Injection type optical testing device for combustion chamber fuel oil atomization

Abstract

The invention belongs to the field of aerospace tests, relates to an optical test technology for fuel oil atomization of a combustion chamber of an aero-engine in a normal pressure environment, and provides an injection type optical test device for fuel oil atomization of a combustion chamber, the injection type optical test device comprises an air inlet section and a test section, the air inlet section is provided with a fuel oil nozzle to be tested and an air swirler, and the test section is provided with an air inlet and an air outlet. An annular jet flow slit communicated with the testing section is formed in the air outlet end face of the air inlet section, and a plurality of optical windows are formed in the front end of the testing section in the circumferential direction. According to the device disclosed by the invention, the glass on the optical window in the test section is removed through the arrangement of the annular jet flow slit, so that a series of negative effects caused by the glass on the optical test are eliminated, and the test efficiency of the optical test and the applicability to different optical test methods are improved; and the structure of the optical testing device is obviously simplified, and the processing difficulty and the processing cost are reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aerospace test, and relates to an optical test device for fuel atomization of a combustion chamber of an aero-engine in an atmospheric environment. BACKGROUND

[0002] Modern advanced aero-engine combustion chambers have increasingly complex and harsh working environments, and combustion indicators are constantly improving, with parameters such as combustion efficiency, flameout boundary, and outlet temperature distribution being representative. This puts high demands on fuel atomization of the combustion chamber, making it necessary to test the fuel atomization performance of the combustion chamber nozzle.

[0003] Optical methods are currently the best and most mainstream method for testing fuel atomization effects. Currently, optical glass is installed to adapt the design of the combustion chamber structure when performing optical tests of the fuel atomization effect of the combustion chamber. During the test, the airflow enters the intake section, passes through the air swirler into the test section, and the fuel is sprayed from the nozzle and enters the test section with the airflow. The optical test equipment measures the fuel particles in the test section through the optical window. This test method has the following limitations: 1. To ensure that the light does not deviate in the measurement path, the optical glass adopts a flat structure, which inevitably changes the flow structure of the combustion chamber. Larger windows can even cause the flow path of the combustion chamber to change from circular to square, resulting in a significant difference between the airflow flow structure in the combustion chamber and the actual situation, which affects the atomization of the fuel, causing the measurement results to differ significantly from the actual situation, and reducing the effectiveness of the test results. 2. The atomized fuel droplets are easily attached to the surface of the optical glass, affecting the optical test results, and even making it impossible to carry out optical tests. 3. Low transmittance of optical glass can negatively affect optical testing, reducing test sensitivity. Different materials of optical glass have different transmittances for different wavelengths of light, making the optical glass not versatile for different optical testing methods. 4. The flatness and roughness of the optical glass and the consistency of each part are required to be high during the test. Insufficient flatness and roughness can cause the test light to deviate and scatter, reducing the accuracy of the test results. Insufficient consistency can cause the light path to change when testing different sections, requiring the test equipment to be recalibrated, which greatly reduces the test efficiency.

[0004] In addition, the above problems are usually solved by reducing the size of the optical glass, making the structure of the testing device close to the actual size of the combustion chamber as much as possible, but the optical test coverage is reduced; higher transmittance optical glass and higher technical index processing method are used, but the cost is significantly increased; the method of air film blowing is used to protect the optical glass from being attached by fuel droplets, but the air volume is difficult to control, and too little air volume will lose the blowing effect, and too much air volume will easily invade the main flow, causing changes in the main flow field structure beyond expectation. SUMMARY

[0005] In order to solve the technical problem that the instability of the quality of the optical glass in the existing optical testing device has a negative impact on the optical test of fuel atomization, the application discloses an ejecting type optical testing device for combustion chamber fuel atomization, which comprises an air inlet section and a testing section, the air inlet section is provided with a measured fuel nozzle and an air swirler, an annular jet slit in communication with the testing section is formed on the air outlet end face of the air inlet section, and a plurality of optical windows are circumferentially formed on the front end of the testing section.

[0006] Further, a plurality of rows of optical windows are arranged along the radial direction of the testing section according to the design length of the jet of atomized fuel formed by the measured fuel nozzle and the air swirler.

[0007] Further, the distance between two adjacent rows of optical windows is 1-1.5 times the arc width of the optical window.

[0008] Further, the ratio of the arc length to the arc width of the optical window is greater than or equal to 5.

[0009] Further, the outer ring surface diameter of the annular jet slit is the same as the inner wall surface diameter of the testing section.

[0010] Further, the sum of the arc lengths of the plurality of optical windows circumferentially formed on the testing section is 98%-99% of the circumference of the testing section.

[0011] Further, a fuel pipe is connected to the measured fuel nozzle, and the fuel pipe is connected to a fuel supply device after penetrating through the mounting hole on the air inlet section.

[0012] Further, a fuel atomization recovery device is connected to the end of the testing section.

[0013] Compared with the prior art, the above at least one technical scheme adopted by the embodiment of the present application can achieve at least the following beneficial effects: a) The optical glass in the application does not need to be installed in a flat structure, so that the shape structure of the test section can be exactly the same as the size of the combustion chamber flame tube, avoiding the influence on the space structure in the test section, thereby maximizing the consistency of the flow field in the test section with the actual flow field structure, reducing the influence of the flow field structure change on fuel atomization, and making the fuel atomization test result more representative.

[0014] b) The application cancels the optical glass, completely eliminates the adhesion of atomized fuel on the surface of the optical glass, and eliminates the negative effects of the quality of the optical glass on the optical test.

[0015] c) In the application, the optical window has optimal light transmittance for all wavebands due to the cancellation of the optical glass, which can improve the quality of optical testing and has the widest adaptability of optical testing methods.

[0016] d) In the application, the cancellation of the optical glass allows the test light to be tested at all optical window cross sections, eliminating the negative effects caused by unstable glass quality and unstable installation quality on the device, saving the time for recalibration of the optical path when changing the measurement cross section, and improving the efficiency of optical testing.

[0017] e) The optical testing range is improved: In the glass-free optical testing device of the application, the total length of the optical window opened circumferentially on one cross section is 98% to 99% of the circumference of the cross section, which is significantly higher than the about 10% of the small window and the about 60% of the square window.

[0018] f) Due to the cancellation of the optical glass and the corresponding installation structure, the structure of the testing device is greatly simplified, and the processing cost is significantly reduced.

[0019] g) On the basis of canceling the optical glass, by machining an annular jet slit communicating with the test section on the outlet end surface of the inlet section, the air discharged from the annular jet slit can be injected into the test section cavity, and the atomized fuel will be swept by the mixed gas of jet air and injection air when it is close to the test section wall, so as to be limited inside the test section cavity, so that the atomized fuel is limited in the test section, avoiding its discharge to the test environment through the optical window, and the injection air also does not have a significant impact on the flow field inside the test section cavity. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0021] Figure 1 Schematic diagram of the ejector type optical testing device for fuel atomization of the combustion chamber; Figure 2 Distribution diagram of a certain row of optical windows at the front end of the testing section; Figure 3 Figure 1 Enlarged view at C in the middle; Figure 4 Schematic diagram of the air flow lines being ejected; Wherein, 1, air inlet; 2, air inlet section; 3, fuel pipe; 4, measured fuel nozzle; 6, testing section; 7, air swirler; 8, testing section wall; 9, optical window; 10, annular jet slit. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the drawings.

[0023] The embodiments of the present application will be described in detail below with reference to the drawings.

[0024] It should be noted that the drawings provided in the following embodiments are only schematic and are not drawn to scale. They are provided merely to illustrate the basic understanding of the present disclosure. In fact, each component in the drawings can actually have a different shape or size, and some components can be omitted or combined. The drawings in the following embodiments are provided merely to illustrate the basic understanding of the present disclosure, and the actual implementation of each component may be a random change in shape, number, size, and layout, and may be more complex.

[0025] The embodiments of the present application provide an ejector type optical testing device for fuel atomization of a combustion chamber, referring to Figures 1 to 3 As shown in the figure, the ejector type optical testing device comprises an air inlet section 2 and a testing section 6, the air inlet section 2 is provided with a measured fuel nozzle 4 and an air swirler 7, the measured fuel nozzle 4 is arranged at the center position of the air swirler 7.

[0026] The air outlet end surface of the air inlet section 2 is provided with an annular jet slit 10 which is in communication with the testing section 6, and the front end of the testing section 6 is provided with a plurality of optical windows 9 along the circumference.

[0027] ​In the present application, under the action of the air cyclone 7, air enters the air intake section 2 from the air inlet 1 at the front end of the air intake section 2, part of the air enters the air cyclone 7 to form atomized fuel with the fuel sprayed by the measured fuel nozzle 4, and the other part of the air enters the test section 6 from the annular jet slit 10 and is emitted to the rear end of the test section 6 closely attached to the test section wall 8 of the test section 6. At this time, the emitted air will have an ejecting effect on the atomized fuel, and the atomized fuel will flow backward in the test section 6 under the ejecting effect of the air, so that it will not be discharged from the optical window 9 to the test environment.

[0028] In addition, no glass or other components are arranged on the optical window 9, the optical window 9 connects the test section 6 with the test environment outside, and the detection device can directly carry out optical testing on the atomized fuel through the optical window 9. In the present application, since no components are arranged on the optical window 9, the negative effects caused by the atomized fuel adhering to the optical glass or other components during optical testing and the unstable quality of the optical glass itself can be avoided.

[0029] As shown in Figure 4 , during operation, under the ejecting effect of the airflow emitted by the annular jet slit 10, the air located outside the test section will enter the inside of the test section through the optical window 9 and flow along the wall without entering the central flow passage of the test section 6, without affecting the main airflow and the atomized fuel.

[0030] Further, according to the design length of the jet flow of the atomized fuel formed by the measured fuel nozzle 4 and the air cyclone 7, a plurality of rows of optical windows 9 are arranged along the radial direction of the test section 6, for example, as shown in Figure 1 , three rows of optical windows 9 can be arranged along the radial direction of the test section 6.

[0031] Further, in order to balance the measurement of cross-sectional density and the jet flow ejecting effect, the distance between the adjacent two rows of optical windows 9 in the present application is 1-1.5 times the arc width of the optical window 9, for example, when the arc width of the optical window 9 is 1-3 mm, the distance between the adjacent two rows of optical windows 9 is 1-4.5 mm.

[0032] Further, in order to better ensure the directionality and circumferential uniformity of the airflow at the outlet of the slit, the ratio of the arc length to the arc width of the optical window 9 can be set to be ≥5.

[0033] Further, the outer ring surface diameter of the annular jet slit 10 is the same as the inner wall diameter of the test section 6, and the radial size of the passage of the annular jet slit 10 can be set to be 1-3 mm.

[0034] Further, the sum of the arc lengths of the plurality of optical windows 9 circumferentially formed on the test section 6 is 98% to 99% of the circumference of the test section 6.

[0035] Further, the fuel pipe 3 is connected to the fuel nozzle 4 to be tested, and the fuel pipe 3 is connected to a fuel supply device after passing through the mounting hole on the air inlet section 2.

[0036] Further, the test section 6 is connected to an atomized fuel recovery device at the end, and a pipeline can also be connected at the end of the test section 6 to directly discharge the atomized fuel into the atmospheric environment.

[0037] The embodiment of the present application achieves the following technical effects: a) In the present application, the optical glass with a flat structure is not required to be installed, so that the shape structure of the test section can be completely the same as the size of the flame tube of the combustion chamber, the influence on the space structure in the test section is avoided, the consistency of the flow field in the test section and the actual flow field structure is maximized, the influence of the flow field structure change on the fuel atomization is reduced, and the test result of the fuel atomization is more representative.

[0038] b) The optical glass is cancelled in the present application, and the attachment of the atomized fuel on the surface of the optical glass and the negative influence of the quality of the optical glass on the optical test are completely eliminated.

[0039] c) In the present application, the optical glass is cancelled, so that the light transmittance of the optical window to all wave bands is optimal, the optical test quality can be improved, and the widest optical test method adaptability is achieved.

[0040] d) In the present application, the optical glass is cancelled, so that the test light can be tested at all optical window sections, the negative effects caused by the unstable quality of the glass and the unstable installation quality on the device are eliminated, the time for recalibrating the optical path when changing the measurement section is saved, and the efficiency of the optical test is improved.

[0041] e) The optical test range is improved: in the glass-free optical test device of the present application, the total length of the optical window circumferentially formed on one section is 98% to 99% of the circumference of the section, compared with about 10% of the existing small window and about 60% of the square window, the test range is greatly improved.

[0042] f) The optical glass and the corresponding installation structure are cancelled, the structure of the test device is greatly simplified, and the processing cost is obviously reduced.

[0043] g) By canceling the optical glass, a ring-shaped jet slit is processed on the outlet end surface of the air inlet section and communicated with the test section, the air discharged in the ring-shaped jet slit is injected into the inner cavity of the test section by adhering to the test section wall surface, the atomized fuel is swept by the mixed gas of the jet air and the injection air when close to the test section wall surface, so as to be limited inside the test section, so that the atomized fuel is limited in the test section, avoiding its discharge to the test environment through the optical window, and the injection air does not have obvious influence on the flow field inside the test section.

[0044] Obviously, those skilled in the art should understand that the above description is only preferred embodiments of the present application, and is not intended to limit the present application. For those skilled in the art, the embodiments of the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0045] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. An optical test device for the ejection of fuel atomization in a combustion chamber, comprising an intake section (2) and a test section (6), said intake section (2) being provided with a fuel nozzle (4) to be tested and an air swirler (7), characterized in that, An annular jet slit (10) is arranged on the outlet end surface of the air inlet section (2) and communicates with the test section (6), and a plurality of optical windows (9) are arranged on the front end of the test section (6) in the circumferential direction.

2. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The jet design length of the atomized fuel formed by the measured fuel nozzle (4) and the air swirler (7) is provided with a plurality of rows of optical windows (9) in the radial direction of the test section (6).

3. The ejector optical test set for combustion chamber fuel atomization of claim 2, wherein, The distance between two adjacent rows of optical windows (9) is 1-1.5 times the arc width of the optical window (9).

4. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The ratio of the arc length to the arc width of the optical window (9) is greater than or equal to 5.

5. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The outer ring surface diameter of the annular jet slit (10) is the same as the inner wall surface diameter of the test section (6).

6. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The sum of the arc lengths of the plurality of optical windows (9) arranged on the test section (6) in the circumferential direction is 98-99% of the circumference of the test section (6).

7. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The fuel pipe (3) is connected to the measured fuel nozzle (4) and is connected to the oil supply device after penetrating through the mounting hole on the air inlet section (2).

8. The ejector optical test set for combustion chamber fuel atomization of claim 1, wherein, The end of the test section (6) is connected to an atomized fuel recovery device.

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