阅读说明：本技术 一种具有旁路进口结构的引射器 (Ejector with bypass inlet structure ) 是由 涂正凯 刘洋 赵俊杰 龚骋原 范丽欣 常华伟 于 2021-07-29 设计创作，主要内容包括：本发明提供了一种具有旁路进口结构的引射器,属于气体引射技术领域,包括：工作流体管路、引射流体管路、吸入室、混合室、旁通二次流管路和扩压室；混合室与扩压室的连接处设置有旁通二次流管路；引射流体管路的入口端和旁通二次流管路的入口端均连接质子交换膜燃料电池电堆出口；混合室用于充分混合工作流体和二次流回流；扩压室用于将混合流体动能转换为压力势能；吸入室用于接收工作流体产生真空低压区域,且将工作流体的部分动量传递至主二次回流；旁通二次流管路用于将旁通二次回流卷吸进入混合室,三股流体充分混合进入扩压室,使流体速度降低且扩压室压力升高。本发明引入旁通二次流管路,增加了引射比,提高了引射器的回氢效率。(The invention provides an ejector with a bypass inlet structure, which belongs to the technical field of gas ejection and comprises the following components: the device comprises a working fluid pipeline, an injection fluid pipeline, a suction chamber, a mixing chamber, a bypass secondary flow pipeline and a diffusion chamber; a bypass secondary flow pipeline is arranged at the joint of the mixing chamber and the pressure expansion chamber; the inlet end of the injection fluid pipeline and the inlet end of the bypass secondary flow pipeline are both connected with the outlet of the proton exchange membrane fuel cell stack; the mixing chamber is used for fully mixing the working fluid and the secondary flow backflow; the pressure expansion chamber is used for converting the kinetic energy of the mixed fluid into pressure potential energy; the suction chamber is used for receiving the working fluid to generate a vacuum low-pressure area and transferring partial momentum of the working fluid to the primary secondary return flow; the bypass secondary flow pipeline is used for sucking bypass secondary backflow into the mixing chamber, and the three flows are fully mixed and enter the pressure expansion chamber, so that the speed of the flows is reduced, and the pressure of the pressure expansion chamber is increased. The invention introduces the bypass secondary flow pipeline, increases the injection ratio and improves the hydrogen return efficiency of the injector.)

1. An eductor having a bypass inlet structure comprising: the device comprises a working fluid pipeline (1), an injection fluid pipeline (2), a suction chamber (3), a mixing chamber (4), a bypass secondary flow pipeline (5) and a diffusion chamber (6);

the working fluid pipeline (1), the suction chamber (3), the mixing chamber (4) and the diffusion chamber (6) are sequentially connected; the inlet side of the working fluid pipeline (1) is connected with a high-pressure hydrogen storage tank; an ejector outlet (11) for mixed gas to flow out is arranged at an outlet of the pressure expansion chamber (6); the bypass secondary flow pipeline (5) is arranged at the joint of the mixing chamber (4) and the pressure expansion chamber (6); the inlet end of the injection fluid pipeline (2) and the inlet end of the bypass secondary flow pipeline (5) are both connected with the outlet of the proton exchange membrane fuel cell stack;

the mixing chamber (4) is used for mixing the working fluid and the secondary flow backflow; the pressure expansion chamber (6) is used for converting kinetic energy of the mixed fluid into pressure potential energy and inputting the mixed fluid to the inlet of the proton exchange membrane fuel cell stack; the suction chamber (3) is used for receiving the working fluid to generate a vacuum low-pressure area and transferring partial momentum of the working fluid to a primary secondary return flow; the bypass secondary flow pipeline (5) is used for sucking bypass secondary return flow into the mixing chamber (4) in an entrainment mode, so that the speed of the working fluid and the secondary return flow of the mixing chamber (4) entering the pressure expansion chamber (6) is reduced, and the pressure of the pressure expansion chamber (6) is increased; wherein, the secondary flow return comprises a main secondary return and a bypass secondary return.

2. The ejector according to claim 1, characterized in that the working fluid circuit (1) comprises a working fluid inlet (7) and a nozzle body; the nozzle body comprises a convergent nozzle (8), a nozzle outlet (9) and a nozzle throat (10) in a funnel shape; wherein the diameter of the nozzle throat (10) is 1.5 mm; the diameter of the nozzle outlet (9) is 2.0 mm; the nozzle outlet (9) is 3.6mm from the mixing chamber (4) inlet.

3. The ejector according to claim 1, characterized in that the mixing chamber (4) is cylindrical with an axial length of 16mm and a radial diameter of 3.6 mm.

4. The ejector according to claim 3, wherein the axial length of the pressure expansion chamber (6) is 45.72mm, the opening angle is 5 ° and the outlet diameter is 10 mm.

5. The eductor of claim 2 wherein the diameter of the eductor fluid conduit is 6mm and the diameter of the bypass secondary flow conduit is 1 mm.

6. The injector according to claim 2 or 5, wherein the working fluid inlet (7) has a diameter of 6mm and is axially a stepped cylinder.

7. The ejector according to any of the claims 1 to 5, wherein the suction chamber (3), the mixing chamber (4), the pressure expansion chamber (6), the ejector fluid line (2) and the bypass secondary flow line (5) are integrated.

Technical Field

The invention belongs to the technical field of gas injection, and particularly relates to an injector with a bypass inlet structure.

Background

In order to improve the utilization rate of fuel, the common method of the proton exchange membrane fuel cell is to adopt closed pulse operation, but the closed operation of an anode easily causes flooding of the cell and influences the performance of the fuel cell; or a hydrogen circulation subsystem is added in the fuel cell to make the hydrogen flow in the cell in a forced circulation way; in addition, another gas management method can improve the utilization rate of hydrogen and promote the drainage, namely a tail gas recycling system. The ejector is a promising tail gas circulation system device, can convert the pressure potential energy of a high-pressure gas storage tank into kinetic energy, realizes the recycling of the hydrogen at the outlet of the anode, and has the advantages of compact structure, reliable operation, no moving parts, easy maintenance, no parasitic power and the like compared with the traditional mechanical circulating pump.

However, ejectors exhibit inferior performance compared to conventional mechanical circulation pumps, and the pursuit of high efficiency ejectors has been a goal of researchers. To date, more and more research has focused on ejector performance analysis under off-design conditions. However, the ejector with optimized geometry maintains good performance only around the design conditions beyond which it degrades rapidly, particularly transitioning to the subcritical mode. The main reason is that the ejector forms a low-pressure area on the basis of pure shearing action, and the momentum waste in the pressure recovery process in the mixing section is the reason for poor performance of the ejector.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide an ejector with a bypass inlet structure, and aims to solve the problems that the existing ejector forms a low-pressure area on the basis of pure shearing action, and kinetic energy is wasted in the process of recovering pressure in a mixing section, so that the performance of the ejector is poor.

To achieve the above object, the present invention provides an ejector with a bypass inlet structure, comprising: the device comprises a working fluid pipeline, an injection fluid pipeline, a suction chamber, a mixing chamber, a bypass secondary flow pipeline and a diffusion chamber;

the working fluid pipeline is connected with the suction chamber; one side of the diffusion chamber is provided with an ejector outlet for mixed gas to flow out; a bypass secondary flow pipeline is arranged at the joint of the mixing chamber and the pressure expansion chamber; the inlet end of the injection fluid pipeline and the inlet end of the bypass secondary flow pipeline are both connected with the outlet of the proton exchange membrane fuel cell stack, and unused fuel gas is recovered;

the inlet side of the working fluid pipeline is connected with a high-pressure hydrogen storage tank; the mixing chamber is used for fully mixing the working fluid and the secondary flow backflow; the pressure expansion chamber is used for converting kinetic energy of the mixed fluid into pressure potential energy and inputting the mixed fluid to an inlet of the proton exchange membrane fuel cell stack; the suction chamber is used for receiving the working fluid to generate a vacuum low-pressure area and transferring partial momentum of the working fluid to the primary secondary return flow; the bypass secondary flow pipeline is used for sucking bypass secondary backflow into the mixing chamber, and the three flows are fully mixed and enter the pressure expansion chamber, so that the speed of the flows is reduced, and the pressure of the pressure expansion chamber is increased.

Preferably, the working fluid conduit comprises a working fluid inlet and a nozzle body; the working fluid inlet is arranged at the inlet side of the working fluid pipeline; the nozzle body comprises a convergent nozzle, a nozzle outlet and a nozzle throat part and is funnel-shaped; wherein the diameter of the throat part of the nozzle is 1.5 mm; the diameter of the nozzle outlet is 2.0 mm; the distance between the outlet of the nozzle and the inlet of the mixing chamber is 3.6 mm;

preferably, the mixing chamber is cylindrical with an axial length of 16mm and a radial diameter of 3.6 mm.

Preferably, the axial length of the diffusion chamber is 45.72mm, the opening angle is 5 degrees, and the diameter of the outlet is 10 mm;

preferably, the diameter of the injection fluid pipeline is 6mm, and the diameter of the bypass secondary flow pipeline is 1 mm;

preferably, the working fluid inlet is 6mm in diameter and is axially a stepped cylinder.

Preferably, the suction chamber, the mixing chamber, the pressure expansion chamber, the injection fluid pipeline and the bypass secondary flow pipeline are integrated.

Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

the ejector with the bypass inlet structure provided by the invention fully utilizes a large low-pressure area in the ejector mixing chamber and the fluid pressure is obviously lower than the pressure of secondary flow backflow no matter under the design working condition or the non-design working condition, and a bypass secondary flow pipeline is introduced, so that the ejection ratio is increased, and the hydrogen backflow efficiency of the ejector is improved. Meanwhile, the ejector reduces the pressure loss of the mixing of the working fluid and the secondary flow, improves the ejection efficiency, increases the fuel utilization rate of the fuel cell in the operation process, and improves the performance of the galvanic pile.

The ejector structure provided by the invention has the advantages that the suction chamber, the mixing chamber, the pressure expansion chamber, the ejection fluid pipeline and the bypass secondary flow pipeline are integrated, and the processing difficulty is lower.

Drawings

Fig. 1 is a schematic three-dimensional structure diagram of an ejector according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the eductor of FIG. 1 according to embodiments of the present invention;

fig. 3 is a graph showing injection performance of the ejector shown in fig. 1 and a conventional ejector according to an embodiment of the present invention in a numerical simulation, the performance varying with an inlet pressure of a working fluid;

description of the labeling:

1: a working fluid (primary flow) line; 2: an ejector fluid (secondary flow) line; 3: a suction chamber; 4: a mixing chamber; 5: bypassing the secondary flow line; 6: a pressure expansion chamber; 7: a working fluid inlet; 8: a convergent nozzle; 9: a nozzle outlet; 10: a nozzle throat; 11: an ejector outlet.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The ejector is a passive device for recovering gas by utilizing pressure potential energy contained in huge pressure difference between the high-pressure gas storage tank and the fuel cell; the high-pressure working fluid flows through the convergent nozzle, pressure potential energy is converted into kinetic energy, the working fluid leaves the nozzle to be sucked into the suction chamber, a vacuum low-pressure area is generated, a part of momentum is transferred to the injection fluid in the suction chamber, the two fluids are fully mixed in the mixing chamber, the pressure is increased through the diffusion chamber, and finally the mixed fluid flows out. In the ejector with the bypass inlet structure, no matter under a design working condition or a non-design working condition, in order to fully utilize a large low-pressure area in a mixing chamber of the ejector, the pressure of fluid (the pressure of the fluid in the low-pressure area in the mixing chamber) is obviously lower than that of secondary flow backflow (the pressure of the injection fluid introduced into an injection fluid pipeline 2 and a bypass secondary flow pipeline 5 in the drawing 1 is generally called as secondary backflow; the injection fluid in the injection fluid pipeline 2 is main secondary backflow; and the bypass secondary flow pipeline 5 is bypass secondary backflow), and the pressure is introduced into the bypass secondary flow pipeline, so that the injection ratio is increased, and the hydrogen backflow efficiency of the ejector is improved. The ejector provided by the invention reduces the pressure loss of the mixing of the working fluid and the secondary flow, improves the ejection efficiency, increases the fuel utilization rate in the operation process of the fuel cell, and improves the performance of the galvanic pile.

Examples

As shown in fig. 1 and 2, the present embodiment provides an ejector having a bypass inlet structure, including: the device comprises a working fluid pipeline 1, an injection fluid pipeline 2, a suction chamber 3, a mixing chamber 4, a bypass secondary flow pipeline 5 and a diffusion chamber 6; the working fluid pipeline 1 is connected with the suction chamber 3; one side of the pressure expansion chamber 6 is provided with an ejector outlet 11 for mixed gas to flow out; a bypass secondary flow pipeline 5 is arranged at the joint of the mixing chamber 4 and the diffusion chamber 6; the inlet end of the injection fluid pipeline 2 and the inlet end of the bypass secondary flow pipeline 5 are both connected with the outlet of the proton exchange membrane fuel cell stack to recover unused fuel gas;

the working fluid conduit 1 comprises a working fluid inlet and a nozzle body; the inlet side of the working fluid pipeline 1 is provided with a working fluid inlet 7 which is connected with a high-pressure hydrogen storage tank; the nozzle body comprises a convergent nozzle 8, a nozzle outlet 9 and a nozzle throat 10; correspondingly, the shapes of the device are respectively a cylindrical section, a gradually-reducing section and a gradually-expanding section, and the device is in a funnel shape; the diameter of the throat 10 of the nozzle is 1.5 mm; the diameter of the nozzle outlet 9 is 2.0 mm; the outlet 9 of the nozzle is 3.6mm away from the inlet of the mixing chamber 4;

the mixing chamber 4 is integrally cylindrical, has the axial length of 16mm and the radial diameter of 3.6mm, and is used for fully mixing working fluid and ejection fluid;

the axial length of the pressure expansion chamber 6 is 45.72mm, the opening angle is 5 degrees, and the diameter of an outlet is 10 mm; the device is used for converting the kinetic energy of the mixed fluid into pressure potential energy and inputting the pressure potential energy to the inlet of the proton exchange membrane fuel cell stack;

the injection fluid pipeline 2 is positioned outside the suction chamber 3 and has the diameter of 6 mm; the bypass secondary flow pipeline 5 is positioned at the joint of the mixing chamber 4 and the diffusion chamber 6, and the diameter of the bypass secondary flow pipeline is 1 mm;

the diameter of the working fluid inlet 7 is 6mm, and the working fluid inlet is axially a stepped cylinder;

the suction chamber 3, the mixing chamber 4, the diffusion chamber 6, the injection fluid pipeline 2 and the bypass secondary flow pipeline 5 are integrated, and the processing difficulty is small.

As shown in fig. 2, when the fuel cell vehicle is running, the high-pressure working fluid flows through the convergent nozzle 8, the flow velocity is increased due to the reduction of the flow cross-sectional area, the pressure potential energy is converted into kinetic energy, and the working fluid leaves the working fluid pipeline 1 and enters the suction chamber 3 to generate a vacuum low-pressure region; a part of momentum is transferred to the first injection fluid in the suction chamber 3, the working fluid and the first injection fluid are fully mixed in the mixing chamber 4, meanwhile, the second injection fluid bypassing the secondary flow pipeline 5 is sucked into the mixing chamber 4, then the three fluids are fully mixed, enter the pressure expansion chamber 6 to reduce the speed and increase the pressure, and finally enter the fuel cell from the ejector outlet 11;

in the embodiment, the performance of the ejector provided by the invention is verified by using a numerical simulation method, the ejector shown in fig. 2 and the ejector without the bypass secondary flow pipeline 5 are subjected to numerical simulation by using fluent software to obtain the ejection performance under different pressures of the working fluid inlet 7, and as shown in fig. 3, the pressure of the working fluid inlet 7 is changed through numerical simulation calculation, and the performance of the ejector with the bypass secondary flow pipeline 5 is improved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.