阅读说明：本技术 一种利用液体进行叶片小微孔角度测量的方法 (Method for measuring angle of small micropores of blade by using liquid ) 是由 初文潮 王志杰 杨锦 张文甲 闫小斌 李水姣 于 2020-11-04 设计创作，主要内容包括：一种利用液体进行叶片小微孔角度测量的方法,首先通过刚性测量针获得所述航空发动机叶片的测量坐标系在光学测量设备上的准确位置,同时获得所述刚性测量针的测量影像。之后利用从所述气膜孔喷出的液柱的测量影像与所述刚性测量针的测量影像进行比对分析,从而计算出所述气膜孔加工所允许的公差范围与液柱在光学测量中的影像数据的对应关系,这样就可以直观的直接利用从所述气膜孔喷出的液柱进行影像测量,获知所述气膜孔是否满足加工要求。本发明所提供的一种利用液体进行叶片小微孔角度测量的方法,可快速直观的对所有叶片的气膜孔角度进行直接测量,获得真实的气膜孔角度数据,大大提升了测量效率。(The method for measuring the angle of the small micropore of the blade by using liquid comprises the steps of firstly obtaining the accurate position of a measurement coordinate system of the blade of the aero-engine on optical measurement equipment through a rigidity measurement needle, and simultaneously obtaining a measurement image of the rigidity measurement needle. And then, comparing and analyzing the measurement image of the liquid column sprayed out of the gas film hole with the measurement image of the rigid measurement needle, thereby calculating the corresponding relation between the tolerance range allowed by the gas film hole processing and the image data of the liquid column in the optical measurement, so that the liquid column sprayed out of the gas film hole can be directly used for image measurement intuitively, and whether the gas film hole meets the processing requirement or not can be known. The method for measuring the angles of the small micropores of the blades by using the liquid can quickly and directly measure the angles of the air film holes of all the blades, obtain real air film hole angle data and greatly improve the measurement efficiency.)

1. A method for measuring the angle of a small micropore of a blade by using liquid is used for directly measuring the actual angle of a film hole of an aircraft engine blade and is characterized by comprising the following steps,

and step A, selecting at least one aero-engine blade for each batch of aero-engine blades, assembling a rigidity measuring needle on at least one air film hole in each group of air film holes, and debugging and measuring on optical measuring equipment, so that the accurate position of a measuring coordinate system of the aero-engine blade on the optical measuring equipment is determined on one hand, and a measuring image of the rigidity measuring needle is obtained on the other hand.

B, taking down the rigid measuring needle, supplying liquid to the aeroengine blade, adjusting liquid supply pressure to enable a liquid column within at least 5mm range close to the air film hole to keep linear, collecting measured image data of the liquid column sprayed out of the air film hole with the rigid measuring needle assembled in the step A, comparing the measured image data with the measured image data of the rigid measuring needle obtained in the step A, obtaining a conversion relation between the image data of the liquid column in optical measurement and the measured image data of the rigid measuring needle, and calculating a corresponding relation between a tolerance range allowed by air film hole machining and the image data of the liquid column in optical measurement Within the range, it can be judged as meeting the processing requirements. If the image data are inconsistent and exceed the image data range corresponding to the processing tolerance, the processing requirement is judged to be not met.

2. The method according to claim 1, wherein in step a, the clamping structure for clamping the aircraft engine blade may comprise a base to which the optical measurement device is connected and a blade holder to which the base is detachably connected.

3. The method of claim 1, wherein in step B, the liquid supply pressure to the aero-engine blade is not less than 0.04 Mpa.

4. The method of claim 3, wherein in step B, the liquid supply pressure to the aero-engine blade is 0.065MPa or 0.08 MPa.

5. The method of claim 1, wherein in step B, a mobile liquid recovery device is provided to recover the liquid column.

6. The method of claim 5, wherein in step B, the liquid recovery device is provided with a U-shaped cavity, and the width of the opening of the U-shaped cavity can be slightly larger than the width of the processing surface.

Technical Field

The invention relates to the technical field of measurement, in particular to a method for measuring the real angle of a small micropore on an aircraft engine blade by using liquid as an optical measurement medium.

Background

For example, for a turbine blade, in order to ensure that the turbine blade still has good mechanical properties under high-temperature and high-pressure environments, the blade needs to be cast into a hollow structure, an exhaust channel is arranged in an inner cavity, and a plurality of film holes are processed on a blade body of the blade, particularly on an exhaust edge of the blade body, so that cold air entering the inner cavity can be sprayed out from the film holes of the blade body, and a layer of cold air protective layer is formed on the blade body while certain blade body heat is taken away, thereby further reducing the temperature of the blade body and ensuring that the blade is not ablated by high-temperature and high-pressure gas. Therefore, the angle of each air film hole has strict requirements, so that the cold air can be ensured to uniformly cover all areas of the blade body,

FIG. 1a is a schematic perspective view of an aircraft engine blade; FIG. 1b is a schematic perspective view of the blade of FIG. 1a from another perspective; FIG. 1c is a schematic cross-sectional structural view of the blade of FIG. 1 a; FIG. 1d is a schematic cross-sectional structural view of the blade body of the blade of FIG. 1 a; FIG. 1e is a schematic diagram of the cross-sectional structure A-A of FIG. 1 d; wherein X, Y, Z marked in fig. 1c, 1d and 1e is a blade measurement coordinate system, which is defined in the ministry of aviation industry of china, and is not repeated herein. Referring to fig. 1a to 1e, the aircraft engine blade 100 adopts a hollow internal cooling structure, a first air inlet 11 which is formed by casting and communicated with an inner cavity and is close to one side of a front edge and a second air inlet 12 which is formed by casting and is close to one side of a rear edge are arranged at the bottom of the blade, a blade tip groove 30 with the depth of 2mm is arranged at the blade tip, an air outlet is arranged in the blade tip groove 30, the rear edge is provided with a processing surface 20 parallel to a Z axis, and a plurality of air film holes 21 communicated with the inner cavity are arranged on the processing surface 20.

The first air inlet 11, the second air inlet 12 and the air outlets in the blade tip slots 30 are directly formed during casting, and the machining surface 20 and the air film holes 21 are formed in a subsequent machining process, wherein the machining surface 20 is machined firstly, and then the air film holes 21 are formed in the machining surface 20 in an electric spark machining mode and then communicated with the inner cavity of the aircraft engine blade 100.

The aperture of the air film hole 21 is generally between phi 0.25mm and phi 0.5mm, the depth is not less than 6mm, at least one group of air film holes 21 are arranged on the processing surface 20, and the aperture and the inclination angle of each group of air film holes 21 are the same. That is, the processing surface 20 may be provided with more than one set of the film holes 21 with different hole diameters, and fig. 1e shows that the same set of the film holes 21 with the same hole diameter are provided on the processing surface 20.

As for the film holes 21, in the production and processing process of the aircraft engine blade 100, connectivity between the film holes 21 and the inner cavity can be verified through a water flow experimental mode, that is, a closable flexible joint is used to be in sealed communication with the tenon parts of the aircraft engine blade 100 (that is, with the first air inlet 11 and the second air inlet 12), and pressurized water flow is input to observe and detect whether all the film holes 21 can drain water, so as to judge whether the film holes 21 are communicated with the inner cavity or not. In addition, as described in a method for measuring the air flow of a turbine blade machine with holes provided in the chinese patent ZL2017112497983 by the inventor, the flow data of the film hole 21 can also be directly measured and obtained.

However, as shown in fig. 1d and 1e, the included angle α of the film hole 21 with respect to the X-axis and the included angle β with respect to the Z-axis of the blade measurement coordinate system also have certain design requirements, for example, the included angle α of the film hole 21 with respect to the X-axis of the blade measurement coordinate system may be designed to be 61.5 ° ± 30 ', and the included angle β of the film hole 21 with respect to the Z-axis of the blade measurement coordinate system may be designed to be 80 ° ± 30'. Because the aperture of the gas film hole 21 is too small, at present, no disclosed technical scheme can be used for directly measuring the angle of the gas film hole 21.

In the existing production process, a large hole with the diameter of 1mm is machined on the aviation engine blade 100 which is machined instead after the parameters of electric spark machining equipment are set, a standard measuring rod with the diameter of 1mm is inserted into a machined hole, the angle of the standard measuring rod is measured by a three-coordinate measuring machine, if the angle is qualified, the angle is qualified through adjusting the angle of a machine tool and/or a clamp, and a small hole with the diameter required by a drawing is reprocessed.

The prior art guarantee method has the following defects:

1. only whether the angle (namely the processing parameter) adjusted by the clamp and/or the machine tool is correct can be judged, for example, the angle is measured by processing the large hole with phi 1 and matching with a measuring rod, the angle of the small hole with the diameter phi 0.25 is qualified by default after the angle is qualified, but the actual large hole with phi 1 is not directly related to the diameter phi 0.25 (the parameter setting of the electric spark processing equipment is different), the error of the measuring method is large, and the error is usually between 1 and 1.5 degrees.

2. The inner cavity of the aero-engine blade 100 is provided with complex loops and reinforcing ribs, interference is easily generated after the measuring rod enters the inner cavity, the measuring rod is inclined to one side, and the measuring angle is inaccurate.

3. The aero-engine blade 100 is made of high-temperature alloy materials, so that the machining difficulty is high, the machining time is long, and generally, about 15 minutes is needed for machining a hole with the diameter of 1 mm.

4. The aero-engine blade 100 with the phi 1 hole machined can only be scrapped, 2-3 blades need to be scrapped during machining of each batch of blades, the price of each blade is 1 to 3 thousands, and waste is extremely large.

Through experimental research and analysis, the inventor group submits three patent applications of 2019111027142 a method for measuring the angle of the small micropore of the blade, 2019111032761 a measuring needle for measuring the angle of the small micropore of the blade and 2019111032776 a method for using the measuring needle for measuring the angle of the small micropore of the blade in 2019, 11 and 13, provides a set of complete technical scheme for directly measuring the angle of the air film hole of the blade by using a rigid measuring needle, can obtain real air film hole angle data, and does not cause physical damage to the blade in the measuring process. Therefore, each blade can be detected, and the qualification rate of finished products can be greatly improved.

Although the above-mentioned scheme of using a rigid measurement needle to perform measurement has high data accuracy, the measurement needle needs to be assembled in at least one of the air film holes 21 in each group of the air film holes 21 on each blade of each batch, and the assembly of the measurement needle is cumbersome, so the labor intensity of workers is still large, and the time consumed for assembling the measurement needle is long, so the overall measurement efficiency still needs to be improved.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a method for measuring the angle of the small pore of a blade by using liquid, so as to reduce or avoid the aforementioned problems.

In order to solve the technical problem, the invention provides a method for measuring the angle of a small micropore of a blade by using liquid, which is used for directly measuring the actual angle of a film hole of an aircraft engine blade and comprises the following steps,

and step A, selecting at least one aero-engine blade for each batch of aero-engine blades, assembling a rigidity measuring needle on at least one air film hole in each group of air film holes, and debugging and measuring on optical measuring equipment, so that the accurate position of a measuring coordinate system of the aero-engine blade on the optical measuring equipment is determined on one hand, and a measuring image of the rigidity measuring needle is obtained on the other hand.

B, taking down the rigid measuring needle, supplying liquid to the aeroengine blade, adjusting liquid supply pressure to enable a liquid column within at least 5mm range close to the air film hole to keep linear, collecting measured image data of the liquid column sprayed out of the air film hole with the rigid measuring needle assembled in the step A, comparing the measured image data with the measured image data of the rigid measuring needle obtained in the step A, obtaining a conversion relation between the image data of the liquid column in optical measurement and the measured image data of the rigid measuring needle, and calculating a corresponding relation between a tolerance range allowed by air film hole machining and the image data of the liquid column in optical measurement Within the range, it can be judged as meeting the processing requirements. If the image data are inconsistent and exceed the image data range corresponding to the processing tolerance, the processing requirement is judged to be not met.

Preferably, in step a, the clamping structure for clamping the aircraft engine blade may include a base connected to the optical measurement device and a blade holder detachably connected to the base.

Preferably, in the step B, the liquid supply pressure for supplying liquid to the aeroengine blade is not less than 0.04 MPa.

Preferably, in the step B, the liquid supply pressure for supplying liquid to the aeroengine blade is 0.065MPa or 0.08 MPa.

Preferably, in step B, a mobile liquid recovery device is provided to recover the liquid column.

Preferably, in step B, the liquid recovery device is provided with a U-shaped cavity, and the width of the opening of the U-shaped cavity may be slightly larger than the width of the processing surface.

The method for measuring the angles of the small micropores of the blades by using the liquid can quickly and directly measure the angles of the air film holes of all the blades, obtain real air film hole angle data and greatly improve the measurement efficiency.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein the content of the first and second substances,

FIG. 1a is a schematic perspective view of an aircraft engine blade;

FIG. 1b is a schematic perspective view of the blade of FIG. 1a from another perspective;

FIG. 1c is a schematic cross-sectional structural view of the blade of FIG. 1 a;

FIG. 1d is a schematic cross-sectional structural view of the blade body of the blade of FIG. 1 a;

FIG. 1e is a schematic diagram of the cross-sectional structure A-A of FIG. 1 d;

FIG. 2 is a schematic diagram of a clamping base used in a method for measuring the angle of a small pore of a blade by using liquid according to an embodiment of the present invention;

fig. 3 is a schematic partial perspective view of a liquid recovery device.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As described in the background art, aiming at the problem that the angle of the air film hole 21 cannot be directly measured due to the fact that the existing aperture is generally between phi 0.25mm and phi 0.5mm, and the depth is not less than 6mm, the inventor conducts deep analysis on the principle of the air film hole, provides a set of complete technical scheme for directly measuring the angle of the air film hole of the blade by using a rigid measuring needle, can obtain real air film hole angle data, and cannot cause physical damage to the blade in the measuring process. Therefore, each blade can be detected, and the qualification rate of finished products can be greatly improved. Although the scheme of using the rigid measurement needle for measurement has high data accuracy, more than one group of the air film holes 21 may be formed in a single blade, and for each blade of each batch, the measurement needle needs to be assembled on at least one air film hole 21 in each group of the air film holes 21, and the assembly of the measurement needle is complicated, so the labor intensity of workers is high, and the assembly time of the measurement needle is long, so the overall measurement efficiency still needs to be improved.

When the aircraft engine blade 100 is manufactured by the team of the inventors, for the aircraft engine blade 100 after the machining is completed, the flow data of all the film holes 21 need to be measured, and specific technical solutions can be referred to a technical solution described in a turbine blade machining hole air flow measurement method of chinese patent ZL2017112497983 previously applied by the inventors, in which the flow of the film holes 21 is measured by using air pressurized to 0.09Mpa, and the team of the inventors finds that, when the flow of the film holes 21 is measured by using pressurized air, the air flow generated by each film hole 21 is ejected in the axial direction of the film hole 21, but the pressurized air is colorless, so that the direct observation cannot be performed by an optical method.

In addition, when the aeroengine blade 100 is manufactured by the inventor team, the connectivity between the inner cavity and each external opening of the aeroengine blade 100 after the machining is finished needs to be tested by means of connecting water pipes, so the inventor team considers that if a constant-pressure water body can be used in the measurement process, the actual angle of the gas film hole 21 can be measured by utilizing the characteristic that the water body and the gas are sprayed out along the axial direction of the gas film hole 21.

The inventors have tested, verified and optimized the following embodiments of the present invention.

Specifically, the invention provides a method for measuring the angle of a small micropore of a blade by using liquid, which is used for measuring the parameters of a gas film hole 21 of an aircraft engine blade 100, wherein the aircraft engine blade 100 adopts a hollow inner-cooling structure, the bottom of the blade is provided with a first gas inlet 11 which is formed by casting and communicated with an inner cavity and is close to one side of a front edge and a second gas inlet 12 which is formed by casting and is close to one side of a rear edge, the blade tip is provided with a blade tip groove 30 with the depth of 2mm, the blade tip groove 30 is provided with a gas outlet, the rear edge is provided with a processing surface 20 with a Z axis parallel, and the processing surface 20 is provided with a plurality of gas film. Which comprises the following steps of,

step A, for each batch of the aero-engine blades 100, selecting at least one aero-engine blade 100, assembling a rigidity measurement probe on at least one of the film holes 21 in each group of the film holes 21, and performing debugging measurement on an optical measurement device, thereby determining an accurate position of a measurement coordinate system of the aero-engine blade 100 on the optical measurement device on one hand, and obtaining a measurement image of the rigidity measurement probe on the other hand.

As described in the prior application "2019111027142 a blade small micropore angle measuring method" by the inventor group, the gas film holes 21 are formed by electric discharge machining, and therefore, the hole diameter and the inclination angle of each group of the gas film holes 21 are the same, which means that only one of the gas film holes 21 needs to be measured for each group of the gas film holes 21.

In addition, for the aero-engine blade 100 selected in each batch and using the rigidity measurement probe to obtain the template reference image, as long as the included angle α between the film hole 21 measured by the rigidity measurement probe and the X-axis and the included angle β between the film hole and the Z-axis of the blade measurement coordinate system satisfy the accuracy requirement, the measurement image obtained by the rigidity measurement probe can be recorded as the comparison template.

Existing optical measuring devices include digital measuring projectors or non-contact three-coordinate measuring machines.

For a digital measurement projector, the digital measurement projector is divided into a digital vertical projector (the optical axis of an objective lens is vertical to a worktable surface) according to the structural form; and digital horizontal projectors (objective optic axis parallel to the work surface). Taking a commonly used digital horizontal projector as an example, as shown in fig. 2 and fig. 1e, as long as the processing surface 20 (i.e. Z axis) is perpendicular to the projection light of the digital horizontal projector, the included angle β between the rigid measurement probe and the processing surface 20 can be easily measured. Referring to fig. 1d, when an included angle α between the film hole 21 and the X axis of the blade measurement coordinate system is measured, it is necessary to make the X-Y plane of the blade measurement coordinate system perpendicular to the projection light, and in the existing measurement of the rigid measurement probe, the included angle α between the film hole 21 and the X axis of the blade measurement coordinate system can be directly measured and obtained as long as the projection of the base for clamping the aircraft engine blade 100 on the X-Y plane of the blade measurement coordinate system does not block the projection of the machining surface 20 and the projection of the rigid measurement probe. That is, when the digital measurement projector is used for measurement, the spatial structure of the fixture needs to be limited to ensure that the measurement obtains the included angle α of the film hole 21 relative to the X-axis of the blade measurement coordinate system.

When a non-contact three-dimensional coordinate measuring machine such as that produced by OGP (Optical metrology Products, Inc) is used for measurement, since a camera is provided in the Z-axis direction (i.e., vertically above), the workpiece to be measured is imaged on a computer monitor by the camera, and then the dimension to be measured is measured by software in the computer. There is thus no restriction on the mounting of the base of the aircraft engine blade 100 as there is with the base of a digital measuring projector.

In the production process of the aircraft engine blade 100, the securing of the machining coordinate system and the measuring coordinate system is accomplished by clamping the dovetail section of the aircraft engine blade 100. As described in the prior application "2019111027142 a method for measuring the angle of a small micropore of a blade" of the inventor team, there are various ways for clamping the aero-engine blade 100 equipped with a rigidity measuring probe, and it can be seen that several prior application patent documents of the inventor team, such as 201610873006.9, 201811495958.7, etc., describe the existing blade clamping ways and technical solutions. For example, the existing base for clamping the aircraft engine blade 100 may include a tenon tooth clamping structure disposed on an index plate, so that the tenon tooth clamping structure can ensure the Z-axis direction of the aircraft engine blade 100 after clamping, and the index plate can adjust the X-Y axis direction of the aircraft engine blade 100.

In order to measure by using liquid, the inventor team is modified on the basis of the existing clamping structure, and fig. 2 is a schematic structural principle diagram of a clamping base used in the method for measuring the small micropore angle of the blade by using liquid according to a specific embodiment of the invention; as shown in fig. 2, the core of the modification is to provide a sealable buffer chamber at the dovetail mounting structure to which an inlet connection is connected, so that a constant pressure liquid can be supplied to the aircraft engine blade 100 during the measurement. Specifically, the clamping structure used in the present invention may include a base 41 connected to an optical measurement device and a blade holder 42 detachably connected to the base 41, the base 41 may be provided with an index plate structure or a multi-axis system, as long as the spatial position of the blade holder 42 can be conveniently adjusted, the blade holder 42 is used for holding the tenon portion of the aircraft engine blade 100, as shown in fig. 2, the blade holder 42 includes a fixed tenon tooth surface and a movable tenon tooth surface, after the fixed tenon tooth surface and the movable tenon tooth surface hold the tenon tooth of the aircraft engine blade 100, a closed buffer cavity 43 is formed at the bottom of the tenon tooth of the aircraft engine blade 100, the blade holder 42 is provided with a liquid inlet joint 44 communicated with the buffer cavity 43, the axial length of the fixed tenon tooth surface and the axial length of the movable tenon tooth surface are slightly greater than the length of the tenon tooth of the aircraft engine blade 100, after the tenon tooth surface and the movable tenon tooth surface clamp the tenon tooth of the aircraft engine blade 100, the spaces at the two axial ends (i.e., in the length direction) of the tenon tooth can be sealed by using yellow wax or a rubber block, so that the sealing property of the buffer cavity 43 can be ensured. The structure of the blade holder 42 for connecting with the base 41 may be provided in a column shape (not shown), so that the base 41 may be provided with a commercially available "3R tooling fixture" structure, so that each aero-engine blade 100 to be tested may be easily assembled to the base 41 after the blade holder 42 is externally clamped.

B, removing the rigid measuring needle, supplying liquid to the aeroengine blade 100, adjusting liquid supply pressure to enable a liquid column which is close to the air film hole 21 and is within at least 5mm to keep linear, collecting measurement image data of the liquid column sprayed out of the air film hole 21 with the rigid measuring needle assembled in the step A, comparing the measurement image data with the measurement image data of the rigid measuring needle obtained in the step A, obtaining a conversion relation between the image data of the liquid column in optical measurement and the measurement image data of the rigid measuring needle, and calculating a corresponding relation between a tolerance range allowed by processing of the air film hole 21 and the image data of the liquid column in optical measurement Within the image data range corresponding to the difference, the processing requirement can be judged to be met. If the image data are inconsistent and exceed the image data range corresponding to the processing tolerance, the processing requirement is judged to be not met.

After the accurate position of the measurement coordinate system of the aircraft engine blade 100 on the optical measurement device and the measurement image of the rigidity measurement needle are obtained in step a, the rigidity measurement needle can be removed to supply liquid to the aircraft engine blade 100, that is, after an adjustable pressure valve is mounted on a water pipe, the liquid can be supplied to the aircraft engine blade 100 through a liquid inlet joint, so that liquid with constant pressure can be sprayed out of all the air film holes 21.

As described in the prior application "2019111027142 a blade small pore angle measuring method" by the team of inventors, according to the practical experience of the team of inventors, in the measurement, as long as the liquid column within 5mm near the gas film hole 21 remains linear, it can be used for accurate measurement.

In addition, in the prior application "2017112497983 method for measuring the air flow rate of a turbine blade machine with holes" of the inventor team, in the technical scheme, after the air outlet of the blade tip groove 30 is sealed by yellow wax, the inner cavity of the aircraft engine blade 100 can bear the air pressure of 0.09 Mpa.

In the present invention, the yellow wax plugging scheme of the prior application "2017112497983 method for measuring air flow of turbine blade machine with holes" of the inventor team can still be used to plug the air outlet of the blade tip groove 30. the inventor found through practice that, because the pore diameter of the film hole 21 is very small, the axial linearity of the liquid column within 5mm close to the film hole 21 can be substantially ensured when the liquid supply pressure is above 0.04 Mpa. Therefore, the liquid supply pressure can be preferably 0.065MPa or 0.08MPa (which can meet the measurement requirements of the same type of blades with different sizes).

Since the liquid column (e.g. water column) has a certain light transmittance, there may be a certain image deviation during the optical measurement, and to solve this problem, in the present invention, after the liquid column ejected from the gas film hole 21 is stabilized, the measurement image data of the liquid column ejected from the gas film hole 21 equipped with the rigidity measurement needle in step a is collected and compared with the measurement image data of the rigidity measurement needle obtained in step a, the difference between the image data of the liquid column in the optical measurement and the measured image data of the rigid measuring needle under the specific pressure can be known, that is, the conversion relationship between the image data of the liquid column in the optical measurement and the measured image data of the rigid measuring needle can be known, therefore, the corresponding relation between the tolerance range allowed by the processing of the gas film hole 21 and the image data of the liquid column in the optical measurement can be calculated, namely the range of the image data of the liquid column in the optical measurement can be obtained. For each batch of the aero-engine blades 100, 3-5 aero-engine blades 100 can be selected to be assembled with rigidity measurement needles for measurement, measurement data of the rigidity measurement needles are recorded, and then liquid columns sprayed out of the air film holes 21 with the rigidity measurement needles are measured, so that a more accurate conversion relation can be obtained by using 3-5 sets of comparison data.

For the other film holes 21 not equipped with the rigidity measurement probe and the other aero-engine blades 100, it may be determined that the machining requirement is met as long as the measurement data obtained from the ejected liquid column matches the measurement data obtained from the liquid column ejected from the film holes 21 equipped with the rigidity measurement probe in step a or is within the range of the image data corresponding to the machining tolerance. If the image data are inconsistent and exceed the image data range corresponding to the processing tolerance, the processing requirement is judged to be not met.

Considering that if a digital measurement projector is used for measurement, for example, focusing operation is required for accurate measurement of each film hole 21, when a batch of the aircraft engine blades 100 are measured, according to the records of the inventor's team in ' 2019111027142 a blade small micropore angle measuring method ', ' 2019111032761 a measuring needle for blade small micropore angle measurement ' and ' 2019111032776 a method for using a measuring needle for blade small micropore angle measurement ' and the like, on 11, 13 th day of 2019, only one of the film holes 21 is measured for each group of the film holes 21, and the other film holes 21 are blocked during measurement,

since the present invention performs measurement through the liquid column ejected from the gas film hole 21, the ejected liquid column must be collected, so that the operation of the measurement equipment is not affected and environmental pollution is not caused.

The inventor provides a movable liquid recovery device to solve the problem of liquid column recovery, fig. 3 is a schematic view of a partial three-dimensional structure of the liquid recovery device, and referring to fig. 3, the liquid recovery device may be provided with a U-shaped cavity, the width of an opening of the U-shaped cavity may be slightly larger than the width of the processing surface 20, before liquid supply, the opening of the U-shaped cavity may be made to be close to the processing surface 20, after the liquid supply pressure is stabilized, the opening of the U-shaped cavity is made to be away from the processing surface 20 by at least 6mm, so that all liquid columns ejected from the gas film holes 21 can enter the U-shaped cavity and converge in a centralized manner, and collection can be performed by using pipelines. The opening of the U-shaped cavity is far away from the processing surface by 20 mm at least 6mm, so that the measurement of the optical measurement equipment on the liquid column within the range of 5mm close to the air film hole 21 is not influenced.

The liquid recovery device is merely an example, and any configuration that can collect the liquid column discharged from the gas film hole 21 may be used for collecting the liquid column in practice.

Further, when the direction of the liquid column ejected from the gas film hole 21 is adjusted to be in the horizontal direction or the downward direction during the measurement, the influence of gravity on the direction of the liquid column during the measurement is minimized.

For example, when the digital vertical projector is used to measure the included angle β of the air film hole 21 with respect to the Z-axis, the positions of the base 41 and the blade holder 42 can be adjusted so that the liquid flow ejected from the air film hole 21 is on the horizontal plane.

When a digital horizontal projector is used for measuring the included angle alpha of the air film hole 21 relative to the X axis of the blade measuring coordinate system, the positions of the base 41 and the blade holder 42 can be adjusted, so that the projection of the liquid flow sprayed out of the air film hole 21 on the X-Y plane is vertical downward.

The greatest difference between the present invention and the prior art is that, on the optical measurement device, the accurate position of the measurement coordinate system of the aircraft engine blade 100 on the optical measurement device is obtained through the rigid measurement needle, and simultaneously, the measurement image of the rigid measurement needle is obtained. And then, comparing and analyzing the measurement image of the liquid column ejected from the gas film hole 21 with the measurement image of the rigid measurement needle, so as to calculate the corresponding relation between the tolerance range allowed by the processing of the gas film hole 21 and the image data of the liquid column in the optical measurement, thus directly performing image measurement by using the liquid column ejected from the gas film hole 21 intuitively, and knowing whether the gas film hole 21 meets the processing requirement.

The method for measuring the angles of the small micropores of the blades by using the liquid can quickly and directly measure the angles of the air film holes of all the blades, obtain real air film hole angle data and greatly improve the measurement efficiency.

It should be appreciated by those of skill in the art that while the present invention has been described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including technical equivalents which are related to the embodiments and which are combined with each other to illustrate the scope of the present invention.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations can be made by those skilled in the art without departing from the spirit and principles of the invention.