CN110044570B - Pneumatic tremor error correction method for pressure measurement experiment of rotating body - Google Patents
Pneumatic tremor error correction method for pressure measurement experiment of rotating body Download PDFInfo
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Abstract
A pneumatic tremor error correction method for a pressure measurement experiment of a rotating body comprises the following steps: preparing an experimental device; selecting a pressure measuring section on the model, and connecting a pressure measuring hole in the pressure measuring section with a pressure measuring pipeline; carrying out air tightness test on the pressure measuring pipeline; sequentially mounting the supporting rod and the model on a model angle adjusting mechanism, leading a pressure measuring pipeline out of a wind tunnel experiment section and connecting a pressure scanning valve, and mounting an acceleration sensor on the surface of the model; adjusting the attack angle of the model to the maximum value set by the experiment; starting wind tunnel blowing and adjusting wind speed until the vibration amplitude of the model reaches the maximum, measuring the vibration frequency and the vibration amplitude of the model, and measuring the pressure value of a pressure measuring hole; closing the wind tunnel and stopping blowing, and connecting a vibration exciter between the model and the inner wall of the wind tunnel experimental section; starting a vibration exciter, applying an exciting force to the model, ensuring that the vibration frequency and amplitude of the model under the exciting force condition are the same as those under the pneumatic vibration condition, and measuring the pressure value of a pressure measuring hole; and calculating a correction coefficient through the pressure value of the pressure measuring hole obtained by the two-stage experiment.
Description
Technical Field
The invention belongs to the technical field of wind tunnel experiments, and particularly relates to a pneumatic tremor error correction method for a pressure measurement experiment of a rotating body.
Background
Wind tunnels are the most basic experimental devices for aerodynamic research and aircraft development, and play a very important role in aerodynamic research and aircraft aerodynamic design.
The pressure measurement experiment of the spinning body is one of conventional experiments of wind tunnels and is used for researching the pressure distribution and the pneumatic performance of the airplane body, in the pressure measurement experiment of the spinning body, because the experiment requires a large attack angle experiment, the spinning body model can be fallen by regular vortex of airflow in the airflow, and the fallen vortex can fall alternately on two sides of the spinning body, so that the left and right pneumatic force of the spinning body model is different, and then the spinning body model can swing left and right, and pneumatic vibration can occur simultaneously, and the pneumatic vibration can not be avoided in the wind tunnel experiment, and because of the existence of the pneumatic vibration, the error of the pressure measurement experiment result can be increased, therefore, the true stress of the spinning body model in the state can not be accurately reflected.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a pneumatic tremor error correction method for a pressure measurement experiment of a rotating body, which can correct pneumatic tremor, effectively reduce the error of the pressure measurement experiment result, more accurately reflect the real stress of a rotating body model in the state through the pressure measurement experiment result, and provide accurate scientific basis for the design of the body of an airplane.
In order to achieve the purpose, the invention adopts the following technical scheme: a pneumatic tremor error correction method for a pressure measurement experiment of a rotating body comprises the following steps:
the method comprises the following steps: preparing experimental equipment, which comprises a rotating body model, a pressure scanning valve, a pressure measuring pipeline, a computer, a model angle adjusting mechanism, a model supporting rod, an acceleration sensor and a vibration exciter;
step two: selecting a pressure measuring section at the head, the middle and the tail of the rotating body model respectively, and connecting a pressure measuring hole in each pressure measuring section with a pressure measuring pipeline respectively;
step three: performing air tightness test on all pressure measuring pipelines connected to the rotating body model to ensure that the air tightness of the pressure measuring pipelines meets the experimental requirements;
step four: firstly, mounting a model supporting rod on a model angle adjusting mechanism, enabling the top end of the model supporting rod to be positioned in a wind tunnel experiment section, then mounting a rotating body model on the top end of the model supporting rod, simultaneously leading all pressure measuring pipelines out of the wind tunnel experiment section through the model supporting rod, then connecting all the led pressure measuring pipelines into a pressure scanning valve, connecting the pressure scanning valve with a computer, and finally mounting an acceleration sensor on the outer surface of the rotating body model;
step five: starting a model angle adjusting mechanism, and adjusting the attack angle of the rotating fuselage model to the maximum value of the attack angle set by the experiment;
step six: starting the wind tunnel to blow air, then adjusting the experimental wind speed until the tremor amplitude of the rotating body model reaches the maximum, measuring the vibration frequency and the vibration amplitude of the rotating body model through an acceleration sensor, and measuring the pressure through a pressure scanning valveThe pressure value of the hole, which is denoted as Pi；
Step seven: closing the wind tunnel and stopping blowing, and connecting a vibration exciter between the rotating body fuselage model and the inner wall of the wind tunnel experimental section;
step eight: starting a vibration exciter, applying an exciting force to the rotating body model, measuring the vibration frequency and the vibration amplitude of the rotating body model in real time through an acceleration sensor to ensure that the vibration frequency and the vibration amplitude of the rotating body model under the exciting force condition are the same as those under the pneumatic vibration condition, measuring the pressure value of a pressure measuring hole through a pressure scanning valve, and recording the pressure value as P'i；
Step nine: calculating the pneumatic tremor error correction coefficient of the rotating fuselage model, wherein the specific calculation formula is as follows:
in the formula, KiIs a pneumatic vibration error correction coefficient, P, of a certain pressure measuring holeiThe pressure value of one pressure measuring hole under the condition of pneumatic vibration, P'iThe pressure value of a certain pressure measuring hole under the condition of exciting force, K is a pneumatic tremble error correction coefficient of the rotating body model, and n is the number of all pressure measuring holes contained in all selected pressure measuring sections.
The invention has the beneficial effects that:
the pneumatic tremor error correction method for the pressure measurement experiment of the rotating body fuselage can correct pneumatic tremor, effectively reduce errors of pressure measurement experiment results, more accurately reflect the real stress of the rotating body fuselage model in the state through the pressure measurement experiment results, and provide accurate scientific basis for the design of the aircraft fuselage.
Drawings
FIG. 1 is a state diagram of a rotating body fuselage model under pneumatic tremor conditions when pressure measurements are taken;
FIG. 2 is a state diagram of a spinning body model under an excitation force condition when a pressure measurement experiment is performed;
FIG. 3 is a schematic structural diagram of a rotating fuselage model according to an exemplary embodiment;
FIG. 4 is a cross-sectional view A-A of FIG. 3;
in the figure, 1-rotation body model, 2-pressure scanning valve, 3-pressure measuring pipeline, 4-computer, 5-model angle adjusting mechanism, 6-model supporting rod, 7-acceleration sensor, 8-vibration exciter, 9-pressure measuring section, 10-pressure measuring hole, 11-wind tunnel experiment section, 12-wind tunnel contraction section and 13-wind tunnel diffusion section.
Detailed Description
The invention is described in further detail below with reference to the figures and the specific embodiments.
In this embodiment, the rotating body fuselage model 1 is of an all-steel structure, as shown in fig. 3 and 4, the head of the rotating body fuselage model 1 is of a cosine parabolic type, the middle of the rotating body fuselage model 1 is of a cylindrical type, the tail of the rotating body fuselage model 1 is of a parabolic type, the total length of the rotating body fuselage model 1 is 532mm, the diameter of the middle of the rotating body fuselage model 1 is 70mm, and the rotating body fuselage model 1 is provided with 112 pressure measuring holes 10 in total; the pressure measurement pipeline 3 adopts a rear wall pipe with the inner diameter of 0.8mm and the outer diameter of 2mm to avoid gas path blockage caused by pipeline bending in the pressure measurement experiment process.
A pneumatic tremor error correction method for a pressure measurement experiment of a rotating body comprises the following steps:
the method comprises the following steps: preparing experimental equipment, which comprises a rotating body model 1, a pressure scanning valve 2, a pressure measuring pipeline 3, a computer 4, a model angle adjusting mechanism 5, a model supporting rod 6, an acceleration sensor 7 and a vibration exciter 8;
step two: selecting a pressure measuring section 9 at the head, the middle and the tail of the rotating body model 1 respectively, and connecting a pressure measuring hole 10 in each pressure measuring section 9 with a pressure measuring pipeline 3 respectively; in this embodiment, each pressure measuring section 9 includes 4 pressure measuring holes 10, so that the three pressure measuring sections 9 include 12 pressure measuring holes 10, and 12 pressure measuring pipes 3 are required in total;
step three: performing air tightness test on all pressure measuring pipelines 3 connected to the rotating body model 1 to ensure that the air tightness of the pressure measuring pipelines 3 meets the experimental requirements; the specific test method comprises the following steps: the free end of the pressure measuring pipeline 3 is connected to an inflator with a pressure gauge, the pressure measuring pipeline 3 is inflated and pressurized by the inflator, after the inflation and pressurization are stopped, high-pressure gas in the pressure measuring pipeline 3 can only be discharged through the pressure measuring hole 10, and when the pressure gauge is observed, the pointer is seen to be lowered at a constant speed, so that the gas path of the pressure measuring pipeline 3 is smooth; then, the pressure measuring pipeline 3 is inflated and pressurized by the inflator again, after the inflation and pressurization are stopped, the pressure measuring hole 10 is blocked by a finger, and the air passage of the pressure measuring pipeline 3 is not leaked when the finger is observed to be motionless when a pressure gauge is observed; at this moment, the air tightness of the pressure measuring pipeline 3 meets the experimental requirements;
step four: firstly, mounting a model support rod 6 on a model angle adjusting mechanism 5, enabling the top end of the model support rod 6 to be positioned in a wind tunnel experiment section 11, then mounting a rotary body model 1 on the top end of the model support rod 6, simultaneously leading all pressure measuring pipelines 3 out of the wind tunnel experiment section 11 through the model support rod 6, then connecting all the pressure measuring pipelines 3 led out into a pressure scanning valve 2, connecting the pressure scanning valve 2 with a computer 4, and finally mounting an acceleration sensor 7 on the outer surface of the rotary body model 1;
step five: starting a model angle adjusting mechanism 5, and adjusting the attack angle of the rotating fuselage model 1 to the maximum value of the attack angle set by the experiment;
step six: in the state shown in fig. 1, the wind tunnel is opened to blow air, then the experimental wind speed is adjusted until the tremor amplitude of the rotating body model 1 reaches the maximum, the vibration frequency and the vibration amplitude of the rotating body model 1 are measured through the acceleration sensor 7, and the pressure value of the pressure measuring hole 10 is measured through the pressure scanning valve 2 and is marked as Pi；
In the present embodiment, the pressure values of the 12 pressure taps 10 are shown in the following table, the vibration frequency of the rotating body-body model 1 is 70Hz, and the amplitude of the rotating body-body model 1 is 12 mm;
| number of |
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Pressure value Pi(pa) | 1210 | 560 | -122 | 562 | 1201 | 556 | -118 | 561 | 1216 | 555 | -124 | 564 |
Step seven: closing the wind tunnel and stopping blowing, and connecting a vibration exciter 8 between the rotating body fuselage model 1 and the inner wall of the wind tunnel experimental section 11;
step eight: in the state shown in fig. 2, the vibration exciter 8 is activated to apply an exciting force to the rotary body model 1, the vibration frequency and amplitude of the rotary body model 1 are measured in real time by the acceleration sensor 7 to ensure that the vibration frequency and amplitude of the rotary body model 1 under the exciting force condition are the same as those under the pneumatic vibration condition, and then the pressure value of the pressure measuring hole 10 is measured by the pressure scanning valve 2 and is recorded as P'i；
In the present embodiment, the pressure values of the 12 pressure taps 10 are shown in the following table, the vibration frequency of the rotating body-body model 1 is 70Hz, and the amplitude of the rotating body-body model 1 is 12 mm;
| number of measuring hole i | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Pressure value P'i(pa) | -12 | 24 | -7 | 22 | -13 | 21 | -8 | 20 | -12 | 21 | -7 | 18 |
Step nine: calculating the pneumatic tremor error correction coefficient of the rotating body fuselage model 1, wherein the specific calculation formula is as follows:
in the formula, KiIs the pneumatic vibration error correction coefficient, P, of a certain pressure cell 10iThe pressure value P 'of one pressure measuring hole 10 under the condition of pneumatic vibration'iThe pressure value of a certain pressure measuring hole 10 under the condition of exciting force, K is a pneumatic vibration error correction coefficient of the rotating body machine body model 1, and n is the number of all pressure measuring holes 10 contained in all selected pressure measuring sections 9;
in the present embodiment, n is 12, and the pneumatic chatter error correction coefficients of the 12 pressure measurement holes 10 are shown in the following table;
| number of measuring hole i | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Ki(％) | 1.0 | 4.5 | 6.1 | 4.1 | 1.1 | 3.9 | 7.3 | 3.7 | 1.0 | 3.9 | 6.0 | 3.3 |
All K in the above tableiAnd substituting the data into a pneumatic tremor error correction coefficient formula of the rotating body fuselage model, and calculating to obtain the K which is 3.8.
The embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention are intended to be included in the scope of the present invention.
Claims (1)
1. A pneumatic tremor error correction method for a pressure measurement experiment of a rotating body is characterized by comprising the following steps:
the method comprises the following steps: preparing experimental equipment, which comprises a rotating body model, a pressure scanning valve, a pressure measuring pipeline, a computer, a model angle adjusting mechanism, a model supporting rod, an acceleration sensor and a vibration exciter;
step two: selecting a pressure measuring section at the head, the middle and the tail of the rotating body model respectively, and connecting a pressure measuring hole in each pressure measuring section with a pressure measuring pipeline respectively;
step three: performing air tightness test on all pressure measuring pipelines connected to the rotating body model to ensure that the air tightness of the pressure measuring pipelines meets the experimental requirements;
step four: firstly, mounting a model supporting rod on a model angle adjusting mechanism, enabling the top end of the model supporting rod to be positioned in a wind tunnel experiment section, then mounting a rotating body model on the top end of the model supporting rod, simultaneously leading all pressure measuring pipelines out of the wind tunnel experiment section through the model supporting rod, then connecting all the led pressure measuring pipelines into a pressure scanning valve, connecting the pressure scanning valve with a computer, and finally mounting an acceleration sensor on the outer surface of the rotating body model;
step five: starting a model angle adjusting mechanism, and adjusting the attack angle of the rotating fuselage model to the maximum value of the attack angle set by the experiment;
step six: starting the wind tunnel to blow air, then adjusting the experimental wind speed until the tremor amplitude of the rotating body model reaches the maximum, measuring the vibration frequency and the vibration amplitude of the rotating body model through an acceleration sensor, measuring the pressure value of a pressure measuring hole through a pressure scanning valve, and recording the pressure value as Pi；
Step seven: closing the wind tunnel and stopping blowing, and connecting a vibration exciter between the rotating body fuselage model and the inner wall of the wind tunnel experimental section;
step eight: starting a vibration exciter, applying an exciting force to the rotating body model, measuring the vibration frequency and the vibration amplitude of the rotating body model in real time through an acceleration sensor to ensure that the vibration frequency and the vibration amplitude of the rotating body model under the exciting force condition are the same as those under the pneumatic vibration condition, measuring the pressure value of a pressure measuring hole through a pressure scanning valve, and recording the pressure value as P'i；
Step nine: calculating the pneumatic tremor error correction coefficient of the rotating fuselage model, wherein the specific calculation formula is as follows:
in the formula, KiIs a pneumatic vibration error correction coefficient, P, of a certain pressure measuring holeiThe pressure value of one pressure measuring hole under the condition of pneumatic vibration, P'iThe pressure value of a certain pressure measuring hole under the condition of exciting force, K is a pneumatic tremble error correction coefficient of the rotating body model, and n is the number of all pressure measuring holes contained in all selected pressure measuring sections.
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| CN117147093B (en) * | 2023-10-30 | 2024-01-23 | 中国航空工业集团公司沈阳空气动力研究所 | Wind tunnel test measuring device for acoustic explosion characteristics of low acoustic explosion supersonic civil aircraft |
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| JPH07260621A (en) * | 1994-03-24 | 1995-10-13 | Mitsubishi Heavy Ind Ltd | Apparatus for reducing interference of wind tunnel wall |
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