Ice profile extraction method

Abstract

The ice profile extraction method comprises the following steps: customizing a hot knife according to the outer profile of a tested section of a test piece; the hot knife is coated with a water-soluble coating; heating the heat knife; inserting a hot knife into an ice mold attached to the outside of the test piece along the tested cross section; the hot knife is taken out, and the ice profile is obtained according to the characteristic change line of the water-soluble coating on the hot knife. According to the ice type contour extraction method, the water-soluble coating is introduced, the steps of hot knife cutting and ice type extraction are combined, and ice type extraction is completed without depending on manual work, so that potential damage to the ice type is avoided, errors caused by manual ice drawing in the ice type extraction process are reduced, and the contour accuracy is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing, and more specifically to the field of ice pattern extraction methods for icing tests. Background Technology

[0002] When flying in cold environments, icing can seriously affect the normal operation of engines. Therefore, icing tests are often included in aero-engine testing. Icing tests include the important step of ice pattern extraction to identify and analyze the shape of ice on engine components and design engines with better performance.

[0003] Existing methods for ice pattern extraction include the hot knife method and the three-dimensional scanning method. However, the three-dimensional scanning method has poor measurement accuracy, while the hot knife method relies on manual ice drawing, which can easily cause potential damage to the ice pattern. Summary of the Invention

[0004] One object of the present invention is to provide an ice-shaped contour extraction method to efficiently obtain accurate ice-shaped contours.

[0005] The ice-shaped contour extraction method to achieve the above objectives includes the following steps:

[0006] A hot knife is customized according to the outer contour of the test section of the specimen; a water-soluble coating is applied to the hot knife;

[0007] Heat the hot knife;

[0008] The hot knife is inserted along the cross section being tested into the ice pattern attached to the outside of the test piece;

[0009] Remove the hot knife and obtain the ice-shaped profile from the characteristic change lines of the water-soluble coating on the hot knife.

[0010] In one or more embodiments, an ice-shaped profile is obtained from the color boundary line of the water-soluble coating on the hot knife.

[0011] In one or more embodiments, the water-soluble coating is a water-based color-changing coating.

[0012] In one or more embodiments, an ice-shaped profile is obtained from the thickness boundary of the water-soluble coating on the hot knife.

[0013] In one or more embodiments, the water-soluble coating is a water-absorbing water-soluble coating.

[0014] In one or more embodiments, an ice-shaped profile is obtained from the roughness boundary of the water-soluble coating on the hot knife.

[0015] In one or more embodiments, the water-soluble coating is a water-soluble polymer coating.

[0016] In one or more embodiments, the cutting edge of the hot knife is blunt or wedge-shaped.

[0017] In one or more embodiments, the hot knife is a split-type hot knife.

[0018] In one or more embodiments, a clamp is used to hold the split-type hot knife, causing the hot knife to cut the ice mold or to separate the hot knife from the ice mold.

[0019] The above-mentioned ice pattern contour extraction method combines the hot knife cutting and ice pattern extraction steps by introducing water-soluble coating, so that ice pattern extraction does not rely on manual labor, thereby avoiding potential damage to the ice pattern. It also eliminates the processes of stencil processing, manual ice drawing, and drawing paper production, reducing the errors caused by manual ice drawing in ice pattern extraction, ensuring the accuracy of the contour, and allowing ice pattern extraction to be performed in locations with limited operating space. Attached Figure Description

[0020] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0021] Figure 1 This is a schematic diagram showing the fit between the hot knife and the blade test specimen;

[0022] Figure 2 This is a schematic diagram of the cross-sectional structure of the hot knife;

[0023] Figures 3A-3B This is a schematic diagram of the first embodiment of the hot blade cutting edge;

[0024] Figures 4A-4B This is a schematic diagram of the second embodiment of the hot blade;

[0025] Figures 5A-5B This is a schematic diagram of the third embodiment of the hot blade cutting edge;

[0026] Figures 6A-6B This is a schematic diagram of the third embodiment of the hot blade cutting edge;

[0027] Figure 7 This is a schematic diagram of a split-type hot knife for extracting ice.

[0028] Figure 8 This is a flowchart of the ice-shaped contour extraction method.

[0029] Symbol marking explanation

[0030] 1. Hot knife

[0031] 2 Test specimens

[0032] 3. Hot knife substrate

[0033] 4. Water-soluble coatings

[0034] 5. Ice type

[0035] 10 blades

[0036] S-shaped ice contour line Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0038] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0039] Aircraft may encounter icing conditions during flight, leading to icing on critical components such as aerodynamic surfaces, sensors, and engine intake components. Since icing alters the aerodynamic shape of these components or blocks sensor access points, it significantly impacts flight safety. During aerospace product design, the impact of icing on component performance is typically analyzed and evaluated; to achieve this, it is necessary to obtain the icing patterns on the component surfaces.

[0040] While existing technologies allow for the acquisition of approximate ice patterns through computational simulation, due to the complexity of the icing process and mechanism, icing experiments remain the most reliable method for obtaining ice pattern data.

[0041] Ice wind tunnels are the most widely used icing simulation devices. However, due to limitations in the air supply and water treatment systems of ice wind tunnels, the cross-sectional dimensions of the test section are limited, which leads to inconvenience in the installation and disassembly of test pieces. Consequently, the measurement of icing patterns can only be carried out inside the ice wind tunnel.

[0042] In addition, after the icing test, the presence of ice on the surface of the test piece is equivalent to an increase in the volume of the test piece in the test section, which further compresses the operating space for ice pattern extraction in the ice wind tunnel.

[0043] Existing methods for ice extraction include three-dimensional scanning and hot knife extraction.

[0044] Three-dimensional scanning works based on the principle of optical reflection. However, because ice is transparent and may contain air bubbles, its optical properties are unstable, resulting in poor accuracy of the ice patterns obtained by three-dimensional scanning. Therefore, while three-dimensional scanning is used to obtain an overall picture of the ice pattern, the hot knife method is still necessary for precise extraction.

[0045] like Figure 1 As shown, the hot knife method first involves customizing a hot knife 1 based on the outer contour of the test section of the specimen. This hot knife is typically made of a high thermal conductivity metal sheet, such as copper. A portion is removed from the sheet to form a cutting edge 10, creating the outer contour of the test section to facilitate the insertion of an ice mold attached to the outside of the specimen. In some embodiments, a clamping plate (not shown in the figure) is also customized, with the same shape as the hot knife.

[0046] In traditional testing, the hot knife 1 is first heated, then inserted into the section to be tested to cut the ice deposits attached to the outside of the test piece.

[0047] Then, take out the hot knife and cut it; cracks will appear in the ice, forming ice fissures.

[0048] Then, a tracing paper with the same shape as the card is fixed on the card plate. The card plate and the tracing paper are then inserted together into the ice crevice cut by the hot knife. The outline of the ice is then traced on the tracing paper by hand.

[0049] Take out the card and tracing paper. The ice pattern on the tracing paper is the ice pattern that needs to be extracted.

[0050] Therefore, the hot knife method directly depicts the outline of the ice shape, thus capturing relatively accurate geometric details such as needle-like features. However, in actual operation, the following problems inevitably exist:

[0051] 1) The traditional hot knife method requires cutting the ice once with a hot knife first, and then tracing the ice with a clamp and tracing paper. The two insertions and removals of the hot knife and clamp on the ice shape may damage the ice shape.

[0052] 2) When drawing ice, it is necessary to ensure that there is enough operating space. If there is not enough operating space, only part of the ice pattern can be drawn. This situation especially limits the extraction of ice patterns from internal flow components, such as the support plate, blades and splitter ring of aero-engines.

[0053] 3) Relying on manual drawing of ice on drawings inevitably results in a certain degree of error.

[0054] To address this problem and efficiently obtain accurate ice-shaped contours, this invention proposes an ice-shaped extraction method based on the principle of the hot knife method.

[0055] Combination Figure 8 As shown in the flowchart, the method includes the following steps:

[0056] First, a hot knife is customized according to the outer contour of the test section of the test piece. The test piece can be various engine components such as support plates, blades, and flow dividers.

[0057] Subsequently, a water-soluble coating is applied to the hot knife, such as... Figures 3A-3B As shown along Figure 2 A cross-sectional view along the AA direction shows a water-soluble coating covering the surface of the hot knife. Preferably, the water-soluble coating can also cover both the upper and lower surfaces of the hot knife.

[0058] Then, heat the hot knife by connecting the hot knife device to a power source and setting it to an appropriate temperature, such that the temperature is high enough to quickly cut the ice.

[0059] A hot knife is inserted along the cross-section of the test piece into the ice mold attached to the outside of the test piece. Under the high temperature of the hot knife, the ice mold is quickly punctured, forming an ice crack.

[0060] After removing the hot knife, the ice-shaped outline is obtained from the characteristic change lines of the water-soluble coating on the hot knife, such as... Figure 2 The ice-shaped outline S-line is shown, without the need for inserting a card or drawing for manual depiction.

[0061] Specifically, this method introduces water-soluble coatings that change properties upon contact with water.

[0062] Water-soluble coatings are coatings whose properties change significantly when exposed to water or other environmental changes. After absorbing moisture, certain physical properties change, resulting in specific boundary lines.

[0063] In other words, water-soluble coatings, based on the phenomenon that the properties of the coating change significantly when it comes into contact with water, can produce visible characteristic change lines, such as color lines, thickness boundaries, and roughness boundaries. With the help of these characteristic change lines, technicians can quickly obtain accurate ice-shaped outlines, enabling hot knife cutting and ice-shaped extraction to be completed in one step, without the need for manual stencil insertion and drawing.

[0064] In some embodiments, an ice-shaped outline can be obtained based on the color boundary line of the water-soluble coating on the hot knife after it comes into contact with water.

[0065] For example, water-soluble coatings may use water-based color-changing coatings. Water-based color-changing coatings are those that undergo a significant color change upon contact with water; they exhibit one color when dry and change to another upon contact with water. Thermochromic coatings can also be used, as they are temperature-sensitive materials that change color depending on temperature. Based on this, when water is applied to a hot knife, a color boundary line will appear, which can be used to accurately obtain the outline of the ice crystal at the measured cross-section.

[0066] In other embodiments, an ice-shaped profile can be obtained based on the thickness boundary of the water-soluble coating on the hot knife after contact with water.

[0067] For example, water-soluble coatings can be made using absorbent water-soluble coatings. These coatings absorb water and swell significantly upon contact with water, causing noticeable changes in physical properties such as volume or thickness. Based on this, a thickness boundary line will appear on the water-soluble coating on the hot knife after contact with water, allowing for the identification of the ice-like surface outline.

[0068] In some other embodiments, an ice-shaped profile can be obtained based on the roughness boundary of the water-soluble coating on the hot knife after contact with water.

[0069] For example, water-soluble coatings can be made from water-soluble polymers, such as polyvinyl alcohol (PVA). Other coatings, such as calcium chloride, can also be used. In high-humidity environments, calcium chloride absorbs moisture and expands, causing the surface to become rough. Upon contact with water, the surface structure and roughness of water-soluble polymer coatings undergo significant changes, producing distinct roughness boundaries and thus achieving an ice-like profile.

[0070] Those skilled in the art will understand that water-soluble coatings include, but are not limited to, the above-described embodiments. Any water-soluble coating whose properties change upon contact with water can be applied to this method.

[0071] This method does not limit the specific shape of the hot blade used for cutting ice, such as Figures 3A to 6B As shown, the cutting edge 10 of the hot knife includes, but is not limited to, a blunt edge or a wedge-shaped edge.

[0072] In some embodiments, a hot knife, such as Figure 1 and Figure 2 As shown, this is an integral part with an opening. For example, a cut is customized on the basis of copper as the base material for the hot knife, and then the integral hot knife is directly inserted into the ice mold along the cross section to be measured.

[0073] To avoid the problem of different locations on the hot knife surface repeatedly passing over the ice pattern during extraction, which could affect the extraction results, hot knives can also be modular, consisting of at least two parts joined together to form a single unit, such as... Figure 7 As shown, the two symmetrical hot blades work together to cut the ice shape.

[0074] For example, in some embodiments, the icing type of engine components is open ice. Open ice refers to ice that is relatively transparent and smooth, without obvious bubbles or cracks. If it adheres to critical components such as aircraft wings or engines, it will change aerodynamic characteristics, increase weight and drag, and seriously affect the performance and handling of the aircraft.

[0075] Type 5 ice may exhibit a bicornuate feature, meaning the surface of the ice may resemble two corners. In this case, the following can be used... Figure 7 The split-type hot knife shown, together with the tooling fixture, separates the hot knife from the ice mold.

[0076] If a clamp is used to hold the two halves of the hot knife separately, so that the hot knife cuts the ice shape or separates the hot knife from the ice shape, this method of extracting the ice shape contour S can avoid affecting the ice shape extraction result.

[0077] The above-mentioned ice-type profile extraction method based on water-soluble coatings has the following advantages:

[0078] By leveraging the properties of water-soluble coatings that change upon contact with water, ice pattern extraction can be performed without manual intervention, eliminating the need for stencil processing, manual ice drawing, and drawing paper preparation. This avoids potential damage to the ice pattern and reduces errors caused by manual ice drawing during extraction, ensuring the accuracy of the outline. Furthermore, this method is not limited by operating space, allowing the hot knife cutting and ice pattern extraction steps to be performed in the same step, thus improving the method's versatility.

[0079] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0080] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0081] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for extracting ice-shaped contours, characterized in that, Includes the following steps: A hot knife is customized according to the outer contour of the test section of the specimen; A water-soluble coating is applied to the hot knife; Heating the hot knife; The hot knife is inserted along the cross section being tested into the ice mold attached to the outside of the test piece; Remove the hot knife and obtain the ice-shaped profile from the characteristic change lines of the water-soluble coating on the hot knife.

2. The ice-shaped contour extraction method as described in claim 1, characterized in that, An ice-shaped outline is obtained from the color boundary line of the water-soluble coating on the hot knife.

3. The ice-shaped contour extraction method as described in claim 2, characterized in that, The water-soluble coating is a water-based color-changing coating.

4. The ice-shaped contour extraction method as described in claim 1, characterized in that, An ice-shaped profile is obtained from the thickness boundary line of the water-soluble coating on the hot knife.

5. The ice-shaped contour extraction method as described in claim 4, characterized in that, The water-soluble coating is a water-absorbent water-soluble coating.

6. The ice-shaped contour extraction method as described in claim 1, characterized in that, An ice-shaped profile is obtained from the roughness boundary line of the water-soluble coating on the hot knife.

7. The ice-shaped contour extraction method as described in claim 6, characterized in that, The water-soluble coating is a water-soluble polymer coating.

8. The ice-shaped contour extraction method as described in claim 1, characterized in that, The cutting edge of the hot knife is blunt or wedge-shaped.

9. The ice-shaped contour extraction method as described in claim 1, characterized in that, The hot knife is a split-type hot knife.

10. The ice-shaped contour extraction method as described in claim 9, characterized in that, The split-type hot knife is held in a clamp to cut the ice shape or to separate the hot knife from the ice shape.

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