A comb tooth device and design method for reverse compensation of non-uniform gap

Abstract

The present invention relates to the field of design of rotating and static sealing elements of aircraft engines, and in particular to a grate device and a design method for reverse compensation of non-uniform gaps. The present invention provides a grate disc provided with a plurality of grate teeth in the axial direction, and a sealing bushing is sleeved on the outside of the grate disc; in a cold state, the radial spacing between the sealing bushing and the plurality of grate teeth on the grate disc gradually increases from the head end to the tail end along the axial direction; in a hot state, the radial spacing between the sealing bushing and the plurality of grate teeth on the grate disc remains consistent; the working environment parameters of the grate disc are determined according to the typical working state of the aircraft engine, and the radial deformation of the grate disc and the sealing bushing is obtained; the reverse compensation amount of the sealing gap is obtained based on the radial deformation amount; and the cold grate gap after reverse compensation is obtained based on the preliminarily selected cold-state spacing and reverse compensation amount of the grate teeth; the present invention can make the hot-state working gap of the grate teeth tend to be uniform under high-temperature working conditions, thereby improving the sealing performance of the grate element.

Description

Technical Field

[0001] The invention relates to the field of design of rotating-static sealing components of aircraft engines, and in particular to a comb tooth device for reverse compensation of non-uniform gaps and a design method thereof. Background Art

[0002] Grate teeth are commonly used rotor-static sealing devices in aircraft engines. They have multiple functions, such as reducing air leakage in compressor and turbine components, sealing the lubricating oil cavity, preventing high-temperature combustion gas from invading the disc cavity, adjusting the flow distribution of the air system to ensure cooling of hot end components, and controlling reasonable chamber pressure distribution to adjust the rotor axial force. They play a vital role in ensuring the working performance and safety of aircraft engines.

[0003] The grate clearance is a key factor affecting sealing performance and operational safety. A gap that is too large will increase leakage and weaken the sealing effect; while a gap that is too small will cause friction between the rotor and stator, causing safety issues such as component wear and vibration of the entire machine. However, during the operation of an aircraft engine, the components expand due to heat, causing the grate working clearance to deviate from the cold clearance. In particular, the structural stiffness of the rotating and stationary components of the grate element is often different, and the axial temperature distribution is also uneven, resulting in inconsistent radial deformation of the grate element. The tooth top clearance may present a non-uniform distribution. The distribution of the cold and hot clearances of the grate is as follows: Figure 2 The appearance of non-uniform sealing gap is not conducive to the sealing performance and operational safety of the grate element. Summary of the Invention

[0004] In view of the above problems, the present invention provides a comb tooth device and design method for reverse compensation of non-uniform gaps, which solves the problem in the prior art that the tooth top gaps of the comb tooth elements are non-uniformly distributed during the operation of the aircraft engine, resulting in a decrease in the sealing performance of the comb tooth elements.

[0005] In a first aspect, the present invention provides a grate device for reverse compensation of non-uniform gaps, comprising a grate disc and a sealing bushing, wherein the outer peripheral surface of the grate disc has a plurality of grate teeth along the axial direction, and the sealing bushing is sleeved on the outside of the grate disc;

[0006] For the grate disc and the sealing bushing: in the cold state, the radial spacing between the grate teeth on the sealing bushing and the grate disc gradually increases from one end to the other end of the grate disc; in the hot state, after the grate disc and the sealing bushing are thermally deformed, the radial spacing between each grate tooth on the sealing bushing and the grate disc remains consistent; the hot state is the state when the aircraft engine is working, and the cold state is the state when the aircraft engine is not working.

[0007] Preferably, the grate device for reverse compensation of non-uniform gap comprises a grate disc and a sealing bushing, wherein the grate disc has a plurality of grate teeth along the axial direction, and the sealing bushing is sleeved on the outside of the grate disc;

[0008] Preferably, the thermal deformation specifically includes: compared with the cold state, the radial thermal deformation of the sealing bushing in the hot state along the axial direction gradually decreases; compared with the cold state, the radial thermal deformation of the comb disc in the hot state along the axial direction gradually increases, and the radial thermal deformation of multiple grate teeth of the comb disc in the axial direction gradually increases.

[0009] Preferably, the radial spacing between the sealing bushing and the plurality of grate teeth on the grate disc is set to 0.15% to 0.3% of the radius of the installation position.

[0010] In a second aspect, the present invention provides a design method for a grate device with reverse compensation for non-uniform gaps, comprising the following steps: Step S1, preliminarily selecting a grate cold state interval based on installation position parameters and working environment parameters of a grate disc;

[0011] Step S2: determining the working environment parameters of the grate disc according to the typical working state of the aircraft engine;

[0012] Step S3: based on the working environment parameters of the grate disc, obtaining the aerodynamic load, thermal load and mechanical load of the grate disc; based on the aerodynamic load, thermal load and mechanical load, obtaining the radial deformation of the grate disc and the sealing bushing;

[0013] Step S4: obtaining a reverse compensation amount of the sealing gap based on the radial deformation amount;

[0014] Step S5: Based on the preliminarily selected cold interval of the grate teeth and the reverse compensation amount, obtain the cold grate tooth gap after reverse compensation, and determine whether the cold grate tooth gap after reverse compensation meets the design conditions. If not, return to step S1 until the cold grate tooth gap after reverse compensation meets the design conditions.

[0015] Preferably, the installation position parameters of the grate disc include: the radial radius position of the grate disc, the number of teeth, the tooth spacing and the tooth top width; the working environment parameters of the grate disc include the rotational speed, pressure, flow and temperature; when the grate cold sealing gap c is preliminarily selected, when the grate disc is in a working condition where the radial dimension increases significantly, the grate cold gap c is set to 0.3% of the installation position radius.

[0016] Preferably, step S3 specifically includes: taking the working environment of the grate disc as the boundary condition, analyzing the aerodynamic load, thermal load, and mechanical load of the grate disc, and further calculating the radial deformation of the sealing bushing under typical working conditions. , ,……, and radial deformation of the grate disc , ,……, ;in is the radial deformation, subscript s represents the stationary part, subscript r represents the rotating part, and subscript numbers 1, 2, ..., N represent the 1st, 2nd, ..., Nth level grate teeth.

[0017] Preferably, step S4 specifically includes: taking the radial deformation difference between the sealing bushing and the grate disc as the reverse compensation value of the sealing gap , where the subscript i represents the i-th level comb teeth, 1≤i≤N.

[0018] Preferably, in step S5, the step of obtaining the cold grate gap after reverse compensation based on the preliminarily selected cold grate gap and the reverse compensation amount specifically includes: calculating the cold grate gap after reverse compensation design. , where 1≤i≤N, c is the preliminarily selected cold sealing gap of the grate teeth.

[0019] Preferably, the design condition in step S5 is that the cold minimum tooth tip clearance after reverse compensation should be no less than 0.15% of the installation position radius.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The present invention performs reverse compensation for non-uniform sealing gaps, proposes a comb tooth device that can reduce the non-uniformity of the hot gap, and describes a reverse compensation design method to support the high-reliability design of aero-engine sealing components.

[0022] (1) By designing the cold clearance to have a distribution opposite to the hot clearance non-uniformity, the present invention can effectively reduce the non-uniformity of the sealing clearance during operation of the aircraft engine. The design provided by the present invention can make the hot working clearance of the grate teeth tend to be uniform under high temperature operating conditions, improve the sealing effect, reduce airflow leakage, and ensure the operating efficiency of the compressor and turbine components.

[0023] (2) The reverse compensation design of the present invention reduces friction between the rotor and stator that can occur due to insufficient clearance, thereby reducing the risk of component wear and overall engine vibration. This design improves the stability and reliability of aircraft engines at different operating temperatures, reduces structural stress caused by non-uniform expansion, and extends the engine's service life.

[0024] (3) The reverse compensation design of the present invention can more effectively adjust the air system flow distribution and control the reasonable chamber pressure distribution, ensure the cooling of the hot end components, and optimize the distribution of axial force, effectively improving the performance of the aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the invention.

[0026] Figure 1 A flow chart of the design method of the comb tooth device with reverse compensation for non-uniform gap provided by the present invention;

[0027] Figure 2 A schematic diagram comparing the cold and hot clearances of conventional grate teeth provided by the present invention;

[0028] Figure 3 A schematic diagram comparing the cold and hot clearances of the rear grate teeth using the reverse compensation design provided by the present invention;

[0029] Figure 4 This is a schematic diagram of the design process for reverse compensation of non-uniform gaps between comb teeth provided by the present invention.

[0030] Figure numerals: 1-comb disc, 2-sealing bushing. DETAILED DESCRIPTION

[0031] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. In addition, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0032] During aircraft engine operation, due to asymmetric structural stiffness or uneven axial temperature, the grate seal gap can exhibit contraction or expansion under conditions of non-uniform component deformation. The present invention improves the uniformity of the hot grate seal gap by inversely compensating for this contraction or expansion-like non-uniform deformation. Embodiments of the present invention provide a working mechanism for a gap inverse compensation grate device operating in both contraction and expansion modes.

[0033] In addition, the present invention does not limit the application type of grate teeth, and the application scenarios are not limited to straight-through grate teeth, but are also applicable to multi-stage grate teeth such as stepped grate teeth and staggered grate teeth.

[0034] This embodiment discloses a comb tooth device for reverse compensation of non-uniform gap. Figure 2 As shown in the figure, the cold clearance of conventional grate teeth is usually designed to be uniform, that is, the clearance at the top of each level of grate teeth is the same. When the aircraft engine is in operation, both the rotating and stationary parts of the grate teeth undergo thermal deformation. The thermal deformation of the stationary parts gradually decreases along the airflow direction, while the thermal deformation of the rotating parts gradually increases. Under the combined effect of the non-uniform deformation of the two parts, the grate seal gap gradually decreases along the airflow direction. Under the conditions of non-uniform deformation of the components, the grate seal gap exhibits a contraction shape.

[0035] Since, under the condition of the same minimum tooth top clearance, the greater the non-uniformity of the comb tooth clearance, the worse the sealing performance, the shrinkage-like non-uniform shape of the comb tooth sealing clearance under the above working state will lead to an increased risk of leakage, resulting in a decrease in the sealing performance of the comb tooth device, affecting the overall performance and safety of the engine.

[0036] To address this problem, the comb device provided in this embodiment designs the cold state gap to have an opposite non-uniform distribution according to the non-uniform type of the hot state gap, thereby performing reverse compensation for the gap.

[0037] In this embodiment, the original grate teeth's hot clearance contracts, while the inverse compensating grate teeth's cold clearance expands, gradually increasing the grate seal gap along the airflow direction. Under the operating load of an aircraft engine, the uneven deformation of stationary and rotating components forces the hot working clearance of the grate teeth toward a more uniform distribution, thus preventing sealing performance degradation caused by uneven sealing gaps.

[0038] like Figure 3 As shown, the non-uniform gap reverse compensation grate device of the present invention comprises a grate disc 1 and a sealing bushing 2. The grate disc 1 has a plurality of grate teeth along the axial direction, and the sealing bushing 2 is sleeved on the outside of the grate disc 1.

[0039] Compared with the cold state, the radial thermal deformation of the sealing bushing 2 in the hot state gradually decreases from the head end to the tail end along the axial direction;

[0040] Compared with the cold state, the grate disc 1 in the hot state has a gradually increasing radial thermal deformation from the head end to the tail end along the axial direction, and the radial thermal deformation of the multiple grate teeth of the grate disc 1 in the axial direction gradually increases from the head end to the tail end;

[0041] In a cold state, the spacing between the sealing bushing 2 and the plurality of grate teeth on the grate disc 1 gradually increases from the head end to the tail end along the axial direction;

[0042] In the hot state, the spacing between the sealing bushing 2 and the plurality of grate teeth on the grate disc 1 remains consistent.

[0043] It can be understood that in order to offset the non-uniform gap distribution caused by thermal deformation, the present invention adopts a reverse compensation design method, designing the cold state gap to be non-uniformly distributed, which is opposite to the expected non-uniform deformation in the hot state. In this way, when the aircraft engine is in working condition, due to the effect of thermal expansion, the originally non-uniform cold state gap will be reversely compensated and tend to be uniform. Through the compensation design in the cold state, a more uniform gap distribution in the hot state is achieved, effectively improving the sealing performance and the overall working efficiency of the engine.

[0044] In some embodiments, when the aircraft engine is in operation, both the rotating and stationary parts of the grate teeth undergo thermal deformation, wherein the thermal deformation of the stationary parts gradually increases and the thermal deformation of the rotating parts gradually decreases along the direction of airflow. Under the combined effect of the non-uniform deformation of the two, the grate tooth sealing gap gradually decreases along the direction of airflow, and the grate tooth sealing gap presents an expansion shape under the condition of non-uniform deformation of the parts.

[0045] In some embodiments, the comb device designs the cold state gap to have an opposite non-uniform distribution according to the non-uniform type of the hot state gap, thereby performing reverse compensation for the gap.

[0046] In some embodiments, the original grate teeth's hot clearance expands, while the inverse compensating grate teeth's cold clearance is designed to contract, gradually reducing the grate seal gap along the airflow direction. Under the operating loads of an aircraft engine, the non-uniform deformation of stationary and rotating components forces the hot working clearance of the grate teeth toward a more uniform distribution, thus preventing sealing performance degradation caused by non-uniformity in the seal gap.

[0047] This embodiment also discloses a comb tooth design method for reverse compensation of non-uniform gap, such as Figure 4 As shown, the following steps are included:

[0048] (1) The grate cold seal clearance c is initially selected based on factors such as the radial position of the grate element, its geometric dimensions (number of teeth, tooth spacing, tooth top width, etc.), and its operating environment (speed, pressure, temperature, etc.). According to the aircraft engine design manual, the grate clearance is recommended to be 0.15% to 0.3% of the installation radius. When the grate element is subjected to operating conditions with significant radial dimension growth, such as large radius, high temperature, and high amplitude vibration, the grate clearance is taken to its upper limit (0.3% of the installation radius).

[0049] (2) Determine the working environment of the comb element, such as speed, temperature, pressure, flow, etc., based on the typical working state of the aircraft engine (such as the cruising state of a civil aircraft engine).

[0050] (3) Taking the working environment of the grate element as the boundary condition, analyze the aerodynamic load, thermal load, and mechanical load of the grate element, and further calculate the radial deformation of the grate stationary parts under typical working conditions. , , ... , and radial deformation of rotating parts , , ... , .in is the radial deformation, the subscript s represents the stationary part, the subscript r represents the rotating part, and the subscript numbers 1, 2, …, N represent the 1st, 2nd, …, Nth level grate teeth.

[0051] In some embodiments, the commercial software ANSYS is used to calculate and analyze the grate tooth load to obtain the radial deformation. .

[0052] (4) The radial deformation difference between the stationary and rotating parts of the grate teeth is used as the reverse compensation value of the sealing gap. , where the subscript i represents the i-th level comb teeth, 1≤i≤N.

[0053] (5) Calculation of cold grate tooth clearance after reverse compensation design , where 1≤i≤N. Since the minimum tooth tip clearance of the grate teeth is a limiting condition for the safe operation of the grate teeth element, according to the recommendations of the aircraft engine design manual, the cold minimum tooth tip clearance after the reverse compensation design should be no less than 0.15% of the installation position radius. If this safety limit condition is not met, the cold clearance of the grate teeth is reselected and the above steps (1) to (5) are repeated until the minimum tooth tip clearance meets the safety design requirements.

[0054] In summary, the present invention can improve the sealing effect, reduce airflow leakage, and ensure the working efficiency of the compressor and turbine components by performing reverse compensation on the sealing gap of the grate device.

[0055] Although the specific embodiments of the present invention have been described in a particular order, it should be understood that such actions or steps are required to be performed in the particular order shown or in a sequential order, or that all illustrated actions or steps are required to be performed to obtain the desired result. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details have been included in the above discussion, these should not be construed as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single implementation in combination. On the contrary, the various features described in the context of a single implementation can also be implemented in multiple implementations individually or in any suitable sub-combination.

[0056] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A design method for a non-uniform gap reverse compensation grate device, the non-uniform gap reverse compensation grate device comprising: A grate disc and a sealing bushing, wherein the outer peripheral surface of the grate disc has a plurality of grate teeth along the axial direction, and the sealing bushing is sleeved on the outside of the grate disc; With respect to the grate disc and the sealing bushing: in a cold state, the radial spacing between the grate teeth on the sealing bushing and the grate disc gradually increases from one end to the other end of the grate disc; in a hot state, after the grate disc and the sealing bushing are thermally deformed, the radial spacing between each grate tooth on the sealing bushing and the grate disc remains consistent; the hot state refers to the state when the aircraft engine is operating, and the cold state refers to the state when the aircraft engine is not operating; It is characterized in that it specifically includes the following steps: Step S1: preliminarily selecting the cold interval of the grate teeth according to the installation position parameters and working environment parameters of the grate tooth disc; Step S2: determining the working environment parameters of the grate disc according to the typical working state of the aircraft engine; Step S3: based on the working environment parameters of the grate disc, obtaining the aerodynamic load, thermal load and mechanical load of the grate disc; based on the aerodynamic load, thermal load and mechanical load, obtaining the radial deformation of the grate disc and the sealing bushing; Step S4: obtaining a reverse compensation amount of the sealing gap based on the radial deformation amount; Step S5: Based on the preliminarily selected cold interval of the grate teeth and the reverse compensation amount, obtain the cold grate tooth gap after reverse compensation, and determine whether the cold grate tooth gap after reverse compensation meets the design conditions. If not, return to step S1 until the cold grate tooth gap after reverse compensation meets the design conditions.

2. The design method of the comb device for non-uniform gap reverse compensation according to claim 1 is characterized in that: The thermal deformation specifically includes: compared with the cold state, the radial thermal deformation of the sealing bushing in the axial direction gradually decreases in the hot state; compared with the cold state, the radial thermal deformation of the grate disc in the axial direction gradually increases in the hot state, and the radial thermal deformation of multiple grate teeth of the grate disc in the axial direction gradually increases.

3. The design method of the comb device for non-uniform gap reverse compensation according to claim 1 is characterized in that: The radial spacing between the sealing bushing and the plurality of grate teeth on the grate disc is set to 0.15% to 0.3% of the radius of the installation position.

4. The design method according to claim 1, characterized in that: In step S1: The installation position parameters of the grate disc include: the radial radius position of the grate disc, the number of teeth, the tooth spacing and the tooth top width; The working environment parameters of the grate disc include speed, pressure, flow and temperature; When the grate teeth cold state interval c is initially selected, when the grate tooth disc is in a working condition where the radial dimension increases significantly, the grate teeth cold state interval c is initially selected to be set to 0.3% of the installation position radius.

5. The design method according to claim 4, characterized in that: Step S3 specifically includes: taking the working environment of the grate disc as the boundary condition, analyzing the aerodynamic load, thermal load, and mechanical load of the grate disc, and further calculating the radial deformation of the sealing bushing under typical working conditions. , ,……, and radial deformation of the grate disc , ,……, ;in is the radial deformation, subscript s represents the stationary part, subscript r represents the rotating part, and subscript numbers 1, 2, ..., N represent the 1st, 2nd, ..., Nth level grate teeth.

6. The design method according to claim 5, characterized in that: Step S4 specifically includes: taking the radial deformation difference between the sealing bushing and the grate disc as the reverse compensation value of the sealing gap , where the subscript i represents the i-th level comb teeth, 1≤i≤N.

7. The design method according to claim 6, characterized in that: In step S5, the step of obtaining the cold grate gap after reverse compensation based on the preliminarily selected grate gap and the reverse compensation amount specifically includes: calculating the cold grate gap after reverse compensation design , where 1≤i≤N, c is the preliminarily selected cold interval of the grate teeth.

8. The design method according to claim 7, characterized in that: The design condition in step S5 is that the minimum cold grate tooth gap after reverse compensation should be no less than 0.15% of the installation position radius.

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