A wind tunnel grid structure with adjustable diameter

Abstract

This invention provides a wind tunnel grid structure with adjustable diameter. To accommodate different inflow turbulence in wind tunnel tests, a conveniently adjustable variable diameter solution is provided. The grid structure consists of a perforated frame, a perforated stainless steel capillary tube, a rubber tube, an air inlet, and an air pump. The rubber tube is tightly fitted onto the perforated stainless steel capillary tube. Appropriate lengths are cut according to the length and width of the frame, and both ends are fixed to the perforated frame to complete the grid mesh weaving and ensure a seal at the joints. When adjusting the orifice diameter, the air pump is connected to the air inlet at the top of the grid. Upon activation, air enters the perforated grid frame through the air inlet, then flows into the perforated stainless steel capillary tube. The rubber tube expands through the small holes in the capillary tube until the desired grid diameter is achieved. Within a distance of 10cm-20cm downstream of the grid, when the grid diameter varies from 1.0-2.0mm, the turbulence intensity can vary from 2.5% to 10%.

Description

Technical Field

[0001] This invention belongs to the technical field of wind tunnel test benches for aero-engine flat plates and blade cascades, and in particular, a wind tunnel grating structure with adjustable diameter. Background Technology

[0002] Flat plate test benches are crucial devices for measuring the aerodynamic performance of flat plates and studying flow mechanisms. Currently, in addition to the Mach number and Reynolds number, the inlet conditions in flat plate tests also include the inlet turbulence intensity. To address variations in inlet turbulence intensity, mainstream test benches typically employ methods such as directly fabricating grids with different apertures, binding wire meshes of different diameters to empty grid frames, or inserting wires of different diameters to alter the inlet turbulence intensity during the test. However, the first method requires fabricating grids with multiple apertures, resulting in significant manufacturing costs; the second method is difficult to fix the wire mesh; and the third method suffers from the problem of thicker diameter wires being difficult to bend and disassemble. To address these issues, we designed a grid structure with easily adjustable diameter, suitable for a suitable turbulence intensity range. This inlet grid does not alter the structure of the test section, can be independently adjusted, and is simple and feasible. Summary of the Invention

[0003] Purpose of the invention: In view of the various drawbacks of current mainstream test benches that use different aperture grids, wire mesh of different diameters bound to empty grid frames, or wires of different diameters inserted to change the turbulence intensity of the test flow, we have designed a simple and easy-to-replace diameter adjustable turbulence grid that can generate a suitable range of inlet turbulence intensity. The design of this inlet turbulence grid does not change other irrelevant factors in the test section.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An adjustable-diameter wind tunnel grid structure is disclosed, comprising a perforated frame, a perforated stainless steel capillary tube, a rubber tube, an air inlet, and an air pump. The rubber tube is tightly fitted onto the perforated stainless steel capillary tube, and cut to an appropriate length according to the length and width of the frame. Both ends are fixed to the perforated frame to complete the grid mesh weaving, and the joints are sealed. When adjusting the aperture, the air pump is connected to the air inlet at the top of the grid. Upon activation, air enters the perforated grid frame through the air inlet, then flows into the perforated stainless steel capillary tube. The air expands through the small holes in the capillary tube until the desired grid diameter is achieved.

[0006] Furthermore, the grille frame dimensions are 162mm*494mm.

[0007] Furthermore, the aperture of the grille is 1mm around its perimeter, and the distance between two adjacent holes is 5mm.

[0008] Furthermore, the stainless steel capillary has an outer diameter of 0.4 mm and a wall thickness of 0.1 mm.

[0009] Furthermore, the rubber tube has an inner diameter of 0.4 mm and an outer diameter of 1 mm.

[0010] Furthermore, the grid diameter can be changed by inflating it with an air pump, allowing the grid diameter to vary between 1-2 mm.

[0011] Furthermore, within a distance of 10cm-20cm downstream of the grid, the turbulence intensity can vary within the range of 2.5%-10%.

[0012] The beneficial effects of the present invention are as follows: The present invention provides a wind tunnel grid structure with adjustable diameter, which is suitable for a suitable inlet turbulence intensity range. The structure can independently adjust the inlet turbulence intensity without changing other irrelevant factors in the test section, thus avoiding the generation of other uncontrollable factors. At the same time, the method has many advantages such as simple structure and easy implementation. Attached Figure Description

[0013] Figure 1 A schematic diagram of a perforated frame and the opening structure on the frame;

[0014] Figure 2 A schematic diagram of a perforated stainless steel capillary tube.

[0015] Figure 3 This is a cross-sectional view of the grille;

[0016] Figure 4 This is a schematic diagram of the connection structure between the air inlet and the air pump.

[0017] Figure 5 This is a schematic diagram of the front and rear grille structure for air blowing;

[0018] In the diagram: 1-rubber tube, 2-perforated stainless steel capillary tube. Detailed Implementation

[0019] Specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Specific details are set forth in the following description for purposes of explanation and not limitation, in order to aid in a comprehensive understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments departing from these specific details.

[0020] It should be noted that, in order to avoid obscuring the invention with unnecessary details, only the device structure and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0021] This invention discloses a wind tunnel grid structure with adjustable diameter. The adjustable diameter wind tunnel grid structure consists of a perforated frame, a perforated stainless steel capillary tube, a rubber tube, an air inlet, and an air pump. When adjusting the aperture, the air pump is connected to the air inlet at the upper end of the grid. When the air pump is activated, air enters the perforated grid frame from the air inlet, then enters the perforated stainless steel capillary tube. The air expands through the small holes in the capillary tube until the desired grid diameter is achieved.

[0022] like Figure 1 The sealing frame on the left is set on the periphery of the perforated frame, forming a cavity between it and the perforated frame. An air nozzle is opened on the sealing frame, and air is pumped in. In this way, the gas enters the perforated stainless steel capillary tube through the through holes opened around the perforated frame, and enters the rubber tube through the air hole, causing the rubber tube to expand.

[0023] Furthermore, numerical simulations were performed on a trough-shaped channel with a turbulence grid. Given an inlet velocity of 10 m / s and an inlet turbulence intensity of 1%, it was calculated that within a distance of 10 cm to 20 cm downstream of the grid, when the grid diameter varied from 1.0 to 2.0 mm, the turbulence intensity could reach a range of 2.5% to 10%.

[0024] Furthermore, since the diameter of the turbulence grid needs to be changed by inflating, it is necessary to ensure that the two ends fixed to the turbulence grid frame are airtight and have good sealing properties.

[0025] Furthermore, in order to ensure uniform expansion of the rubber tube, holes are evenly opened circumferentially on the stainless steel surface, with adjacent openings at the same cross-section 72° apart.

[0026] Furthermore, since the test requires the diameter of the rubber tube to vary within the range of 1mm-2mm, the selected rubber tube should be a rubber hose with good ductility.

[0027] Example

[0028] As shown in Table 1, when the inlet velocity is 10 m / s and the inlet turbulence intensity is 1%, the turbulence intensity within a distance of 10 cm-20 cm downstream of the grid is calculated. By inflating the rubber tube to change the diameter of the rubber tube of the woven grid, different diameter turbulence grids produce different turbulence intensities, which meets the working condition requirements of the test with variable inlet turbulence intensity.

[0029] Table 1 shows the turbulence intensity generated by turbulence grids of different diameters at distances of 10cm and 20cm from the leading edge of the test plate.

[0030]

[0031] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wind tunnel grid structure with adjustable diameter, characterized in that, The device includes a perforated frame, a sealing frame, a perforated stainless steel capillary tube, a rubber tube, an air inlet, and an air pump. The perforated stainless steel capillary tube is inserted into the perforated frame to form multiple grids. The rubber tube is fitted onto the perforated stainless steel capillary tube. The air inlet is connected to the air pump, and the other end of the air inlet is connected to the sealing frame. The sealing frame is located around the perforated frame, forming a cavity with it. Multiple through holes for inserting the perforated stainless steel capillary tube are provided around the perimeter of the perforated frame. Multiple air holes are provided on the perforated stainless steel capillary tube.

2. The wind tunnel grid structure with adjustable diameter according to claim 1, characterized in that, The dimensions of the perforated frame are 162mm*494mm.

3. The wind tunnel grid structure with adjustable diameter according to claim 1, characterized in that, The diameter of the through hole is 1 mm, and the distance between two adjacent through holes is 5 mm.

4. The wind tunnel grid structure with adjustable diameter according to claim 1, characterized in that, The perforated stainless steel capillary has an outer diameter of 0.4 mm and a wall thickness of 0.1 mm.

5. The wind tunnel grid structure with adjustable diameter according to claim 1, characterized in that, The rubber tube has an inner diameter of 0.4 mm and an outer diameter of 1 mm.

6. The wind tunnel grid structure with adjustable diameter according to claim 1, characterized in that, Within a distance of 10cm-20cm downstream of the grid, the turbulence intensity varies from 2.5% to 10%.

Images