A steam ejector and a method of ejecting

Abstract

The application discloses a steam ejector and an ejecting method, and belongs to the technical field of steam ejectors. The steam ejector comprises, from left to right, a receiving chamber, a mixing chamber and a diffuser chamber which are sequentially connected; the receiving chamber is provided with a nozzle at an inlet end; a fluid channel is arranged below the receiving chamber; the mixing chamber comprises a converging section and a throat section connected to a right end of the converging section; the converging section is in a hollow cylindrical shape; a drainage groove is arranged below an inlet end of the converging section, and the drainage groove is used for storing condensate generated due to phase change during movement of steam; a drainage hole is arranged below the drainage groove; an adjusting assembly is matched with the drainage hole, and the adjusting assembly is used for discharging the condensate accumulated in the drainage groove. The steam ejector can effectively solve the problem that the entraining performance is reduced due to accumulated liquid at an inlet of a mixing chamber of an existing steam ejector.

Description

Technical Field

[0001] This invention relates to the field of steam ejector technology, and more specifically to a steam ejector and ejection method. Background Technology

[0002] A steam ejector is a vacuum-generating device, representing the application of jet technology in heat transfer. Steam ejectors are characterized by their simple structure and high stability, and are widely used in chemical, refrigeration, and other fields.

[0003] In the prior art, for example, Chinese Patent CN 111946673 B discloses a steam ejector, including a receiving chamber, a mixing chamber, and a diffuser chamber that are interconnected, and a nozzle disposed at the inlet of the receiving chamber, with an air inlet located below the receiving chamber; the mixing chamber includes a contraction section and a transition section, and the nozzle includes an inlet section, a tapering section, a throat section, and an expansion section; the transition section and the throat section are hollow cylinders. A structural optimization method for a steam ejector is also disclosed, including CFD numerical simulation, establishing an objective function model, and structural optimization calculations. The steam ejector optimized by this invention has good performance coefficients, low gas consumption, reasonable overall design, minimized volume, and low operating costs.

[0004] However, the energy transfer in a steam ejector relies on the mixing, friction, and impact between fluids, resulting in highly complex internal flow conditions, often accompanied by special flow phenomena such as shock waves, congestion, and phase change flow. When steam experiences rapid cooling under supersonic flow, non-equilibrium condensation occurs. A portion of the condensate forms large droplets at the mixing chamber inlet, and due to the obstruction of the incoming steam flow, these droplets accumulate locally near the inlet, causing liquid accumulation. This accumulation reduces the flow area of ​​the ejector steam, lowers its mass flow rate, and ultimately degrades the ejector's performance. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a steam ejector and injection method, aiming to solve the problem of decreased ejection performance due to liquid accumulation at the mixing chamber inlet of existing steam ejectors. To achieve the above objective, this invention provides the following technical solution:

[0006] A steam ejector includes a receiving chamber, a mixing chamber, and a diffuser chamber connected sequentially from left to right; a nozzle is provided at the inlet end of the receiving chamber, and an ejector fluid channel is provided below the receiving chamber; the mixing chamber includes a converging section and a throat section connected to the right end of the converging section; the converging section is hollow cylindrical; a flow channel is provided below the inlet end of the converging section, the flow channel being used to store condensate generated by the phase change of steam during its movement; a drain hole is provided below the flow channel; an adjustment component is fitted onto the drain hole, the adjustment component being used to discharge the condensate accumulated in the flow channel.

[0007] Furthermore, the adjusting assembly includes a bolt that is sealed to the drain hole.

[0008] Furthermore, the regulating component includes a guide tube; one end of the guide tube is connected to the drainage groove through a drain hole, and the other end of the guide tube is connected to the ejector fluid channel.

[0009] Furthermore, the inner wall of the drainage channel is provided with a membrane with selective permeability, which is used to allow liquid to pass through while blocking gas from passing through.

[0010] Furthermore, the drainage channel is filled with a porous medium.

[0011] Furthermore, the inlet angle of the drainage channel is 30° to 60°.

[0012] Furthermore, the depth of the drainage channel is one-fifth to one-third of the diameter of the inlet of the tapering section.

[0013] Furthermore, the length of the drainage channel is one-quarter to one-half the length of the tapered section.

[0014] Furthermore, the receiving chamber, mixing chamber, diffuser chamber, and diversion channel are all made of stainless steel.

[0015] A steam ejector injection method is provided, which employs the aforementioned steam ejector, wherein working steam is injected into the receiving chamber through a nozzle, and ejector steam enters the receiving chamber through an ejector fluid channel; the working steam and ejector steam are mixed in a mixing chamber and then discharged through a diffuser chamber.

[0016] The beneficial effects of this invention are:

[0017] 1. The steam ejector provided by the present invention can store the condensate accumulated at the inlet of the mixing chamber by adding a diversion groove structure, thereby solving the problem of reduced steam flow area caused by condensate accumulation;

[0018] 2. The steam ejector provided by this invention, by setting a drain hole and a guide pipe structure on the diversion tank, can store and return the condensate accumulated at the inlet of the mixing chamber, solving the problem of reduced steam flow area caused by condensate accumulation, thereby solving the problem of reduced steam mass flow rate and improving the ejection performance of the steam ejector; the condensate stored in the diversion tank can be returned to the ejector fluid channel through the guide pipe, achieving the effect of recycling;

[0019] 3. The steam ejector provided by the present invention can effectively recover condensate and avoid the phenomenon of high-speed steam flowing back through the guide pipe by setting a membrane with selective permeation function in the diversion channel;

[0020] 4. The steam ejector provided by the present invention can effectively fill the steam ejector by setting a porous medium in the diversion channel, thereby reducing the impact on the ejection performance of the steam ejector; and can also effectively store and absorb condensate. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a steam ejector provided in Embodiment 2 of the present invention;

[0022] Figure 2 This is a schematic diagram of the overall structure of a steam ejector provided in Embodiment 3 of the present invention;

[0023] Figure 3 yes Figure 2 Enlarged schematic diagram of the structure at point A in the middle;

[0024] Figure 4 This is a schematic diagram of the structure of the diversion groove of a steam ejector provided by the present invention;

[0025] Figure 5 This invention simulates the pressure cloud diagram of a steam ejector with different inlet angles for the diversion channel.

[0026] Figure 6 This is a graph showing the experimental results of the effect of different inlet angles of the diversion channel on the ejector performance of the steam ejector;

[0027] Figure 7 This invention simulates the pressure cloud diagram of a steam ejector with diversion channels of different depths.

[0028] Figure 8 This is a graph showing the experimental results of the effect of different depths of the diversion channel on the ejection performance of the steam ejector;

[0029] Figure 9 This invention simulates the pressure cloud diagram of a steam ejector with diversion channels of different lengths.

[0030] Figure 10This is a graph showing the experimental results of the effect of different lengths of the diversion channel on the ejection performance of the steam ejector;

[0031] In the attached diagram: 1-receiving chamber, 2-mixing chamber, 21-contraction section, 22-throat section, 3-diffuser chamber, 4-nozzle, 5-ejector fluid channel, 6-drainage groove, 7-bolt, 8-guide tube, 9-membrane, 10-porous medium. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited to the following embodiments.

[0033] Example 1:

[0034] See attached Figures 1-10 A steam ejector includes a receiving chamber 1, a mixing chamber 2, and a diffuser chamber 3 connected sequentially from left to right; a nozzle 4 is provided at the inlet end of the receiving chamber 1, and an ejector fluid channel 5 is provided below the receiving chamber 1; the mixing chamber 2 includes a tapered section 21 and a throat section 22 connected to the right end of the tapered section 21; the tapered section 21 is a hollow cylinder; a flow channel 6 is provided below the inlet end of the tapered section 21, the flow channel 6 being used to store condensate generated by the phase change of steam during its movement; a drain hole is provided below the flow channel 6; an adjustment component is fitted onto the drain hole, the adjustment component being used to discharge the condensate accumulated in the flow channel 6. As described above, the steam ejector provided by this invention includes a receiving chamber 1, a converging section 21, a throat section 22, and a diffuser chamber 3 connected sequentially from left to right. A nozzle 4 is provided at the inlet end of the receiving chamber 1, and an ejector fluid channel 5 is provided below the receiving chamber 1. A guide groove 6 is provided below the inlet end of the converging section 21, and the guide groove 6 and the converging section 21 are connected as a single unit. The guide groove 6 can store the condensate generated by the phase change of steam during its movement. During operation, working steam enters the receiving chamber 1 through the nozzle 4, and ejected steam enters the receiving chamber 1 through the ejector fluid channel 5. They then flow together through the mixing chamber 2 for mixing, and finally exit through the diffuser chamber 3. The generated condensate can be temporarily stored in the guide groove 6, and the condensate in the guide groove 6 can be discharged through a drain hole and an adjusting component located below the guide groove 6. This invention, by adding the guide groove 6, can store the condensate accumulated at the inlet of the mixing chamber 2, solving the problem of reduced ejector steam flow area caused by condensate accumulation, thereby improving the ejector performance of the steam ejector.

[0035] Example 2:

[0036] See attached Figures 1-10 Based on Embodiment 1, the adjusting assembly includes a bolt 7, which is sealed to the drain hole. As can be seen from the above structure, as... Figure 1As shown, specifically, the adjusting component includes bolt 7, which can be used to seal the drain hole of the diversion channel 6. When the condensate accumulates to a certain level, bolt 7 can be adjusted to drain the condensate. During operation, working steam enters the receiving chamber 1 through nozzle 4, and ejector steam enters the receiving chamber 1 through ejector fluid channel 5. They then flow together through the mixing chamber 2 for mixing, and the resulting condensate is stored in the diversion channel 6. Since the condensate accumulates in the diversion channel 6 at the inlet of the mixing chamber 2, it does not cause a decrease in the flow area of ​​the ejector steam, thus the ejector performance of the steam ejector will not be affected. After the steam ejector has been running for a period of time, when the condensate in the diversion channel 6 accumulates to a certain level, bolt 7 at the bottom of the diversion channel 6 can be adjusted to open the drain hole for drainage. After drainage is completed, adjusting bolt 7 allows the steam ejector to continue operating.

[0037] Example 3:

[0038] See attached Figures 1-10 Based on Embodiment 1, the adjusting assembly includes a guide pipe 8; one end of the guide pipe 8 is connected to the drainage groove 6 through a drain hole, and the other end of the guide pipe 8 is connected to the ejector fluid channel 5. From the above structure, it can be seen that, as... Figure 2 As shown, specifically, the regulating component includes a guide pipe 8. One end of the guide pipe 8 is connected to the drainage channel 6 via a drain hole, and the other end is connected to the ejector fluid channel 5. That is, the drainage channel 6 and the ejector fluid channel 5 are connected through the guide pipe 8. The condensate produced during the operation of the steam ejector is stored in the drainage channel 6 and then flows back to the ejector fluid channel 5 through the guide pipe 8. This solves the problem of reduced ejector steam flow area caused by condensate accumulation, thereby addressing the issue of reduced ejector performance. Furthermore, since the condensate ultimately flows back to the water storage tank below the ejector fluid channel 5, it also achieves a recycling effect.

[0039] The inner wall of the drainage channel 6 is provided with a selectively permeable membrane 9, which allows liquid to pass through while blocking gas. As can be seen from the above structure, during the return of the condensate to the ejector fluid channel 5, entrainment of vapor is inevitable. The membrane 9 is a selectively permeable membrane, characterized in that only liquid can pass through, while gas cannot. Figure 3 As shown, a selectively permeable membrane 9 is provided on the inner wall of the diversion channel, allowing only condensate to flow in, which can effectively prevent steam inside the steam ejector from entering the guide pipe 8. This invention does not limit the type of membrane 9; any membrane with selective permeability that meets the usage requirements can be used. For example, the selectively permeable membrane 9 can be an existing polyvinyl alcohol membrane.

[0040] The drainage channel 6 is filled with a porous medium 10. As can be seen from the above structure, the drainage channel 6 is located below the inlet end of the tapering section 21 and the drainage channel 6 protrudes downward. The setting of the drainage channel 6 changes the original steam flow area and will have a certain negative impact on the ejection performance. Therefore, a porous medium 10 is set in the drainage channel 6. The porous medium 10 can effectively fill the drainage channel 6 and reduce the impact on the ejection performance of the steam ejector; it can also effectively store and absorb condensate. The porous medium 10 can be an existing foam porous material. For example, the article "Preparation and Performance Study of Foam Porous Water Absorbent Material" published by Zhao Hongkai et al. mentions a foam porous water absorbent material with a good water absorption effect. For details, please refer to the literature: [1] Zhao Hongkai, Zhang Kehan, Rui Shoupeng. Preparation and Performance Study of Foam Porous Water Absorbent Material [J]. Modern Chemical Industry, 2021, 41(04): 146-150.

[0041] The inlet angle of the drainage channel 6 is 30° to 60°. From the above structure, it can be seen that... Figure 4 As shown, the length of the drainage channel 6 is l, the depth of the drainage channel 6 is h, and the inlet angle of the drainage channel 6 is θ. Figure 5 As shown, the simulation results of the steam ejector pressure cloud diagrams for the guide channel 6 with different inlet angles are illustrated. The pressure cloud diagrams show that different inlet angles cause changes in the pressure before and after the guide channel 6, and also affect the pressure along the central axis. Preferably, the inlet angle of the guide channel 6 is 45°. When θ = 45°, the pressure on the left side of the guide channel 6 is lower, which is beneficial for the entrainment effect of the working steam on the ejector steam, thus improving the ejector performance. The ejector coefficient μ is an important indicator for evaluating the working performance of a steam ejector. It represents the mass of ejector steam that a unit mass of working steam can draw under certain operating conditions. Numerically, it can be expressed as the ratio of the mass flow rate of the ejector steam to the mass flow rate of the working steam, i.e.:

[0042]

[0043] Where: m p This indicates the mass flow rate of the working steam, expressed in kg / s; m s This indicates the mass flow rate of the ejector steam, expressed in kg / s. For example... Figure 6 As shown, by comparing the changes in ejector performance with different inlet angles of the diversion channel 6, it can be seen that the steam ejector has the highest ejector performance when the inlet angle of the diversion channel 6 is 45°.

[0044] The depth of the drainage groove 6 is one-fifth to one-third of the inlet diameter of the tapered section 21. As can be seen from the above structure, the tapered section 21 is a hollow cylinder with its axis extending in the left-right direction. The inlet diameter of the tapered section 21 is also the diameter of its leftmost end. Figure 7As shown, simulations were performed on the pressure cloud diagrams of steam ejectors with different depths of the guide channel 6, where the inlet diameter of the tapered section 21 is 24 mm. The pressure cloud diagrams show that a pressure difference is generated inside the guide channel 6 at different depths, with lower pressure closer to the steam inlet and higher pressure further away. As the depth of the guide channel 6 increases, the pressure difference gradually decreases, and when the depth exceeds the optimal depth, the pressure difference gradually disappears. Preferably, the depth of the guide channel 6 is one-quarter of the inlet diameter of the tapered section 21. Meanwhile, as... Figure 8 As shown, comparing the effects of different depths of the diversion groove 6 on the ejector performance, it can be seen that when the depth of the diversion groove 6 is one-fifth to one-third of the inlet diameter of the tapered section 21, the steam ejector has higher ejector performance. Among them, when the depth of the diversion groove 6 is one-quarter of the inlet diameter of the tapered section 21, the steam ejector has the highest ejector performance.

[0045] The length of the drainage channel 6 is one-quarter to one-half the length of the tapered section 21. From the above structure, it can be seen that... Figure 9 As shown, simulations were performed on the pressure cloud diagrams of steam ejectors with different lengths of the guide channel 6, where the length of the tapered section 21 is 90 mm. The pressure cloud diagrams show that pressure differences are generated before and after the guide channel 6 of different lengths, with lower pressure closer to the steam inlet and higher pressure further away. As the length of the guide channel 6 increases, the pressure difference gradually decreases. When the length exceeds the optimal length, the pressure difference gradually disappears, and a sudden increase in pressure occurs from the tapered section 21, leading to a sharp decline in ejector performance. Preferably, the length of the guide channel 6 is one-third the length of the tapered section 21. Meanwhile, as... Figure 10 As shown, comparing the effects of different lengths of the guide groove 6 on the ejector performance, it can be seen that when the length l of the guide groove 6 is less than one-third of the length of the tapered section 21, the ejector coefficient of the steam ejector gradually increases; when the length l of the guide groove 6 is greater than one-third of the length of the tapered section 21, the ejector performance of the steam ejector decreases significantly; when the length l of the guide groove is one-third of the length of the tapered section 21, the ejector performance is improved the most.

[0046] The receiving chamber 1, mixing chamber 2, diffuser chamber 3, and diversion channel 6 are all made of stainless steel. As can be seen from the above structure, the use of stainless steel in the receiving chamber 1, mixing chamber 2, diffuser chamber 3, and diversion channel 6 improves the service life of the steam ejector.

[0047] Example 4:

[0048] See attached Figures 1-4Based on Embodiment 3, a steam ejector injection method is provided, employing the aforementioned steam ejector. High-pressure steam is injected into the receiving chamber 1 through nozzle 4, and ejector steam enters the receiving chamber 1 through ejector fluid channel 5. The high-pressure steam and ejector steam mix in the mixing chamber 2 and then exit through the diffuser chamber 3. As can be seen from the above structure, during operation, working steam enters the receiving chamber 1 through nozzle 4, and ejector steam enters the receiving chamber 1 through ejector fluid channel 5. They then flow together through the mixing chamber 2 for mixing and finally exit through the diffuser chamber 3. The resulting condensate is stored in the guide trough 6 and then flows back to the ejector fluid channel 5 through the guide pipe 8. Since the condensate at the inlet of the mixing chamber 2 no longer causes a decrease in the ejector steam flow area due to accumulation, the ejector performance will not be affected.

[0049] The refrigerant used in the steam ejector provided by this invention is water vapor, but it is not limited to water vapor. It can also be extended to a series of refrigerants that can undergo phase change, such as water, carbon dioxide, hydrogen, and oxygen.

[0050] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A steam ejector, characterized in that: The system includes a receiving chamber (1), a mixing chamber (2), and a diffuser chamber (3) connected sequentially from left to right. The receiving chamber (1) has a nozzle (4) at its inlet end and an ejector fluid channel (5) below it. The mixing chamber (2) includes a tapered section (21) and a throat section (22) connected to the right end of the tapered section (21). The tapered section (21) is a hollow cylinder. A flow channel (6) is provided below the inlet end of the tapered section (21). The inlet angle of the flow channel (6) is 30° to 60°. The flow channel (6) is used to store the condensate generated by the phase change of steam during its movement. A drain hole is provided below the flow channel (6). An adjustment component is fitted on the drain hole. The adjustment component is used to discharge the condensate accumulated in the flow channel (6). The regulating component includes a guide pipe (8); one end of the guide pipe (8) is connected to the drainage groove (6) through a drain hole, and the other end of the guide pipe (8) is connected to the ejector fluid channel (5).

2. A steam ejector according to claim 1, characterized in that: The inner wall of the drainage channel (6) is provided with a membrane (9) with selective permeability function, which is used to allow liquid to pass through while preventing gas from passing through.

3. A steam ejector according to claim 1, characterized in that: The drainage channel (6) is filled with a porous medium (10).

4. A steam ejector according to claim 1, characterized in that: The depth of the drainage channel (6) is one-fifth to one-third of the inlet diameter of the tapering section (21).

5. A steam ejector according to claim 1, characterized in that: The length of the drainage channel (6) is one-quarter to one-half the length of the tapered section (21).

6. A steam ejector according to claim 1, characterized in that: The receiving chamber (1), mixing chamber (2), diffuser chamber (3), and diversion channel (6) are all made of stainless steel.

7. A steam ejector injection method, characterized in that: Using a steam ejector as described in any one of claims 1 to 6, working steam is injected into the receiving chamber (1) through the nozzle (4), and ejector steam enters the receiving chamber (1) through the ejector fluid channel (5); the working steam and ejector steam are mixed in the mixing chamber (2) and then discharged through the diffuser chamber (3).

Images