107 cathode inlet

109 cathode outlet

111 oxidizing gas source

113 cathode gas supply line

115 cathode exhaust line

117 intercooler

119 humidifier

200 turbo charger

201 air compressor

203 turbine

205 electric motor

207 rotating shaft

300 turbine

301 wheel disc

301a radially outer edge

303 turbine blade

305 rotation axis

306 direction of rotation

307 front end

307a front end head

309 tail end

311 body

311a pressure surface

311b suction surface

311c side surface

S buffer space

Detailed Description

Preferred embodiments of the present application are described in detail below with reference to examples. It should be understood by those skilled in the art that these exemplary embodiments are not meant to limit the present application in any way. Furthermore, the features in the embodiments of the present application may be combined with each other without conflict. In the different figures, like parts are denoted with like reference numerals and other parts are omitted for the sake of brevity, which does not indicate that the turbine blades, turbines, turbochargers and fuel cell systems of the present application may not include other parts. It should be understood that the dimensions, proportions and numbers of elements in the drawings are not intended to limit the present application.

Fig. 2 schematically illustrates an exemplary fuel cell system 100, and a turbocharger 200 according to a preferred embodiment of the present application can be used with the fuel cell system 100. The fuel cell system 100 may be used in a vehicle, for example, to provide electrical power to drive a vehicle motor to provide power or to cause an on-board system to perform various functions. As shown in fig. 2, the fuel cell system 100 may be, for example, a PEMFC, and includes a stack 101. The stack 101 includes an anode 103 and a cathode 105. During operation of the fuel cell system 100, hydrogen gas and air are supplied to the anode 103 and the cathode 105 of the stack 101, respectively. Hydrogen molecules entering the anode 103 are adsorbed by the catalyst and ionized into hydrogen ions and electrons, the hydrogen ions are transferred to the cathode 105 via a proton exchange membrane (not shown) in the stack 101, and the electrons flow to the cathode 105 through an external circuit (not shown) to form an electric current. Air enters the cathode 105 from the cathode inlet 107, and oxygen in the air combines with hydrogen ions and electrons into water molecules at the cathode 105 and exits the cathode outlet 109 along with other gases in the air. The gas discharged from the cathode outlet may be referred to as "cathode off-gas". Due to the high moisture content of the cathode off-gas, part of the moisture may be in the form of water droplets. That is, the cathode off-gas carries water droplets.

With continued reference to fig. 2, the fuel cell system 100 includes a cathode air supply line 113 configured to be connected between an oxidizing gas source 111 (e.g., the ambient environment surrounding the fuel cell system 100) and the cathode inlet 107 and to supply air to the cathode inlet 107, and a cathode exhaust line 115 configured to communicate the cathode outlet 109 with the exterior of the fuel cell system 100 (e.g., the ambient environment surrounding the fuel cell system 100) and to exhaust cathode exhaust gas from the fuel cell system 100.

The turbocharger 200 according to the preferred embodiment of the present application includes an air compressor 201 and a turbine 203. The turbine 203 is connected to the cathode exhaust line 115 to be driven by the cathode exhaust gas in the cathode exhaust line 115. An air compressor 201 is connected to the cathode air supply line 113 and is configured to be driven at least in part by the turbine 203 to supply air to the cathode inlet 107. That is, the air compressor 201 is operatively coupled to the turbine 203 to be at least partially driven by the turbine 203. The cathode exhaust gas in the cathode exhaust line 115 impacts turbine blades (not shown in fig. 2) of the turbine 203 to rotate a turbine (not shown in fig. 2) of the turbine 203, which rotates an impeller (not shown) of the air compressor 201 via a transmission mechanism. The rotating impeller draws fresh air into the cathode air supply line 113 and pressurizes the air to supply air to the cathode inlet 107.

In some examples, as shown in fig. 2, the turbocharger 200 may be an electric turbocharger that includes an electric motor 205. The motor 205 is coupled to the shaft 207 to drive the shaft 207 to rotate when energized. The impeller of the air compressor 201 is mounted on a rotating shaft 207 and is rotated by the rotating shaft 207. The turbine of the turbine 203 is also mounted on the rotating shaft 207, and drives the rotating shaft 207 to rotate when the cathode off-gas pushes the turbine to rotate, so as to drive the impeller of the air compressor 201 to rotate. In this way, the motor 205 and the turbine 203 can rotate the rotating shaft 207 together, thereby driving the impeller of the air compressor 201 to rotate. Since the turbine 203 recovers energy from the cathode off-gas for driving the air compressor 201, the operating efficiency of the fuel cell system 100 is improved.

In other examples, the turbocharger 200 may be a mechanical turbocharger, for example, where the fuel cell system 100 includes both an electric turbocharger and a mechanical turbocharger, the mechanical turbocharger 200 may be used to primarily pressurize the air. In the case where the turbocharger 200 is a mechanical turbocharger, the turbine of the turbine 203 and the impeller of the air compressor 201 may be mounted on the same shaft to achieve coaxial transmission. When the cathode exhaust gas pushes the turbine of the turbine 203 to rotate, the turbine drives the rotating shaft to rotate, so as to drive the impeller of the air compressor 201 to rotate. Since the turbine 203 recovers energy from the cathode off-gas for driving the air compressor 201, the operating efficiency of the fuel cell system 100 is improved.

As shown in fig. 2, the fuel cell system 100 may further include an intercooler 117 and a humidifier 119. An intercooler 117 is connected to cathode air supply line 113 downstream of air compressor 201 and is configured to cool the pressurized air as it passes therethrough. A humidifier 119 is connected to the cathode air supply line 113 downstream of the intercooler 117 and is configured to humidify the pressurized, cooled air as it passes therethrough. It should be appreciated that the intercooler 117 and humidifier 119 may take any suitable form, for example, the intercooler 117 may be an air cooling device, a liquid cooling device, or a combination thereof, and the humidifier 119 may be self-humidifying, as the present application is not limited thereto. It should also be understood that other suitable components may be provided in the cathode gas supply line 113 from the air compressor 201 to the cathode inlet 107, or the intercooler 117 and/or humidifier 119 may be absent, as well as being non-limiting of the present application. It should also be appreciated that other suitable components may be disposed on the cathode exhaust line 115 from the cathode inlet 107 to the turbine 203, and the application is not limited thereto.

The configuration of the turbine 300 of the turbine 203 of the turbocharger 200 and the turbine blades 303 thereof will be specifically described below with reference to fig. 3 to 8. The turbine 300 is configured for connection to the cathode exhaust line 115 of the fuel cell system 100 to be driven by the cathode exhaust gas. As shown in fig. 3 to 8, the turbine 300 includes a disk 301 and a plurality of turbine blades 303 arranged on the disk 301. The disk 301 is generally disc shaped and defines the diameter of the turbine 300. That is, the diameter of the disk 301 is equal to the diameter of the turbine 300. Disk 301 also defines an axis of rotation 305 (FIG. 5) of turbine 300. In the present application, unless otherwise specified, "axial" refers to the direction of extension of the axis of rotation 305 about which the turbine 300 of the turbomachine 203 or its turbine blades 303 rotate, "radial" refers to the radial direction with respect to the axis of rotation 305, and "circumferential" refers to the circumferential direction with respect to the axis of rotation 305, i.e. the direction around the axis of rotation 305. The disk 301 includes a radially outer edge 301a that extends along a circumferential direction of the turbine 300.

The plurality of turbine blades 303 are ternary twisted blades, and are uniformly arranged on the disk 301 along the circumferential direction of the turbine 300. The turbine blades 303 and the disk 301 may be made of any suitable material, such as aluminum. The turbine blades 303 may be integrally formed with the wheel disc 301 (e.g., by post-cast finish molding, electrical discharge machining, wax precision casting, and numerical control machining), or separately formed and then fixedly coupled (e.g., by welding or plugging) to the wheel disc 301. The turbine blades 303 are configured to be urged to rotate in a rotation direction 306 (typically a single rotation direction as indicated by an arrow in fig. 5) about a rotation axis 305 under the impact of the cathode off-gas to bring the pulley disc 301 to rotate in the rotation direction 306 about the rotation axis 305. The wheel disc 301 is configured to be mounted to a spindle 207, such as shown in fig. 2, and to drive the spindle 207 to rotate when rotated about an axis of rotation 305.

As shown in fig. 3, the turbine blade 303 includes a leading end 307 that is radially outermost, a trailing end 309 that is radially innermost, and a body 311 that extends between the leading end 307 and the trailing end 309. The leading end 307 of each two adjacent turbine blades 303 defines an inlet for cathode exhaust gas, the trailing end 309 of each two adjacent turbine blades 303 defines an outlet for cathode exhaust gas, and the body 311 of each two adjacent turbine blades 303 and the portion of the disk 301 between the body 311 define a flow passage for cathode exhaust gas. The cathode exhaust gas enters the flow passage between the leading ends 307 of adjacent turbine blades 303, impacts the turbine blades 303 to urge the turbine 300 to rotate about the axis of rotation 305 in a rotational direction 306, and subsequently exits the flow passage between the trailing ends 309 of adjacent turbine blades 303 (e.g., generally axially opposite).

As best shown in fig. 6-8, the leading end 307 of the turbine blade 303 has a rounded convex profile. The front end 307 having a rounded convex profile means that the profile of the front end 307 is rounded and convex away from the body 311. This makes it possible to reduce the erosion of the water droplets by the leading end 307. In this application, unless otherwise noted, the contour of the leading end 307 of the turbine blade 303 refers to the overall shape or contour of the leading end 307, which is defined to the periphery of the leading end 307. Compared with the turbine blade 3 shown in fig. 1, the smooth convex contour of the front end 307 of the turbine blade 303 according to the present application can effectively reduce the impact of the water droplets in the cathode off-gas on the front end 307 of the turbine blade 303, thereby reducing the erosion of the front end 307 by the water droplets. This can reduce the risk of the turbine blade 303 breaking, improve the reliability of the turbine blade 303 and extend its useful life. In addition, this can also effectively retard the efficiency of turbocharger 200 from degrading with use.

With continued reference to fig. 6-8, the body 311 of the turbine blade 303 includes a pressure surface 311a and a suction surface 311b disposed on an opposite side of the pressure surface 311 a. The front end 307 includes a front end surface, and the body 311 further includes a side 311c connecting the pressure side 311a, the suction side 311b, and the front end surface. The front end 307 includes a rounded front end head 307a, and a front end surface of the front end 307 gradually expands from the front end head 307a so that the pressure surface 311a and the suction surface 311b are connected by the front end surface. In some examples, the front end surface of the front end 307 may extend linearly expanding from the front head 307 a. In other partial examples, the front end surface of the front end 307 may extend non-linearly expanding from the front end head 307 a. The front end surface of the front end 307 gradually expands from the front end head 307a so that the turbine blade 303 can smoothly transition from the rounded front end head 307a to the body 311. This helps to further reduce the erosion of the leading end 307 of the turbine blade 303 and the body 311 by water droplets.

As shown in fig. 7 and 8, the cross section of the leading end 307 of the turbine blade 303 in the radial direction is a round curved surface. That is, each radial cross-section of the leading end 307 of the turbine blade 303 is a rounded curved surface. In some examples, each radial cross-section of the leading end 307 of the turbine blade 303 is semi-circular. Such a semi-circular shape enables the surface of the front end 307 to be more uniformly stressed, thereby further mitigating water droplet erosion of the front end 307. In other examples, the radial cross-section of the leading end 307 of the turbine blade 303 may take other suitable shapes.

The turbine blade 303 may also include a protective structure (not shown in the figures) disposed on the leading end 307. In some examples, the protective structure may be a water-droplet erosion resistant coating applied on the leading end 307. For example, the water droplet erosion resistant coating may increase the hardness of the front end surface of the front end 307. Such a water droplet erosion resistant coating may be a hard material coating such as a titanium alloy coating. It should be understood that the water droplet erosion resistant coating may also be other suitable coatings, such as those known in the art to resist water droplet erosion. In other partial examples, the protective structure may be a water droplet erosion resistant protector secured (e.g., welded or plugged) to the front end 307 and conforming in shape to the shape of the front end 307. For example, the protection member against the erosion of water droplets may be a thin sheet or film formed of a hard material to increase the hardness of the leading end surface of the leading end 307. Such a protection against erosion by water droplets may be, for example, a titanium alloy foil. By providing such a protective structure on the leading end 307, erosion of the leading end 307 by water droplets can be further reduced.

In some examples, as shown in fig. 6-8, the turbine blades 303 may also be configured such that a radially outermost portion of the forward end 307 is radially set back a predetermined distance inward relative to a radially outer edge 301a of the disk 301 to form a buffer space S between the forward end 307 and the radially outer edge 301 a. Such a buffer space S enables the cathode off-gas to first contact the radially outer edge 301a of the disk 301 when entering the turbine 203, thereby providing a buffer before the cathode off-gas contacts the front ends 307 of the turbine blades 303. This makes it possible to further reduce the erosion of the water droplets by the leading end 307. The predetermined distance of setback may be 2% to 5%, such as 2%, 3%, 4%, or 5% of the diameter of the disc 301. Such a predetermined distance can provide an effective buffer space S between the front end 307 and the radially outer edge 301a without significantly affecting the performance of the turbocharger 200. In some examples, the predetermined distance of setback may be at least 1 millimeter, such as 1 millimeter, 2 millimeters, or more. In other examples, the predetermined distance of setback may be between 1 mm and 10 mm. It should be understood that the radially outermost portion of the aforementioned leading end 307 is not necessarily the leading tip portion 307 a.

Although in the embodiment shown in fig. 2-8 all turbine blades 303 have the same ternary twist configuration, it should be understood that the present application is not so limited. In other embodiments, the turbine blades 303 may have different tertiary twist configurations, such as a combination of long and short blades. The long blades and the short blades are uniformly arranged in the circumferential direction of the turbine 300, and the short blades are located between two adjacent long blades.

The present application is described in detail above with reference to specific embodiments. It is to be understood that both the foregoing description and the embodiments shown in the drawings are to be considered exemplary and not restrictive of the application. It will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the application, and these changes and modifications do not depart from the scope of the application.

Claims (10)

1. A turbine blade (303) for a fuel cell system, the turbine blade (303) being configured for connection on a cathode exhaust line of the fuel cell system to be driven by cathode exhaust gas, the turbine blade (303) comprising a leading end (307) outermost in a radial direction, a trailing end (309) innermost in the radial direction, and a body (311) extending between the leading end (307) and the trailing end (309), wherein the leading end (307) has a rounded convex profile.

2. The turbine blade (303) of claim 1, wherein:

the body (311) comprises a pressure surface (311a) and a suction surface (311b) disposed on an opposite side of the pressure surface (311 a); and

the front end (307) comprises a rounded front end head (307a), and a front end surface of the front end (307) gradually expansively extends from the front end head (307a) such that the pressure surface (311a) and the suction surface (311b) are connected by the front end surface.

3. The turbine blade (303) of claim 1, wherein a cross-section of the leading end (307) in the radial direction is a rounded curve.

4. The turbine blade (303) of claim 3, wherein the cross-section is semi-circular.

5. The turbine blade (303) of any of claims 1 to 4, characterized in that the turbine blade (303) comprises a water droplet erosion resistant coating applied on the leading end (307).

6. The turbine blade (303) as claimed in any of claims 1 to 4, characterized in that the turbine blade (303) comprises a protection against water droplet erosion that is fixed on the front end (307) and conforms in shape to the shape of the front end (307).

7. A turbine (300) for a turbine of a fuel cell system, the turbine being configured for connection on a cathode exhaust line of the fuel cell system to be driven by cathode exhaust gas, the turbine (300) comprising:

a wheel disc (301); and

a plurality of turbine blades (303) according to any of claims 1 to 6, the turbine blades (303) being fixedly coupled with or integrally formed with the wheel disc (301) and being evenly arranged on the wheel disc (301) along the circumference of the turbine wheel (300), the front ends (307) of each two adjacent turbine blades (303) defining an inlet for the cathode exhaust gas.

8. The turbine (300) of claim 7, characterized in that the disk (301) comprises a radially outer edge (301a) extending along a circumferential direction of the turbine (300), a radially outermost portion of the nose (307) being radially retracted a predetermined distance inward along the radial direction relative to the radially outer edge (301a) to form a buffer space between the nose (307) and the radially outer edge (301 a).

9. The turbine (300) of claim 8, characterized in that the predetermined distance is 2% to 5% of the diameter of the disk (301).

10. A turbocharger for a fuel cell system, the turbocharger comprising:

a turbine comprising the turbine (300) according to any one of claims 7 to 9 and connected on a cathode exhaust line of the fuel cell system to be driven by cathode exhaust gas; and

an air compressor configured to be at least partially driven by the turbine, the air compressor being connected to a cathode air supply line of the fuel cell system to supply air to the fuel cell system.

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