A wind tunnel test system and method for measuring the surface wind speed of a stack

Abstract

The present invention discloses a wind tunnel test system for measuring the surface wind speed of a stack, comprising: a stack model to be measured, which is used to obtain the surface wind speed based on a probe; and a wind flow field system, which is used to simulate natural wind and perform tests on the stack model to be measured based on the natural wind to obtain the surface wind speed of the stack model to be measured. The present invention also discloses a wind tunnel test method for measuring the surface wind speed of a stack, comprising: constructing a wind flow field system, blowing air on the stack model to be measured through the wind flow field system, and obtaining the wind speed data of each surface of the stack model to be measured; obtaining a plurality of wind speed ratios based on the wind speed data of each surface of the stack model to be measured; performing weighted averaging on the area of each surface based on the plurality of wind speed ratios to obtain a comprehensive wind speed ratio; obtaining a wind speed influence coefficient based on the comprehensive wind speed ratio, and calculating the surface wind speed of the stack based on the wind speed influence coefficient.

Description

Technical Field

[0001] The present invention belongs to the field of wind speed measurement, and particularly relates to a wind tunnel test system and method for measuring the wind speed on the surface of a stack. Background Art

[0002] With the rapid development of the national economy, the demand for coal and various ores is increasing continuously. The dust generated during the temporary storage of various bulk cargo stacks in port yards not only causes serious air pollution, but also takes away a large amount of dust, resulting in economic losses of materials. The dust in port bulk cargo yards is mainly divided into dynamic operation disturbance dust generation and static storage wind erosion dust generation from the perspective of dust generation causes. Static dust generation refers to the conversion of bulk cargo stored in the yard and spilled on the yard roads and stack gaps from a static state to a suspended state under the direct action of wind; while dynamic dust generation is mainly formed when goods pass through the air during yard operations and are diffused by the wind under the action of wind, such as the loading and unloading operations between ships and shores, the loading and unloading vehicle operations on the yard, and the pollution caused by the combination of vibration and wind during the start-up of belt conveyors.

[0003] The prediction of the static storage wind erosion dust generation amount during the operation period in the environmental impact assessment stage of dry bulk cargo terminal projects is a key issue for project approval. The size of the static dust generation amount mainly depends on the wind speed acting on the surface of the stack. Therefore, the selection of wind speed parameters becomes a key factor in the accuracy of static dust generation amount prediction. At present, more than ten years have passed since the formula derivation. Due to the simple wind tunnel test conditions, relatively backward data acquisition components and analysis equipment at that time, only the dust generation amount tests under different steady incoming winds were designed, and the turbulent wind effects of ground roughness, yard layout, etc. on the dust generation on the stack surface cannot be comprehensively considered, resulting in a series of problems such as inconsistent wind speed values in the actual application of the formula, affecting the accuracy of dust generation amount prediction, and causing great trouble to the environmental impact assessment work of dry bulk cargo terminal construction projects. Therefore, there is an urgent need in society for a method that can solve the defects existing in the above-mentioned prior art, and provide a strong technical guarantee for eliminating the application defects of the standard formula, improving the accuracy of environmental impact assessment prediction of dry bulk terminal construction projects, and the rigid binding force of environmental impact assessment documents. Summary of the Invention

[0004] The purpose of the present invention is to provide a wind tunnel test system and method for measuring the wind speed on the surface of a stack to solve the problems existing in the above-mentioned prior art.

[0005] On the one hand, to achieve the above purpose, the present invention provides a wind tunnel test system for measuring the wind speed on the surface of a stack, including: a stack model to be measured, and a wind flow field system;

[0006] The stack model to be measured is used to obtain the surface wind speed based on a probe;

[0007] The air flow field system is used to simulate natural wind and test the to-be-tested stack model based on the natural wind to obtain the surface wind speed of the to-be-tested stack model.

[0008] Optionally, the shape of the to-be-tested stack model is a frustum of a pyramid, and probes are installed on each surface of the frustum of the pyramid, and the probes are used to measure the wind speed.

[0009] Optionally, on three surfaces along the long side direction of the frustum of the pyramid, a probe is installed every 10 cm. If the length of the long side is less than or equal to 10 cm, only one probe is installed on each surface.

[0010] Optionally, the air flow field system includes a cavity, a fan, a wind profile adjustment module and a turntable;

[0011] The cavity is used to carry out wind tunnel tests and boundary restrictions;

[0012] The fan is used to output wind;

[0013] The wind profile adjustment module is used to adjust the output wind to simulate natural wind. The wind profile adjustment module includes a spire and a roughness device;

[0014] The turntable is used to place the to-be-tested stack model.

[0015] Optionally, the air flow field system further includes a test module, and the test module is used to test and obtain the average wind speed, gradient reference wind speed, wind speed profile, turbulence intensity and pulsating wind power spectrum in the wind field of the air flow field system.

[0016] On the other hand, to achieve the above object, a wind tunnel test method for measuring the surface wind speed of a stack includes the following steps:

[0017] Construct an air flow field system, blow air on the to-be-tested stack model through the air flow field system, and obtain the wind speed data of each surface of the to-be-tested stack model;

[0018] Obtain a number of wind speed ratios based on the wind speed data of each surface of the to-be-tested stack model;

[0019] Perform weighted averaging on the area of each surface based on a number of the wind speed ratios to obtain a comprehensive wind speed ratio;

[0020] Obtain a wind speed influence coefficient based on the comprehensive wind speed ratio.

[0021] Optionally, in the process of blowing air on the to-be-tested stack model through the air flow field system, it includes:

[0022] When the air flow field system blows air on the to-be-tested stack model, data is obtained once every time the turntable rotates 22.5°, and the blowing angles include 0° to 360°.

[0023] Optionally, in the process of obtaining the wind speed data of each surface of the to-be-tested stacking model, it includes: arranging test probes on each surface of the to-be-tested stacking model respectively, and obtaining the wind speed data of each surface of the to-be-tested stacking model based on the test probes.

[0024] Optionally, in the process of obtaining several wind speed ratios based on the wind speed data of each surface of the to-be-tested stacking model, it includes:

[0025] S1. Obtaining the wind speed ratio of the current surface based on the wind speed data of any surface and the reference wind speed;

[0026] S2. Calculating all surfaces by the method in S1 to obtain several of the wind speed ratios.

[0027] The technical effects of the present invention are as follows:

[0028] Compared with the prior art, a wind tunnel test system for measuring the wind speed on the stacking surface of the present invention adopts a wind profile adjustment module, which can more realistically simulate different wind loads and simulate the real wind flow field information of the environment where the stacking yard is located; the Owen probes on the stacking surface can record the wind speed information of each side of the stacking, which helps to more accurately predict the static dust generation amount in the stacking yard; the wind speed data processing method provided by the present invention can effectively compare the operation effects of environmental protection facilities. Description of the Drawings

[0029] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0030] Figure 1 It is a simulation diagram of the wind tunnel wind load test in the embodiment of the present invention;

[0031] Figure 2 It is a general view of the stacking model with Owen probes installed in the embodiment of the present invention;

[0032] Figure 3 It is a plan view of the stacking with Owen probes installed in the embodiment of the present invention;

[0033] Figure 4 It is a structural diagram of the Owen probe in the embodiment of the present invention. Detailed Embodiments

[0034] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the drawings and combine the embodiments to detail this application.

[0035] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0036] Embodiment 1

[0037] As Figure 1 shown, in this embodiment, a wind tunnel test system for measuring the surface wind speed of a stack is provided, including: a stack model to be measured and a wind flow field system;

[0038] The stack model to be measured is used to obtain the surface wind speed based on a probe.

[0039] The wind flow field system is used to simulate natural wind and test the stack model to be measured based on the natural wind to obtain the surface wind speed of the stack model to be measured.

[0040] The shape of the stack model to be measured is a trapezoid body, and probes are installed on each surface of the trapezoid body. The probes are used to measure the wind speed.

[0041] On three surfaces along the long side direction of the trapezoid body, a probe is installed every 10 cm. If the length of the long side is less than or equal to 10 cm, only one probe is installed on each surface.

[0042] The wind flow field system includes a tunnel body, a fan, a wind profile adjustment module, and a turntable;

[0043] The tunnel body is used to carry out the wind tunnel test and boundary restriction;

[0044] The fan is used to output wind;

[0045] The wind profile adjustment module is used to adjust the output wind to simulate natural wind. The wind profile adjustment module includes a spire and a roughness device;

[0046] The turntable is used to place the stack model to be measured.

[0047] The wind flow field system further includes a test module, and the test module is used to test and obtain the average wind speed, gradient reference wind speed, wind speed profile, turbulence intensity, and pulsating wind power spectrum in the wind flow field system.

[0048] On the other hand, this embodiment also provides a wind tunnel test method for measuring the surface wind speed of a stack, including the following steps:

[0049] Construct a wind flow field system, blow the stack model to be measured through the wind flow field system, and obtain the wind speed data of each surface of the stack model to be measured;

[0050] Obtain a number of wind speed ratios based on the wind speed data of each surface of the stack model to be measured;

[0051] Based on several wind speed ratios, the area of each surface is weighted and averaged to obtain a comprehensive wind speed ratio;

[0052] Based on the comprehensive wind speed ratio, a wind speed influence coefficient is obtained.

[0053] Optionally, during the process of blowing air on the stack model to be measured by the air flow field system, it includes:

[0054] When the air flow field system blows air on the stack model to be measured, the turntable rotates 22.5° each time to obtain data once, and the blowing angles include 0° to 360°.

[0055] During the process of obtaining the wind speed data of each surface of the stack model to be measured, it includes: arranging test probes on each surface of the stack model to be measured respectively, and obtaining the wind speed data of each surface of the stack model to be measured based on the test probes.

[0056] During the process of obtaining several wind speed ratios based on the wind speed data of each surface of the stack model to be measured, it includes:

[0057] S1. Obtain the wind speed ratio of the current surface based on the wind speed data of any surface and the reference wind speed;

[0058] S2. Calculate all surfaces by the method in S1 to obtain several wind speed ratios.

[0059] Embodiment 2

[0060] According to the content in Embodiment 1, this Embodiment 2 specifically discloses:

[0061] (1) Wind tunnel wind load simulation

[0062] In the atmospheric boundary layer, the wind speed increases with the increase of the height from the ground. When the pressure field remains unchanged with height, the law of the wind speed increasing with height mainly depends on the ground roughness and the vertical temperature gradient. The wind tunnel test for measuring the wind speed on the stack surface is carried out in the simulated atmospheric boundary layer turbulent wind field, and the type of the simulated wind field should be determined according to the topographic and geomorphic conditions within 2 kilometers upstream of the simulated area. In the "Load Code for the Design of Building Structures" GB50009-2012, the geomorphology (or surface roughness) is divided into four categories:

[0063] Type A refers to the offshore sea surface and islands, coasts and desert areas, the gradient wind height (i.e., the atmospheric boundary layer height) HG = HGA = 300m, and the power function index α representing the average wind speed profile A = 0.12;

[0064] Type B refers to fields, villages, jungles, hills, and towns and suburbs with relatively sparse houses, HG = HGB = 350m, and the power function index α representing the average wind speed profile B = 0.15;

[0065] Class C refers to the urban area with dense building clusters, where HG = HGC = 450 m, and the power function exponent α representing the average wind speed profile C = 0.22;

[0066] Class D refers to the urban area with dense building clusters and a large number of high-rise buildings, where HG = HGD = 550 m, and the power function exponent α representing the average wind speed profile D = 0.30.

[0067] The wind speed profile is related to the ground roughness and wind climate. From the perspective of engineering applications, a unified wind speed profile expression can be adopted. The wind speed profile expression and the turbulence intensity profile expression are respectively:

[0068] v z = v 10 (z / 10) α

[0069] I z (z) = I 10 (z / 10) -α

[0070] In the formula, v z is the average wind speed (m / s) at the height of z (m), v 10 is the basic wind speed at the height of 10 m, α is the wind speed profile exponent. When z is less than 5 m, it is taken as 5 m, and I z (z) is the turbulence intensity at the height of z (m). I 10 is the nominal turbulence intensity at the height of 10 m. Corresponding to the ground roughness of Class A, B, C, and D, it can be taken as 0.12, 0.14, 0.23, and 0.39 respectively.

[0071] To ensure that the wind tunnel test for measuring the wind speed on the stack surface meets the similarity of the above-mentioned wind profile inflow, it is necessary to simulate the wind tunnel wind load. As Figure 1 shown, in the present invention, spires are arranged at the entrance of the wind tunnel test section, and roughness devices such as rough elements are placed from the entrance of the wind tunnel test section to the location of the stack model to be measured. The size and placement density of the rough elements are adjusted to regulate the inflow characteristics in the wind tunnel, separate the inflow to increase the turbulence intensity, and through repeated experiments, the most suitable device is determined to generate the wind field (wind profile, turbulence profile, wind spectrum, etc.) required by the specification.

[0072] (2) Wind field measurement and debugging

[0073] The wind field debugging and measurement adopts the Cobra probe of the three-dimensional pulsating wind speed measuring instrument of the Australian Turbulent Flow Instrumentation Company. The present invention fixes the probe on a suspended three-dimensional mobile measurement frame, which can measure the average wind speed, wind speed profile, turbulence and pulsating wind power spectrum of the flow field at different heights in the wind tunnel test section.

[0074] The Cobra probe is a four-hole pressure probe with a sampling frequency of 1250Hz and a measurement accuracy of 0.3%. It can measure three-component pulsating wind speed and static pressure. It can measure pulsating wind speed above 1000Hz within a ±45° cone range and can explore flow field information with unknown directions. It is a more robust measuring instrument than traditional hot wire probes.

[0075] The sampling time of the Cobra probe is 60 seconds each time. The wind speed profile and turbulence profile are drawn by software, where the ordinate is set to the actual height in the wind tunnel, and the abscissa is set to the wind profile (average wind speed ratio and turbulence intensity). The average wind speed ratio is defined as the ratio of the average wind speed of the incoming flow at different heights to the incoming flow wind speed at a height of 1m. The turbulent wind speed of the incoming flow needs to approximately obey the normal distribution, and the wind speed spectrum needs to obey the Karman spectrum.

[0076] (3) Model making

[0077] like Figure 2 As shown in the figure, the stacking model is simplified into a trapezoidal body. The velocity distribution on the stacking surface is measured by an Irwin probe. Except for the bottom surface, an Irwin probe is pre-buried perpendicular to the surface at the center of each surface of each stacking model. At least 5 velocity measurement points are set for each stacking model. For a longer stack, N measurement points can be added on the three surfaces along the long side. The stacking plane diagram with Irwin probes installed is shown in the figure. Figure 3 The total static pressure of the Owen probe is connected to the pressure scanning valve through a 1.0m long PVC pipe to measure the pressure difference and convert it into wind speed. The model is installed on the wooden turntable of the wind tunnel.

[0078] like Figure 4 As shown, the Owen probe is a sensor that measures velocity by sensing pressure changes. Therefore, it is a non-directional velocity probe. The velocity obtained is the velocity vector sum of the measured points. The Owen probe is also called a pedestrian height wind measurement probe, and its shape is cylindrical. The end face of the column is flush with the measured surface, with a pressure measuring hole in the middle. A very thin probe extends from the center of the pressure measuring hole. The probe height is 1.67mm, and the corresponding full-size height is about 1.0m (according to the model geometry scale ratio of 1:600). When the top of the probe is in the boundary layer, the pressure difference ΔP between the probe pressure (total pressure) and the pressure of the cylindrical pressure measuring hole (static pressure) and the velocity U of the airflow at the top of the probe can be expressed by the following formula:

[0079]

[0080] In the formula, υ is the air viscosity coefficient, ρ is the air density, h is the probe height, and A and B are calibration coefficients determined through calibration experiments. Before the experiment, a three-dimensional pulsating anemometer Cobra probe and an electronic differential pressure scanning valve were used to measure the air flow velocity U at the top of the probe and the probe differential pressure ΔP respectively. Using the linear least squares method, the calibration coefficients A and B were solved. The wind speeds used during calibration were 2 m / s, 3 m / s, 4 m / s, 5 m / s, 7 m / s, 9 m / s, and 10 m / s respectively. The above calibration coefficients are similar to the adjustment coefficients in the expression, dimensionless, and will not be used in the subsequent calculation process after calibration.

[0081] (4) Data acquisition

[0082] The wind pressure measurement uses the ESP series 64-channel high-precision micro electronic differential pressure scanning valve produced by PSI Company in the United States, with a range of 10”WC. The pressure scan data acquisition uses the DTC Initium system, and the measurement resolution is 0.003%F.S. In order to eliminate the cumbersome process of in-situ calibration in the electronic pressure scanning technology, the advanced analog circuit design is integrated with PSI's innovative digital temperature compensation (DTC) technology, and a unique sensor installation process is adopted, which can accurately measure the bridge resistance, so as to use the personalized compensation algorithm embedded in the scanning valve to correct the thermal error in real time. Without on-line range calibration, the best accuracy can be maintained. Therefore, this electronic pressure scanning system can provide the best accuracy at the entire working temperature of the scanning valve only after initial zeroing.

[0083] (5) Wind tunnel test

[0084] The main body of the test model and other structure models (mountains, buildings, bridges, windbreak nets...) are fixed on the wooden turntable of the wind tunnel to facilitate the adjustment of the wind direction during the test. During the test, a three-dimensional pulsating anemometer is used to measure the incoming flow wind speed. The average wind speed is set to 10 m / s. For each case, the wind direction angle ranges from 0° to 360°, with an interval of 22.5°, for a total of 16 wind direction angles.

[0085] (6) Data processing

[0086] Through the above-mentioned wind tunnel test of the wind environment of the stacking model, the wind speed U at each position on the surface of the stack is obtained i , and the ratio of this wind speed to the reference wind speed V is defined as the dimensionless wind speed ratio R i , as shown in the following formula,

[0087]

[0088] In the formula, V is the basic wind speed at a height of 10 m.

[0089] The wind speed ratio is used to calculate the wind speed on the stack surface under any incoming meteorological wind speed.

[0090] The wind speed ratio at the position i on the stack surface of the storage yard is area-weighted averaged to calculate the wind direction θ. j The comprehensive wind speed ratio R(θ j ) of the lower storage yard is as follows:

[0091]

[0092] In the formula, A i is the attached area of position i. By statistically weighting and averaging the wind frequencies under each wind direction, the comprehensive wind speed ratio R of the storage yard is obtained as follows:

[0093]

[0094] In the formula, f(θ j ) is the wind frequency of the wind direction θ. j By comparing the comprehensive wind speed ratio of the lower storage yard in each working condition with the reference working condition, the wind speed influence coefficient δ w of the storage yard is obtained as follows:

[0095] δw δ = R / R b

[0096] In the formula, R b and R are the comprehensive wind speed ratios of the storage yard under the reference working condition and the comparison working condition respectively. The test is divided into the reference working condition and the comparison working condition. The reference working condition is the control group, and the comparison working condition is the experimental group. The wind speed influence coefficient is the ratio of the experimental group to the control group, similar to the normalization process.

[0097] As mentioned above, it is only the preferred specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A wind tunnel test system for measuring the surface wind speed of a stack, characterized in that, Including: The stack model to be measured, the air flow field system; The stack model to be measured is used to obtain the surface wind speed based on the probe; The air flow field system is used to simulate natural wind and test the stack model to be measured based on the natural wind to obtain the surface wind speed of the stack model to be measured; The shape of the stack model to be measured is a trapezoid body, and probes are installed on each surface of the trapezoid body, and the probes are used to measure the wind speed; On three surfaces along the long side direction of the trapezoid body, a probe is installed every 10 cm. If the length of the long side is less than or equal to 10 cm, only one probe is installed on each surface; The air flow field system includes a cavity, a fan, a wind profile adjustment module and a turntable; The cavity is used to carry out wind tunnel tests and boundary restrictions; The fan is used to output wind; The wind profile adjustment module is used to adjust the output wind to simulate natural wind. The wind profile adjustment module includes a nose cone and a roughness device; The turntable is used to place the stack model to be measured; Through the above-mentioned wind tunnel test of the wind environment of the stacking model, the wind speed U at each position on the stacking surface is obtained i , and the ratio of this wind speed to the reference wind speed V is defined as the dimensionless wind speed ratio R i , as shown in the following formula In the formula, V is the basic wind speed at a height of 10 m; The wind speed ratio is used to calculate the stack surface wind speed under any incoming flow meteorological wind speed; The wind speed ratio at the surface position i of the yard stack is area-weighted and averaged to calculate the wind direction θ j The comprehensive wind speed ratio R(θ j ) of the lower yard is as follows: Where, A i is the attached area at position i. Then, the wind frequency in each wind direction is statistically weighted and averaged to obtain the comprehensive wind speed ratio R of the yard, as shown in the following formula: where f(θ j ) is the wind frequency of wind direction θ j . By comparing the comprehensive wind speed ratio of the lower yard in each working condition with the reference working condition, the wind speed influence coefficient δ w of the yard is obtained, as shown in the following formula: δ w = R / R b Wherein, R b and R are the comprehensive wind speed ratios of the yard under the reference working condition and the comparison working condition respectively.

2. The system according to claim 1, wherein The air flow field system further includes a test module, and the test module is used to test and obtain the average wind speed, gradient reference wind speed, wind speed profile, turbulence intensity and pulsating wind power spectrum in the wind field of the air flow field system.

3. A wind tunnel test method for measuring the surface wind speed of a stack, characterized in that, Including the following steps: Construct an air flow field system, blow the stack model to be measured through the air flow field system, and obtain the wind speed data of each surface of the stack model to be measured; Based on the wind speed data of each surface of the stack model to be measured, obtain a number of wind speed ratios; Based on a number of the wind speed ratios, perform weighted averaging on the area of each surface to obtain a comprehensive wind speed ratio; Based on the comprehensive wind speed ratio, obtain a wind speed influence coefficient; During the process of blowing the stack model to be measured through the air flow field system, it includes: When the air flow field system blows the stack model to be measured, the turntable rotates 22.5° each time to obtain data, and the blowing angle includes 0° to 360°; During the process of obtaining the wind speed data of each surface of the stack model to be measured, it includes: arranging test probes on each surface of the stack model to be measured, and obtaining the wind speed data of each surface of the stack model to be measured based on the test probes; During the process of obtaining a number of wind speed ratios based on the wind speed data of each surface of the stack model to be measured, it includes: S1. Obtain the wind speed ratio of the current surface based on the wind speed data of any surface and the reference wind speed; S2. Calculate all surfaces by the method in S1 to obtain a number of the wind speed ratios; Through the above-mentioned wind tunnel test of the wind environment of the stacking model, the wind speed U at each position on the stacking surface is obtained i , and the ratio of this wind speed to the reference wind speed V is defined as the dimensionless wind speed ratio R i , as shown in the following formula In the formula, V is the basic wind speed at a height of 10 m; The wind speed ratio is used to calculate the stack surface wind speed under any incoming flow meteorological wind speed; The wind speed ratio at the surface position i of the yard stack is area-weighted averaged to calculate the wind direction θ j The comprehensive wind speed ratio R(θ j ) of the lower yard is given by the following equation: where A i is the attached area at position i. Then, the wind frequencies in each wind direction are statistically weighted and averaged to obtain the comprehensive wind speed ratio R of the yard, as shown in the following formula: where f(θ j ) is the wind frequency of wind direction θ j . By comparing the comprehensive wind speed ratio of the lower yard in each working condition with the reference working condition, the wind speed influence coefficient δ w of the yard is obtained, as shown in the following formula: δ w = R / R b where R b and R are the comprehensive wind speed ratios of the storage yard under the reference condition and the comparison condition, respectively.

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