A method for profiling static calibration of a flexible wall nozzle

Abstract

The application discloses a kind of for flexible wall nozzle profile static debugging method, it is in to solve the existing method in the process of flexible wall supersonic nozzle profile static debugging, nozzle profile iteration correction number is more, and the problem of low work efficiency.It includes the following steps: (1) according to the nozzle profile static debugging method of conventional static debugging profile corresponding to the first Mach number is debugged, until the deviation of measured profile and theoretical profile meets the requirements;(2) the nozzle profile corresponding to the second Mach number and the nozzle profile corresponding to the first Mach number are obtained on each actuator control variable difference, etc.This application obtains the nozzle static debugging profile corresponding to the first Mach number, and regards it as reference profile, with the difference between the adjacent Mach number theoretical profile or the last nozzle static debugging profile as adjustment amount to control actuator adjustment, and the obtained nozzle profile is used as the initial profile of the nozzle profile static debugging of the adjacent Mach number.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace and aerodynamic research, in particular to a method for static debugging of a flexible wall nozzle profile. BACKGROUND

[0002] The flexible wall nozzle can change the bending shape of the flexible plate by controlling the stroke of the actuator distributed at different axial positions of the flexible wall of the nozzle, so that the flexible plate is matched with the aerodynamic theoretical profile of the nozzle, so as to obtain the nozzle profile of different Mach numbers. Figure 1 The working principle diagram of the flexible wall nozzle is given.

[0003] The supersonic profile of the flexible wall nozzle is obtained in the following manner: taking a two-dimensional nozzle as an example, after the nozzle is installed in place, the measured profile data of the nozzle is obtained, and the difference is obtained by comparing with the theoretical profile; then, the actuator is controlled to adjust and correct these differences. Since the nozzle profile is a whole, the nozzle profile changes of each node controlled by the actuator are mutually influenced, and need to be iteratively corrected until the measured profile and the theoretical profile meet the requirements. This process is called "static debugging of nozzle profile". At this time, the "ideal profile" in theory is considered to be obtained.

[0004] In fact, due to the mass of the flexible wall surface and the profile control accuracy, etc., the test results based on the so-called "theoretical profile" may not be the most ideal test Mach number. Therefore, on the basis of the static debugging profile of the nozzle, dynamic debugging of the nozzle based on wind tunnel test needs to be carried out to obtain the real test results of the nozzle profile at each Mach number, and the nozzle profile is further corrected by controlling the actuator to realize further improvement of the nozzle profile.

[0005] As can be seen from the above description, as long as the static debugging profile of the nozzle does not change, or does not appear the extreme case of replacing the nozzle wall plate, the correction amount obtained by the dynamic debugging of the nozzle relative to the static debugging profile of the nozzle is basically unchanged. Therefore, the static debugging profile of the nozzle is the basis for obtaining a high-quality nozzle profile. As long as the static debugging profile of the nozzle is unchanged, the nozzle profile used for test will not change greatly, and the flow field quality of the entire wind tunnel will also not change greatly. At the same time, considering that the static debugging of the nozzle profile does not need to carry out wind tunnel test, and the corresponding complex supporting test device is not needed, the time cost, labor cost and fund cost can be greatly reduced. Therefore, the static debugging profile detection becomes an important means for the flow field quality inspection of the supersonic wind tunnel with the flexible wall nozzle.

[0006] The position of the nozzle may be changed due to the deformation of the nozzle wall caused by stress release of the nozzle and ground subsidence, which may cause the static debugging profile of the nozzle to deviate from the theoretical profile. When these conditions are found through profile detection, the static debugging profile of the nozzle needs to be corrected again so that the deviation of the static debugging profile of the nozzle from the theoretical profile reenters the error band that meets the requirements.

[0007] The conventional method is as follows. For the static debugging profile of the nozzle corresponding to a Mach number, the current actual profile data is measured, the difference between the actual profile data and the theoretical profile data is obtained by comparison, the difference is converted into the adjustment amount of the corresponding position actuator, the profile is corrected, and then the measurement-adjustment is repeated until the difference between the actual profile and the theoretical profile meets the requirements. At this time, the static debugging profile of the nozzle corresponding to the Mach number is obtained. Then, the static debugging profile of the nozzle corresponding to the next Mach number is replaced, and the above work is repeated. The above work is repeated until the static debugging profiles of the nozzles corresponding to all Mach numbers are obtained.

[0008] Therefore, there is an urgent need for a method to solve the above problems. SUMMARY

[0009] The application aims to provide a profile static debugging method for a flexible wall nozzle.

[0010] To achieve the above object, the application adopts the following technical scheme.

[0011] A profile static debugging method for a flexible wall nozzle comprises the following steps.

[0012] (1) For the static debugging profile of the nozzle corresponding to the first Mach number, the conventional static debugging method of the nozzle profile is used for debugging until the deviation between the actual profile and the theoretical profile meets the requirements, and a new nozzle profile corresponding to the first Mach number is obtained.

[0013] (2) The difference between the control amount of the nozzle profile corresponding to the second Mach number and the nozzle profile corresponding to the first Mach number is obtained.

[0014] (3) The difference between the control amount obtained in step (2) is used as the adjustment amount of each actuator to correct the new nozzle profile corresponding to the first Mach number obtained in step (1), and the obtained nozzle profile is used as the initial profile of the nozzle profile static debugging for the second Mach number. The conventional static debugging method of the nozzle profile is used for debugging until the deviation between the actual profile and the theoretical profile meets the requirements, and a new nozzle profile corresponding to the second Mach number is obtained.

[0015] (4) repeating steps (2), (3) until the static debugging of all Mach number nozzle profiles is completed;

[0016] In the step (2), if it is the first time to perform the static debugging of the nozzle profile, the difference in the control amount of each actuator for the nozzle profile corresponding to the first Mach number and the second Mach number is the difference between the theoretical profiles;

[0017] In the step (2), if it is the first time to perform the static debugging of the nozzle profile, the difference in the control amount of each actuator for the nozzle profile corresponding to the first Mach number and the second Mach number is the difference between the theoretical profiles;

[0018] comprising the following steps:

[0019] (a) for a certain nozzle static debugging profile, there are N Mach numbers, N is a natural number and N≥3, which are sequentially recorded as the first Mach number, the second Mach number, …, the Nth Mach number; the first Mach number, the second Mach number, …, the Nth Mach number sequentially increase, or the first Mach number, the second Mach number, …, the Nth Mach number sequentially decrease;

[0020] (b) for the nozzle static debugging profile corresponding to the first Mach number, the conventional nozzle profile static debugging method is performed until the measured profile and the theoretical profile deviation meet the requirements, and a new nozzle profile corresponding to the first Mach number is obtained;

[0021] (c) obtaining the difference in the control amount of each actuator for the nozzle profile corresponding to the second Mach number and the nozzle profile corresponding to the first Mach number;

[0022] (d) taking the difference in the control amount obtained in step (c) as the adjustment amount of each actuator, correcting the new nozzle profile corresponding to the first Mach number obtained in step (b), and taking the obtained nozzle profile as the initial profile of the second Mach number participating in this time nozzle profile static debugging, and performing the conventional nozzle profile static debugging method until the measured profile and the theoretical profile deviation meet the requirements, and a new nozzle profile corresponding to the second Mach number is obtained;

[0023] (e) obtaining the difference between the control amount of the nozzle profile corresponding to the third Mach number and the control amount of the nozzle profile corresponding to the second Mach number on each actuator, and taking the difference between the control amount of the nozzle profile corresponding to the third Mach number and the control amount of the nozzle profile corresponding to the second Mach number on each actuator as the adjustment amount of each actuator, correcting the nozzle profile corresponding to the newly obtained second Mach number obtained in step (d) according to the conventional nozzle profile static debugging method until the deviation between the measured profile and the theoretical profile meets the requirements, and obtaining the nozzle profile corresponding to the newly obtained third Mach number; and repeating the above steps until the static debugging of the nozzle profiles corresponding to all Mach numbers is completed.

[0024] In step e, the difference between the control amount of the nozzle profile corresponding to the Mth Mach number and the control amount of the nozzle profile corresponding to the (M-1)th Mach number on each actuator is obtained, and the difference between the control amount of the nozzle profile corresponding to the Mth Mach number and the control amount of the nozzle profile corresponding to the (M-1)th Mach number on each actuator is taken as the adjustment amount of each actuator. In this way, steps (c) and (d) are repeated in turn until the static debugging of the nozzle profiles corresponding to all Mach numbers is completed.

[0025] M is a natural number, and M≤N.

[0026] The Mth Mach number and the (M-1)th Mach number are two adjacent Mach numbers for the same nozzle static debugging profile.

[0027] As mentioned above, all Mach number nozzle profiles are based on the same nozzle, and the deviation of the nozzle static debugging profile caused by the change of the whole or part of the nozzle is a common problem of all nozzle profiles, and does not only occur in part of the Mach number nozzle profile. In short, assuming that the nozzle has a reference profile, all Mach number corresponding nozzle profiles can be obtained by superimposing the adjustment amount of each actuator on the reference profile, and the deviation of the nozzle static debugging profile can be considered as a change of the reference profile. If the reference profile is corrected back to the original reference profile, then only the different actuator adjustment amounts need to be superimposed on this basis to obtain the nozzle static debugging profile corresponding to each Mach number.

[0028] The problem of the current method is that for each Mach number corresponding nozzle static debugging profile, a so-called "large" correction is first performed, i.e. the reference profile is basically corrected back to the original reference profile, and then a plurality of "small" fine-tuning corrections are performed according to the measured results until the deviation between the measured profile and the theoretical profile meets the requirements.

[0029] For large-scale supersonic wind tunnel, the nozzle size is large, the time for completing a measurement of nozzle profile and the time for nozzle reshaping are relatively long. The flexible wall nozzle can theoretically realize any Mach number profile in the design range of Mach number, and the nozzle profile is often more, resulting in a long time and low efficiency for the entire nozzle profile debugging work.

[0030] To solve the above problems, the present application provides a profile static debugging method for a flexible wall nozzle, which effectively solves the problems of long time and low efficiency of nozzle profile static debugging.

[0031] Unlike the prior art, after obtaining the nozzle static debugging profile corresponding to the first Mach number, the present application regards it as a "reference profile", takes the difference between it and the theoretical profile of the adjacent Mach number or the last nozzle static debugging profile as the adjustment amount to control the actuator to implement adjustment, and obtains the nozzle profile as the initial profile for the nozzle profile static debugging of the adjacent Mach number.

[0032] Specifically, the operation steps are as follows:

[0033] (1) For the nozzle static debugging profile corresponding to a certain Mach number A, the conventional nozzle profile static debugging method is used for debugging until the measured profile and the theoretical profile meet the requirements.

[0034] (2) Obtain the difference in control amount of each actuator between the nozzle profile corresponding to Mach number B and the nozzle profile corresponding to Mach number A. It should be noted that if it is the first time to perform nozzle profile static debugging, the difference in control amount of each actuator between the nozzle profile corresponding to Mach number A and the nozzle profile corresponding to Mach number B is the difference between the theoretical profiles, and if it is to perform nozzle profile static debugging again, the difference in control amount of each actuator between the nozzle profile corresponding to Mach number A and the nozzle profile corresponding to Mach number B is the difference in control amount of each actuator between the last nozzle static debugging profile and the corresponding profile.

[0035] (3) Take the obtained difference as the adjustment amount of each actuator, correct the newly obtained nozzle profile corresponding to Mach number A in step (1), and obtain the nozzle profile as the initial profile for the nozzle profile static debugging of Mach number B. The subsequent work is carried out according to the conventional nozzle profile static debugging method. Repeat the above steps until the static debugging of all Mach number nozzle profiles is completed.

[0036] "adjacent" is a key point, because the same actuator between adjacent Mach number profiles will not appear a large change, in addition to the core of the patent to avoid "a large number" of correction, the "small amount" of correction of the previous Mach number profile can also be reflected in the next Mach number profile static tuning, so as to reduce the number of iterations required for the Mach number profile static tuning, from the whole Mach number range of nozzle profile static tuning, it is equivalent to a continuous optimization process, the more later the Mach number nozzle profile static tuning starts, the smaller the deviation of the profile from the theoretical profile, that is, the better the profile quality, after a period of iteration, it is even possible to obtain the original profile that meets the requirements without any modification. BRIEF DESCRIPTION OF DRAWINGS

[0037] The application will be described by way of example and with reference to the accompanying drawings in which:

[0038] Figure 1 The working principle diagram of the flexible wall nozzle.

[0039] Figure 2 The deviation amount of the original profile of Mach number 1.5 and the profile after nozzle static tuning and the Mach number 1.6 original profile obtained based on M = 1.5 adjustment profile according to the method of the application compared with the respective theoretical profiles in Example 1. DETAILED DESCRIPTION

[0040] All features disclosed in this specification, or all steps of any methods or processes disclosed, may be combined in any combination, except combinations where at least some of the features and / or steps are mutually exclusive.

[0041] Any of the features disclosed in this specification, unless specifically stated otherwise, can be replaced by alternative features serving the same, or a similar, purpose.

[0042] Example 1

[0043] The profile static debugging method for the flexible wall nozzle of the present embodiment comprises the following steps.

[0044] (1) For the first Mach number M = 1.5 corresponding nozzle static debugging profile, the conventional nozzle profile static debugging method is used for debugging until the deviation between the measured profile and the theoretical profile meets the requirements, and a brand new Mach number M = 1.5 corresponding nozzle profile is obtained.

[0045] (2) Obtain the difference between the control amount of the second Mach number M = 1.6 corresponding nozzle profile and the first Mach number M = 1.5 corresponding nozzle profile on each actuator.

[0046] In step (2), if it is the first time to perform the static adjustment of the nozzle profile, the difference in the control amount of each actuator corresponding to the nozzle profile at the first Mach number M = 1.5 and the second Mach number M = 1.6 is the difference between the theoretical profiles.

[0047] In step (2), if it is the first time to perform the static adjustment of the nozzle profile, the difference in the control amount of each actuator corresponding to the nozzle profile at the first Mach number M = 1.5 and the second Mach number M = 1.6 is the difference between the theoretical profiles.

[0048] (3) The difference in the control amount of each actuator obtained in step (2) is used as the adjustment amount of each actuator, the newly obtained nozzle profile corresponding to the first Mach number M = 1.5 obtained in step (1) is corrected, and the obtained nozzle profile is used as the initial profile of the nozzle profile participating in the static adjustment of the second Mach number M = 1.6, and the static adjustment is performed according to the conventional nozzle profile static adjustment method until the measured profile and the theoretical profile satisfy the requirement, and the newly obtained nozzle profile corresponding to the second Mach number M = 1.6 is obtained.

[0049] (4) The difference in the control amount of each actuator between the nozzle profile corresponding to the Mth Mach number and the nozzle profile corresponding to the (M-1)th Mach number (where M is a natural number, and M ≤ N) is obtained, and the difference in the control amount of each actuator between the nozzle profile corresponding to the Mth Mach number and the nozzle profile corresponding to the (M-1)th Mach number is used as the adjustment amount of each actuator, and in this way, steps (2) and (3) are repeated in turn until the static adjustment of all Mach number nozzle profiles is completed.

[0050] The relevant test data is shown in Tables 1-4.

[0051] Table 1

[0052]

[0053] Table 2

[0054]

[0055]

[0056] Table 3

[0057]

[0058]

[0059] Table 4

[0060]

[0061]

[0062] The upper M1.5-1 in Table 1 is the original profile measurement result of the upper profile corresponding to the first Mach number M = 1.5 for the static debugging of the nozzle; the upper M1.5-2 in Table 2 is the profile measurement result after the static debugging of the nozzle corresponding to the first Mach number M = 1.5 for the static debugging of the nozzle; the upper M1.6-1 in Table 3 is the original profile measurement result of the upper profile corresponding to the second Mach number M = 1.6 for the static debugging of the nozzle; and the upper M1.6-2 in Table 4 is the original profile measurement result of the upper profile corresponding to the second Mach number M = 1.6 for the static debugging of the nozzle according to the method of the application.

[0063] Figure 2 The deviation amount of the original profile of Mach number 1.5 and the profile after the static debugging of the nozzle and the original profile of M = 1.6 obtained by adjusting the profile according to the method of the application based on M = 1.5 from the respective theoretical profiles is given. It can be seen that, compared with the original profile of M = 1.5, there is an average deviation of about 0.4 mm before the axial position 14000 mm, and the deviation amount of the original profile of M = 1.6 in this interval is only 0.2 mm, and there is no large deviation of more than 0.8 mm as in M = 1.5, and a "small amount" of correction can be directly performed.

[0064] The method provided by the application has been verified by the static debugging work of the nozzle profile of a 2m order wind tunnel. Since the large deviation amount from the theoretical profile has been corrected in the static debugging of the nozzle profile corresponding to the first Mach number, the initial profile of the subsequent Mach number obtained according to the method only has a small deviation from the theoretical profile, and only a small amount of adjustment is needed to obtain a satisfactory static debugging profile of the nozzle, and some do not even need to be corrected, the initial profile is the final nozzle profile, the working time is greatly reduced, the working efficiency is greatly improved, at the same time, unnecessary nozzle profile forming work is reduced, the service life of the nozzle profile and the corresponding actuator can be prolonged.

[0065] In summary, the present application has the advantage of reducing the first "large" correction of the nozzle contour corresponding to each Mach number, only the first "large" correction of the nozzle contour corresponding to the first Mach number is needed, and then the contour is basically only "small" correction, or even no correction to obtain a qualified nozzle contour. Taking a 2m order supersonic wind tunnel with a two-dimensional flexible wall nozzle as an example, the nozzle contour corresponding to one Mach number usually needs to be measured once for the original contour, once for the nozzle contour after "large" correction, and twice for the nozzle contour after "small" correction, to obtain the final nozzle static adjustment contour corresponding to the Mach number, a total of 4 times of nozzle forming and measuring. However, due to the long length of the nozzle and the large height between the upper and lower flexible walls, the upper and lower nozzle contours need to be formed and measured separately, and it is not possible to form the upper and lower contours at the same time and complete the measurement, which means that the upper and lower contours corresponding to one Mach number need to be formed and measured 8 times, the average time for forming the contour is about 0.5 hours, and the average time for measuring the contour and obtaining the correction amount is about 0.25 hours, so the time consumed for the static adjustment of the contour corresponding to one Mach number is 6 hours, and the time consumed for the static adjustment of the entire nozzle contour is 180 hours according to 30 Mach numbers. By using the present application, except for the first Mach number, the time consumed is not changed, and the remaining single Mach number needs to be formed and measured twice for the original contour and three times for the "small" correction nozzle (the reduction from 4 times to 3 times is because the original contour actually contains the small correction of the Mach number contour obtained in the previous process, and the small correction of the original contour will be relatively less), that is, except for the first Mach number, the time consumed for the static adjustment of the nozzle contour corresponding to the remaining single Mach number is about 3.75 hours, and the time consumed for the static adjustment of the nozzle contour corresponding to all 30 Mach numbers is 114.75 hours, which is more than 30% of the time saved. At the same time, the reduction of the nozzle contour forming work can prolong the service life of the nozzle contour and the corresponding actuator.

[0066] The present application is not limited to the foregoing specific embodiments. The present application extends to any new feature or any new combination disclosed in this specification, and any new method or process steps or any new combination disclosed.

Claims

1. A method of profile static calibration for a flexible wall nozzle, characterized in that, The method comprises the following steps: (1) for the first Mach number corresponding nozzle static debugging profile, according to the conventional nozzle profile static debugging method, debugging is carried out until the deviation between the measured profile and the theoretical profile meets the requirements, and a new first Mach number corresponding nozzle profile is obtained; (2) the difference between the second Mach number corresponding nozzle profile and the first Mach number corresponding nozzle profile on the control amount of each actuator is obtained; (3) the difference in control amount obtained in step (2) is used as the adjustment amount of each actuator, the new first Mach number corresponding nozzle profile obtained in step (1) is corrected, and the obtained nozzle profile is used as the initial profile of the second Mach number participating in this time nozzle profile static debugging, and according to the conventional nozzle profile static debugging method, debugging is carried out until the deviation between the measured profile and the theoretical profile meets the requirements, and a new second Mach number corresponding nozzle profile is obtained; (4) steps (2) and (3) are repeated until the static debugging of all Mach number nozzle profiles is completed; In step (2), if it is the first time to carry out nozzle profile static debugging, the difference between the first Mach number and the second Mach number corresponding nozzle profile on the control amount of each actuator is the difference between the theoretical profiles; In step (2), if the nozzle profile static debugging is carried out again, the difference between the first Mach number and the second Mach number corresponding nozzle profile on the control amount of each actuator is the difference in control amount of each actuator corresponding to the last nozzle static debugging profile.

2. The method of profile static calibration for a flexible wall nozzle according to claim 1, wherein The Mach number is N, and N is a natural number greater than or equal to 3.

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