Patent Publication Number: US-2021184232-A1

Title: Ejector nozzle and ejector including same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0167676 filed in the Korean Intellectual Property Office on Dec. 16, 2019, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an ejector nozzle and an ejector including the same, and more particularly, to an ejector nozzle, which satisfies both a low-flow rate region and a high-flow rate region, and an ejector including the same. 
     BACKGROUND ART 
     A diameter of a nozzle is considered as an important factor in a system that moves a fluid by using an ejector. 
     If the nozzle has a large size, it is easy to implement a desired performance in a high-flow rate section, but a flow velocity is decreased, and a performance of the ejector deteriorates in a low-flow rate section. In contrast, if the nozzle has a small size, a high flow velocity may be generated in the low-flow rate section, but the nozzle is difficult to utilize in the high-flow rate section because it is difficult to allow a large amount of fluid in the high-flow rate section to pass through the nozzle. 
     Accordingly, there is a need for an ejector having a nozzle capable of dealing with various flow rates. 
     SUMMARY OF THE INVENTION 
     The present disclosure has been made in an effort to provide an ejector nozzle, which satisfies both a low-flow rate region and a high-flow rate region by changing a size of an entire flow path of the ejector nozzle based on a flow rate of a supplied fluid, and an ejector including the same. 
     The present disclosure has also been made in an effort to provide an ejector nozzle, which may reduce costs, implement high efficiency with a compact structure, and thus improve reliability in respect to products and performances, and an ejector including the same. 
     An exemplary embodiment of the present disclosure provides an ejector nozzle including a first tube having a first flow path into which a fluid is introduced, and a second tube provided outside the first tube and having an inner diameter larger than an inner diameter of the first tube, the second tube defining a second flow path between the first tube and the second tube, in which the first tube further includes a communication port that penetrates the first tube to allow the first flow path to communicate with the second flow path and is openably and closably provided, and in which when the communication port is opened, a part of the fluid flowing in the first flow path is allowed to flow along the second flow path. 
     Another exemplary embodiment the present disclosure provides an ejector including an ejector nozzle, the ejector including an ejector body including a first inlet part into which a supply gas supplied from a hydrogen storage tank is introduced, and a second inlet part into which a recirculation gas, which is discharged from a fuel cell stack and recirculates to the fuel cell stack, is introduced, and an ejector nozzle provided in the ejector body and configured to eject the supply gas introduced into the first inlet part to circulate the recirculation gas, in which the ejector nozzle includes a first tube having a first flow path into which the supply gas is introduced, and a second tube provided outside the first tube and having an inner diameter larger than an inner diameter of the first tube, the second tube defining a second flow path between the first tube and the second tube, in which the first tube further includes a communication port that penetrates the first tube to allow the first flow path to communicate with the second flow path and is openably and closably provided, and in which when the communication port is opened, a part of the supply gas flowing in the first flow path is allowed to flow along the second flow path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view illustrating an example of a fuel cell system to which the present disclosure is applied. 
         FIG. 2  is a cross-sectional view schematically illustrating an ejector according to the present disclosure. 
         FIG. 3  is a cross-sectional view illustrating an ejector nozzle according to the present disclosure. 
         FIG. 4  is a cross-sectional view illustrating a state in which a communication port of the ejector nozzle illustrated in  FIG. 3  is opened. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. 
     First, the exemplary embodiments described below are exemplary embodiments suitable for understanding technical features of an ejector nozzle and an ejector including the same according to the present disclosure. However, the present disclosure is not limitedly applied to the exemplary embodiments described below, the technical features of the present disclosure are not limited by the exemplary embodiment described herein, and various modifications can be implemented within the technical scope of the present disclosure. 
     An ejector  50  including an ejector nozzle  100  according to the present disclosure may be applied to a fuel cell system.  FIG. 1  illustrates an example of a fuel cell system. 
     Referring to  FIG. 1 , a fuel cell system  10  according to the present disclosure includes a fuel cell stack  20 , a compressor (not illustrated) configured to compress air and supply the compressed air to the fuel cell stack  20 , and a hydrogen storage tank  30  configured to supply hydrogen to the fuel cell stack  20 . The air compressed by the compressor may be supplied to an air electrode  21  of the fuel cell stack  20  along an air supply line. The hydrogen stored in the hydrogen storage tank  30  may be supplied to a fuel electrode  23  of the fuel cell stack  20  along a hydrogen supply line  32 . A hydrogen supply valve  31  configured to control the supply of the hydrogen may be provided in the hydrogen supply line  32 . 
     The fuel cell stack  20  may have various structures capable of producing electricity by means of an oxidation-reduction reaction between fuel (e.g., hydrogen) and an oxidant (e.g., air). The present disclosure is not restricted or limited by the structure of the fuel cell stack  20 . 
     The fuel cell system  10  includes a recirculation line  40  through which the gas (hydrogen) discharged from the fuel cell stack  20  recirculates to the fuel cell stack  20 . For convenience of description, the hydrogen, which is gas that circulates to the fuel cell stack through the recirculation line  40 , is referred to as a recirculation gas, and the hydrogen, which is gas supplied from the hydrogen storage tank to the fuel cell stack  20 , is referred to as a supply gas. The recirculation gas and the supply gas may be hydrogen. 
     A water trap  60  may be provided in the recirculation line  40  to remove condensate water contained in the hydrogen which is the gas that recirculates to the fuel cell stack  20 . The ejector  50  may be provided in the recirculation line  40  to supply the supply gas and the recirculation gas. 
       FIG. 2  illustrates the ejector  50  including the ejector nozzle  100  according to the present disclosure. 
     Referring to  FIG. 2 , the ejector  50  including the ejector nozzle  100  according to the present disclosure includes an ejector body  51  and the ejector nozzle  100 . 
     The ejector body  51  includes a first inlet part  53  into which the supply gas Q 1  supplied from the hydrogen storage tank  30  is introduced, and a second inlet part  54  into which the recirculation gas Q 2 , which is discharged from the fuel cell stack  20  and recirculates to the fuel cell stack  20 , is introduced. In addition, the ejector body  51  may include a chamber  52  in which a mixture (Q 1 +Q 2 ) of the supply gas Q 1  and the recirculation gas Q 2 , which are introduced from the first inlet part  53  and the second inlet part  54 , respectively, flows. 
     The ejector nozzle  100  may be provided in the ejector body  51  and may eject the supply gas Q 1  introduced into the first inlet part  53  to circulate the recirculation gas Q 2 . 
     Specifically, the ejector  50  allows the high-pressure supply gas Q 1 , which is supplied from the hydrogen storage tank  30 , to flow at a high velocity through the ejector nozzle  100 , and as a result, the low-pressure recirculation gas Q 2  may be drawn and flow to the fuel cell stack  20 . That is, the ejector  50  may act as a kind of pump that ejects the supply gas Q 1  from the ejector nozzle  100  and draws the recirculation gas Q 2 . 
       FIGS. 3 and 4  illustrate the ejector nozzle  100  according to the present disclosure. 
     Referring to  FIGS. 3 and 4 , the ejector nozzle  100  may be provided in the form of a dual tube including a first tube  110  and a second tube  120 . The first tube  110  includes a first flow path  112  into which the fluid is introduced. The second tube  120  is provided outside the first tube  110 , has an inner diameter larger than an inner diameter of the first tube  110 , and defines a second flow path  122  between the first tube  110  and the second tube  120 . 
     The fluid Q 1  introduced into the ejector nozzle  100  to be described below may be the supply gas Q 1  to be supplied to the fuel cell stack  20  as described above. However, the ejector nozzle  100  according to the present disclosure is not limited as being used for the ejector  50  provided in the fuel cell system  10 , but the ejector nozzle  100  may be applied to the ejectors  50  used in various fields. Further, the fluid introduced into the ejector nozzle  100  is not limited to the supply gas Q 1  to be supplied to the fuel cell stack  20 . 
     The first tube  110  and the second tube  120  may be provided as hollow tubes having different sizes. The first flow path  112  may be formed in the first tube  110 , and the second flow path  122  may be positioned between an outer surface of the first tube  110  and an inner surface of the second tube  120 . The fluid may be introduced through an inlet port  114  of the first tube  110 , flow along the first flow path  112 , and then be ejected. 
     The first tube  110  further includes a communication port  115  openably and closably provided and penetratively formed to allow the first flow path  112  to communicate with the second flow path  122 . When the communication port  115  is opened, a part of the fluid flowing through the first flow path  112  is allowed to flow along the second flow path  122 . 
     Specifically, the communication port  115  may be selectively opened, such that a part of the fluid introduced into the first flow path  112  may flow to the second flow path  122 . The fluid introduced into the first tube  110  may flow only along the first flow path  112  when the communication port  115  is closed, and the fluid introduced into the first tube  110  may flow along both the first flow path  112  and the second flow path  122  when the communication port  115  is opened. 
     Therefore, it is possible to obtain an effect of changing a diameter of an entire flow path that constitutes the nozzle. For example, it is possible to change the diameter of the entire flow path of the ejector nozzle  100  by opening or closing the communication port  115  based on a flow rate of the fluid introduced into the ejector nozzle  100 . Therefore, it is possible to provide a structure that satisfies both a low-flow rate region and a high-flow rate region by changing a size of the entire flow path of the ejector nozzle  100  based on the flow rate of the fluid to be supplied. 
     Specifically, when the fluid is introduced at a low flow rate, the communication port  115  is closed such that the fluid may flow only to the first flow path  112 . Therefore, the fluid may be discharged to the outside of the nozzle at a high flow velocity even though the flow rate is low. 
     When the fluid is introduced at a high flow rate, the communication port  115  is opened such that the fluid may flow along both the first flow path  112  and the second flow path  122 . Therefore, the size of the entire flow path through which the fluid passes is increased, such that the fluid may be allowed to pass at a high flow rate. 
     Referring to  FIGS. 3 and 4 , the present disclosure may further include opening/closing members  116  and elastic members  130 . The opening/closing member  116  may be provided in the first tube  110  in order to open or close the communication port  115 . 
     The elastic member  130  may be provided between the first tube  110  and the second tube  120  and may provide elastic force that allows the opening/closing member  116  to open or close the communication port  115  based on the flow rate of the fluid introduced into the first flow path  112 . In this case, the elastic member  130  may be configured as, but not limited to, an elastic spring. 
     As described above, the present disclosure may allow the opening/closing member  116  to perform the opening or closing operation, without a separate control means, by using the elastic member  130  that elastically operates based on a pressure in the nozzle which is determined in accordance with a flow rate. Therefore, the present disclosure may reduce costs and implement high efficiency with a compact structure, thereby improving reliability in respect to products and performances. 
     More specifically, the first tube  110  may further include a first body part  111  and a first discharge port  113 . 
     The communication port  115  may penetrate the first body part  111 , and the first flow path  112  may be formed in the first body part  111 . The first discharge port  113  may be provided at one side tip of the first body part  111  so that the fluid is discharged from the first discharge port  113 . 
     The second tube  120  may include a second body part  121  having the second flow path  122 , and a second discharge port  123  provided at one side tip of the second body so that the fluid is discharged from the second discharge port  123 . In this case, a diameter of the second discharge port  123  may be larger than a diameter of the first discharge port  113 . Therefore, a diameter of an entire discharge port, from which the fluid is discharged, may also be changed as the communication port  115  is opened or closed. 
     The opening/closing member  116  may be hingedly coupled to the first body part  111  so as to be able to open or close the communication port  115 . Specifically, the communication port  115  may penetrate a part of the first body part  111  and may be formed in the form of a hole as an example. However, the shape of the communication port  115  is not limited thereto, but the communication port  115  may be variously modified to have various shapes as long as the communication port  115  may allow the first flow path  112  and the second flow path  122  to communicate with each other. 
     The opening/closing member  116  may have various shapes as long as the opening/closing member  116  may close or open the communication port  115 . For example, the opening/closing member  116  may be connected to the first body part  111  by means of a hinge H so that one end of the opening/closing member  116  is disposed adjacent to the communication port  115 . Further, the opening/closing member  116  may be provided to be rotatable in a direction toward the second tube  120  about the portion connected by means of the hinge H. In addition, in the state in which the opening/closing member  116  closes the communication port  115 , the rotation of the opening/closing member  116  in the direction toward the first flow path  112  may be restricted. 
     The elastic member  130  may provide elastic force to the opening/closing member  116 . For example, one end of the elastic member  130  may be fixed to the inner surface of the second tube  120 , and the other end of the elastic member  130  may be fixed to the opening/closing member  116  in the first tube  110 . 
     When a flow rate of the fluid introduced into the first flow path  112  is within a reference range, the elastic member  130  elastically supports the opening/closing member  116  to allow the opening/closing member  116  to close the communication port  115 . In contrast, when a flow rate of the fluid introduced into the first flow path  112  exceeds the reference range, the elastic member  130  is elastically deformed by a pressure of the introduced fluid to allow the opening/closing member  116  to open the communication port  115 . 
     Specifically, when a flow rate of the introduced fluid is within the reference range (a low flow rate, see  FIG. 3 ), elastic supporting force of the elastic member  130  may allow the opening/closing member  116  to maintain a state in which the communication port  115  is closed. In this case, the fluid introduced into the first tube  110  may flow only through the first flow path  112  and then be ejected from the first discharge port  113 . Therefore, the fluid may be discharged at a high flow velocity even though the flow rate is low. 
     When a flow rate of the introduced fluid exceeds the reference range (a high flow rate, see  FIG. 4 ), a pressure of the introduced fluid overcomes the elastic force of the elastic member  130 , such that the opening/closing member  116  may open the communication port  115  while rotating in the direction toward the second tube  120 . In this case, the elastic member  130  may be compressed and deformed. When the communication port  115  is opened, the first flow path  112  and the second flow path  122  communicate with each other, such that a part of the fluid flowing to the first flow path  112  may be introduced into the second flow path  122 , and the fluid may be discharged through the first discharge port  113  and the second discharge port  123 . 
     Thereafter, when a flow rate of the introduced fluid is decreased again to be within the reference range, the opening/closing member  116  may close the communication port  115  while being rotated in the direction toward the first flow path  112  by elastic restoring force of the elastic member  130 . As described above, the present disclosure may deal with various flow rates. 
     According to the present disclosure, the diameter of the entire flow path in the ejector nozzle may be changed depending on the flow rate of the fluid introduced into the ejector nozzle. Therefore, it is possible to provide the structure that satisfies both the low-flow rate region and the high-flow rate region by changing the size of the entire flow path of the ejector nozzle based on the flow rate of the fluid to be supplied. 
     In addition, the present disclosure may allow the opening/closing member to perform the opening or closing operation, without a separate control means, by using the elastic member that elastically operates based on the pressure in the nozzle which is determined in accordance with the flow rate. Therefore, the present disclosure may reduce costs and implement high efficiency with a compact structure, thereby improving reliability in respect to products and performances. 
     While the specific exemplary embodiments of the present disclosure have been described above, the spirit and scope of the present disclosure are not limited to the specific exemplary embodiments, and those skilled in the art to which the present disclosure pertains may variously modify and change the present disclosure without departing from the subject matter of the present disclosure disclosed in the claims. 
     According to the present disclosure, the diameter of the entire flow path in the ejector nozzle may be changed depending on the flow rate of the fluid introduced into the ejector nozzle. Therefore, it is possible to provide the structure that satisfies both the low-flow rate region and the high-flow rate region by changing the size of the entire flow path of the ejector nozzle based on the flow rate of the fluid to be supplied. 
     In addition, the present disclosure may allow the opening/closing member to perform the opening or closing operation, without a separate control means, by using the elastic member that elastically operates based on the pressure in the nozzle which is determined in accordance with the flow rate. Therefore, the present disclosure may reduce costs and implement high efficiency with a compact structure, thereby improving reliability in respect to products and performances.