Method for adjusting gas flow of inner cavity of hollow blade

Abstract

The invention belongs to the technical field of engine design, and particularly relates to a hollow blade inner cavity gas flow adjusting method. When the gas flow value of the hollow blade is small, flow adjustment is conducted, the flow is influenced by the rib height of the inner cavity, the gas flow is adjusted to reach an expected value by adjusting the rib height of the blade, and the method comprises the steps that the gas flow of the hollow blade is detected through a flow instrument, and dissection analysis is conducted on the rib height of the inner cavity of the detected blade; establishing a proportional relation between gas flow and rib height of the hollow blade; the height of an inner cavity rib needing to be adjusted is determined according to the inner cavity flow of the hollow blade, local corrosion is conducted on the inner cavity to reduce the rib height, the corrosion time is determined according to the corresponding relation between the rib height and the inner cavity gas flow, the rib height of the hollow blade is reduced through corrosion, and the inner cavity gas flow of the hollow blade is increased. The problem that the flow of the hollow blade is small in the engineering production process can be effectively solved, and accurate and efficient control over the flow of the blade is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engine design, and particularly relates to a hollow blade inner cavity gas flow adjusting method suitable for a hollow blade formed by precision investment casting. BACKGROUND

[0002] The inner cavity gas flow of the hollow blade is a key characteristic of the blade and is one of the detection requirements for verifying the inner cavity gas flow capacity of the blade. The cooling effect directly determines the reliability of the engine use performance. Therefore, as an important index of blade cooling, whether the gas flow meets the standard relates to whether the blade cooling performance meets the assembly requirements.

[0003] The hollow blade is mostly formed by precision investment casting. To ensure the cooling capacity of the hollow blade, the inner cavity size needs to be strictly controlled during the design and preparation of the ceramic core mold during the casting process to ensure the consistency and stability of the casting process. In actual engineering production, due to the deviation of the casting production, the flow of the hollow blade is unstable.

[0004] The patent with publication number CN106769062A proposes a method for adjusting the flow of the inner cavity of the blade. The flow is adjusted by deforming the mechanical extrusion cover plate. This scheme is only suitable for the blade combined by the cover plate and the base through brazing and is not suitable for the hollow blade integrally formed by precision investment casting. The hollow blade does not have an independent extrudable cover plate structure but an integrally formed inner cavity rib structure. In addition, mechanical extrusion easily causes uneven deformation of the blade structure, damages the sealing property and structural strength, and needs complex sealing blocks, adjusting frames and other devices, which are complicated to operate and have low adjustment efficiency.

[0005] The patent with publication number CN106523038A proposes a configuration structure of a hollow blade cooling medium orifice plate and an assembly method thereof. The flow is limited by assembling the orifice plate at the blade root cooling medium inlet. The core is to passively limit the flow through external components rather than to correct the structural deviation of the blade itself. This scheme needs to repeatedly disassemble and assemble the orifice plate for trial adjustment, which is time-consuming and laborious. Moreover, it cannot accurately correct the rib height deviation of the inner cavity of the blade caused by casting and can only coarsely limit the overall inlet flow, failing to achieve accurate flow regulation of a single chamber.

[0006] The patent with publication number CN116838432A proposes a turbine blade inner cavity flow adjusting device, turbine blade and method. The water flow is adjusted by adding a grouped throttling sleeve at the water inlet. This scheme is aimed at water, which has significant differences in fluid characteristics from gas and cannot be directly applied to gas flow adjustment. At the same time, the adjustment mode depends on the size grouping of the throttling sleeve, which has poor flexibility. Moreover, it also limits the flow by externally adding components and cannot solve the problem of insufficient flow capacity caused by the rib height deviation of the inner cavity of the blade, which may also affect the assembly compatibility of the blade.

[0007] In summary, the prior art does not directly form a hollow blade for investment precision casting, and cannot meet the repair and precise control requirements of unqualified flow blades in production. SUMMARY

[0008] In view of the problems in the prior art, the purpose of the present application is to provide a hollow blade inner cavity gas flow adjustment method, which can effectively solve the problem of small flow of hollow blades in the engineering production process, and realize precise and efficient control of the flow of such blades.

[0009] In order to solve the above technical problems, the present application is realized by the following technical scheme: A hollow blade inner cavity gas flow adjustment method, the hollow blade is an integral structure directly formed by investment precision casting, and the inner cavity is provided with one or two or more combined structures of transverse ribs, longitudinal ribs, diagonal ribs and cross ribs, and the height of the ribs has a greater impact on the inner cavity gas flow than the impact of the gas inlet and outlet holes at both ends of the inner cavity. The specific steps are as follows: Step one: use a flow meter to detect the flow of 5-10 hollow blades, and ensure that the flow distribution of the hollow blades is discrete, then dissect the blades and measure the height of the inner cavity ribs, and establish the proportional relationship between the rib height and the flow of the hollow blades; Step two: conduct different time corrosion tests on the dissection opened blades, and measure the rib height after corrosion and calculate the rib height reduction, and establish the curve relationship between the corrosion time and the rib height reduction; Step three: use a flow meter to detect the flow of the hollow blade whose flow needs to be adjusted; Step four: according to the proportional relationship of step one, combined with the difference between the actual flow and the target flow, determine the required rib height reduction of the blade to be adjusted; Step five: according to the required rib height reduction in step four and the relationship between the corrosion time and the rib height reduction determined in step two, confirm the corrosion time required for the inner cavity of the hollow blade; Step six: corrode the inner cavity of the hollow blade, block one end of the hollow blade, pour the corrosion agent from the other end, and corrode the inner cavity for the corrosion time; Step seven: clean the corroded blade to remove the poured corrosion agent; Step eight: dry the hollow blade after corrosion and cleaning, and then detect the inner cavity flow again; Step nine: if the inner cavity flow is adjusted to the required range, the flow test is qualified; if the inner cavity flow still cannot meet the requirements, repeat steps four to nine.

[0010] The hollow blade inner cavity gas flow adjustment method is used for adjusting the flow of the hollow blade with a small flow value, and the flow is affected by the inner cavity rib height, and the flow is adjusted to the expected value by adjusting the rib height.

[0011] The hollow blade inner cavity gas flow adjustment method uses the corrosion agent to adjust the rib height in step six, and only the height of the rib is reduced to increase the inner cavity gas flow.

[0012] The hollow blade inner cavity gas flow adjustment method separately corrodes the single cavity of the hollow blade in step six, and does not affect the flow of other cavities.

[0013] The hollow blade inner cavity gas flow adjustment method is used for adjusting the flow of the hollow blade with a small flow value, and the flow is affected by the inner cavity rib height, and the flow is adjusted to the expected value by adjusting the rib height.

[0014] The design idea of the present application is: The flow deviation of the investment precision casting hollow blade is mainly caused by the casting fluctuation of the inner cavity rib height, and the influence of the rib height on the flow is much greater than that of the inlet and outlet gas holes (for example, a reduction of 0.03mm in the rib height can increase the flow by more than 0.025m 3 / h, and a change of 0.1mm in the size of the inlet and outlet gas holes only changes the flow by 0.01m 3 / h). Based on this, the present application dissects 5-10 pieces of blades with discrete distributed flow, carries out multiple corrosion tests on the dissected blades, records the rib height reduction under different corrosion times, and fits the curve of the corrosion time and the rib height reduction. The present application selects chemical corrosion as the rib height adjustment method according to the structural characteristics of the integrally formed blade by investment precision casting, the corrosion only acts on the protruding part of the inner cavity rib, does not damage the overall structure of the blade, and by plugging the outlet of one end of the blade and pouring the corrosion agent in a direction, the single cavity adjustment of the multi-cavity blade can be realized; if the flow does not reach the standard after one corrosion, the adjustment can be repeated until the standard is reached.

[0015] The gas flow of the hollow blade is detected by using the flow meter, and the gas flow of the hollow blade is proportional to the rib height; the rib height of the hollow blade is adjusted by using the corrosion agent, the height of the rib to be adjusted is confirmed according to the proportional relationship between the gas flow of the hollow blade and the rib height, the height of the rib can only be reduced by using the corrosion agent, so the flow can only be increased, and the corrosion time for adjusting the rib height needs to be tested and confirmed in advance.

[0016] The advantages and beneficial effects of the present application are: 1. The hollow blades produced by casting will inevitably have interval distribution due to the casting deviation flow, and the present application can specifically increase the gas flow of the hollow blades with small flow test, actively reduce the rib height to correct the structural defects of the blades, and make the blades with unqualified gas flow test meet the technical requirements.

[0017] 2. This invention uses a corrosive agent to precisely corrode the inner cavity ribs without damaging the overall structure and sealing of the blade, maintaining the original structural strength and assembly compatibility of the blade, and overcoming the defects of mechanical extrusion methods that are prone to structural damage.

[0018] 3. This invention achieves quantitative adjustment by establishing the rib height-flow ratio relationship and the corrosion time-rib height decrease curve, ensuring the accuracy of flow adjustment and allowing for repeated adjustments until the target is met, thus solving the problems of insufficient adjustment accuracy and poor flexibility in existing technologies.

[0019] 4. This invention can complete the adjustment through a simple process of flow detection, corrosion, cleaning, and re-inspection. It is convenient to operate, highly efficient, and reduces adjustment costs. It is especially suitable for repairing defective blades in mass production. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the shape of the inner cavity ribs of a hollow rotor blade. In the diagram, 1 is the hollow blade, 2 is the first cavity, 3 is the air inlet of the first cavity, 4 is the air inlet of the second cavity, 5 is the second cavity, 6 is the inner cavity rib, 7 is the air outlet of the second cavity, and 8 is the air outlet of the first cavity.

[0021] Figure 2 This is a graph showing the ratio of the rib height of the hollow rotor blades to the gas flow rate.

[0022] Figure 3 This is a graph showing the relationship between the amount of rib height removed from hollow rotor blades and the corrosion time. Detailed Implementation

[0023] In its specific implementation, this invention proposes a method for adjusting the gas flow rate inside a hollow blade. When the gas flow rate is too low, the flow rate is adjusted. The flow rate is affected by the rib height within the hollow blade. Adjusting the rib height helps to adjust the gas flow rate to the desired value. This includes using a flow meter to verify the gas flow rate of the hollow blade, performing a dissection analysis of the rib height within the blade to establish a proportional relationship between the gas flow rate and the rib height; determining the required rib height based on the internal flow rate; performing localized corrosion within the hollow blade to reduce the rib height; and determining the corrosion time based on the correlation between the rib height and the internal gas flow rate. By reducing the rib height through corrosion, the gas flow rate inside the hollow blade is increased.

[0024] like Figure 1 As shown, the hollow blade 1 has a first cavity 2 and a second cavity 5 in its inner cavity channel. One end of the first cavity 2 is the first cavity air inlet 3, and the other end of the first cavity 2 is the first cavity air outlet 8. One end of the second cavity 5 is the second cavity air inlet 4, and the other end of the second cavity 5 is the second cavity air outlet 7. An inner cavity rib 6 is provided on the upper part of the first cavity 2 and the second cavity 5. The inner cavity rib 6 is one or a combination of two or more of the following structures: transverse rib, longitudinal rib, oblique rib, and cross rib.

[0025] To make the technical solutions described in this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. The scope of protection claimed herein is not limited to those described.

[0026] Example 1

[0027] In this embodiment, a method for adjusting the gas flow rate inside a hollow rotor blade specifically includes the following steps: Select 5-10 nickel-based hollow rotor blades and use a flow meter to measure their flow rate. For example... Figure 1 The diagram shows the shape of the ribs inside the hollow rotor blade. The blade is divided into a first cavity 2 and a second cavity 5. The flow rate in the first cavity 2 is relatively stable and does not exceed the required range. The flow rate in the second cavity 5 is discretely distributed; the flow rate in the second cavity 5 of some blades is less than the required value. The flow rate in the second cavity 5 of these blades needs to be adjusted by increasing the flow rate value to meet the requirements.

[0028] The selected blades were dissected, and the rib height of the second cavity 5 of the blade was measured and compared with the flow rate of the second cavity 5 of the blade to establish the proportional relationship between the rib height of the second cavity 5 of the hollow rotor blade and the flow rate. Figure 2 As shown.

[0029] Corrosion tests were conducted on the dissected blades at different times, and the rib height was measured again and compared with the rib height measured before corrosion. A curve relationship between the rib height removal amount and corrosion time of the hollow rotor blade was established. Figure 3 As shown; The flow rate of a hollow rotor blade was measured using a flow meter. The flow rate in the second cavity 5 of this blade was 0.933 m³ / s. 3 / h, less than the minimum value required by the standard of 0.950 m 3 / h, the flow rate of this blade needs to be adjusted to meet the requirements.

[0030] Based on the verified flow rate of the blade, and Figure 2 The relationship between rib height and flow rate shown in the diagram confirms that if the blade flow rate meets the requirements, the blade rib height needs to be reduced by approximately 0.03 mm. Then, based on... Figure 3 The curve relationship between corrosion time and rib height reduction confirms that the corrosion time required to adjust the blade flow rate to the minimum requirement is 2~3 min.

[0031] The outlet 7 of the second cavity of the nickel-based hollow rotor blade was sealed. A corrosive agent (HNO3:HCl:FeCl3:H2O = 200mL:200mL:250g:600mL) was poured into the inlet 4 and corroded for 3 minutes. The corrosive agent was then poured out. The seal on the outlet 7 of the second cavity of the hollow rotor blade was removed, and the corrosive agent inside the hollow rotor blade was cleaned. The blade was then dried by drying or blowing. After ensuring the inner cavity was dry, the flow rate of the second cavity 5 of the hollow rotor blade was re-measured. The flow rate of the second cavity 5 was 0.958 m³ / s. 3 / h, the test results meet the requirements.

[0032] Example 2

[0033] The flow rate of a hollow rotor blade was measured using a flow meter. The flow rate in the first chamber 2 of the blade met the requirements, while the flow rate in the second chamber 5 was 0.945 m³ / s. 3 / h, less than the minimum value required by the standard of 0.950m 3 / h, the flow rate of this blade needs to be adjusted to meet the requirements.

[0034] Based on the verified flow rate of the blade, and Figure 2 The relationship between rib height and flow rate shown in the diagram confirms that if the blade flow rate meets the requirements, the blade rib height needs to be reduced by 0.02 mm. Then, based on... Figure 3 The curve relationship between corrosion time and rib height reduction confirms that the corrosion time required to adjust the blade flow rate to the minimum requirement is 1~2 min.

[0035] The outlet 7 of the second cavity of the nickel-based hollow rotor blade was sealed. A corrosive agent (HNO3:HCl:FeCl3:H2O = 200mL:200mL:250g:600mL) was poured into the inlet 4 and corroded for 1.5 minutes. The corrosive agent was then poured out. The seal on the outlet 7 of the second cavity of the hollow rotor blade was removed, and the corrosive agent inside the hollow rotor blade was cleaned. The blade was then dried by drying or blowing. After ensuring the inner cavity was dry, the flow rate of the second cavity 5 of the hollow rotor blade was re-measured. The flow rate of the second cavity 5 was 0.964 m³ / s. 3 / h, the test results meet the requirements.

[0036] The results show that this invention addresses the rib height casting deviation problem in investment casting of hollow blades, and achieves damage-free, high-precision adjustment of gas flow by modifying the blade's own structure.

Claims

1. A method for adjusting the gas flow rate inside a hollow blade cavity, characterized in that, The hollow blade is a one-piece structure directly formed by investment casting. Its inner cavity is provided with one or more of the following structures: transverse ribs, longitudinal ribs, oblique ribs, and cross ribs. The height of the ribs has a greater impact on the gas flow rate in the inner cavity than on the gas inlet and outlet holes at both ends of the inner cavity. The specific steps are as follows: Step 1: Use a flow meter to detect the flow rate inside 5-10 hollow blades. It is necessary to ensure that the flow rate distribution of the hollow blades is discrete. Then, dissect the blades and measure the height of the inner ribs to establish the proportional relationship between the rib height and the flow rate of the hollow blades. Step 2: Conduct corrosion tests on the dissected blades for different durations, measure the rib height after corrosion, calculate the rib height reduction, and establish a curve relationship between corrosion time and rib height reduction. Step 3: Use a flow meter to measure the flow rate of the hollow blade that needs to be adjusted; Step 4: Based on the proportional relationship in Step 1, and combined with the difference between the actual flow rate and the target flow rate, determine the required reduction in rib height for the blade to be adjusted. Step 5: Based on the required reduction in rib height in Step 4 and the relationship between corrosion time and rib height reduction determined in Step 2, confirm the required corrosion time for the hollow blade's inner cavity. Step Six: Perform internal corrosion on the hollow blade. Block one end of the hollow blade outlet and pour the corrosive agent into the other end. Perform internal corrosion according to the specified corrosion time. Step 7: Clean the corroded blades to remove the corrosive agent that was poured in. Step 8: After drying or blowing the cleaned hollow blades, perform the internal flow test again; Step 9: If the flow rate in the cavity is adjusted to the required range, the flow rate test is qualified; If the flow rate in the cavity still cannot meet the requirements, repeat steps four through nine.

2. The method for adjusting the gas flow rate inside the hollow blade cavity according to claim 1, characterized in that, For hollow blades with low flow rates, flow rate adjustment is performed. The flow rate is affected by the height of the inner cavity ribs. The flow rate is adjusted to reach the expected value by adjusting the blade rib height.

3. The method for adjusting the gas flow rate inside the hollow blade cavity according to claim 1, characterized in that, In step six, an erosive agent is used to adjust the rib height, reducing only the rib height to increase the gas flow rate inside the cavity.

4. The method for adjusting the gas flow rate inside the hollow blade cavity according to claim 1, characterized in that, In step six, the single chamber of the hollow blade is etched separately without affecting the flow rate of other chambers.

5. The method for adjusting the gas flow rate inside the hollow blade cavity according to claim 1, characterized in that, Hollow blades are nickel-based hollow rotor blades used in engines.

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