Flow profile simulation device and method for ship model flow load test in wind tunnel

Abstract

The present invention relates to a flow profile simulation device for a ship model flow load test in a wind tunnel, comprising a lifting floor arranged in the wind tunnel; a turntable rotatably embedded on the lifting floor for adjusting the position of the ship model; a suction panel arranged on the lifting floor; a static pressure box arranged at the bottom of the suction panel; a suction pump arranged below the wind tunnel and connected with the suction pump through a connecting pipe; the suction flow of the air above the lifting floor is adjusted by adjusting the power of the suction pump; an inverted wedge is arranged at the front end of the lifting floor for reducing the wind speed at a high place; the inverted wedge is composed of a first plate, and the first plate is an inverted triangular plate; the distance between the bottom of the lifting floor and the bottom of the wind tunnel is greater than 200mm; the front end of the lifting floor is the front edge of the lifting floor, the front edge of the lifting floor is cut corner-processed, and the distance between the front edge of the lifting floor and the center of the ship model is 500-750mm. The present invention can reduce the influence of the boundary layer on the flow load test and obtain a flow load test result closer to the actual one.

Description

Technical Field

[0001] The invention relates to the field of experiment and test technology, in particular to a flow section simulation device and method for a ship model flow load test in a wind tunnel. Background Art

[0002] Ships or offshore platforms (hereinafter referred to as "platforms") in the marine environment are often affected by ocean currents below the water surface. When studying the characteristics of ocean currents around platforms and the effects of flow loads, a rigid wall is often used to simulate the sea surface, and the model is inverted and the wind medium is used instead of the water medium to carry out wind tunnel measurements of ship model flow loads. Due to the vertical variation of the actual flow velocity, flow profiles are usually used to represent it. Uniform flow is also often used in engineering design, and non-uniform flow is also used. Commonly used exponential flow profiles and linear flow profiles have expressions:

[0003] Uniform flow:

[0004]

[0005] Exponential type:

[0006]

[0007] Linear:

[0008]

[0009] in:

[0010] U c (z)——flow velocity at height z (z≤0), m / s;

[0011] U c0 ——Flow velocity at the water surface (z = 0), m / s;

[0012] z——vertical position, with the value vertical to the water surface being upward, m;

[0013] d——water depth, m;

[0014] d 0 ——reference depth, m;

[0015] α——exponent, usually α=1 / 7.

[0016] For actual platform flow load, when uniform flow conditions are used, the speed at different vertical positions is the same; when non-uniform flow is used, the speed at the water surface is high and the speed far from the water surface is low. In the wind tunnel test, the model is installed in an inverted manner. During the test, due to the effect of air viscosity, a boundary layer will exist in the area close to the rigid plate.

[0017] Due to the existence of the boundary layer, the speed at the bottom area of ​​the raised floor close to the simulated water surface in the test area is relatively low, which is inconsistent with the actual situation. This will cause the flow load obtained from the model test to be too small. In addition, the existence of shear flow in the low-speed area will induce the external flow to produce a local angle of attack, affecting the lift and torque.

[0018] Therefore, we propose a flow profile simulation device and method for ship model flow load test in wind tunnel. Summary of the invention

[0019] In view of the shortcomings of the above-mentioned existing production technology, the applicant provides a flow profile simulation device and method for flow load testing of ship models in a wind tunnel, thereby reducing the impact of the boundary layer on the flow load test and obtaining flow load test results that are closer to the actual ones.

[0020] The technical solution adopted by the present invention is as follows:

[0021] The flow profile simulation device for the ship model flow load test in the wind tunnel includes:

[0022] Raised floor, set in a wind tunnel;

[0023] A turntable, which is rotated and embedded in the raised floor, is used to adjust the position of the ship model;

[0024] Suction panels, set on raised floors;

[0025] A static pressure box, arranged at the bottom of the suction panel;

[0026] The suction pump is arranged below the wind tunnel and is connected with the suction pump through a connecting pipe; the suction flow rate of the air above the lifting floor is adjusted by adjusting the power of the suction pump.

[0027] It is further characterized by:

[0028] The front end of the lifting floor is provided with an inverted spike for reducing the wind speed at high places.

[0029] The inverted wedge is composed of a first plate, and the first plate is an inverted triangular plate.

[0030] The inverted wedge is composed of a first plate and a second plate, the second plate is fixed on one side of the first plate, and both the first plate and the second plate are inverted triangular plates.

[0031] The inverted wedge is composed of a second plate and two first plates, and the two first plates are respectively rotatably arranged on both sides of the second plate.

[0032] The distance between the bottom of the raised floor and the bottom of the wind tunnel is greater than 200 mm.

[0033] The front end of the lifting floor is the front edge of the lifting floor, the front edge of the lifting floor is chamfered, and the distance between the front edge of the lifting floor and the center of the ship model is 500-750mm.

[0034] The length of the suction panel is the same as the width of the raised floor.

[0035] The flow profile simulation method for the ship model flow load test in the wind tunnel includes the following steps:

[0036] Step 1: Process the raised floor and install it in the wind tunnel;

[0037] Step 2: Inlay the suction panel in the raised floor;

[0038] Step 3: Set up a static pressure box under the suction panel;

[0039] Step 4: The static pressure box is connected to the suction pump through a connecting pipe;

[0040] Step 5: Select the wind speed for the wind tunnel test and start blowing. When the required wind speed is reached, adjust the flow rate of the suction pump, collect the velocity values ​​at different heights, and perform dimensionless processing until the flow profile meets the requirements and uniform flow simulation is achieved.

[0041] Before proceeding to step five, an inverted wedge is added to the front end of the raised floor. The wind speed at high altitude is adjusted by the inverted wedge to complete the simulation of non-uniform flow.

[0042] The beneficial effects of the present invention are as follows:

[0043] The present invention has a compact and reasonable structure and is easy to operate. The wind speed of the wind tunnel test is selected, the blowing starts, the suction pump starts to work, the suction pump sucks the air on the lifting floor, and the suction pump discharges the air on the lifting floor from the exhaust port through the connecting pipe and the static pressure box. The suction flow rate is adjusted by adjusting the power of the suction pump so that the flow profile meets the test requirements. Uniform flow simulation is achieved, thereby reducing the influence of the boundary layer on the convection load test, and obtaining a flow load test result that is closer to the actual result.

[0044] At the same time, the present invention also has the following advantages:

[0045] (1) An inverted wedge is added to the front end of the raised floor. A plurality of inverted wedges are provided, and the plurality of inverted wedges are arranged at intervals at the front end of the raised floor. By providing the inverted wedges, the wind speed at a high place is reduced, so that the wind speed at a high place is lower than the wind speed at a low place, thereby completing the non-uniform flow simulation.

[0046] (2) The inverted wedge is composed of a first plate and a second plate. One side of the second plate is fixed to a middle position on one side of the first plate. Both the first plate and the second plate are inverted triangular plates, which makes it more convenient to fix the inverted wedge.

[0047] (3) The inverted wedge is composed of a second plate and two first plates. The two first plates are respectively rotated and arranged on both sides of the second plate. An angle is set between the second plate and the first plate. The size of the angle is adjusted by rotating the first plate, so that the inverted wedge can adapt to different cross-sectional requirements, making the applicability of the inverted wedge more enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of uniform flow simulation of the present invention.

[0049] Figure 2 for Figure 1 Top view of the .

[0050] Figure 3 It is a schematic diagram of the non-uniform flow simulation of the present invention.

[0051] Figure 4 for Figure 3 Top view of the .

[0052] Figure 5 Schematic diagram of the inverted wedge of the present invention Figure 1 .

[0053] Figure 6 for Figure 5 Side view of.

[0054] Figure 7 The inverted wedge of the present invention is shown in FIG. Figure 2 .

[0055] Figure 8 Schematic diagram of the inverted wedge of the present invention Figure 3 .

[0056] Fig. 9 for Figure 8 Top view of the .

[0057] Among them: 1. suction panel; 2. lifting floor; 201. lifting floor front edge; 3. static pressure box; 4. connecting pipe; 5. suction pump; 6. exhaust port; 7. ship model; 8. inverted wedge; 801. first plate; 802. first plate; 9. bottom of wind tunnel; 10. turntable. DETAILED DESCRIPTION

[0058] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0059] like Figure 1-Figure 2As shown, the flow profile simulation device for the ship model flow load test in the wind tunnel includes a suction panel 1, a lifting floor 2, a static pressure box 3, a connecting pipe 4, a suction pump 5, an exhaust port 6, a ship model 7 and a turntable 10. The lifting floor 2 is arranged in the wind tunnel, the two sides of the lifting floor 2 are fixed to the two sides of the wind tunnel, and the distance between the bottom of the lifting floor 2 and the bottom 9 of the wind tunnel is greater than 200 mm, the turntable 10 is rotatably embedded in the lifting floor 2, and the ship model 7 is fixed on the turntable 10, and the rotation of the turntable 10 drives the rotation of the ship model 7, thereby completing the adjustment of the ship model 7;

[0060] The front end of the raised floor 2 has a raised floor front edge 201, and the raised floor front edge 201 is chamfered. The raised floor 2 is inlaid with a suction panel 1 between the raised floor front edge 201 and the turntable 10, and the suction panel 1 is provided with a suction hole. The raised floor 2 is provided with a static pressure box 3 below the suction panel 1, and the bottom of the static pressure box 3 is provided with a connecting pipe 4 connected thereto, and the connecting pipe 4 passes through the bottom 9 of the wind tunnel. The suction pump 5 is located below the bottom 9 of the wind tunnel, and one end of the connecting pipe 4 is connected to the suction pump 5, and the suction pump 5 is provided with an exhaust port 6.

[0061] The distance between the front edge 201 of the lifting floor and the center of the ship model 7 is 500-750 mm, the length of the suction panel 1 is the same as the width of the lifting floor 2, and the width of the suction panel 1 is greater than or equal to 200 mm.

[0062] In specific applications, the wind speed of the wind tunnel test is selected, the blowing starts, the suction pump 5 starts working, the suction pump 5 sucks the air on the raised floor 2, and the suction pump 5 discharges the air on the raised floor 2 from the exhaust port 6 through the connecting pipe 4 and the static pressure box 3. The suction flow rate is adjusted by adjusting the power of the suction pump 5 so that the flow profile meets the test requirements. The uniform flow simulation is realized, so that the influence of the boundary layer on the flow load test can be reduced, and the flow load test results closer to the actual ones can be obtained.

[0063] When simulating non-uniform flow, since the test method of the inverted ship model 7 is adopted, the wind speed near the bottom 9 of the wind tunnel is required to be higher, while the wind speed at the top of the wind tunnel near the bottom of the ship model 7 is required to be lower. Due to the influence of the wind tunnel boundary layer, the wind speed at the bottom 9 of the wind tunnel will be lower, while the wind speed at the top will be higher, which is contrary to the requirement trend of the non-uniform flow profile to be simulated for the change of wind speed along the height. Therefore, it is extremely difficult to simulate the non-uniform flow profile in the wind tunnel to carry out the flow load test.

[0064] like Figure 3-Figure 4 As shown, an inverted spike 8 is added to the front end of the raised floor 2, and a plurality of inverted spikes 8 are provided, and the plurality of inverted spikes 8 are arranged at intervals at the front end of the raised floor 2. The number of inverted spikes 8 is generally 5-7. By providing the inverted spikes 8, the wind speed at a high place is reduced, so that the wind speed at a high place is lower than the wind speed at a low place, and the non-uniform flow simulation is completed.

[0065] like Figure 7 As shown, the inverted wedge 8 is composed of a first plate 801, which is an inverted triangular plate. When installing the inverted wedge 8, it needs to be fixed by a beam and a frame. The inverted wedge 8 has a simple structure, but the fixing method is a little complicated.

[0066] like Figure 5-Figure 6 As shown, the inverted wedge 8 is composed of a first plate 801 and a second plate 802, one side of the second plate 802 is fixed to a middle position on one side of the first plate 801, and the first plate 801 and the second plate 802 are both inverted triangular plates; when installing the inverted wedge 8, it needs to be fixed by a crossbeam.

[0067] like Figure 8-Figure 9 As shown, the inverted wedge 8 is composed of a second plate 802 and two first plates 801. The two first plates 801 are respectively rotated and arranged on both sides of the second plate 802. An angle is set between the second plate 802 and the first plate 801. The size of the angle is adjusted by rotating the first plate 801, so that the inverted wedge 8 can adapt to different cross-sectional requirements, thereby enhancing the applicability of the inverted wedge 8.

[0068] The flow profile simulation method for the ship model flow load test in the wind tunnel includes the following steps:

[0069] Step 1: Processing the lifting floor 2 and installing the lifting floor 2 in the wind tunnel;

[0070] Step 2: embedding the suction panel 1 in the raised floor 2;

[0071] Step 3: Arrange a static pressure box 3 below the suction panel 1;

[0072] Step 4: The static pressure box 3 is connected to the suction pump 5 through the connecting pipe 4;

[0073] Step 5: Select the wind speed for the wind tunnel test and start blowing. When the required wind speed is reached, adjust the flow rate of the suction pump 5, collect the velocity values ​​at different heights, and perform dimensionless processing until the flow profile meets the requirements to achieve uniform flow simulation.

[0074] When performing non-uniform flow simulation, before performing step five, an inverted wedge 8 is first added to the front end of the raised floor 2, and the wind speed at a high place is adjusted by the inverted wedge 8 to complete the simulation of the non-uniform flow.

[0075] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. Flow profile simulation device for ship model flow load test in wind tunnel, It is characterized in that include: A raised floor (2) is provided in a wind tunnel; A turntable (10) is rotatably mounted on the raised floor (2) and is used to adjust the position of the ship model (7); A suction panel (1) is arranged on a raised floor (2); A static pressure box (3) is arranged at the bottom of the suction panel (1); A suction pump (5) is arranged below the wind tunnel and is connected to the suction pump (5) via a connecting pipe (4); the suction flow rate of the air above the raised floor (2) is adjusted by adjusting the power of the suction pump (5); The distance between the bottom of the raised floor (2) and the bottom (9) of the wind tunnel is greater than 200 mm; The length of the suction panel (1) is the same as the width of the raised floor (2); The front end of the raised floor (2) is provided with an inverted spike (8) for reducing the wind speed at high altitudes.

2. The flow profile simulation device for the ship model flow load test in the wind tunnel as claimed in claim 1, Features: The inverted wedge (8) is composed of a first plate (801), and the first plate (801) is an inverted triangular plate.

3. The flow profile simulation device for the ship model flow load test in the wind tunnel as claimed in claim 1, Features: The inverted wedge (8) is composed of a first plate (801) and a second plate (802), the second plate (802) being fixed to one side of the first plate (801), and the first plate (801) and the second plate (802) are both inverted triangular plates.

4. The flow profile simulation device for the ship model flow load test in the wind tunnel as claimed in claim 1, Features: The inverted wedge (8) is composed of a second plate (802) and two first plates (801), and the two first plates (801) are respectively rotatably arranged on both sides of the second plate (802).

5. The flow profile simulation device for the ship model flow load test in the wind tunnel as claimed in claim 4, Features: The front end of the lifting floor (2) is a lifting floor front edge (201), the lifting floor front edge (201) is chamfered, and the distance between the lifting floor front edge (201) and the center of the ship model (7) is 500-750 mm.

6. A method for simulating a flow profile of a ship model flow load test in a wind tunnel, using the flow profile simulating device for a ship model flow load test in a wind tunnel as claimed in any one of claims 1 to 5, It is characterized in that The steps include: Step 1: Processing the lifting floor (2) and installing the lifting floor (2) in the wind tunnel; Step 2: embedding the suction panel (1) in the raised floor (2); Step 3: Arrange a static pressure box (3) below the suction panel (1); Step 4: The static pressure box (3) is connected to the suction pump (5) via a connecting pipe (4); Step 5: When simulating non-uniform flow, an inverted wedge (8) is added to the front end of the raised floor (2), and the wind speed at a high point is adjusted by the inverted wedge (8) to complete the simulation of non-uniform flow.

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