CN104596769A - Real thrust measuring and calculating method for test run of aero-engine on indoor test bed - Google Patents

Abstract

The invention belongs to the technical field of aero-engines and particularly relates to a real thrust measuring and calculating method for test run of an aero-engine on an indoor test bed. The real thrust measuring and calculating method specifically comprises the steps of 1 determining the spatial position of a control body, 2 arranging a rear cross section measuring point on a lip rear cross section (2), 3 arranging front cross section measuring point on a far front cross section (1), 4 obtaining wind speed values and static pressure values on the measuring points, and 5 obtaining a real thrust value of the test run of the aero-engine on the indoor test bed. According to the real thrust measuring and calculating method, the area of air intake cross section of the engine is reasonably selected, the flow pipe surface for air flowing in a test run workshop serves as a control face, an air intake channel additional resistance correction formula is derived and real thrust is calculated by applying momentum theorem. The real thrust measuring and calculating method has the advantages of being clear in control body division, fewer in correction terms, simple and convenient to calculate and the like, and the problem of real thrust measurement and calculation during the test run of the aero-engine on the indoor test bed can be solved.

Description

Aeromotor is at the true thrust measuring method of indoor test cell run

Technical field

The invention belongs to aero engine technology field, be specifically related to the true thrust measuring method of a kind of aeromotor at indoor test cell run.

Background technology

Aeromotor is on indoor test bay during test run, and engine environment has air current flow, on airflow function engine, produces the resistance contrary with thrust.Exactly because the existence of these resistances, the aeroengine thrust recorded at indoor test bay just must can obtain true thrust magnitude through pneumatic additional drag correction.

Aeromotor to be intersected mainly through platform and indoor test bay in the open in the true thrust measuring and calculating of indoor test cell run to test run method obtains abroad at present.For a long time, China lacks outdoor benchmark test bay for calibrating engine standard part, can only from foreign procurement, and the cost of test run of therefore intersecting is higher.In addition, for the type of China's independent research, we use for reference not have outdoor ready-made confession abroad, cannot be calculated by the method for intersection test run to the true thrust of aeromotor.Relative to intersection test run, the true thrust being calculated aeromotor by the correction of indoor test bay pneumatic additional drag affects little by weather condition, and implement relatively simple, advantage is obvious.Therefore extensively adopt at home.But the major defect being calculated the true thrust of aeromotor by the correction of indoor test bay pneumatic additional drag is: because the test of stream field distribution is accurate not, cause discharge calculation error comparatively large, cause aeromotor large in the true thrust magnitude error of indoor test cell run.

Summary of the invention

The object of the invention is to propose the true thrust measuring method of a kind of aeromotor at indoor test cell run.

The object of the invention is to be achieved through the following technical solutions.

Aeromotor, at a true thrust measuring method for indoor test cell run, is characterized in that: its concrete operation step is as follows:

Step one, determine the locus of control volume.Described control volume is an imaginary space.Determine that the concrete operation step of control volume locus is:

Step 1.1: engine is fixed on the test bay of test cell; Engine axis is positioned at horizontal level.

Step 1.2: set up two dimensional surface rectangular coordinate system: using engine axis as X-axis, and in X-axis with the distance of engine front and engine lip plane for the position of engine lip (4) diameter 9 times is for initial point, to cross initial point direction straight up for Y-axis.

Step 1.3: the enclosure space that control volume is made up of cross section (2) and the surface of revolution (3) after front square section (1) far away, lip, and whole control volume is positioned at inside, test cell.Front square section (1) far away is positioned at before engine, and front square section far away (1) was positioned at the initial point of described two dimensional surface rectangular coordinate system, and perpendicular in the plane of X-axis; After lip, cross section (2) are positioned at after engine, and after lip, cross section (2) are positioned at distance engine lip plane a rice, and are parallel in the plane of front square section (1) far away, a value by people for presetting, and a ∈ [1.5,2].The axis of the described surface of revolution (3) overlaps with engine axis.

The defining method of the described surface of revolution (3) is:

Step a: determine the first position, reference mark.The cross section that control volume is fastened at described two dimensional surface rectangular coordinate is called control volume cross section; On the intersecting lens of control volume cross section and front square section far away (1), multiple sensor is set, uses M _irepresent i-th sensor above described two dimensional surface rectangular coordinate system X-axis, i ∈ [1, N], and i is positive integer; N > 3 and N is positive integer.Described sensor is speed pickup or pressure transducer.

Find i-th sensor that formula (1) is set up, and using first reference mark of i-th sensor position as control volume cross section;

$\left\{\begin{array}{c}|m_{i^{\′}}-m_{i^{\′}+1}|>\mathrm{\σ}\\ |m_{i^{\′}-1}-m_{i^{\′}}|>\mathrm{\σ}\end{array}\right.---\left(1\right)$

Wherein, i ' ∈ [2, N-1] and i ' is positive integer; m _{i '}represent the measured value that the i-th ' individual sensor records; σ is a threshold value preset, and the span of σ is m _{i '}0.1% ~ 10% of middle maximal value.

Step b: determine the second position, reference mark.

Behind control volume cross section and lip cross section (2) intersecting lens on, multiple sensor is set, uses M _jrepresent the jth sensor above described two dimensional surface rectangular coordinate system X-axis, j ∈ [1, N '], and j is positive integer; N ' > 3 and N ' is positive integer.Described sensor is speed pickup or pressure transducer.

Find the jth sensor that formula (2) is set up, and using second reference mark of a jth sensor position as control volume cross section;

$\left\{\begin{array}{c}|m_j-m_{j+1}|>{\mathrm{\σ}}^{\′}\\ |m_{j-1}-m_j|>{\mathrm{\σ}}^{\′}\end{array}\right.---\left(2\right)$

Wherein, j ' ∈ [2, N '-1] and j ' is positive integer; m _{j '}represent the measured value that jth ' individual sensor records; σ ' is a threshold value preset, and the span of σ ' is m _{j '}0.1% ~ 10% of middle maximal value.

Step c: determine turning spur.Connect the first reference mark and the second reference mark with a curve, and the ordinate value meeting other any point on described curve except the second reference mark is greater than the second reference mark ordinate value, then described curve is called turning spur.

Steps d: take X-axis as axis rotating 360 degrees by turning spur, namely obtains the surface of revolution (3).

By the operation of above-mentioned steps, namely obtain the locus of control volume.

Step 2, after lip, cross section (2) arrange rear section gauge point.

On the basis that step one operates, after lip, cross section (2) arrange rear section gauge point; Be specially:

Step 2.1: with the central point of cross section after lip (2) for the center of circle, with for radius, cross section after lip (2) are divided into the individual region of K ', wherein, t ' ∈ [1, T '-1], the value of K ' by artificially pre-determining, K ' ∈ [2,5]; R ₁for the radius of cross section after lip (2).Symbol T is used in the individual region of K ' from the center of cross section after lip (2) to edge respectively ₁', T ₂' ..., T _{k '}' represent.

Step 2.2: according to practical measurement requirement, arranges the rear section gauge point of varying number respectively in the individual region of K ' described in step 2.1.

Step 3, starting section measurement point is set on front square section (1) far away.

On the basis of step 3 operation, front square section (1) far away arranges starting section measurement point; Be specially:

Step 3.1: with the central point of front square section (1) far away for the center of circle, with for radius, front square section (1) far away is divided into T region, wherein, t ∈ [1, T-1], the value of T by artificially pre-determining, T ∈ [2,8]; R ₂for the radius of front square section (1) far away.

Step 3.2: the area calculating K region of front square section (1) far away respectively, the area in K region uses symbol A respectively _krepresent, k ∈ [1, K]; The area of front square section (1) far away represents with symbol A, symbol T is used in K the region from the center of front square section (1) far away to edge respectively ₁, T ₂..., T _krepresent.

Step 3.3: according to practical measurement requirement, arranges the starting section measurement point of varying number respectively in K region, and after ensureing, the projected position of section gauge point on front square section (1) far away is equipped with starting section measurement point.

Step 4, obtain air speed value on measurement point and static pressure.

On the basis of step 3 operation, in each of front section gauge point and rear section gauge point all arrange air velocity transducer and static pressure transducer; Then make engine operation in preset state, measure air speed value on each starting section measurement point and rear section gauge point and static pressure by air velocity transducer and static pressure transducer.

Step 5, obtain the true thrust magnitude of aeromotor at indoor test cell run.

On the basis of step 4 operation, the air speed value recorded and static pressure are processed, obtain the true thrust magnitude of aeromotor at indoor test cell run at starting section measurement point and rear section gauge point.Be specially:

Step 5.1: calculate the upper T of front square section (1) far away by formula (3) ₁the mass rate in region (uses symbol w ₁represent).

w ₁＝ρv ₁A ₁(3)

Wherein, ρ is test cell atmospheric density; v ₁for the upper T of front square section (1) far away ₁the wind speed average of all starting sections measurement point in region; A ₁for T ₁region area.

Step 5.2: judge | w ₁-w _j|≤σ ₁whether set up, if set up, then by T ₁region is set to territory, preadmission air-flow area under control; Wherein w _jfor the charge flow rate of engine.Otherwise, if | w ₁-w _j| > σ ₁and w ₁> w _j, then T is reduced ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up; If | w ₁-w _j| > σ ₁and w ₁< w _j, then T is expanded ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up.

Step 5.3: if T in step 5.2 ₁the area in region changes, then recalculate T ₂the area A in region ₂.

Step 5.4: calculate T by formula (4) _{k '}the mass rate in region (uses symbol w _{k '}represent), k ' ∈ [2, K], T _{k '}represent T ₂, T ₃..., T _k.

w _k′＝ρv _k′A _k′(4)

Wherein, ρ is test cell atmospheric density; v _{k '}for T _{k '}all starting sections measurement point wind speed average in region; A _{k '}for T _{k '}region area.

Step 5.5: calculate inlet additive drag by formula (5) and (use symbol F _cIrepresent).

F _CI＝w ₀v ₀+w' ₀(v ₀-v ₁')-(P ₁'-P ₀')A' ₀-(P ₁'-P ₀)A ₀(5)

Wherein, w ₀the gas mass flows entering engine, w ₀=w ₁; v ₀average velocity in front square section (1) preadmission gas flow tube far away, v ₀=v ₁; W' ₀the gas mass flows of Secondary Flow, v ₁' be all after the average velocity of section gauge point; P ₀it is average static pressure in territory, front square section (1) preadmission air-flow area under control far away; P ₀' be the average static pressure of starting section measurement point of front square section (1) far away part except preadmission gas flow tube; P ₁' be whole rear section gauge point average static pressure; A ₀front square section (1) far away upper pre-admission stream tube area, i.e. T ₁region area, A ₀=A ₁; A' ₀the upper area except preadmission gas flow tube of front square section (1) far away, A' ₀=A-A ₀.

Step 5.6: calculate aeromotor by formula (6) and (use symbol F at the true thrust magnitude of indoor test cell run _grepresent).

F _g=F _m+ F _cradle+ F _base+ F _tailpipe+ F _cI+ F _other(6)

Wherein, F _mbe measure thrust, obtained by the measurement of thrust scale; F _cradlebe frontal resistance, calculate by formula (7); F _basebe base drag, calculate by formula (8); F _tailpipebe the additional drag of nozzle, calculate by formula (9); F _cIit is inlet additive drag; F _otherbeing other thrust, is artificial estimated value in advance; Other thrust comprises the thrust that Spring deformation, the distortion of stream pipe, frictional resistance etc. produce.

$F_{\mathrm{Cradle}}=\frac{\mathrm{\&rho;}}{2}{\mathrm{\&Sigma;}}_{i}C{d}_i{A}_i^{\&prime;}{v}_i^2---\left(7\right)$

Wherein, Cd _ibe the damage factor of i-th obturator on test bay, i gets positive integer; A _i' be the blocked area of i-th obturator on test bay; V _iit is the gas velocity in i-th obturator front on test bay.

F _base＝(P _nozzle-P ₀)·A _nozzle(8)

Wherein, P _nozzleit is nozzle Surface Static Pressure; P ₀it is average static pressure in territory, front square section (1) preadmission air-flow area under control far away; A _nozzlebe nozzle project to nozzle cross section annular outer surface amass.

F _tailpipe＝(P _tailpipe-P ₀)·A _tailpipe(9)

Wherein, P _tailpipeit is the cross section static pressure of nozzle; A _tailpipeit is the area of section of engine jet pipe.

Beneficial effect

The present invention propose aeromotor indoor test cell run true thrust measuring method compared with the prior art comparatively, have the following advantages:

1. the present invention adopts apart from the nearer border circular areas of test cell wall choosing of control volume air inlet cross section (front square section (1) far away), the circulation area of bypass gas flow is reduced, is more convenient to measuring and calculating.

2. control volume air inlet cross section choose employing border circular areas, measurement parameter is evenly distributed, reduces the uncertainty of measurement of differential static pressure between cross section.

3. the present invention has the advantages such as control volume division is clear, correction term is few, computation process is easy, can solve the measuring and calculating problem of aeromotor true thrust when indoor test cell run.

Accompanying drawing explanation

Fig. 1 is control volume schematic cross-section in the specific embodiment of the invention;

Wherein, cross section, the 3-surface of revolution, 4-engine lip after 1-front square section far away, 2-lip;

Fig. 2 is that in the specific embodiment of the invention, after lip, cross section (2) go up rear section gauge point position view;

Fig. 3 is that in the specific embodiment of the invention, front square section (1) far away is gone forward section gauge point position view.

Embodiment

Below by the drawings and specific embodiments, content of the present invention is described further.

The present embodiment uses described aeromotor to calculate the true thrust of aeromotor at indoor test cell run at the true thrust measuring method of indoor test cell run, and concrete operation step is as follows:

Step one, determine the locus of control volume.

Step 1.1: engine is fixed on the test bay of test cell; Engine axis is positioned at horizontal level.

Step 1.2: set up two dimensional surface rectangular coordinate system: using engine axis as X-axis, and in X-axis with the distance of engine front and engine lip plane be the position of 12 meters for initial point, to cross initial point direction straight up for Y-axis.

Step 1.3: the enclosure space that control volume is made up of cross section (2) and the surface of revolution (3) after front square section (1) far away, lip, and whole control volume is positioned at inside, test cell.Front square section (1) far away is positioned at before engine, and front square section far away (1) was positioned at the initial point of described two dimensional surface rectangular coordinate system, and perpendicular in the plane of X-axis; After lip, cross section (2) are positioned at after engine, and after lip, cross section (2) are positioned at 1.5 meters, distance engine lip plane, and are parallel in the plane of front square section (1) far away.The axis of the described surface of revolution (3) overlaps with engine axis.

The defining method of the described surface of revolution (3) is:

Step a: determine the first position, reference mark.The cross section that control volume is fastened at described two dimensional surface rectangular coordinate is called control volume cross section; On the intersecting lens of control volume cross section and front square section far away (1), multiple sensor is set, uses M _irepresent i-th speed pickup above described two dimensional surface rectangular coordinate system X-axis, i ∈ [1, N]; N=5.

Find i-th sensor that formula (1) is set up, and using first reference mark of i-th sensor position as control volume cross section; In formula (1), the value of σ is m _{i '}1% of middle maximal value.

Step b: determine the second position, reference mark.

Behind control volume cross section and lip cross section (2) intersecting lens on, multiple sensor is set, uses M _jrepresent the jth speed pickup above described two dimensional surface rectangular coordinate system X-axis, j ∈ [1, N '], N '=4.

Find the jth sensor that formula (2) is set up, and using second reference mark of a jth sensor position as control volume cross section; In formula (1), the value of σ ' is m _{j '}1% of middle maximal value.

Step c: determine turning spur.Connect the first reference mark and the second reference mark with a curve, and the ordinate value meeting other any point on described curve except the second reference mark is greater than the second reference mark ordinate value, then described curve is called turning spur.

Steps d: take X-axis as axis rotating 360 degrees by turning spur, namely obtains the surface of revolution (3).

By the operation of above-mentioned steps, namely obtain the locus of control volume, control volume cross section as shown in Figure 1.

Step 2, after lip, cross section (2) arrange rear section gauge point.

On the basis that step one operates, after lip, cross section (2) arrange rear section gauge point; Be specially:

Step 2.1: with the central point of cross section after lip (2) for the center of circle, respectively with 2 meters and 4 meters for radius, cross section after lip (2) are divided into 3 regions, and after lip, the radius of cross section (2) is 5.5 meters.Symbol T is used in 3 regions from the center of cross section after lip (2) to edge respectively ₁', T ₂', T ₃' represent.

Step 2.2: according to practical measurement requirement, the T of cross section (2) after lip ₁after ' region arranges 2, section gauge point is (at T ₁on the border in ' region), at T ₂(wherein section gauge point is positioned at T after 4 for section gauge point after ' region arranges 6 ₂' intra-zone, after 2, section gauge point is positioned at T ₂on the outer boundary in ' region), at T ₃(wherein section gauge point is positioned at T after 8 for section gauge point after ' region arranges 10 ₃' intra-zone, after 2, section gauge point is positioned at T ₃on the outer boundary in ' region), as shown in Figure 2.

Step 3, starting section measurement point is set on front square section (1) far away.

On the basis of step 3 operation, front square section (1) far away arranges starting section measurement point; Be specially:

Step 3.1: with the central point of front square section (1) far away for the center of circle, respectively with 2 meters and 4 meters for radius, cross section after lip (2) are divided into 3 regions, and the radius of front square section (1) far away is 5.75 meters.

Step 3.2: the area calculating 3 regions of front square section (1) far away respectively, the area in 3 regions uses symbol A respectively _krepresent, k ∈ [1,3]; The area of front square section (1) far away represents with symbol A, symbol T is used in 3 regions from the center of front square section (1) far away to edge respectively ₁, T ₂, T ₃represent.

Step 3.3: according to practical measurement requirement, at T ₁9 starting section measurement points are arranged, at T in region ₂region arranges that (wherein 4 starting section measurement points are positioned at T to 12 starting section measurement points ₂intra-zone, 4 starting section measurement points are positioned at T ₂on the inner boundary in region, 4 starting section measurement points are positioned at T ₂on the outer boundary in region), at T ₃region arranges that (wherein 8 starting section measurement points are positioned at T to 12 starting section measurement points ₃intra-zone, 4 starting section measurement points are positioned at T ₃on the outer boundary in region), and the rear projected position of section gauge point on front square section (1) far away is equipped with starting section measurement point, as shown in Figure 3.

Step 4, obtain air speed value on measurement point and static pressure.

On the basis of step 3 operation, in each of front section gauge point and rear section gauge point all arrange air velocity transducer and static pressure transducer; Then make engine operation in preset state, measure air speed value on each starting section measurement point and rear section gauge point and static pressure by air velocity transducer and static pressure transducer.

Step 5, obtain the true thrust magnitude of aeromotor at indoor test cell run.

On the basis of step 4 operation, the air speed value recorded and static pressure are processed, obtain the true thrust magnitude of aeromotor at indoor test cell run at starting section measurement point and rear section gauge point.Be specially:

Step 5.1: calculate the upper T of front square section (1) far away by formula (3) ₁the mass rate w in region ₁.

Step 5.2: judge | w ₁-w _j|≤σ ₁whether set up, if set up, then by T ₁region is set to territory, preadmission air-flow area under control; Wherein w _jfor the charge flow rate of engine.Otherwise, if | w ₁-w _j| > σ ₁and w ₁> w _j, then T is reduced ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up; If | w ₁-w _j| > σ ₁and w ₁< w _j, then T is expanded ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up.

Step 5.3: if T in step 5.2 ₁the area in region changes, then recalculate T ₂the area A in region ₂.

Step 5.4: calculate T by formula (4) _{k '}the mass rate w in region _{k '}.

Step 5.5: calculate inlet additive drag F by formula (5) _cI.

Step 5.6: calculate the true thrust magnitude F of aeromotor at indoor test cell run by formula (6) _g.F in formula (6) _cradlecalculated by formula (7); F in formula (6) _basecalculated by formula (8); F in formula (6) _tailpipecalculated by formula (9).

Through the operation of above-mentioned steps, the true thrust magnitude F of aeromotor at indoor test cell run can be obtained _g.

Claims (2)

1. aeromotor is at a true thrust measuring method for indoor test cell run, it is characterized in that: its concrete operation step is as follows:

Step one, determine the locus of control volume; Described control volume is an imaginary space; Determine that the concrete operation step of control volume locus is:

Step 1.1: engine is fixed on the test bay of test cell; Engine axis is positioned at horizontal level;

Step 1.2: set up two dimensional surface rectangular coordinate system: using engine axis as X-axis, and in X-axis with the distance of engine front and engine lip plane for the position of engine lip (4) diameter 9 times is for initial point, to cross initial point direction straight up for Y-axis;

Step 1.3: the enclosure space that control volume is made up of cross section (2) and the surface of revolution (3) after front square section (1) far away, lip, and whole control volume is positioned at inside, test cell; Front square section (1) far away is positioned at before engine, and front square section far away (1) was positioned at the initial point of described two dimensional surface rectangular coordinate system, and perpendicular in the plane of X-axis; After lip, cross section (2) are positioned at after engine, and after lip, cross section (2) are positioned at distance engine lip plane a rice, and are parallel in the plane of front square section (1) far away, a value by people for presetting, and a ∈ [1.5,2]; The axis of the described surface of revolution (3) overlaps with engine axis;

By the operation of above-mentioned steps, namely obtain the locus of control volume;

Step 2, after lip, cross section (2) arrange rear section gauge point;

On the basis that step one operates, after lip, cross section (2) arrange rear section gauge point; Be specially:

Step 2.1: with the central point of cross section after lip (2) for the center of circle, with for radius, cross section after lip (2) are divided into the individual region of K ', wherein, t ' ∈ [1, T '-1], the value of K ' by artificially pre-determining, K ' ∈ [2,5]; R ₁for the radius of cross section after lip (2); Symbol T ' is used in the individual region of K ' from the center of cross section after lip (2) to edge respectively ₁, T ' ₂..., T ' _{k '}represent;

Step 2.2: according to practical measurement requirement, arranges the rear section gauge point of varying number respectively in the individual region of K ' described in step 2.1;

Step 3, starting section measurement point is set on front square section (1) far away;

On the basis of step 3 operation, front square section (1) far away arranges starting section measurement point; Be specially:

Step 3.1: with the central point of front square section (1) far away for the center of circle, with for radius, front square section (1) far away is divided into T region, wherein, t ∈ [1, T-1], the value of T by artificially pre-determining, T ∈ [2,8]; R ₂for the radius of front square section (1) far away;

Step 3.2: the area calculating K region of front square section (1) far away respectively, the area in K region uses symbol A respectively _krepresent, k ∈ [1, K]; The area of front square section (1) far away represents with symbol A, symbol T is used in K the region from the center of front square section (1) far away to edge respectively ₁, T ₂..., T _krepresent;

Step 3.3: according to practical measurement requirement, arranges the starting section measurement point of varying number respectively in K region, and after ensureing, the projected position of section gauge point on front square section (1) far away is equipped with starting section measurement point;

Step 4, obtain air speed value on measurement point and static pressure;

On the basis of step 3 operation, in each of front section gauge point and rear section gauge point all arrange air velocity transducer and static pressure transducer; Then make engine operation in preset state, measure air speed value on each starting section measurement point and rear section gauge point and static pressure by air velocity transducer and static pressure transducer;

Step 5, obtain the true thrust magnitude of aeromotor at indoor test cell run;

On the basis of step 4 operation, the air speed value recorded and static pressure are processed, obtain the true thrust magnitude of aeromotor at indoor test cell run at starting section measurement point and rear section gauge point; Be specially:

Step 5.1: calculate the upper T of front square section (1) far away by formula (3) ₁the mass rate w in region ₁;

w ₁＝ρv ₁A ₁(3)

Wherein, ρ is test cell atmospheric density; v ₁for the upper T of front square section (1) far away ₁the wind speed average of all starting sections measurement point in region; A ₁for T ₁region area;

Step 5.2: judge | w ₁-w _j|≤σ ₁whether set up, if set up, then by T ₁region is set to territory, preadmission air-flow area under control; Wherein w _jfor the charge flow rate of engine; Otherwise, if | w ₁-w _j| > σ ₁and w ₁> w _j, then T is reduced ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up; If | w ₁-w _j| > σ ₁and w ₁< w _j, then T is expanded ₁the area in region, repeats step 5.1 to 5.2, until | w ₁-w _j|≤σ ₁set up;

Step 5.3: if T in step 5.2 ₁the area in region changes, then recalculate T ₂the area A in region ₂;

Step 5.4: calculate T by formula (4) _{k '}the mass rate w in region _{k '}, k ' ∈ [2, K], T _{k '}represent T ₂, T ₃..., T _k;

w _k′＝ρv _k′A _k′(4)

Wherein, ρ is test cell atmospheric density; v _{k '}for T _{k '}all starting sections measurement point wind speed average in region; A _{k '}for T _{k '}region area;

Step 5.5: calculate inlet additive drag F by formula (5) _cI;

F _CI＝w ₀v ₀+w′ ₀(v ₀-v′ ₁)-(P′ ₁-P′ ₀)A′ ₀-(P′ ₁-P ₀)A ₀(5)

Wherein, w ₀the gas mass flows entering engine, w ₀=w ₁; v ₀average velocity in front square section (1) preadmission gas flow tube far away, v ₀=v ₁; W ' ₀the gas mass flows of Secondary Flow, v ' ₁the average velocity of all rear section gauge points; P ₀it is average static pressure in territory, front square section (1) preadmission air-flow area under control far away; P ' ₀it is the average static pressure of front square section (1) far away starting section measurement point of part except preadmission gas flow tube; P ' ₁whole rear section gauge point average static pressure; A ₀front square section (1) far away upper pre-admission stream tube area, i.e. T ₁region area, A ₀=A ₁; A ' ₀the upper area except preadmission gas flow tube of front square section (1) far away, A ' ₀=A-A ₀;

Step 5.6: calculate the true thrust magnitude F of aeromotor at indoor test cell run by formula (6) _g;

F _g=F _m+ F _cradle+ F _base+ F _tailpipe+ F _cI+ F _other(6)

Wherein, F _mbe measure thrust, obtained by the measurement of thrust scale; F _cradlebe frontal resistance, calculate by formula (7); F _basebe base drag, calculate by formula (8); F _tailpipebe the additional drag of nozzle, calculate by formula (9); F _cIit is inlet additive drag; F _otherbeing other thrust, is artificial estimated value in advance; Other thrust comprises the thrust that Spring deformation, the distortion of stream pipe, frictional resistance etc. produce;

$F_{\mathrm{Cradle}}=\frac{\mathrm{\&rho;}}{2}{\mathrm{\&Sigma;}}_i{\mathrm{Cd}}_i{A}_i^{\&prime;}{v}_i^2---\left(7\right)$

Wherein, Cd _ibe the damage factor of i-th obturator on test bay, i gets positive integer; A ' _iit is the blocked area of i-th obturator on test bay; V _iit is the gas velocity in i-th obturator front on test bay;

F _base＝(P _nozzle-P ₀)·A _nozzle(8)

Wherein, P _nozzleit is nozzle Surface Static Pressure; P ₀it is average static pressure in territory, front square section (1) preadmission air-flow area under control far away; A _nozzlebe nozzle project to nozzle cross section annular outer surface amass;

F _tailpipe＝(P _tailpipe-P ₀)·A _tailpipe(9)

Wherein, P _tailpipeit is the cross section static pressure of nozzle; A _tailpipeit is the area of section of engine jet pipe.

2. a kind of aeromotor as claimed in claim 1 is at the true thrust measuring method of indoor test cell run, it is characterized in that: the defining method of the surface of revolution described in step 1.3 (3) is:

Step a: determine the first position, reference mark; The cross section that control volume is fastened at described two dimensional surface rectangular coordinate is called control volume cross section; On the intersecting lens of control volume cross section and front square section far away (1), multiple sensor is set, uses M _irepresent i-th sensor above described two dimensional surface rectangular coordinate system X-axis, i ∈ [1, N], and i is positive integer; N > 3 and N is positive integer; Described sensor is speed pickup or pressure transducer;

Find i-th sensor that formula (1) is set up, and using first reference mark of i-th sensor position as control volume cross section;

$\left\{\begin{array}{c}|m_{i^{\&prime;}}-m_{i^{\&prime;}+1}|>\mathrm{\&sigma;}\\ |m_{i^{\&prime;}-1}-m_{i^{\&prime;}}|>\mathrm{\&sigma;}\end{array}\right.---\left(1\right)$

Wherein, i ' ∈ [2, N-1] and i ' is positive integer; m _{i '}represent the measured value that the i-th ' individual sensor records; σ is a threshold value preset, and the span of σ is m _{i '}0.1% ~ 10% of middle maximal value;

Step b: determine the second position, reference mark;

Behind control volume cross section and lip cross section (2) intersecting lens on, multiple sensor is set, uses M _jrepresent the jth sensor above described two dimensional surface rectangular coordinate system X-axis, j ∈ [1, N '], and j is positive integer; N ' > 3 and N ' is positive integer; Described sensor is speed pickup or pressure transducer;

Find the jth sensor that formula (2) is set up, and using second reference mark of a jth sensor position as control volume cross section;

$\left\{\begin{array}{c}|m_j-m_{j+1}|>{\mathrm{\&sigma;}}^{\&prime;}\\ |m_{j-1}-m_j|>{\mathrm{\&sigma;}}^{\&prime;}\end{array}\right.---\left(2\right)$

Wherein, j ' ∈ [2, N '-1] and j ' is positive integer; m _{j '}represent the measured value that jth ' individual sensor records; σ ' is a threshold value preset, and the span of σ ' is m _{j '}0.1% ~ 10% of middle maximal value;

Step c: determine turning spur; Connect the first reference mark and the second reference mark with a curve, and the ordinate value meeting other any point on described curve except the second reference mark is greater than the second reference mark ordinate value, then described curve is called turning spur;

Steps d: take X-axis as axis rotating 360 degrees by turning spur, namely obtains the surface of revolution (3).