1. A measuring point arrangement method of a 3+4+ 5-meter-shaped harrow flow meter is characterized by comprising the following steps: the method comprises the following steps:

s1, a Mi-shaped harrow flow meter is arranged at an outlet of the elliptic section of the air inlet, 2 vertical measurement bent frames which are coincided with a short semi-axis of the elliptic section and 2 horizontal measurement bent frames which are coincided with a long semi-axis of the elliptic section are arranged on the Mi-shaped harrow flow meter, and 4 inclined measurement bent frames which are respectively positioned in four quadrants of the elliptic section are also arranged on the Mi-shaped harrow flow meter;

s2, 3 total pressure measuring points are arranged on 3 quartering points of each vertical measuring bent frame at equal intervals in the step S1, 4 total pressure measuring points are arranged on 4 quintuple equal points of each inclined measuring bent frame at equal intervals, and 5 total pressure measuring points are arranged on 5 sextuple equal points of each horizontal measuring bent frame at equal intervals;

s3, arranging 1 total pressure measuring point at the intersection of each vertical measuring bent, each inclined measuring bent and each horizontal measuring bent (namely the center of the inlet channel elliptic section outlet) in the step S1;

and S4, arranging 1 static pressure measuring point at the intersection point of the central line of each vertical measuring bent, each inclined measuring bent and each horizontal measuring bent of the step S1 and the outlet of the elliptic section of the air inlet channel.

2. The method for arranging the measuring points of the 3+4+ 5-meter-shaped harrow flow meter according to claim 1, which is characterized in that: the included angle between the central line of the inclination measurement bent frame and the long half shaft of the elliptic section of the air inlet channel is determined by the following formula:

θ＝arctan(b/a)，0＜θ＜π/2。

3. the method for arranging the measuring points of the 3+4+ 5-meter-shaped harrow flow meter according to any one of claims 1-2, is characterized in that: the data processing method of the measuring point arrangement method comprises the following steps:

firstly, acquiring measuring point data:

obtaining total pressure values of 32 measuring points from a measuring bent frame of the Mi-shaped harrow flow meter, obtaining 1 total pressure value from a central measuring point of the Mi-shaped harrow flow meter, and obtaining 8 wall surface static pressure values from a static pressure measuring point of an oval section outlet of an air inlet channel;

secondly, carrying out area division on an outlet of the elliptic section of the air inlet channel:

dividing the area of the outlet with the elliptic section into 40 area units which have equal areas and are not overlapped without intervals from the circumferential direction and the radial direction;

thirdly, solving the total pressure of the central point of the unit area of each region:

interpolating along each measuring bent frame to obtain the total pressure at the face center of the equal-area unit area on the bent frame;

fourthly, solving the static pressure of the central point of the unit area of each area:

carrying out arithmetic average on the static pressure values of 8 wall surfaces to obtain the average static pressure of the central point of the Mi-character Rake flowmeter, and obtaining the static pressure of the central point of each area unit area on a certain measuring bent frame through linear interpolation of the static pressure of the wall surface corresponding to the measuring bent frame and the average static pressure of the central point, thereby obtaining the static pressure of the central point of the area unit of 40 areas;

fifthly, solving the flow on each area unit:

calculating the Mach number and the flow aerodynamic function at the area central point of each zone unit according to the total pressure and the static pressure at the area central point of 40 zone units and the area of each zone unit, thereby obtaining the flow on the unit surface of each zone, wherein the flow on each zone unit is determined by the following formula:

sixthly, solving the flow of the elliptic outlet section:

the flow rates over the 40 area cell faces were summed to give an elliptical outlet cross-sectional flow rate determined by the following equation:

Background

The air inlet channel of the aircraft adopts an elliptical cross-section outlet design, so that the aircraft is compact in structure and flexible in design, and can be easily integrated with a precursor and a combustion chamber, and therefore, the air inlet channel is more and more frequently used in the design of the hypersonic aircraft. The outlet flow of the air inlet channel is an important index matched with the hypersonic aircraft engine, and is also an important way for air inlet channel design check, performance evaluation and numerical calculation method inspection.

For an air inlet channel adopting an elliptical section outlet design, the flow measurement usually adopts a meter-shaped harrow flow meter, and the measuring point arrangement method of the meter-shaped harrow flow meter disclosed at present has two methods: firstly, adopting an equal-area distribution method of 5 multiplied by 8 measuring points at the outlet of the air inlet, dividing the elliptic section of the outlet of the air inlet into 5 multiplied by 8 area units which are not overlapped with each other and have no gap with each other, and arranging total pressure measuring points at the center of the area of each area unit by utilizing a Mi-shaped Rake flowmeter; and secondly, the outlet of the air inlet channel is equidistantly distributed by adopting 41 measuring points, the area of the outlet of the elliptic section is divided into eight parts by utilizing 8 rake positions of the Mi-character rake flow meter, 1 pitot pressure measuring point is arranged at the central intersection point of the 8 rake positions, 5 pitot pressure measuring points are equidistantly arranged on each rake position along the radial direction, and the Mi-character rake flow meter is provided with 41 pitot pressure measuring points.

The two measuring point arrangement methods mainly have the following defects: when the size of the elliptic section of the outlet of the air inlet channel is small, firstly, a measuring point close to the wall surface is easy to generate shock wave/boundary layer interference with the wall surface, and further the accuracy of a measuring result is influenced; and secondly, the pressure measuring pipe with the elliptical section and the short half shaft is easy to generate pneumatic interference and block a flow channel, and particularly, the fixed central point is difficult to process and install due to geometric interference.

Therefore, the measuring point arrangement of the meter-shaped harrow flow meter is the key point for measuring the flow of the outlet with the elliptic section of the air inlet channel.

Disclosure of Invention

The invention aims to provide a measuring point arrangement method of a 3+4+ 5-meter-shaped harrow flow meter, and solves the problems that the existing measuring point arrangement method can cause inaccurate measuring results, geometric interference of measuring points and easy blockage of measuring points on a flow channel.

In order to achieve the purpose, the technical scheme of the invention is as follows: a measuring point arrangement method of a 3+4+ 5-meter-shaped harrow flow meter comprises the following steps:

s1, a Mi-shaped harrow flow meter is arranged at an outlet of the elliptic section of the air inlet, 2 vertical measurement bent frames which are coincided with a short semi-axis of the elliptic section and 2 horizontal measurement bent frames which are coincided with a long semi-axis of the elliptic section are arranged on the Mi-shaped harrow flow meter, and 4 inclined measurement bent frames which are respectively positioned in four quadrants of the elliptic section are also arranged on the Mi-shaped harrow flow meter;

s2, 3 total pressure measuring points are arranged on 3 quartering points of each vertical measuring bent frame at equal intervals in the step S1, 4 total pressure measuring points are arranged on 4 quintuple equal points of each inclined measuring bent frame at equal intervals, and 5 total pressure measuring points are arranged on 5 sextuple equal points of each horizontal measuring bent frame at equal intervals;

s3, arranging 1 total pressure measuring point at the intersection of each vertical measuring bent, each inclined measuring bent and each horizontal measuring bent (namely the center of the inlet channel elliptic section outlet) in the step S1;

and S4, arranging 1 static pressure measuring point at the intersection point of the central line of each vertical measuring bent, each inclined measuring bent and each horizontal measuring bent of the step S1 and the outlet of the elliptic section of the air inlet channel.

Further, the included angle between the center line of the inclination measurement bent frame and the major half axis of the elliptic section of the air inlet channel is determined by the following formula:

θ＝arctan(b/a)，0＜θ＜π/2。

further, the data processing method of the measuring point arrangement method comprises the following steps:

firstly, acquiring measuring point data:

obtaining total pressure values of 32 measuring points from a measuring bent frame of the Mi-shaped harrow flow meter, obtaining 1 total pressure value from a central measuring point of the Mi-shaped harrow flow meter, and obtaining 8 wall surface static pressure values from a static pressure measuring point of an oval section outlet of an air inlet channel;

secondly, carrying out area division on an outlet of the elliptic section of the air inlet channel:

dividing the area of the outlet with the elliptic section into 40 area units which have equal areas and are not overlapped without intervals from the circumferential direction and the radial direction;

thirdly, solving the total pressure of the central point of the unit area of each region:

interpolating along each measuring bent frame to obtain the total pressure at the face center of the equal-area unit area on the bent frame;

fourthly, solving the static pressure of the central point of the unit area of each area:

carrying out arithmetic average on the static pressure values of 8 wall surfaces to obtain the average static pressure of the central point of the Mi-character Rake flowmeter, and obtaining the static pressure of the central point of each area unit area on a certain measuring bent frame through linear interpolation of the static pressure of the wall surface corresponding to the measuring bent frame and the average static pressure of the central point, thereby obtaining the static pressure of the central point of the area unit of 40 areas;

fifthly, solving the flow on each area unit:

calculating the Mach number and the flow aerodynamic function at the area central point of each zone unit according to the total pressure and the static pressure at the area central point of 40 zone units and the area of each zone unit, thereby obtaining the flow on the unit surface of each zone, wherein the flow on each zone unit is determined by the following formula:

sixthly, solving the flow of the elliptic outlet section:

the flow rates over the 40 area cell faces were summed to give an elliptical outlet cross-sectional flow rate determined by the following equation:

compared with the prior art, the beneficial effect of this scheme:

according to the scheme, the total pressure measuring points on the star-shaped harrow flow meter measuring bent are reasonably distributed according to the size of the inlet passage oval section outlet, so that the problem of mutual interference between the measuring points at the edge of the flow meter and the shock wave boundary layer of the inner wall surface of the oval section outlet can be avoided, the aerodynamic interference and the geometric interference between the total pressure measuring points on the measuring bent can be avoided, and a scientific basis is provided for flow calculation and data processing of the oval section outlet.

Drawings

FIG. 1 is a distribution diagram of measured points at the outlet of the elliptical cross section of the inlet in this embodiment.

Detailed Description

The present invention will be described in further detail below by way of specific embodiments:

reference numerals in the drawings of the specification include: the device comprises a horizontal measurement bent frame 1, a vertical measurement bent frame 2 and an inclination measurement bent frame 3.

Examples

The description of the related symbols and terms in this embodiment is as follows:

as shown in figure 1: a measuring point arrangement method of a 3+4+ 5-meter-shaped harrow flow meter comprises the following steps:

s1, a Mi-shaped harrow flow meter is arranged at an outlet of the elliptic section of the air inlet, 2 vertical measurement bent frames 2 coincident with a short semi-axis of the elliptic section and 2 horizontal measurement bent frames 1 coincident with a long semi-axis of the elliptic section are arranged on the Mi-shaped harrow flow meter, and 4 inclined measurement bent frames 3 respectively positioned in four quadrants of the elliptic section are further arranged on the Mi-shaped harrow flow meter.

Wherein, the included angle between the central line of the inclination measurement bent frame 3 and the long semi-axis of the elliptic section of the air inlet channel is determined by the following formula:

θ＝arctan(b/a)，0＜θ＜π/2。

s2 and S1, 3 total pressure measurement points are arranged at equal intervals on 3 quartering points of each vertical measurement bent 2, 4 total pressure measurement points are arranged at equal intervals on 4 quintuple points of each inclined measurement bent 3, and 5 total pressure measurement points are arranged at equal intervals on 5 sextuple points of each horizontal measurement bent 1.

And S3, arranging 1 total pressure measuring point at the intersection of each vertical measuring bent 2, each inclined measuring bent 3 and each horizontal measuring bent 1 (namely the center of the inlet passage oval section outlet) in the step S1.

S4, and 1 static pressure measuring point is arranged at the intersection point of the central line of each vertical measuring bent 2, each inclined measuring bent 3 and each horizontal measuring bent 1 of the step S1 and the outlet of the elliptical section.

3 total pressure measuring points are respectively arranged on each vertical measuring bent 2 at equal intervals, and the total pressure measuring points are respectively positioned on 4 equal division points of the central line of the vertical measuring bent 2, namely the interval between the total pressure measuring points is b/4; 4 total pressure measuring points are respectively arranged on each inclined measuring bent 3 at equal intervals, the total pressure measuring points are respectively positioned on 5 equal division points of the central line of the inclined measuring bent 3, namely the distance between the total pressure measuring points is 1/5; 5 total pressure measuring points are respectively arranged on each horizontal measurement bent 1 at equal intervals, and the total pressure measuring points are respectively positioned on 6 equal division points of the central line of the horizontal measurement bent 1, namely the interval between the total pressure measuring points is a/6; 1 total pressure measuring point is arranged at the center of the outlet of the elliptic section of the air inlet channel, and the total pressure measuring points are totally 33.

1 static pressure measuring point is respectively arranged at the intersection of the central line of each measuring bent of the Mi-character rake flowmeter and the inner wall surface of the outlet of the oval section, and 8 static pressure measuring points are counted.

The data processing method comprises the following steps:

firstly, acquiring measuring point data:

and obtaining total pressure values of 32 measuring points from the measurement bent of the Mi-character-shaped harrow flow meter, obtaining 1 total pressure value from the central measuring point of the Mi-character-shaped harrow flow meter, and obtaining 8 wall surface static pressure values from the static pressure measuring points on the wall surface of the outlet with the oval section.

Secondly, carrying out area division on an outlet of the elliptic section of the air inlet channel:

the area of the outlet with the elliptic section is divided into 40 area units which are equal in area and do not overlap with each other without intervals from the circumferential direction and the radial direction.

Thirdly, solving the total pressure of the central point of the unit area of each region:

and (4) interpolating along each measuring bent frame to obtain the total pressure at the face center of the equal-area unit area on the bent frame.

The interpolation method comprises the following steps: using Akima or other interpolation methods; each measuring rack is provided with 5-7 total pressure values in the radial direction (namely two horizontal measuring racks 1 are respectively provided with 5 total pressure measurement point values, 1 total pressure measurement point value at the center of the Mi-shaped harrow flow meter, 1 wall surface total pressure value (namely a wall surface static pressure measurement point value), and 7 measurement point values in total; similarly, two vertical measuring racks 2 are respectively provided with 3 total pressure measurement point values, 1 total pressure measurement point value at the center of the Mi-shaped harrow flow meter, and 1 wall surface total pressure value (namely a wall surface static pressure measurement point value), and 5 measurement point values in total, four inclined measuring racks 3 are respectively provided with 4 total pressure measurement point values, 1 total pressure measurement point value at the center of the Mi-shaped harrow flow meter, and 1 wall surface total pressure value (namely a wall surface static pressure measurement point value), and 6 measurement point values in total), the total pressure values of each measuring rack are interpolated, so that the total pressure values of 5 region unit area centers distributed according to the equal ring area on the rack can be obtained, thus, the total pressure in the center of the 40 cell areas is determined.

Fourthly, solving the static pressure of the central point of the unit area of each area:

and (3) carrying out arithmetic average on static pressure values of 8 wall surface measuring points to obtain the average static pressure of the central point of the Mi-character rake flowmeter, and obtaining the static pressure of the central point of each area unit area on a certain measuring bent through linear interpolation between the wall surface static pressure corresponding to the measuring bent and the average static pressure of the central point, thereby obtaining the static pressure of the central point of the area of 40 area units.

Fifthly, solving the flow on each area unit:

calculating the Mach number and the flow aerodynamic function at the area central point of each zone unit according to the total pressure and the static pressure at the area central point of 40 zone units and the area of each zone unit, thereby obtaining the flow on the unit surface of each zone, wherein the flow on each zone unit is determined by the following formula:

sixthly, solving the flow of the elliptic outlet section:

the flow rates over the 40 area cell faces were summed to give an elliptical outlet cross-sectional flow rate determined by the following equation:

the foregoing are merely examples of the present invention and common general knowledge of known specific structures and/or features of the schemes has not been described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.