A flow channel structure for changing the local flow field of blade pneumatic thermal deicing

Abstract

The present application belongs to the technical field of blade air-thermal deicing, and relates to a flow channel structure for changing the local flow field of blade air-thermal deicing. The flow channel structure is a reinforced heating section in a blade where heat exchange intensity needs to be improved. A plurality of basic flow channel units are arranged in the reinforced heating section. Each basic flow channel unit is composed of two parallel flow channel baffles, and is arranged at the leading edge of the blade or between the first web plate and the second web plate. Each basic flow channel unit is composed of two parallel flow channel baffles, and a U-shaped flow channel is formed in the direction of the hot air flow. A flow guide plate is designed and arranged on the flow channel baffle to change the flow trajectory and flow velocity of the original hot air flow, so as to increase the turbulent flow intensity of the hot fluid in the middle section of the blade and the heat exchange effect with the blade. The flow velocity of the hot air flowing through the basic flow channel unit is increased by 2-3 times, and a good balance between speed improvement and resistance loss can be achieved, that is, without excessive energy consumption under the premise of improving the heat exchange effect.

Description

Technical Field

[0001] This invention belongs to the technical field of blade air-thermal de-icing systems, specifically relating to a flow channel structure that alters the local flow field during blade air-thermal de-icing. Background Technology

[0002] Gas-heated de-icing is a commonly used technology at present. However, due to the long length of the blades, there are uneven thickness distributions in both the tangential and spanwise directions. If only gas-heated de-icing is used for de-icing, the following problems exist: Although the blades are relatively severely iced, the thinner blades allow for better heating of the blade tips by the hot airflow, making it less prone to icing at the blade tips. In contrast, the middle section of the blade, especially the leading edge, has a larger blade thickness, and although there is hot airflow inside, the heating effect is poor. Summary of the Invention

[0003] The purpose of this invention is to provide a flow channel structure that alters the local flow field of air-thermal de-icing on blades, thereby solving the problem of poor air-thermal de-icing effect in the middle section of the blade.

[0004] This invention is achieved through the following technical solution:

[0005] A flow channel structure for altering the local flow field of air-thermal de-icing in blades, wherein the flow channel structure is an enhanced heating section in the blades that requires increased heat transfer intensity.

[0006] Several basic flow channel units are provided in the enhanced heating section to construct U-shaped flow channels in the direction of hot air flow and change the hot air flow area in the enhanced heating section.

[0007] The blade has a first web and a second web inside, and the basic flow channel unit is composed of parallel first flow channel baffles and second flow channel baffles.

[0008] When the enhanced heating section is set inside the leading edge of the blade, one end of the first flow channel baffle has a flow passage gap with the first web plate, and the other end is attached to the inner wall surface of the leading edge of the blade. The arrangement direction of the first flow channel baffle is perpendicular to the first web plate. The second flow channel baffle is vertically fixed on the first web plate, and a flow passage gap is left between the second flow channel baffle and the inner surface of the leading edge of the blade.

[0009] When the enhanced heating section is located between the first web and the second web, one end of the first flow channel baffle is vertically fixed to the second web, and the other end is left with a flow passage gap to the first web; one end of the second flow channel baffle is vertically fixed to the first web, and the other end is left with a flow passage gap to the second web.

[0010] Furthermore, the basic flow channel units are arranged at equal intervals, which is the same as the interval between the first flow channel baffle and the second flow channel baffle.

[0011] Furthermore, guide vanes are provided on the first flow channel baffle and the second flow channel baffle.

[0012] Furthermore, the first and second flow channel baffles are placed vertically, while the guide plate is placed horizontally.

[0013] Furthermore, the guide vanes are arranged in pairs, with each pair of guide vanes symmetrically distributed along the center of the height of the flow channel baffle in the height direction of the flow channel baffle.

[0014] Furthermore, the guide plate on the first flow channel baffle is located on the side close to the second flow channel baffle, while the guide plate on the second flow channel baffle is located on the side away from the first flow channel baffle.

[0015] Furthermore, the deflector includes a front end and a rear end. The front end is a rectangular straight plate, and the rear end is an arc-shaped plate.

[0016] Furthermore, the width of the rectangular plate is the same as the distance between the first flow channel baffle and the second flow channel baffle.

[0017] Furthermore, the area of ​​the flow region formed between the end of the first flow channel baffle and the first web plate 13 is 1 / 2 to 1 / 3 of the area of ​​the flow region formed between the leading edge of the blade and the first web plate at the corresponding position.

[0018] Furthermore, the flow area formed at the end of the second flow channel baffle and the leading edge of the blade at point 7 is 1 / 2 to 1 / 3 of the flow area formed between the leading edge of the blade and the first web at the corresponding position.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] This invention discloses a flow channel structure that alters the local flow field during blade de-icing. Within a selected, enhanced heat transfer region at the blade's leading edge, several basic flow channel units are configured. Each unit consists of two parallel flow channel baffles, creating a U-shaped flow channel along the direction of the hot airflow. This alters the original flow trajectory and velocity of the hot airflow, increasing the turbulence intensity in the mid-section of the blade and enhancing the heat transfer effect. Increasing the velocity of the hot airflow through the basic flow channel units by 2-3 times achieves a good balance between velocity increase and drag loss, meaning that excessive energy consumption is avoided while still improving heat transfer efficiency.

[0021] Furthermore, symmetrical guide vanes are arranged in pairs along the height of the flow channel baffle to divide the hot airflow in the main flow direction into multiple streams, which are then guided through the guide vanes to different areas of the leading edge of the blades where heat exchange needs to be enhanced, thereby improving the thermal utilization efficiency of the hot airflow.

[0022] Furthermore, the deflector consists of two parts: a rectangular plate and a circular arc plate. The length of the rectangular plate, the radius of the circular plate, and the arc length, etc., need to be designed in accordance with the specific location of the deflector and the target heating area of ​​the diverted hot airflow.

[0023] Furthermore, the spacing between the first flow channel baffle and the first web plate, as well as the flow passage area between the second flow channel baffle and the leading edge of the blade, are designed based on the increase in hot airflow velocity within the basic flow channel unit. The spacing between the two flow channel baffles is also adjusted to ensure that the flow area of ​​the hot airflow through the basic flow channel unit is the same, avoiding additional pressure loss caused by local velocity differences. Overall, the flow velocity within the flow channel unit is 2 to 3 times higher than the flow velocity before entering the flow channel. Velocity changes are minimized during internal flow to reduce flow resistance. Attached Figure Description

[0024] Figure 1 This is an overall diagram of a blade air-thermal de-icing system based on existing blade air-thermal de-icing technology and combined with the selected blade areas that require enhanced heat exchange.

[0025] Figure 2 A schematic diagram of the basic flow channel unit arranged within the blade to construct a U-shaped local flow channel;

[0026] Figure 3 A schematic diagram of the flow channel baffle at the front end of the corrugated pipe section;

[0027] Figure 4 This is a schematic diagram of the baffle plate.

[0028] Among them, 1. blade root; 2. blower; 3. heater; 5. ventilation pipe; 6. wind deflector; 7. blade leading edge; 8. blade tip; 9. flow channel baffle; 10. basic flow channel unit; 11. controller; 13. first web plate; 14. second web plate; 15. first flow channel baffle; 16. second flow channel baffle; 17. guide plate. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0030] The components described and illustrated in the accompanying drawings and embodiments of this invention can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely to illustrate one selected embodiment of the invention. All other embodiments obtained by those skilled in the art based on the accompanying drawings and embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0031] Under the constraints of equipment output power, blade safety, and overall operating economy, this invention identifies areas where additional gas-heat transfer efficiency needs to be improved in both the chordal and spanwise directions of the blade. Instead of simply increasing gas-heat de-icing operating parameters (such as flow rate and temperature) in ways that compromise blade safety and operating economy, this invention employs normal, common operating methods to address the de-icing needs of the blade root and tip (preliminary conclusions regarding blade icing areas). For the middle and / or other areas of the blade, due to blade thickness or more severe icing, areas requiring enhanced heat transfer are selected. Within these areas, localized enhanced heat transfer structures are designed.

[0032] like Figure 1 As shown, this diagram illustrates the overall layout of the air-thermal de-icing system and flow channels for the specific blade region requiring enhanced localized heat exchange, based on the commonly used air-thermal de-icing technology in the industry. The controller 11 controls the blower 2 to draw air into the heater 3, where it is heated to a certain temperature. The air is then delivered into the internal cavity flow channel of the blade through the ventilation pipe 5. Through design calculations, a baffle 6 is installed at a suitable position on the blade, creating a U-shaped hot airflow region between the blade leading edge 7, blade tip 8, first web 13, and second web 14. During the hot air flow, the blade is heated.

[0033] Among them, the tip 8 has a narrow flow channel, high airflow velocity, and relatively thin blade thickness, resulting in good heat exchange between the hot airflow and the blade. Although icing is more severe at the tip 8 due to the higher overall rotational linear velocity, the overall icing problem in this area can be solved through optimized design of the gas-thermal de-icing system, based on the aforementioned reasons. Building upon the solution to the de-icing problem at this location, without changing the parameters of the hot airflow (such as flow rate and temperature), a basic flow channel unit 10 is installed in a selected area in the middle section of the blade (such as the leading edge 7 and a portion between the first web 13 and the second web 14) to enhance heat exchange in the thick blade area.

[0034] like Figure 2As shown, the basic flow channel unit 10 is composed of two parallel flow channel baffles 9. The first flow channel baffle 15 has a flow passage area with the first web 13, and its other end is attached to the inner wall surface of the blade leading edge 7. Its arrangement direction is perpendicular to the first web 13, so that the hot air can flow into the interior of the basic flow channel unit 10 through the rectangular flow passage area. The second flow channel baffle 16 is fixed vertically on the first web 13, and it has a certain area with the inner surface of the blade leading edge 7.

[0035] By designing and adjusting the dimensions of the flow passage area, the flow velocity of the hot air through the basic flow channel unit 10 can be increased by 2 to 3 times. This achieves a good balance between velocity increase and resistance loss, meaning that excessive energy consumption is not generated while improving heat exchange efficiency. Reasonable setting of the dimensions within the basic flow channel unit 10, such as gaps and plate spacing, ensures that the average flow velocity of the hot air within the basic flow channel unit 10 remains constant.

[0036] The distance between the first flow channel baffle 15 and the first web plate 13, as well as the flow area between the second flow channel baffle 16 and the leading edge 7 of the blade, are designed based on the increase in hot airflow velocity. The distance between the two flow channel baffles is adjusted accordingly so that the flow area of ​​the hot airflow through the basic flow channel unit 10 is the same.

[0037] The specific technical solution is as follows: Based on the blade structure at the location of the basic flow channel unit 10, the distance between the first flow channel baffle 15 and the first web plate 13 is determined so that the area of ​​the flow region formed between the end of the first flow channel baffle 15 and the first web plate 13 is 1 / 2 to 1 / 3 of the area of ​​the flow passage region formed between the leading edge 7 of the blade and the first web plate 13 at the corresponding position. The distance between the two flow channel baffles is adjusted accordingly so that the flow passage area of ​​the hot airflow through the basic flow channel unit is the same. Similarly, the area of ​​the flow region formed between the end of the second flow channel baffle 16 and the leading edge 7 of the blade is 1 / 2 to 1 / 3 of the area of ​​the flow passage region formed between the leading edge 7 of the blade and the first web plate 13 at the corresponding position.

[0038] Considering the large overall size of the blade midsection, improving the heating effect of the air-heat de-icing system on the blade surface in the midsection requires focusing on enhancing the heat exchange effect between the hot airflow and the internal surface in direct contact with it. In this invention, a guide plate 17 is correspondingly provided in the basic flow channel unit 10 to guide more of the airflow in the main flow area of ​​the hot airflow to the vicinity of the inner surface of the blade, thereby enhancing heat exchange.

[0039] For pneumatic de-icing systems, the internal flow channels of the blades, along the spanwise direction, are generally gradient flow channels with a gradually decreasing cross-section, such as... Figure 2 As shown, after setting the basic flow channel unit 10, the hot fluid mainly achieves the increase in flow velocity and turbulence in the spanwise direction. In the direction perpendicular to the chord and spanwise directions in the middle section of the blade, the change in airflow velocity is relatively insignificant.

[0040] like Figure 3 As shown, several pairs of guide vanes 17 are designed and arranged on the first flow channel baffle 15 and the second flow channel baffle 16 of the basic flow channel unit 10, taking into account the blade position and cross-sectional shape. The guide vanes 17 on the first flow channel baffle 15 are positioned on the side closest to the second flow channel baffle 16, while the guide vanes 17 on the second flow channel baffle 16 are positioned on the side furthest from the first flow channel baffle 15. The two flow channel baffles are placed vertically, and the guide vanes 17 are placed horizontally; the width of the guide vanes 17 is the distance between the two flow channel baffles.

[0041] Several pairs of guide vanes 17 are symmetrically distributed along the height center of the flow channel baffle in the height direction. The spacing between each flow channel baffle is the same. It can be adjusted based on the flow field distribution and heat transfer effect of the heat flow field, with the goal of improving the overall heat transfer uniformity of the blade leading edge 7 surface and solving the de-icing requirements of the entire blade.

[0042] like Figure 4 As shown, the guide plate 17 consists of two parts. The front end is a rectangular straight plate. As mentioned above, its width is the distance between the two flow channel baffles 9 in the basic flow channel unit 10. On the one hand, it is to better guide the flow, and on the other hand, it also serves to fix the two baffles. The length L1 of the rectangular straight plate depends on the specific arrangement position of the guide plate 17. The radius R1 of the arc-shaped part of the guide plate 17 is specifically set according to the enhanced heating area and flow guiding effect of the guide plate 17 on the leading edge 7 of the blade.

[0043] The purpose of setting multiple pairs of guide vanes 17 is to change the flow distribution and flow direction of the hot fluid in the height direction of the flow channel baffle 9, that is, to split the hot fluid and guide it to the inner surface of the leading edge where heat exchange needs to be enhanced. By changing the flow direction and increasing the flow velocity, the turbulence of the flow field is increased, thereby improving the overall heat exchange effect.

[0044] Combination Figures 1-3 The overall design structure requires the use of experimental or numerical simulation methods to observe and optimize the heat transfer effect within the selected local heat transfer enhancement section in the middle section of the blade.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A flow passage structure for changing a local flow field of a blade pneumatic de-icing, characterized by, The flow channel structure is a reinforced heating section in the blade where the heat exchange intensity needs to be improved; A plurality of basic flow channel units (10) are arranged in the reinforced heating section to form U-shaped flow channels in the direction of the hot gas flow and change the hot gas flow area in the reinforced heating section; A first web (13) and a second web (14) are arranged in the blade, and the basic flow channel unit (10) is composed of parallel first flow channel baffles (15) and second flow channel baffles (16); When the reinforced heating section is arranged in the blade leading edge (7), one end of the first flow channel baffle (15) is arranged with a flow gap from the first web (13), and the other end is attached to the inner wall surface of the blade leading edge (7), and the arrangement direction of the first flow channel baffle (15) is perpendicular to the first web (13); the second flow channel baffle (16) is vertically fixed on the first web (13), and the second flow channel baffle (16) is arranged with a flow gap from the inner surface of the blade leading edge (7); When the reinforced heating section is arranged between the first web (13) and the second web (14), one end of the first flow channel baffle (15) is vertically fixed on the second web (14), and the other end is arranged with a flow gap from the first web (13); one end of the second flow channel baffle (16) is vertically fixed on the first web (13), and the other end is arranged with a flow gap from the second web (14); A flow guide plate (17) is arranged on the first flow channel baffle (15) and the second flow channel baffle (16); The first flow channel baffle (15) and the second flow channel baffle (16) are arranged vertically, and the flow guide plate (17) is arranged horizontally; The flow guide plates (17) are arranged in pairs, and each pair of flow guide plates (17) is symmetrically distributed along the height center of the flow channel baffles in the height direction of the flow channel baffles; The flow guide plate (17) arranged on the first flow channel baffle (15) is arranged on the side close to the second flow channel baffle (16), and the flow guide plate (17) arranged on the second flow channel baffle (16) is arranged on the side deviated from the first flow channel baffle (15); The flow guide plate (17) comprises a front end portion and a rear end portion, the front end portion is a rectangular straight plate, and the rear end portion is a circular arc plate; The width of the rectangular straight plate is the same as the spacing between the first flow channel baffle (15) and the second flow channel baffle (16).

2. The flow channel structure for changing the local flow field of blade pneumatic de-icing according to claim 1, characterized in that, The basic flow channel units (10) are arranged at equal intervals, and the interval is the same as the spacing between the first flow channel baffle (15) and the second flow channel baffle (16).

3. The flow channel structure for changing the local flow field of blade pneumatic de-icing according to claim 1, characterized in that, The flow area formed between the end of the first flow channel baffle (15) and the first web (13) is 1 / 2-1 / 3 of the flow area formed between the corresponding position of the blade leading edge (7) and the first web (13).

4. The flow channel structure for changing the local flow field of blade pneumatic de-icing according to claim 1, characterized in that, The flow area formed between the end of the second flow channel baffle (16) and the blade leading edge (7) is 1 / 2-1 / 3 of the flow area formed between the corresponding position of the blade leading edge (7) and the first web (13).

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