JP3787594B2 - Nozzle shape adjustment method for supersonic wind tunnel equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nozzle shape adjustment method for supersonic wind tunnel equipment used for development and testing of aircraft, rockets, and the like.
[0002]
[Prior art]
Even in recent years when the technology of computational fluid dynamics (CFD) has been developed, wind tunnel tests are still required for actual fluid-related product development.
[0003]
Recently, the requirements for data obtained by wind tunnel tests are becoming very strict, and it is required to implement tests with higher accuracy for the uniformity and turbulence of wind tunnel airflow. With the advancement of wind tunnel tests, further advancement is required for the shape design method of the flexible nozzle.
[0004]
As shown in FIG. 8, a general supersonic wind tunnel facility 101 includes an accumulator 103 having an air storage tank 102, a pressure regulating valve 103a and a rectifying screen 103b, a flexible nozzle 104 having a jack 104a as an actuator vertically or horizontally. A measurement unit 105 and a diffusion tube 106 are provided. Then, the upper and lower nozzle walls of the flexible nozzle 104 are deformed symmetrically by the jack 104 a to generate a uniform air flow distribution at the measurement unit 105, and a wind tunnel test is performed on the model 107 supported by the measurement unit 105. It has become.
[0005]
When designing the flexible nozzle 104, a nozzle inflection point (see FIG. 1) following the throat portion (see reference numeral 1 in FIG. 1) of the flexible nozzle 104 communicating with the collective cylinder 103 using the characteristic curve method. 1) (see reference numeral 5 in FIG. 1), a nozzle shape in which the airflow distribution in the measuring unit 105 is uniform is obtained by canceling the wave generated before the entrance of the measuring unit 105, and with respect to this nozzle shape A method of correcting the boundary layer exclusion thickness that develops along the nozzle wall surface is mainly used.
[0006]
However, in the conventional design method described above, the wave cannot be completely canceled due to an estimation error of the boundary layer exclusion thickness, and a sufficiently uniform airflow distribution may not be obtained in the measurement unit 105 in some cases.
[0007]
In addition, wind tunnel equipment has been proposed that achieves a desired airflow distribution by measuring the static pressure distribution on the flexible nozzle and feedback-controlling the nozzle curve with respect to the static pressure target value of the ideal nozzle curve (for example, patents). Reference 1). That is, this wind tunnel facility is a flexible nozzle formed of an elastic wall and provided with a plurality of static pressure holes in the flow direction, a pressure sensor for detecting pressure in the static pressure holes, and the flexible nozzle attached to the flexible nozzle. An actuator that changes the shape of the flexible nozzle, and a control device that receives the output of the pressure sensor and operates the actuator to generate a desired static pressure distribution in the flexible nozzle.
[0008]
[Patent Document 1]
JP-A-6-300660 (2nd to 3rd pages, FIG. 1)
[0009]
[Problems to be solved by the invention]
However, in order to realize the airflow accuracy proposed in the above-mentioned Patent Document 1, it is necessary to adjust the nozzle curve with high precision, so a large number of static pressure holes and actuators are required, and the actual manufacturing is possible. This is considered difficult, and there is a concern that the turbulence of airflow may occur from the static pressure hole. In the case of a supersonic wind tunnel, a shock wave appears. However, such a shock wave cannot be eliminated only by correcting the shape based on the measurement of the static pressure on the surface.
[0010]
The present invention has been made to solve the above-mentioned problems, and it is intended to improve the uniformity of the airflow distribution in the measurement unit, and to achieve a highly accurate wind tunnel test, and a method for adjusting the nozzle shape of a supersonic wind tunnel facility. Is to provide.
[0011]
[Means for Solving the Problems]
The present invention relates to a supersonic wind tunnel facility having a flexible nozzle, and the influence of the single deformation at each deformation position between the nozzle throat portion and the inlet of the measurement portion on the air flow distribution in the measurement portion by CFD analysis or actual measurement. If obtained, it is possible to estimate the airflow distribution in the measurement part when those deformations are given simultaneously by superimposing the influence on the airflow distribution in the measurement part by the single deformation at each deformation position, The reason why it can be estimated in this way will be described first.
[0012]
As shown in FIG. 1 (showing a supersonic wind tunnel two-dimensional nozzle), a predetermined nozzle shape is set as an initial shape at each deformation position 3 between the throat portion 1 of the nozzle and the inlet 2 of the measurement portion. By giving a fixed amount of deformation, a change in the air flow distribution is given in the measurement unit 4. Here, as shown in FIG. 2, the deformation given at each deformation position 3 is given so that the deformation amount at the deformation position 3 is maximized, but the deformation is the nozzle curve 6 in the initial design (see the broken line). ) Is formed so that a continuous curve 7 is formed which is smoothly connected.
[0013]
FIG. 3 shows the amount of change in the Mach number distribution in the nozzle obtained by CFD analysis when the above-described deformation is applied to the initial nozzle shape. As shown in the figure, the flow is constricted on the front side of the deformation position 3, and the compression wave is generated on the rear side, so that the expansion wave is generated on the rear side, and the Mach number distribution in the nozzle changes.
[0014]
FIG. 4 shows a case where the nozzle is initially deformed at the deformation positions 3a and 3b (see the second figure from the top and the top in FIG. 4), and at the deformation positions 3a and 3b at the same time (the single deformation). 4) (see the third figure from the top in FIG. 4), the amount of change in the Mach number distribution with respect to the initial shape of each shape and the initial shape of each single deformation obtained by CFD analysis. This is a case where the change amount of the Mach number is linearly superimposed (see the lowermost diagram in FIG. 4).
[0015]
As shown in FIG. 4, the CFD analysis result (see the third figure from the top in FIG. 4) of the shape simultaneously deformed at the deformation positions 3a and 3b and the amount of change in the Mach number with respect to the initial shape of each single deformed shape. It can be seen that the distribution is well matched with that obtained by linearly superimposing (see the lowermost diagram in FIG. 4). This means that the Mach number distribution of the measurement part when the nozzle shape is deformed simultaneously using the aerospace laboratory supersonic wind tunnel equipment (1m x 1m) and when the deformation is applied independently is shown in Pitot Lake. It is also confirmed from the measurement results.
[0016]
Thus, by superimposing the influence of the single deformation at each deformation position on the Mach number distribution, it is possible to estimate the Mach number distribution having a shape in which the deformation positions are simultaneously deformed. Therefore, it is considered that the deformation at each deformation position can be optimized based on this estimation so as to make the airflow distribution in the measurement unit uniform.
[0017]
FIG. 5 shows the respective Mach number distributions from the CFD analysis results of the initial nozzle shape (see the upper diagram in FIG. 5) and the nozzle shape after deformation optimization (see the lower diagram in FIG. 5). It is. Accordingly, as described above, it is recognized that the uniformity of the air flow distribution in the measurement unit is improved by adopting the nozzle shape in which the deformation at each deformation position is optimized so as to make the air flow distribution in the measurement unit uniform. It is done.
[0018]
In this way, the Mach number distribution of the nozzle shape in which the deformation amount is simultaneously given to each position while changing the deformation amount for each deformation position is estimated, and the Mach number distribution in the measurement unit becomes the most uniform among them. It can be seen that an optimum nozzle shape can be obtained by obtaining a combination of each position and the amount of deformation.
[0019]
Based on this knowledge, during in the invention of claim 1 made the nozzle shape adjustment method, has a flexible nozzle which is elastically deformable formed, to the inlet of the measuring section from the throat portion of the flexible nozzle identifying a plurality of deformed position, wherein a nozzle shape adjustment method of the air flow distribution adjusting supersonic wind tunnel at the measuring unit by the deformation of the deformed position, a predetermined nozzle shape as the initial shape, the determined by CFD analysis the influence on the air flow distribution in deformation the measurement portion of the sole at each deformed position, the deformation amount of the at each deformed position and its position as a variable, defined a number of combinations thereof with adjustable range It is provided with a database, by superimposing effect on airflow distribution within the measuring portion by a single deformation in the respective modification position, the adjustable range Characterized in that estimating the air flow distribution in the measuring unit for all combinations, the optimized nozzle shape the deformation of each deformed position so as to uniformly the air flow distribution in the measuring section on the basis of the estimated in And Here, the predetermined nozzle shape means, for example, an initial nozzle shape designed by a conventional design method, and the invention of claim 1 is a nozzle shape adjusting method for newly installing a wind tunnel facility. Further, the deformation at the deformation position means that the nozzle wall is displaced by the operation of the actuator from the position of the initial shape. Of course, the nozzle shape optimized for deformation at each deformation position is different for each required Mach number.
[0020]
In the adjustable range, the combinations are arranged in a map, for example, and the airflow distribution in the measurement unit is sequentially estimated for all the combinations arranged in order to make the airflow distribution in the measurement unit uniform. The combination of the optimal deformation position and the deformation amount at that position is found.
[0021]
In this way, the influence of the single deformation at each deformation position on the air flow distribution in the measurement unit is obtained by CFD analysis, and the single deformation at each deformation position is overlapped using the analysis result, and the deformation is performed. Since the air flow distribution in the measurement section is estimated and the optimized shape of the flexible nozzle is determined, the air flow is further improved compared with the wind tunnel equipment having the supersonic nozzle designed by the conventional design method as it is. It is possible to realize highly efficient wind tunnel facilities. Since compression waves and expansion waves are generated before and after the deformation position, they are adjusted so that they are combined well to create a uniform flow in the measurement section.
[0022]
Also, not only when designing from the beginning with a predetermined nozzle shape as the initial shape, but also when adjusting the nozzle shape of the existing supersonic wind tunnel equipment to improve the uniformity of the airflow distribution at the measurement unit It can also be applied to. In this case, instead of obtaining the influence of the single deformation at each deformation position on the air flow distribution in the measurement unit by CFD analysis, it is obtained by actual measurement by air flow distribution measurement in the measurement unit of the flexible nozzle. Good. That is, the influence of the single deformation at each deformation position on the airflow distribution in the measurement unit is obtained by actual measurement by the airflow distribution measurement in the measurement unit, and the influence on the airflow distribution in the measurement unit by the single deformation at each deformation position is superimposed. By estimating the airflow distribution in the measurement unit when these deformations are given simultaneously, and the nozzle shape with optimized deformation at each deformation position so that the airflow distribution in the measurement unit is made uniform based on this estimation To do.
[0023]
If it does in this way, the flexible nozzle of the existing supersonic wind tunnel equipment can be renovated to a thing with higher uniformity of airflow in a measurement part.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 6 is a flowchart showing the flow of processing for the first embodiment of the nozzle shape adjusting method for supersonic wind tunnel equipment according to the present invention. In addition, as a supersonic wind tunnel installation in 1st Embodiment, it demonstrates below using what is shown in FIG.
[0025]
In the case of adjusting the nozzle shape of a newly installed wind tunnel facility by the adjustment method according to the present invention, as shown in FIG. 6, first, the conventional design method (for example, the MOC / BL method) performed so far is used. An initial design shape is determined for the shape (step S1). CFD analysis (numerical fluid analysis) is performed on the initial design shape (the state in which no deformation is given at any deformation position) (step S2), and the airflow distribution of the measurement unit 105 which is the basis of the analysis is estimated.
[0026]
Next, the jack 104a (actuator) at each deformation position is independently operated, and the effect of the unit amount deformation due to the operation on the air flow distribution in the measurement unit 105 is obtained parametrically by CFD analysis (step S3). That is, by CFD analysis, what kind of turbulence of airflow occurs in the measurement unit 105 when the nozzle wall (deformation position) is pressed or pulled for each jack 104a is calculated.
[0027]
Then, a new jack 104a (deformation position) and a combination of the displacement amounts are given (step S4). Here, “giving a new jack 104a and a combination of the displacements” means that the position of the jack 104a and the displacements thereof are variables.
[0028]
Then, for the combination of the new jack 104a (deformation position) and the amount of displacement, a Mach number distribution is estimated for the nozzle shape deformed based on the linear superposition calculation (step S5). Here, “calculation of linear superposition” uses the influence of the deformation of the unit amount obtained by the CFD analysis. In the case of the same deformation position, the above calculation is proportional to the magnitude of the deformation amount. Although the influence due to the deformation of the unit amount is increased, in the case of the combination at different deformation positions, the influence due to the deformation at each deformation position is simply added.
[0029]
Based on the estimation result, it is determined whether or not the deviation of the Mach number of the measurement unit 105 is minimum (step S6). If the deviation of the estimation result is minimum, the airflow distribution of the measurement unit is made uniform. It determines that it is the combination of the optimal jack 104a and its displacement amount (step S7). The nozzle shape is vertically or horizontally symmetrical.
[0030]
If it is not the minimum, it is determined whether the processing for all the jacks and the combinations of the displacement amounts is completed (step S8). If the processing is completed, the optimum jack 104a and the combination of the displacement amounts are determined. (Step S9), the process is terminated as it is. On the other hand, if not completed, the process returns to step S4 to give a new jack combination and displacement, and repeat the processes of steps S5 and S6. Here, “determining whether or not the processing for all combinations of jacks and their displacement amounts has been completed” means that the jack 104a (deformation position) and an adjustable range in which the deformation amount at that position can be changed as a variable in advance. This means that all combinations of the adjustable range are estimated, and the examination of whether or not the deviation of the estimation result is the minimum has been completed.
[0031]
In addition, the control means of the wind tunnel equipment for controlling the stroke amount of the jack 104a (actuator) is provided as a database with the nozzle shape obtained by adjusting the airflow distribution described above and optimized for deformation at each deformation position. By doing so, it is possible to adjust the deformation of each deformation position to an optimized nozzle shape by performing adjustment control by the control means without performing optimization processing using CFD analysis again. In other words, once the nozzle shape is obtained by optimizing the deformation at each deformation position so as to make the airflow distribution in the measurement unit uniform, the optimization process using CFD analysis can be performed again by using it as a database. There is no need to do it.
[0032]
In the above embodiment, a case of a newly installed supersonic wind tunnel facility having a predetermined nozzle shape as an initial shape has been described. However, the present invention is not limited to this, and the existing wind tunnel facility can be used. It is also possible to modify the existing wind tunnel facility by adjusting (optimizing) the shape of the flexible nozzle as an initial shape.
(Second Embodiment)
FIG. 7 is an explanatory diagram showing a state in which a measurement system for carrying out the second embodiment of the nozzle shape adjusting method for supersonic wind tunnel equipment according to the present invention is incorporated in the wind tunnel equipment.
[0033]
In order to carry out the second embodiment (adjustment method) according to the present invention, as shown in FIG. 7, the existing superstructure configured from the collective cylinder 12 to the measuring section 14 through the flexible nozzle 13 is used. The sonic wind tunnel equipment 11 needs to incorporate a measurement system including a Pitot Lake 18 for measuring the airflow distribution in the measurement unit 14. In the case of existing wind tunnel equipment, the initial shape of the nozzle is unknown, so CFD analysis cannot be used, and the effect of single deformation at each deformation position on the air flow distribution in the measurement section is replaced with CFD analysis. This is because it is necessary to actually measure.
[0034]
A plurality of jacks 13a (actuators) that change the shape of the flexible nozzle 13 are attached to the flexible nozzle 13 formed to be elastically deformable at regular intervals along the flow direction. The jack 13a is controlled by the actuator setting personal computer 15 via the machine-side control panel 16, and is deformed by pressing or pulling the nozzle wall of the flexible nozzle 13 (deformation of deformation position).
[0035]
The collective cylinder pressure and temperature of the collective cylinder 12 are measured by the first measuring device 17. Moreover, the pitot lake 18 is arrange | positioned at the measurement part 14 on the model support apparatus 31, The pitor lake total pressure is measured with the 2nd measuring apparatus 19 with a measurement part static pressure. The pitot rake position in the measurement unit 14 is controlled by moving the model support device 31 by the control device 20.
[0036]
Then, the measurement unit when each jack 13a (deformation position) is deformed by a unit amount based on signals from the first and second measurement devices 17, 19 and the control device 20 by the personal computer 21 for calculating the optimum nozzle shape. The airflow distribution (Mach number distribution) at 14 is obtained.
[0037]
Using the relationship data between the deformation of each jack 13a and the airflow distribution at the measurement unit 14, the optimum nozzle shape is calculated as in the first embodiment. That is, in the first embodiment, instead of the processing in steps S1 to S3 in FIG. 6, the influence of the single deformation at each deformation position on the airflow distribution in the measurement unit is the same as that in the measurement unit of the flexible nozzle. The point calculated | required by the measurement by airflow distribution measurement differs, and the process of subsequent step S4-S9 is performed similarly.
[0038]
Thus, basically, as in the first embodiment, the unit amount is changed by each jack 13a, and the change in the air flow distribution in the measurement unit 14 in that case is obtained, and the principle of superposition is based on the change. Thus, the nozzle shape that optimizes the deformation at each deformation position (deformation by the jack 13a) is determined. That is, in this embodiment, a plurality of deformation positions are specified between the flexible nozzle throat portion and the inlet of the measurement portion, and the influence of the single deformation at each deformation position on the air flow distribution in the measurement portion is determined flexibly. The airflow distribution in the measurement unit is estimated by superimposing the influence of the single deformation at each deformation position on the airflow distribution in the measurement unit by measuring the airflow distribution in the nozzle measurement unit.
[0039]
Each jack 13a is driven and controlled by the actuator (jack) setting personal computer 15 via the machine-side control panel 16 based on the actuator setting value (the stroke amount of the jack 13a) obtained from the calculation result. In this way, in the existing wind tunnel equipment, at the respective deformation positions between the throat portion of the flexible nozzle 13 and the inlet of the measurement unit 14, the deformation optimized by the jack 13a is given to the measurement unit 14. Higher airflow distribution uniformity than the current nozzle shape is provided.
[0040]
Further, the control means for controlling the stroke amount of the jack (actuator) is provided as a database with the nozzle shape obtained by adjusting the airflow distribution as described above and optimized for the deformation at each deformation position. As in the case of the embodiment, it is possible to adjust the deformation at each deformation position to the optimized nozzle shape by adjusting control by the control means without performing actual measurement again.
[0041]
If the wind tunnel equipment is equipped with a nozzle shape that optimizes the deformation of each deformation position so that the air flow distribution in the measurement part is made uniform based on the estimation by the method described above, it is necessary for the wind tunnel test. If the Mach number distribution is selected, the deformation positions are deformed so that the wind tunnel facility satisfies the Mach number distribution, and the air flow distribution in the measurement unit can be made uniform.
[0042]
Therefore, a preferable aspect as a supersonic wind tunnel facility has a flexible nozzle formed so as to be elastically deformable, and specifies a plurality of deformation positions between the throat portion of the flexible nozzle and the inlet of the measurement portion, A supersonic wind tunnel facility in which a plurality of actuators for deforming the nozzle wall at the position are provided at the deformation position, and the airflow distribution in the measurement unit is adjusted by deformation of the deformation position by operation of the actuator. A control means for controlling the operation is provided, and this control means specifies a plurality of deformation positions from the throat portion of the flexible nozzle to the inlet of the measurement portion, using a predetermined nozzle shape as an initial shape as a database. Then, the effect of single deformation at each deformation position on the air flow distribution in the measurement unit is obtained by CFD analysis, and measurement by single deformation at each deformation position is performed. It has a nozzle shape that optimizes the deformation at each deformation position so as to superimpose the influence on the air flow distribution in the unit, estimate the air flow distribution in the measurement unit, and make the air flow distribution in the measurement unit uniform. is there.
[0043]
In addition, when applied to existing supersonic wind tunnel equipment, the database provided in the control means specifies a plurality of deformation positions between the throat part of the flexible nozzle and the inlet of the measurement part, for example, a pitot lake The effect of a single deformation at each deformation position on the air flow distribution in the measurement unit is obtained by measuring the air flow distribution in the measurement unit, and the influence of the single deformation at each deformation position on the air flow distribution in the measurement unit is repeated. In addition, the airflow distribution in the measurement unit may be estimated, and the nozzle shape may be optimized so that the deformation at each deformation position is optimized so as to make the airflow distribution in the measurement unit uniform.
[0044]
In addition, as shown in FIG. 9, by adjusting the nozzle shape using the present invention in the Aerospace Technology Laboratory supersonic wind tunnel facility (1 m × 1 m), ± 1.0% is obtained before adjustment. The deviation of the Mach number at the center of the measurement part that was exceeded was ± 0.5% or less after the adjustment, and it was confirmed that an effect was obtained for uniform airflow distribution.
[0045]
【The invention's effect】
The present invention is implemented as described above, and has the following effects.
[0046]
The present invention utilizes the fact that the airflow distribution in the measurement section when these deformations are given simultaneously can be estimated by superimposing the influence on the airflow distribution in the measurement section by a single deformation at each deformation position of the flexible nozzle. Therefore, high uniformity of airflow distribution can be easily provided in the measurement unit. Therefore, in the case of a newly installed supersonic wind tunnel facility, a wind tunnel having even higher airflow uniformity in the measurement unit than a wind tunnel facility having a supersonic nozzle (flexible nozzle) designed by a conventional method. Equipment can be realized. In the case of existing supersonic wind tunnel equipment, it is possible to modify the supersonic nozzle (flexible nozzle) so as to further improve the air flow uniformity in the measurement unit.
In particular, the influence of a single deformation at each deformation position on the air flow distribution in the measurement unit is obtained by CFD analysis, and the deformation positions at the respective deformation positions and the positions are used as variables, and a large number of combinations within an adjustable range. Therefore, it is not necessary to perform optimization processing using CFD analysis again.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a two-dimensional nozzle of a supersonic wind tunnel.
FIG. 2 is an explanatory diagram of a deformed shape given to each deformed position.
FIG. 3 is an enlarged cross-sectional view of a main part showing a change in Mach number distribution due to single deformation.
FIG. 4 is an enlarged cross-sectional view of a main part showing superposition of a change amount of a Mach number distribution due to single deformation, two-point simultaneous deformation, and a change amount of Mach number distribution due to two single deformations.
FIG. 5 is an enlarged cross-sectional view of a main part showing a Mach number distribution of an initial shape and an optimum shape.
FIG. 6 is a flowchart showing a process flow of the first embodiment of the nozzle shape adjusting method of the supersonic wind tunnel equipment according to the present invention.
FIG. 7 is an explanatory diagram showing a state in which a measurement system for carrying out the second embodiment of the nozzle shape adjusting method for supersonic wind tunnel equipment according to the present invention is incorporated in the wind tunnel equipment.
FIG. 8 is a schematic configuration diagram of a general supersonic wind tunnel facility.
FIG. 9 is a diagram comparing measurement unit Mach number distributions before and after adjusting the nozzle shape using an actual machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Nozzle throat part 2 Entrance of measurement part 3 Nozzle deformation position 3a Nozzle deformation position 3b Nozzle deformation position 4 Measurement part 5 Nozzle inflection point 6 Initial design nozzle curve 7 Deformation nozzle curve 11 Wind tunnel equipment 13 Flexible nozzle 13a Jack (actuator)
14 Measuring unit 18 Pitore Lake 101 Supersonic wind tunnel equipment 104 Flexible nozzle 104a Jack (actuator)
105 Measuring unit

Claims (2)

Has a flexible nozzle which is elastically deformable formed, of the measurement section from the throat portion of the flexible nozzle to identify multiple deformed position until the inlet, said at the measuring unit by the deformation of the deformed position A method for adjusting the nozzle shape of a supersonic wind tunnel facility for adjusting the airflow distribution,
A predetermined nozzle shape as the initial shape, the influence of deformation of sole in the respective modification position has on the air flow distribution in the measuring unit determined by CFD analysis, the deformation amount of the at each deformed position and its position as a variable, Many combinations of them are defined within the adjustable range and are prepared as a database.
By superimposing effect on airflow distribution within the measuring portion by a single deformation in the respective modification position estimates airflow distribution in the measuring unit for all the combinations in the adjustable range,
The nozzle shape adjustment method of supersonic wind tunnel, characterized in that the optimized nozzle shape deformation of each deformed position so as to uniformly the air flow distribution in the measuring section on the basis of this estimation. The influence of deformation of sole in the respective modification position has on the air flow distribution within the measuring unit in place to determine the CFD analysis, ultra according to claim 1, obtained by actual measurement by the air flow distribution measurement in the measurement portion of said flexible nozzle Nozzle shape adjustment method for sonic wind tunnel equipment.

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