Apparatus and method for generating dual frequency oscillations in liquid film thickness

Abstract

This application provides an apparatus and method for generating dual-frequency oscillations in the thickness of a liquid film. The apparatus includes a supply module and a data acquisition module. The supply module includes multiple supply units arranged in parallel, each supply unit comprising a supply section and a disturbance section. The supply section supplies liquid to a liquid-liquid coaxial centrifugal nozzle, and the disturbance section emits vibrations of a preset frequency to the liquid-liquid coaxial centrifugal nozzle. The data acquisition module acquires vibration information and analyzes and processes the vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle generates dual-frequency oscillations. For the liquid-liquid coaxial centrifugal nozzle, a first inertial flow pulsation generator is used to apply disturbance to the inflow of the inner nozzle, and a second inertial flow pulsation generator is used to apply disturbance to the inflow of the outer nozzle. The oscillations of the inner and outer liquid films converge at the merged total liquid film, thereby causing the total liquid film thickness to generate dual-frequency oscillations.

Description

Technical Field

[0001] This application relates to the field of aerospace technology, and in particular to an apparatus and method for generating dual-frequency oscillations in the thickness of a liquid film. Background Technology

[0002] Liquid-liquid coaxial centrifugal nozzles are widely used in bicomponent liquid rocket engines. During engine operation, pressure fluctuations caused by combustion in the combustion chamber are fed back to the nozzle, resulting in fluctuations in nozzle parameters (propellant flow rate and pressure). The nozzle then feeds back these fluctuations to the supply line, causing pressure fluctuations in the supply line. The fluctuations in the supply line and the combustion chamber pressure together form fluctuations in the nozzle pressure drop, which in turn causes changes in the propellant flow rate. This effect propagates to the downstream combustion chamber and, under suitable conditions, can promote unstable combustion.

[0003] Disturbances in injection pressure can cause high-frequency flow pulsations within the nozzle. These pulsations are crucial parameters for injection dynamics and are significant for studying unstable combustion at low and medium frequencies. According to Bazarov's nozzle dynamics theory, the high-frequency flow pulsations at the centrifugal nozzle outlet are often caused by oscillations in the thickness of the liquid film adhering to the nozzle wall. Therefore, inducing dual-frequency or even multi-frequency oscillations within the nozzle is an extremely important step in conducting dynamic characteristic tests on liquid-liquid coaxial centrifugal nozzles.

[0004] Chinese invention patent application CN102410288A discloses a disc-type flow pulsation generator. A motor drives a disc on a shaft to rotate. The through-hole of the disc connects or closes with the liquid flow channel in the sleeve at regular intervals, controlling the opening and closing of the liquid flow channel to cause the flow rate (i.e., liquid film thickness) to oscillate according to an approximately sinusoidal pattern. The motor speed can be adjusted via a frequency converter to regulate the flow pulsation frequency. By adjusting the opening of the valve before entering the flow pulsation generator, flow pulsations of different amplitudes can be obtained.

[0005] However, the aforementioned disc-type flow pulsation generator can be used for general single-channel centrifugal nozzles to produce a single-frequency oscillation in the liquid film thickness within the nozzle. However, for liquid-liquid coaxial centrifugal nozzles widely used in rocket engines, the impact and fusion of the inner and outer liquid films at the nozzle's short indentation makes a single-frequency oscillation of the liquid film thickness insufficient for studying the dual-channel oscillation characteristics of the liquid-liquid coaxial centrifugal nozzle. Therefore, it is impossible to use a conventional device to produce dual-frequency oscillations in the liquid film thickness within the nozzle.

[0006] Therefore, there is an urgent need for a device and method to generate dual-frequency oscillations in the thickness of a liquid film, in order to solve the technical problems in the prior art to a certain extent. Summary of the Invention

[0007] The purpose of this application is to provide an apparatus and method for generating dual-frequency oscillations in liquid film thickness, which is particularly suitable for liquid-liquid coaxial centrifugal nozzles, and can also be applied to single centrifugal nozzles with double rows of tangential holes, thus solving the technical problem that the liquid film thickness in the centrifugal nozzle can only generate single-frequency oscillations in the prior art.

[0008] This application provides a device for generating dual-frequency oscillations in liquid film thickness, applicable to a liquid-liquid coaxial centrifugal nozzle. The liquid-liquid coaxial centrifugal nozzle includes an inner nozzle, an outer nozzle, and a housing; the inner nozzle and the outer nozzle are coaxially mounted on the housing; an electrode head is disposed below the outer nozzle; the device for generating dual-frequency oscillations in liquid film thickness includes: A supply module includes multiple supply units arranged in parallel; at least one of the supply units supplies liquid to the inner nozzle, and at least another supply unit supplies liquid to the outer nozzle; each supply unit includes a supply section and a disturbance section disposed in the supply section and close to the liquid-liquid coaxial centrifugal nozzle; the supply section is used to supply liquid to the liquid-liquid coaxial centrifugal nozzle, and the disturbance section is used to emit vibrations of a preset frequency to the liquid-liquid coaxial centrifugal nozzle; The acquisition module includes an imaging unit, a sensing unit, and a processing unit electrically connected to the imaging unit and the sensing unit respectively; the imaging unit corresponds to the nozzle of the liquid-liquid coaxial centrifugal nozzle and is used to capture spray images; the sensing unit is used to acquire vibration information of the liquid-liquid coaxial centrifugal nozzle; the processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film sprayed from the nozzle of the liquid-liquid coaxial centrifugal nozzle generates dual-frequency oscillation.

[0009] In the above technical solution, the supply unit further comprises two units, namely a first supply unit and a second supply unit; The first supply unit is connected to the inner nozzle and is used to supply liquid to the inner nozzle; The second supply unit is connected to the external nozzle and is used to supply liquid to the external nozzle.

[0010] In the above technical solution, the supply section of the first supply unit further includes: The first high-pressure nitrogen cylinder contains high-pressure nitrogen; and The first high-pressure liquid storage tank is connected to the first high-pressure nitrogen cylinder via a first gas pipe; a first inlet pressure sensor and a first pressure reducing valve are sequentially installed on the first gas pipe from the first high-pressure nitrogen cylinder to the first high-pressure liquid storage tank.

[0011] In the above technical solution, the disturbance part of the first supply unit further includes: A first signal generator having a first sinusoidal signal with a first preset frequency; A first power amplifier is electrically connected to the first signal generator; the first signal generator is capable of transmitting a sinusoidal signal of a preset frequency to the first power amplifier; the first power amplifier is capable of amplifying the first sinusoidal signal of the preset frequency into an amplified signal; and A first inertial flow pulsation generator has one end connected to the first power amplifier and the other end connected to the inner nozzle; the first power amplifier can transmit the amplified signal to the first inertial flow pulsation generator, which provides a first preset disturbance to the inner nozzle.

[0012] In the above technical solution, the first inertial flow pulsation generator further includes: A first exciter is connected to the first power amplifier; and The first rigid tube is installed vertically on the vibration table of the first exciter. One end of the first rigid tube is connected to the first high-pressure liquid storage tank through the first liquid pipe, and the other end is connected to the inner nozzle through the second liquid pipe. When the vibration table of the first exciter vibrates with a first preset disturbance, the preset disturbance can be transmitted to the inner nozzle in sequence through the first rigid tube and the second liquid pipe.

[0013] In the above technical solution, the supply section of the second supply unit further includes: The second high-pressure nitrogen cylinder contains high-pressure nitrogen; and The second high-pressure liquid storage tank is connected to the second high-pressure nitrogen cylinder through a second gas pipe; a second first inlet pressure sensor and a second pressure reducing valve are sequentially installed on the second gas pipe from the second high-pressure nitrogen cylinder to the second high-pressure liquid outlet tank. The disturbance part of the second supply unit includes: The second signal generator has a second sinusoidal signal with a second preset frequency; A second power amplifier is electrically connected to the second signal generator; the second signal generator can transmit the sinusoidal signal of the preset frequency to the second power amplifier; the second power amplifier can amplify the second sinusoidal signal of the preset frequency into an amplified signal; and The second inertial flow pulsation generator has one end connected to the second power amplifier and the other end connected to the inner nozzle; the second power amplifier can transmit the amplified signal to the second inertial flow pulsation generator, which then provides a second preset disturbance to the outer nozzle; The second inertial flow pulsation generator includes: A second exciter is connected to the power amplifier; and The second rigid tube is installed vertically on the vibration table of the second exciter. One end of the second rigid tube is connected to the second high-pressure liquid storage tank through the third liquid tube, and the other end is connected to the inner nozzle through the fourth liquid tube. When the vibration table of the second exciter vibrates with the second preset disturbance, the second preset disturbance can be transmitted to the outer nozzle in sequence through the second rigid tube and the fourth liquid tube.

[0014] In the above technical solution, the imaging unit further includes: A light source provides light; and A high-speed camera is positioned opposite the light source on both sides of the spray field of the liquid-liquid coaxial centrifugal nozzle to capture spray images.

[0015] In the above technical solution, the sensing unit further includes: A first pressure sensor is disposed at the inlet of the inner nozzle to collect the first pressure at the inlet of the inner nozzle; A second pressure sensor is disposed in the liquid collection chamber of the inner nozzle and is used to collect the second pressure of the liquid collection chamber of the inner nozzle. A third pressure sensor is installed at the inlet of the external nozzle to collect the third pressure at the inlet of the external nozzle. A fourth pressure sensor is installed in the liquid collection chamber of the external nozzle to collect the fourth pressure in the liquid collection chamber of the external nozzle. A first accelerometer is installed in the first rigid tube and is used to measure the first acceleration of the first rigid tube. A second accelerometer, installed in the second rigid tube, is used to measure the second acceleration of the second rigid tube; and A thickness sensor, electrically connected to the electrode head, is used to measure the thickness of the swirling liquid film adhering to the inner wall of the liquid-liquid coaxial centrifugal nozzle.

[0016] In the above technical solution, the processing unit further includes: The data acquisition card is electrically connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor, the first accelerometer, the second accelerometer, and the thickness sensor, respectively. The computer, together with the high-speed camera and the data acquisition card, can analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

[0017] This application also provides a method for generating dual-frequency oscillations in the liquid film thickness within a liquid-liquid coaxial centrifugal nozzle, based on an apparatus for generating dual-frequency oscillations in the liquid film thickness, comprising the following steps: Start-up procedure: Turn on the first supply unit and the second supply unit respectively to supply liquid working fluid to the inner nozzle and the outer nozzle; Disturbance application step: Disturbance is applied to the inner nozzle and the outer nozzle respectively using the disturbance part of the first supply unit and the disturbance part of the second supply unit; Signal acquisition steps: Vibration information is acquired using the imaging unit and sensors; Analysis and processing steps: The processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

[0018] Compared with the prior art, this application has the following beneficial effects: This application provides a device for generating dual-frequency oscillations in liquid film thickness, applicable to a liquid-liquid coaxial centrifugal nozzle. The liquid-liquid coaxial centrifugal nozzle includes an inner nozzle, an outer nozzle, and a housing; the inner nozzle and the outer nozzle are coaxially mounted on the housing; an electrode head is disposed below the outer nozzle; the device for generating dual-frequency oscillations in liquid film thickness includes: A supply module includes multiple supply units arranged in parallel; at least one of the supply units supplies liquid to the inner nozzle, and at least another supply unit supplies liquid to the outer nozzle; each supply unit includes a supply section and a disturbance section disposed in the supply section and close to the liquid-liquid coaxial centrifugal nozzle; the supply section is used to supply liquid to the liquid-liquid coaxial centrifugal nozzle, and the disturbance section is used to emit vibrations of a preset frequency to the liquid-liquid coaxial centrifugal nozzle; The acquisition module includes an imaging unit, a sensing unit, and a processing unit electrically connected to the imaging unit and the sensing unit respectively; the imaging unit corresponds to the nozzle of the liquid-liquid coaxial centrifugal nozzle and is used to capture spray images; the sensing unit is used to acquire vibration information of the liquid-liquid coaxial centrifugal nozzle; the processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film sprayed from the nozzle of the liquid-liquid coaxial centrifugal nozzle generates dual-frequency oscillation.

[0019] A method based on a device that generates dual-frequency oscillations in the thickness of a liquid film includes the following steps: Start-up procedure: Turn on the first supply unit and the second supply unit respectively to supply liquid working fluid to the inner nozzle and the outer nozzle; Disturbance application step: Disturbance is applied to the inner nozzle and the outer nozzle respectively using the disturbance part of the first supply unit and the disturbance part of the second supply unit; Signal acquisition steps: Vibration information is acquired using the imaging unit and sensors; Analysis and processing steps: The processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

[0020] In summary, for the liquid-liquid coaxial centrifugal nozzle, a first inertial flow pulsation generator is used to apply disturbance to the inflow of the inner nozzle, and a second inertial flow pulsation generator is used to apply disturbance to the inflow of the outer nozzle. The oscillations of the inner and outer liquid films converge at the fused total liquid film, thereby causing the total liquid film thickness to oscillate at two frequencies. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the device provided in this application for generating dual-frequency oscillations in the liquid film thickness; Figure 2 A cross-sectional view of the liquid-liquid coaxial centrifugal nozzle provided in this application; Figure 3 for Figure 2 AA section view in the middle; Figure 4 for Figure 2 BB section view in the middle; Figure 5 A cross-sectional view of the first rigid tube provided for this application; Figure 6 A schematic diagram of the flow and impact of the inner and outer liquid films in the liquid-liquid coaxial centrifugal nozzle provided in this application; Figure 7 The time sequence diagrams are for the vibration acceleration of the inner nozzle path hard pipe, the vibration acceleration of the outer nozzle path hard pipe, the inner nozzle inlet pressure, the outer nozzle inlet pressure, the inner nozzle liquid collecting chamber pressure, the outer nozzle liquid collecting chamber pressure, and the liquid film thickness in Test 1 of this application. Figure 8 for Figure 7 The FFT transform result curve; Figure 9 The time sequence diagrams are for the vibration acceleration of the inner nozzle path hard pipe, the vibration acceleration of the outer nozzle path hard pipe, the inner nozzle inlet pressure, the outer nozzle inlet pressure, the inner nozzle liquid collecting chamber pressure, the outer nozzle liquid collecting chamber pressure, and the liquid film thickness in Test 2 of this application. Figure 10 for Figure 9 The FFT transform result curve; Figure 11The time sequence diagrams are for the acceleration of the inner nozzle path hard pipe vibration, the acceleration of the outer nozzle path hard pipe vibration, the inner nozzle inlet pressure, the outer nozzle inlet pressure, the inner nozzle liquid collecting chamber pressure, the outer nozzle liquid collecting chamber pressure, and the liquid film thickness in Test 3 of this application. Figure 12 for Figure 11 The FFT transform result curve; Figure 13 This is a schematic flowchart of the method for generating dual-frequency oscillations in the liquid film thickness inside a coaxial centrifugal nozzle, as provided in this application.

[0023] Reference numerals: 1-Liquid-liquid coaxial centrifugal nozzle; 11-Inner nozzle; 12-Outer nozzle; 13-Housing shell; 14-Electrode head; 15-First copper electrode; 16-Second copper electrode; 17-Separator; 18-Lower base; 19-First wire; 110-Second wire; 111-Inner nozzle inlet; 112-Outer nozzle inlet; 113-Inner nozzle collecting chamber; 114-Outer nozzle collecting chamber; 115-Inner liquid film; 116-Outer liquid film; 117-Impact point; 118-Total liquid film; 2-Working fluid supply system; 21-Inner nozzle path; 22-Outer nozzle path; 211-First high-pressure nitrogen cylinder; 212-First high-pressure liquid storage tank; 213-First inertial flow pulsation generator; 214-First signal generator; 215-First power amplifier; 216-First gas pipe; 217-First inlet pressure sensor; 218-First pressure reducing valve; 219-First liquid pipe; 2110-First mass flow meter; 2111-First opening valve; 2112-First solenoid valve; 2113-First filter; 2114-Second liquid pipe; 2115-First vibrator; 2116-First rigid pipe inlet; 2117-First rigid pipe; 211 8-First rigid tube outlet; 2119-Oscillation in the internal nozzle line; 221-Second high-pressure nitrogen cylinder; 222-Second high-pressure liquid storage tank; 223-Second inertial flow pulsation generator; 224-Second signal generator; 225-Second power amplifier; 226-Second gas pipe; 227-Second inlet pressure sensor; 228-Second pressure reducing valve; 229-Third liquid pipe; 2210-Second mass flow meter; 2211-Second opening valve; 2212-Second solenoid valve; 2213-Second filter; 2214-Fourth liquid pipe; 2215-Second vibrator; 2217-Second rigid tube; 2219-Oscillation in the external nozzle line; 3-Acquisition module; 31-High-speed camera; 32-Liquid film thickness sensor; 33-First pressure sensor; 34-Second pressure sensor; 35-Third pressure sensor; 36-Fourth pressure sensor; 37-First accelerometer; 38-Second accelerometer; 39-Data acquisition card; 310-Power supply; 311-Computer; 312-Light source. Detailed Implementation

[0024] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0025] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0026] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0027] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0028] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0029] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., swung 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0030] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0031] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0032] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0033] Based on the existing technology of disc-type flow pulsation generators, which can only cause the liquid film thickness within the nozzle to oscillate at a single frequency, and are insufficient to study the dual-path oscillation characteristics of liquid-liquid coaxial centrifugal nozzles, this application provides a device for generating dual-frequency oscillations in the liquid film thickness. The following describes the device in conjunction with... Figures 1-13 The specific structure of this application is described in detail.

[0034] This application provides a device for generating dual-frequency oscillations in liquid film thickness. This device can also be applied to a single centrifugal nozzle with double-row tangential orifices, solving the problem in existing centrifugal nozzles where liquid film thickness can only generate single-frequency oscillations. The following detailed explanation uses a liquid-liquid coaxial centrifugal nozzle as an example, combined with… Figure 2As shown, the liquid-liquid coaxial centrifugal nozzle 1 includes an inner nozzle 11, an outer nozzle 12, and a housing 13. The inner nozzle 11 and the outer nozzle 12 are coaxially mounted on the housing 13; an electrode head 14 of a liquid film thickness sensor 32 is mounted on the lower end of the outer nozzle 12. The electrode head 14 includes a lower base 18, a partition 17, a first copper electrode 15, a second copper electrode 16, a first wire 19, and a second wire 110. The channel diameters in the lower base 18, partition 17, first copper electrode 15, and second copper electrode 16 are all consistent with the channel diameter of the outer nozzle, all being DO. The lower base 18, second copper electrode 16, partition 17, and first copper electrode 15 are sequentially bonded together with sealant. In actual installation, the inner nozzle 11 is first installed in the housing 13, then the outer nozzle 12 is installed axially, and finally the electrode head 14 is installed outside the outer nozzle 12. Four bolts are used to connect and press the housing 13, inner nozzle 11, outer nozzle 12, and electrode head 14 together in series to ensure a tight seal.

[0035] Combination Figures 2-4 As shown, where R ti R is the swirl radius of the internal nozzle; to D is the swirl radius of the external nozzle; ti D is the diameter of the tangential orifice of the internal nozzle. to D is the diameter of the tangential orifice of the external nozzle. o The diameter of the swirling channel of the liquid-liquid coaxial centrifugal nozzle.

[0036] Combination Figure 1 As shown, the device for generating dual-frequency oscillations in the liquid film thickness includes a supply module and a data acquisition module 3; wherein, the supply module includes multiple supply units arranged in parallel.

[0037] At least one supply unit supplies liquid to the inner nozzle, and at least another supply unit supplies liquid to the outer nozzle. In this embodiment, two supply units are used as an example: a first supply unit and a second supply unit. The first supply unit is connected to the inner nozzle and supplies liquid to it; the second supply unit is connected to the outer nozzle and supplies liquid to it. Both the first and second supply units include a supply section and a disturbance section located on the supply section and close to the liquid-liquid coaxial centrifugal nozzle. The supply section of the first supply unit supplies liquid to the inner nozzle of the liquid-liquid coaxial centrifugal nozzle, and the disturbance section of the first supply unit emits vibrations at a preset frequency to the inner nozzle of the liquid-liquid coaxial centrifugal nozzle. The supply section of the second supply unit supplies liquid to the outer nozzle of the liquid-liquid coaxial centrifugal nozzle, and the disturbance section of the second supply unit emits vibrations at a preset frequency to the outer nozzle of the liquid-liquid coaxial centrifugal nozzle.

[0038] The acquisition module includes an imaging unit, a sensing unit, and a processing unit electrically connected to the imaging unit and the sensing unit respectively. The imaging unit corresponds to the nozzle of the liquid-liquid coaxial centrifugal nozzle and is used to capture spray images. The sensing unit is used to acquire vibration information of the liquid-liquid coaxial centrifugal nozzle. The processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film sprayed from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillation.

[0039] In this embodiment, it is still combined Figure 1 As shown, the first supply unit includes an internal nozzle path 21, which employs a squeeze-type liquid supply method. The supply section of the first supply unit includes a first high-pressure nitrogen cylinder 211 and a first high-pressure liquid storage tank 212. The disturbance section of the first supply unit includes a first inertial flow pulsation generator 213, a first signal generator 214, and a first power amplifier 215.

[0040] Specifically, the first high-pressure nitrogen cylinder 211 is connected to the inlet of the first high-pressure liquid storage tank 212 via a first gas pipe 216. A first inlet pressure sensor 217 and a first pressure reducing valve 218 are installed on the first gas pipe 216. The outlet of the first high-pressure liquid storage tank 212 is connected to the first rigid pipe inlet 2116 of the first rigid pipe 2117 of the first inertial flow pulsation generator 213 via a first liquid pipe 219. A first mass flow meter 2110, a first opening valve 2111, a first solenoid valve 2112, and a first filter 2113 are sequentially installed on the first liquid pipe 219. The first rigid pipe outlet 2118 of the first rigid pipe 2117 of the first inertial flow pulsation generator 213 is connected to the inner nozzle inlet 111 of the inner nozzle 11 via a second liquid pipe 2114.

[0041] Furthermore, the first signal generator 214 inputs a pre-set first sine wave signal with a first preset frequency to the first power amplifier 215. The signal amplified by the first power amplifier 215 is then input to the first inertial flow pulsation generator 213. Combined with... Figure 5 As shown, the first inertial flow pulsation generator 213 includes a first vibrator 2115, a first rigid pipe inlet 2116, a first rigid pipe 2117, and a first rigid pipe outlet 2118. The first rigid pipe 2117 is vertically mounted on the vibration table of the first vibrator 2115. When the vibration table of the first vibrator 2115 vibrates with a first preset disturbance, it also drives the first rigid pipe 2117 to vibrate up and down together.

[0042] Furthermore, both the first liquid pipe 219 and the second liquid pipe 2114 are rubber hoses with a certain degree of flexibility. When the first vibrator 2115 drives the first rigid pipe 2117 to vibrate, the first liquid pipe 219 and the second liquid pipe 2114 can vibrate together, thus generating an oscillation 2119 in the inner nozzle path 21.

[0043] In this embodiment, it is still combined Figure 1 As shown, the second supply unit includes an external nozzle path 22, which supplies liquid to an external nozzle 12. The external nozzle 12 employs a squeeze-type liquid supply method. The supply section of the second supply unit includes a second high-pressure nitrogen cylinder 221 and a second high-pressure liquid storage tank 222. The disturbance section of the second supply unit includes a second inertial flow pulsation generator 223, a second signal generator 224, and a second power amplifier 225.

[0044] Specifically, the second high-pressure nitrogen cylinder 221 is connected to the inlet of the second high-pressure liquid storage tank 222 via a second gas pipe 226. A second inlet pressure sensor 227 and a second pressure reducing valve 228 are installed on the second gas pipe 226. The outlet of the second high-pressure liquid storage tank 222 is connected to the second rigid pipe inlet of the second rigid pipe 2217 of the second inertial flow pulsation generator 223 via a third liquid pipe 229. A second mass flow meter 2210, a second opening valve 2211, a second solenoid valve 2212, and a second filter 2213 are sequentially installed on the third liquid pipe 229. The second rigid pipe outlet of the second rigid pipe 2217 of the second inertial flow pulsation generator 223 is connected to the outer nozzle inlet 112 of the outer nozzle 12 via a fourth liquid pipe 2214.

[0045] Furthermore, the second signal generator 224 inputs a pre-set second sine wave signal with a second preset frequency to the second power amplifier 225, and the signal after being amplified by the second power amplifier 225 is then input to the second inertial flow pulsation generator 223.

[0046] Furthermore, the third liquid pipe 229 and the fourth liquid pipe 2214 are both rubber hoses with a certain degree of flexibility. When the second vibrator 2215 drives the second rigid pipe 2217 to vibrate, the third liquid pipe 229 and the fourth liquid pipe 2214 can vibrate together, thus generating an oscillation 2219 in the pipeline of the outer nozzle 12.

[0047] In this embodiment, the imaging unit of the acquisition module includes a light source and a high-speed camera. The light source provides light. The high-speed camera and the light source are respectively positioned opposite each other on opposite sides of the spray field of the liquid-liquid coaxial centrifugal nozzle, for capturing spray images.

[0048] In this embodiment, the sensing unit includes the following components: a first pressure sensor disposed at the inlet of the inner nozzle for collecting a first pressure at the inlet of the inner nozzle; a second pressure sensor disposed at the liquid collecting chamber of the inner nozzle for collecting a second pressure at the liquid collecting chamber of the inner nozzle; a third pressure sensor disposed at the inlet of the outer nozzle for collecting a third pressure at the inlet of the outer nozzle; a fourth pressure sensor disposed at the liquid collecting chamber of the outer nozzle for collecting a fourth pressure at the liquid collecting chamber of the outer nozzle; a first accelerometer disposed at the first rigid tube for measuring a first acceleration of the first rigid tube; a second accelerometer disposed at the second rigid tube for measuring a second acceleration of the second rigid tube; and a thickness sensor electrically connected to the electrode head for measuring the thickness of the inner wall-mounted swirling liquid film of the liquid-liquid coaxial centrifugal nozzle.

[0049] In this embodiment, the processing unit includes a data acquisition card and a computer. The data acquisition card is electrically connected to a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, a first accelerometer, a second accelerometer, and a thickness sensor, respectively. The computer is connected to a high-speed camera and the data acquisition card, and is capable of analyzing and processing the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

[0050] Further explanation based on the above structure: The high-speed camera 31 and the light source 312 are respectively placed on opposite sides of the spray field to capture spray images. The measurement point of the first pressure sensor 33 is on the second liquid pipe 2114 and connected to the front end of the inner nozzle inlet 111. The measurement point of the second pressure sensor 34 is the inner nozzle liquid collection chamber 113. The measurement point of the third pressure sensor 35 is on the fourth liquid pipe 2214 and connected to the front end of the outer nozzle inlet 112. The measurement point of the fourth pressure sensor 36 is the outer nozzle liquid collection chamber 114. The first accelerometer 37 and the second accelerometer 38 are respectively installed on the first rigid pipe 2117 and the second rigid pipe 2217, and are used to measure the acceleration when the first exciter 2115 and the second exciter 2215 drive the first rigid pipe 2117 and the second rigid pipe 2217 to vibrate. The data measured by the liquid film thickness sensor 32, the first pressure sensor 33, the second pressure sensor 34, the third pressure sensor 35, the fourth pressure sensor 36, the first accelerometer 37, and the second accelerometer 38 are all collected by the data acquisition card 39 and finally output to the computer 311; the data acquisition card 39 is powered by the power supply 310.

[0051] Combination Figure 6 As shown, the liquid film thickness sensor 32 is connected to the electrode head 14 via the first wire 19 and the second wire 110, respectively, and is used to measure the thickness of the liquid film adhering to the wall of the liquid-liquid coaxial centrifugal nozzle 1. The liquid film thickness measured here is the thickness of the total liquid film 118 after the inner liquid film 115 and the outer liquid film 116 are combined at the impact point 117 at the short end of the nozzle retraction.

[0052] Combination Figure 13 As shown, a method for generating dual-frequency oscillations in the liquid film thickness within a coaxial centrifugal nozzle using the above structure includes the following steps: Start-up steps: Start the first supply unit and the second supply unit respectively to supply liquid working fluid to the inner nozzle and the outer nozzle; specifically, open the first pressure reducing valve 218 and the first solenoid valve 2112 on the inner nozzle path 21, and adjust the first opening valve 2111 to control the flow rate of the inner nozzle 11. Open the second pressure reducing valve 228 and the second solenoid valve 2212 on the outer nozzle path 22, and adjust the second opening valve 2211 to control the flow rate of the outer nozzle 12.

[0053] The disturbance application steps are as follows: Disturbances are applied to the inner nozzle and the outer nozzle using the disturbance units of the first and second supply units, respectively. Specifically, after the flow rates of the inner and outer nozzles stabilize, the first inertial flow pulsation generator 213 is activated, and the first rigid tube 2117 is controlled to vibrate at a specified frequency by adjusting the first signal generator 214, thereby applying a disturbance of the specified frequency to the incoming flow of the inner nozzle 11. Similarly, the second inertial flow pulsation generator 223 is activated, and the second rigid tube 2217 is controlled to vibrate at a specified frequency by adjusting the second signal generator 224, thereby applying a disturbance of the specified frequency to the incoming flow of the outer nozzle 12.

[0054] Signal acquisition steps: Use the imaging unit and sensors to collect vibration information; specifically, observe the real-time display of the measurement parameters, and after the oscillation of the flow from the inner and outer nozzles stabilizes, observe the oscillation of the liquid film thickness. If dual-frequency oscillation occurs, collect the data; if dual-frequency oscillation does not occur, repeat the disturbance application steps.

[0055] Analysis and processing steps: The processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

[0056] The following three sets of experiments were conducted using the aforementioned device and method to induce dual-frequency oscillations in the liquid film thickness.

[0057] Figure 7 and Figure 8 The demonstration shows Experiment 1, where the internal nozzle flow rate is 22 g / s, the external nozzle flow rate is 70 g / s, the first inertial flow pulsation generator 213 vibrates at 70 Hz, and the second inertial flow pulsation generator 223 vibrates at 160 Hz, and the acceleration G of the first rigid tube is shown. i The acceleration G of the second rigid tube o Internal nozzle inlet 111 front end pressure P fi External nozzle inlet 112 front end pressure P fo Pressure P in the internal nozzle liquid collection chamberci External nozzle liquid collection chamber pressure P co Time series diagram of nozzle outlet liquid film thickness h ( Figure 7 ), and the FFT transformation results of the corresponding parameters ( Figure 8 ).

[0058] Figure 9 and Figure 10 The demonstration shows Experiment 2, where the internal nozzle flow rate is 22 g / s, the external nozzle flow rate is 70 g / s, the first inertial flow pulsation generator 213 vibrates at 115 Hz, and the second inertial flow pulsation generator 223 vibrates at 160 Hz, and the acceleration G of the first rigid tube is shown. i The acceleration G of the second rigid tube o Internal nozzle inlet 111 front end pressure P fi External nozzle inlet 112 front end pressure P fo Pressure P in the internal nozzle liquid collection chamber ci External nozzle liquid collection chamber pressure P co Time series diagram of nozzle outlet liquid film thickness h ( Figure 9 ), and the FFT transformation results of the corresponding parameters ( Figure 10 ).

[0059] Figure 11 heat exchange Figure 12 The demonstration shows Experiment 3, where the internal nozzle flow rate is 30 g / s, the external nozzle flow rate is 150 g / s, the first inertial flow pulsation generator 213 vibrates at 70 Hz, and the second inertial flow pulsation generator 223 vibrates at 160 Hz, showing the acceleration G of the first rigid tube. i The acceleration G of the second rigid tube o Internal nozzle inlet 111 front end pressure P fi External nozzle inlet 112 front end pressure P fo Pressure P in the internal nozzle liquid collection chamber ci External nozzle liquid collection chamber pressure P co Time series diagram of nozzle outlet liquid film thickness h ( Figure 11 ), and the FFT transformation results of the corresponding parameters ( Figure 12 ).

[0060] The test results from the above operating conditions show that when a certain inflow pulsation is applied to the inner and outer nozzles respectively, the liquid inlets of the inner and outer nozzles, as well as the liquid collection chambers of the inner and outer nozzles, will experience pressure oscillations at corresponding frequencies. At the nozzle outlet, the measured liquid film thickness also shows stable oscillations corresponding to the frequencies of the two input inflow pulsations, meaning that the liquid film thickness exhibits artificially controlled dual-frequency oscillations, which meets the requirements of the observed phenomenon.

[0061] In summary, a first inertial flow pulsation generator 213 is used to apply disturbance to the inflow from the inner nozzle 11 of the liquid-liquid coaxial centrifugal nozzle 1, and a second inertial flow pulsation generator 223 is used to apply disturbance to the inflow from the outer nozzle 12. The oscillations of the inner and outer liquid films converge at the fused total liquid film, thereby causing the total liquid film thickness to oscillate at two frequencies.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A device for generating dual-frequency oscillations in liquid film thickness, suitable for a liquid-liquid coaxial centrifugal nozzle, the liquid-liquid coaxial centrifugal nozzle comprising an inner nozzle, an outer nozzle, and a housing; the inner nozzle and the outer nozzle being coaxially mounted on the housing; an electrode head being disposed below the outer nozzle; characterized in that, The device for generating dual-frequency oscillations in the liquid film thickness includes: A supply module includes multiple supply units arranged in parallel; at least one of the supply units supplies liquid to the inner nozzle, and at least another supply unit supplies liquid to the outer nozzle; each supply unit includes a supply section and a disturbance section disposed in the supply section and close to the liquid-liquid coaxial centrifugal nozzle; the supply section is used to supply liquid to the liquid-liquid coaxial centrifugal nozzle, and the disturbance section is used to emit vibrations of a preset frequency to the liquid-liquid coaxial centrifugal nozzle; The acquisition module includes an imaging unit, a sensing unit, and a processing unit electrically connected to the imaging unit and the sensing unit respectively; the imaging unit corresponds to the nozzle of the liquid-liquid coaxial centrifugal nozzle and is used to capture spray images; the sensing unit is used to acquire vibration information of the liquid-liquid coaxial centrifugal nozzle; the processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film sprayed from the nozzle of the liquid-liquid coaxial centrifugal nozzle generates dual-frequency oscillation.

2. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 1, characterized in that, The supply unit has two components, namely a first supply unit and a second supply unit; The first supply unit is connected to the inner nozzle and is used to supply liquid to the inner nozzle; The second supply unit is connected to the external nozzle and is used to supply liquid to the external nozzle.

3. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 2, characterized in that, The supply section of the first supply unit includes: The first high-pressure nitrogen cylinder contains high-pressure nitrogen; and The first high-pressure liquid storage tank is connected to the first high-pressure nitrogen cylinder via a first gas pipe; a first inlet pressure sensor and a first pressure reducing valve are sequentially installed on the first gas pipe from the first high-pressure nitrogen cylinder to the first high-pressure liquid storage tank.

4. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 3, characterized in that, The disturbance part of the first supply unit includes: A first signal generator having a first sinusoidal signal with a first preset frequency; A first power amplifier is electrically connected to the first signal generator; the first signal generator is capable of transmitting a sinusoidal signal of a preset frequency to the first power amplifier; the first power amplifier is capable of amplifying the first sinusoidal signal of the preset frequency into an amplified signal; and A first inertial flow pulsation generator has one end connected to the first power amplifier and the other end connected to the inner nozzle; the first power amplifier can transmit the amplified signal to the first inertial flow pulsation generator, which provides a first preset disturbance to the inner nozzle.

5. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 4, characterized in that, The first inertial flow pulsation generator includes: A first exciter is connected to the first power amplifier; and The first rigid tube is installed vertically on the vibration table of the first exciter. One end of the first rigid tube is connected to the first high-pressure liquid storage tank through the first liquid pipe, and the other end is connected to the inner nozzle through the second liquid pipe. When the vibration table of the first exciter vibrates with a first preset disturbance, the first preset disturbance can be transmitted to the inner nozzle in sequence through the first rigid tube and the second liquid pipe.

6. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 5, characterized in that, The supply section of the second supply unit includes: The second high-pressure nitrogen cylinder contains high-pressure nitrogen; and The second high-pressure liquid storage tank is connected to the second high-pressure nitrogen cylinder via a second gas pipe; a second inlet pressure sensor and a second pressure reducing valve are sequentially installed on the second gas pipe from the second high-pressure nitrogen cylinder to the second high-pressure liquid storage tank. The disturbance part of the second supply unit includes: The second signal generator has a second sinusoidal signal with a second preset frequency; A second power amplifier is electrically connected to the second signal generator; the second signal generator can transmit the sinusoidal signal of the preset frequency to the second power amplifier; the second power amplifier can amplify the second sinusoidal signal of the preset frequency into an amplified signal; and The second inertial flow pulsation generator has one end connected to the second power amplifier and the other end connected to the inner nozzle; the second power amplifier can transmit the amplified signal to the second inertial flow pulsation generator, which then provides a second preset disturbance to the outer nozzle; The second inertial flow pulsation generator includes: A second exciter is connected to the power amplifier; and The second rigid tube is installed vertically on the vibration table of the second exciter. One end of the second rigid tube is connected to the second high-pressure liquid storage tank through the third liquid tube, and the other end is connected to the inner nozzle through the fourth liquid tube. When the vibration table of the second exciter vibrates with the second preset disturbance, the second preset disturbance can be transmitted to the outer nozzle in sequence through the second rigid tube and the fourth liquid tube.

7. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 6, characterized in that, The camera unit includes: A light source provides light; and A high-speed camera is positioned opposite the light source on both sides of the spray field of the liquid-liquid coaxial centrifugal nozzle to capture spray images.

8. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 7, characterized in that, The sensing unit includes: A first pressure sensor is installed at the inlet of the inner nozzle to collect the first pressure at the inlet of the inner nozzle. A second pressure sensor is disposed in the liquid collection chamber of the inner nozzle and is used to collect the second pressure of the liquid collection chamber of the inner nozzle. A third pressure sensor is installed at the inlet of the external nozzle to collect the third pressure at the inlet of the external nozzle. A fourth pressure sensor is disposed in the liquid collection chamber of the external nozzle and is used to collect the fourth pressure in the liquid collection chamber of the external nozzle; A first accelerometer is installed in the first rigid tube and is used to measure the first acceleration of the first rigid tube. A second accelerometer, installed in the second rigid tube, is used to measure the second acceleration of the second rigid tube; and A thickness sensor, electrically connected to the electrode head, is used to measure the thickness of the swirling liquid film adhering to the inner wall of the liquid-liquid coaxial centrifugal nozzle.

9. The apparatus for generating dual-frequency oscillations in liquid film thickness according to claim 8, characterized in that, The processing unit includes: The data acquisition card is electrically connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor, the first accelerometer, the second accelerometer, and the thickness sensor, respectively. The computer, together with the high-speed camera and the data acquisition card, can analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

10. A method for generating dual-frequency oscillations in the liquid film thickness within a coaxial liquid-liquid centrifugal nozzle, characterized in that, The device for generating dual-frequency oscillations in the thickness of a liquid film includes the following steps: Start-up procedure: Turn on the first supply unit and the second supply unit respectively to supply liquid working fluid to the inner nozzle and the outer nozzle; Disturbance application step: Disturbance is applied to the inner nozzle and the outer nozzle respectively using the disturbance part of the first supply unit and the disturbance part of the second supply unit; Signal acquisition steps: Vibration information is acquired using the imaging unit and sensors; Analysis and processing steps: The processing unit is used to analyze and process the acquired vibration information to determine whether the thickness of the liquid film ejected from the nozzle of the liquid-liquid coaxial centrifugal nozzle produces dual-frequency oscillations.

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