Scalable coaxial dual nozzle injector and method for variable operating condition fuel cell

Abstract

The present invention belongs to the field of injectors, and provides a retractable coaxial dual-nozzle injector and a working method for a variable operating condition fuel cell. The retractable coaxial dual-nozzle injector includes a shell, and a bellows, a spring, a nozzle assembly, a secondary flow, a mixing chamber and a diffusion chamber are arranged inside the shell; the secondary flow, the mixing chamber and the diffusion chamber are connected in sequence; the nozzle assembly includes a first nozzle and a second nozzle coaxially nested, and the first nozzle is arranged inside the second nozzle; the bellows is connected in series between the outlet and the inlet of the second nozzle, so that the second nozzle moves with the fluid pressure, so that the outlet position and the outlet area of ​​the nozzle assembly can change with the operating condition; the spring is sleeved on the outside of the second nozzle, one end of the spring is fixed on the second nozzle, and the other end is fixed on the shell, so as to ensure the coaxiality of the second nozzle during the extension and retraction process.

Description

Technical Field

[0001] The invention belongs to the field of injectors, and in particular relates to a retractable coaxial double-nozzle injector and method for a variable operating condition fuel cell Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Proton exchange membrane fuel cells are energy conversion devices that convert the chemical energy of hydrogen into electrical energy. Due to its advantages of high efficiency, fast startup, high power density, and low operating noise, it has become a green alternative to internal combustion engines as a power source for automobiles. As one of the important subsystems in fuel cells, the hydrogen supply subsystem usually uses a mechanical pump to recycle hydrogen to improve the hydrogen utilization rate of fuel cells. However, mechanical pumps are expensive, have poor sealing, poor stability, and generate additional power consumption. The ejector has the advantages of low cost, good sealing, low noise, and no parasitic power consumption during use, and has the development trend of replacing mechanical pumps.

[0004] The ejector has a simple structure and no moving parts, and is generally suitable for fixed operating conditions. However, the inventors have found that fuel cells often operate under variable operating conditions, and the flow and pressure of the primary flow vary with power. Therefore, the performance of the ejector with a fixed structure deteriorates under variable operating conditions, especially in the low-power area. Since the primary flow and pressure are small, they cannot meet the requirements of the fuel cell cycle. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned background technology, the first aspect of the present invention provides a retractable coaxial dual-nozzle injector for a variable operating condition fuel cell, which can not only realize the regulation of variable flow rate, but also improve the injection performance under different flow rates, especially the injection performance in the small flow area.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A telescopic coaxial double-nozzle injector for a variable-operating-mode fuel cell, comprising a housing, wherein a bellows, a spring, a nozzle assembly, a secondary flow, a mixing chamber and a pressure-diffusing chamber are arranged inside the housing; the secondary flow, the mixing chamber and the pressure-diffusing chamber are connected in sequence;

[0008] The nozzle assembly includes a first nozzle and a second nozzle coaxially nested, wherein the first nozzle is arranged inside the second nozzle; the bellows is connected in series between the outlet and the inlet of the second nozzle so that the second nozzle moves with the expansion and contraction of the fluid pressure, thereby achieving that the outlet position and outlet area of ​​the nozzle assembly can change with the working conditions; the spring sleeve is arranged outside the second nozzle, one end of the spring is fixed on the second nozzle, and the other end is fixed on the shell to ensure the coaxiality of the second nozzle during the expansion and contraction process.

[0009] Furthermore, a first protrusion is provided on the second nozzle, and the bellows is connected to the first protrusion.

[0010] Furthermore, one end of the spring is fixed on the first protrusion.

[0011] Furthermore, a second protrusion is provided on the shell, and the other end of the spring is fixed on the second protrusion.

[0012] Furthermore, the first protrusion and the second protrusion are arranged along the fluid injection direction.

[0013] Further, both the first nozzle and the second nozzle are closable.

[0014] In order to solve the above problems, the second aspect of the present invention provides a method for operating the telescopic coaxial dual-nozzle injector for a variable operating condition fuel cell as described above, which comprises:

[0015] According to the relationship among the primary flow pressure, the projection area of ​​the nozzle assembly, the elastic coefficient and the length of the spring, the working state of the first nozzle and the second nozzle is changed to adapt to the change of the primary flow pressure and achieve the best spraying effect.

[0016] Furthermore, the relationship among the primary flow pressure, the projected area of ​​the nozzle assembly, the elastic coefficient of the spring and the length is: the product of the primary flow pressure and the projected area of ​​the nozzle assembly is equal to the product of the elastic coefficient of the spring and the length.

[0017] Furthermore, the working states of the first nozzle and the second nozzle include:

[0018] The first nozzle is closed, and the second nozzle is opened. As the primary flow pressure increases, the spring is compressed, the second nozzle is forced to move rightward, and the outlet area increases, so as to be suitable for the case where the flow rate does not exceed the maximum injection amount of the second nozzle;

[0019] The first nozzle and the second nozzle are both opened. As the primary flow pressure increases, the second nozzle moves to the right, the outlet area becomes larger, and the flow rate reaches the maximum.

[0020] Furthermore, the working states of the first nozzle and the second nozzle also include:

[0021] The first nozzle is opened and the second nozzle is closed, so as to be applicable to the situation where the primary flow pressure is constant.

[0022] The beneficial effects of the present invention are:

[0023] In view of the shortcoming that traditional fixed nozzles cannot adjust the flow rate, the present invention proposes a retractable coaxial double-nozzle injector, in which a bellows is connected in series between the outlet and the inlet of the second nozzle, so that the second nozzle can move with the fluid pressure, thereby achieving that the outlet position and outlet area of ​​the nozzle assembly can change with the working conditions; a spring is sleeved on the outside of the second nozzle to ensure the coaxiality of the second nozzle during the extension and retraction process, which on the one hand realizes the regulation of variable flow rate, and on the other hand improves the injection performance under different flow rates, especially improves the injection performance in the small flow area, which is not available in fixed structure injectors.

[0024] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 is a cross-sectional view of a retractable coaxial dual-nozzle injector for a variable operating condition fuel cell according to an embodiment of the present invention;

[0027] Figure 2 The force condition of the retractable coaxial dual-nozzle injector for a variable-operating-condition fuel cell according to an embodiment of the present invention;

[0028] Figure 3 is the reference axis direction of the telescopic coaxial dual-nozzle injector for a variable operating condition fuel cell according to an embodiment of the present invention;

[0029] Figure 4 It is a nozzle projection of a retractable coaxial dual-nozzle injector for a variable operating condition fuel cell according to an embodiment of the present invention.

[0030] Among them, 1 is a bellows, 2 is a spring, 3 is a first nozzle, 4 is a second nozzle, 5 is a secondary flow, 6 is a mixing chamber, and 7 is a diffusion chamber. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] In the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present invention, and do not specifically refer to any part or element in the present invention and should not be understood as limitations on the present invention.

[0035] In the present invention, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. Relevant scientific research or technical personnel in this field can determine the specific meanings of the above terms in the present invention according to specific circumstances, and they should not be understood as limiting the present invention.

[0036] In order to solve the problems existing in the above-mentioned background technology, the present embodiment provides a retractable coaxial dual-nozzle injector for a variable operating condition fuel cell, which is suitable for a variable operating condition fuel cell, can not only realize the regulation of variable flow rate, but also improve the injection performance under different flow rates, especially can improve the injection performance in the small flow area.

[0037] Reference Figure 1 This embodiment provides a retractable coaxial dual-nozzle injector for a variable-operating-condition fuel cell, which includes a housing, wherein a bellows 1, a spring 2, a nozzle assembly, a secondary flow 5, a mixing chamber 6, and a diffusion chamber 7 are arranged inside the housing; the secondary flow 5, the mixing chamber 6, and the diffusion chamber 7 are connected in sequence;

[0038] The nozzle assembly includes a first nozzle 3 and a second nozzle 4 which are coaxially nested, and the first nozzle 3 is arranged inside the second nozzle 4; the bellows 1 is connected in series between the outlet and the inlet of the second nozzle 4, so that the second nozzle 4 moves with the expansion and contraction of the fluid pressure, thereby realizing that the outlet position and outlet area of ​​the nozzle assembly can change with the working conditions; the spring sleeve 2 is arranged outside the second nozzle 4, one end of the spring 2 is fixed on the second nozzle 4, and the other end is fixed on the shell, so as to ensure the coaxiality of the second nozzle 4 during the expansion and contraction process.

[0039] In this embodiment, a first protrusion is provided on the second nozzle 4, and the bellows 1 is connected to the first protrusion. One end of the spring is fixed to the first protrusion. In this way, the stability of the connection between the bellows and the second nozzle is achieved by providing the protrusion.

[0040] It should be noted that, in other embodiments, the connection between the bellows and the second nozzle may also be achieved by other structures, such as a threaded structure, etc. Those skilled in the art may specifically select other existing connection methods according to actual conditions.

[0041] Specifically, a second protrusion is provided on the housing, and the other end of the spring 2 is fixed on the second protrusion, so as to ensure the stability of the spring connection.

[0042] The first protrusion and the second protrusion are arranged along the fluid injection direction, which simplifies the fixing structure of the bellows and the spring and enables the bellows and the spring to cooperate with each other in the best way, thereby improving the injection capacity of the injector.

[0043] In this embodiment, both the first nozzle and the second nozzle can be closed, so as to adapt to different primary flow pressure conditions.

[0044] Under the variable working conditions of the fuel cell, the primary flow pressure P corresponds to the nozzle expansion position x, from which the elastic coefficient k of the spring can be determined, and the material of the spring and the length of the spring can be selected according to the elastic coefficient k. The bellows mainly has expansion and sealing functions, and the elasticity can be ignored. Good sealing is required everywhere, and the material should be resistant to hydrogen embrittlement, such as 316L stainless steel.

[0045] PS cosθ=kx

[0046] Through the above formula, and the pressure change range P1 to P2, the spring expansion and contraction distance x1 to x2 can be determined, and the appropriate spring length can be selected to ensure linear change.

[0047] Conversely, for a designed variable nozzle injector with a nozzle change position, the applicable operating condition change range P1 to P2 can be inferred in reverse.

[0048] In this embodiment, Figure 1The working method of the telescopic coaxial dual nozzle injector for a variable operating condition fuel cell shown includes:

[0049] According to the relationship among the primary flow pressure, the projection area of ​​the nozzle assembly, the elastic coefficient and the length of the spring, the working state of the first nozzle and the second nozzle is changed to adapt to the change of the primary flow pressure and achieve the best spraying effect.

[0050] In this embodiment, the relationship between the primary flow pressure, the projected area of ​​the nozzle assembly, the elastic coefficient of the spring and the length is: the product of the primary flow pressure and the projected area of ​​the nozzle assembly is equal to the product of the elastic coefficient of the spring and the length. Figure 2 , Figure 3 and Figure 4 That is, the force of the fuel gas acting in the horizontal direction is equal to the pressure multiplied by the projection area S cosθ of the second nozzle, which is equal to the elastic coefficient k of the spring multiplied by the telescopic distance x.

[0051] In this embodiment, the working states of the first nozzle and the second nozzle include:

[0052] The first nozzle is closed, and the second nozzle is opened. As the primary flow pressure increases, the spring is compressed, the second nozzle is forced to move rightward, and the outlet area increases, so as to be suitable for the case where the flow rate does not exceed the maximum injection amount of the second nozzle;

[0053] The first nozzle is opened and the second nozzle is closed, so as to be applicable to the case where the primary flow pressure is constant;

[0054] The first nozzle and the second nozzle are both opened. As the primary flow pressure increases, the second nozzle moves to the right, the outlet area becomes larger, and the flow rate reaches the maximum.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A retractable coaxial dual-nozzle injector for a variable operating condition fuel cell, characterized in that: It comprises a shell, wherein a bellows, a spring, a nozzle assembly, a secondary flow inlet, a mixing chamber and a pressure diffusion chamber are arranged inside the shell; the secondary flow inlet, the mixing chamber and the pressure diffusion chamber are connected in sequence; The nozzle assembly comprises a first nozzle and a second nozzle coaxially nested, wherein the first nozzle is arranged inside the second nozzle; the bellows is connected in series between the outlet and the inlet of the second nozzle, so that the second nozzle moves with the expansion and contraction of the fluid pressure, thereby realizing that the outlet position and outlet area of ​​the nozzle assembly can change with the change of working conditions; the spring is sleeved outside the second nozzle, one end of the spring is fixed on the second nozzle, and the other end is fixed on the housing, so as to ensure the coaxiality of the second nozzle during the expansion and contraction process; The second nozzle is provided with a first protrusion, and the bellows is connected to the first protrusion; one end of the spring is fixed to the first protrusion; the housing is provided with a second protrusion, and the other end of the spring is fixed to the second protrusion; According to the relationship among the primary flow pressure, the projection area of ​​the nozzle assembly, the elastic coefficient and the length of the spring, the opening or closing working state of the first nozzle and the second nozzle is changed to adapt to the change of the primary flow pressure and achieve the best spraying effect.

2. The retractable coaxial dual-nozzle injector for a variable operating condition fuel cell according to claim 1, characterized in that: The first protrusion and the second protrusion are arranged along the fluid ejection direction.

3. The retractable coaxial dual-nozzle injector for a variable operating condition fuel cell according to claim 1, characterized in that: Both the first nozzle and the second nozzle can be closed.

4. A method for operating a retractable coaxial dual-nozzle injector for a variable operating condition fuel cell as claimed in any one of claims 1 to 3, characterized in that: include: According to the relationship among the primary flow pressure, the projection area of ​​the nozzle assembly, the elastic coefficient and the length of the spring, the opening or closing working state of the first nozzle and the second nozzle is changed to adapt to the change of the primary flow pressure and achieve the best spraying effect; The relationship among the primary flow pressure, the projected area of ​​the nozzle assembly, the elastic coefficient of the spring and the length is: the product of the primary flow pressure and the projected area of ​​the nozzle assembly is equal to the product of the elastic coefficient of the spring and the length.

5. The operating method of the telescopic coaxial dual-nozzle injector for a variable operating condition fuel cell according to claim 4, characterized in that: The working states of the first nozzle and the second nozzle include: The first nozzle is closed, and the second nozzle is opened. As the primary flow pressure increases, the spring is compressed, the second nozzle is forced to move rightward, and the outlet area increases, so as to be suitable for the case where the flow rate does not exceed the maximum injection amount of the second nozzle; The first nozzle and the second nozzle are both opened. As the primary flow pressure increases, the second nozzle moves to the right, the outlet area becomes larger, and the flow rate reaches the maximum.

6. The operating method of the telescopic coaxial dual-nozzle injector for a variable operating condition fuel cell according to claim 5, characterized in that: The working states of the first nozzle and the second nozzle also include: The first nozzle is opened and the second nozzle is closed, so as to be applicable to the situation where the primary flow pressure is constant.

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