CN111579196A - Wind tunnel measuring method and device for aerodynamic characteristics of power transmission conductor - Google Patents
Wind tunnel measuring method and device for aerodynamic characteristics of power transmission conductor Download PDFInfo
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- CN111579196A CN111579196A CN202010473064.9A CN202010473064A CN111579196A CN 111579196 A CN111579196 A CN 111579196A CN 202010473064 A CN202010473064 A CN 202010473064A CN 111579196 A CN111579196 A CN 111579196A
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
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- G—PHYSICS
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
- G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
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- G—PHYSICS
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
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Abstract
The invention discloses a wind tunnel measurement method and a device for aerodynamic characteristics of a transmission conductor, which use wind tunnel experiments and aerodynamic knowledge for reference and comprise the following steps: (1) determining the type of a wire used for a pneumatic characteristic wind tunnel experiment and a test working condition; (2) designing and manufacturing a movable grid for a wind tunnel experiment, and determining the arrangement position of an experimental device; (3) starting the wind tunnel, testing a flow field and processing data to obtain corresponding turbulence characteristic parameters and flow velocity distribution; (4) designing a wind tunnel measuring device for the aerodynamic characteristics of the transmission conductor, and installing and debugging the wind tunnel measuring device; (5) starting the wind tunnel, testing the pneumatic characteristic recording data of the transmission conductor under different working conditions until all the working conditions are tested; (6) comparing the aerodynamic data under various working conditions, analyzing the change rule, and completing the aerodynamic characteristic test of the transmission conductor; the method can accurately acquire the pneumatic parameters of the power transmission wire model under various wind speeds and wind direction angles, improves the test efficiency, and has strong engineering value and practical significance.
Description
Technical Field
The invention relates to the field of wind tunnel experiment measurement, in particular to a wind tunnel measurement method and device for aerodynamic characteristics of a transmission conductor.
Background
The aerodynamic characteristics refer to the law that aerodynamic force and aerodynamic torque acting on an object to be researched change along with parameters such as the geometric shape, the motion attitude, the speed and the atmospheric density of the object, and the low-speed wind tunnel generates and controls airflow in an artificial mode to simulate the flowing condition of gas around the object to be tested, and is a pipeline-shaped experimental device which is used for observing physical phenomena and the effect of the quantified airflow on an entity, and is the most common and effective tool for researching the aerodynamic characteristics. In the prior art, the design specifications of 110 kV-750 kV overhead transmission lines (GB5045-2010) and the design technical specifications of overhead transmission line tower structures (DL/T5154-2012) in China both stipulate that the resistance coefficient is 1.2 when the wire diameter is less than 17mm, and 1.1 when the wire diameter is greater than or equal to 17 mm; however, the current specifications at home and abroad only stipulate the whole split conductor, and for the split conductor, when wind load is calculated, all sub-conductors are calculated according to a single conductor, and the influence of mutual shielding among the sub-conductors on the resistance coefficient is not considered. The section of the bare conductor can be approximately regarded as a circle, the aerodynamic characteristics are similar to the problem of classical cylindrical streaming, and factors such as wind speed, turbulence, wind direction angle, conductor outer diameter, conductor surface roughness and icing condition can influence the aerodynamic characteristics of the conductor. Such a difference is easy to be unexpected under the action of strong wind, which damages components or equipment in a certain range nearby and seriously endangers the safe operation of the whole substation.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a wind tunnel measurement method and device for the aerodynamic characteristics of a power transmission conductor, determines a measurement scheme for the aerodynamic characteristics flow field of the power transmission conductor, designs a device comprehensively considering the wind tunnel environment, is simple and convenient in installation and disassembly processes, improves the test efficiency, designs a wind tunnel measurement device for the aerodynamic characteristics of the power transmission conductor, ensures the safe and reliable operation of a six-component balance in the experimental process, and has strong engineering value and practical significance.
The object of the invention is achieved on the one hand by: a wind tunnel measurement method for aerodynamic characteristics of power transmission conductors comprises the following steps:
(1) the method for determining the type and the test working condition of the wire used in the aerodynamic characteristic wind tunnel experiment specifically comprises the following steps: testing simulation wind speed, testing simulation turbulence intensity and testing simulation wind direction angle;
(2) designing the size of a grid for an experiment according to the size of the wind tunnel and the condition of turbulence intensity required to be simulated in the experiment, and assembling and manufacturing a movable grid for the wind tunnel experiment by using steel;
(3) electrifying to start the wind tunnel, measuring the speed distribution of a power transmission conductor model test area by using a hot wire anemometer after the wind speed reaches the test simulation wind speed, closing the wind tunnel, and processing data to obtain corresponding turbulence characteristic parameters and flow speed distribution;
(4) sequentially adding the designed grids into the wind tunnel, repeating the step (3) to obtain turbulence characteristic parameters and flow velocity distribution corresponding to the grid turbulence field until all grid flow field tests are completed, and moving the test instrument and the grids out of the wind tunnel;
(5) designing a wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, installing and debugging the wind tunnel, and integrally installing a power transmission conductor model on a six-component balance to ensure that test equipment is firm and reliable;
(6) sequentially powering on and starting a six-component balance test system, powering on and starting a wind tunnel, testing the aerodynamic force of a power transmission conductor and recording data after the wind speed reaches the test simulation wind speed, changing the inflow wind direction angle of the power transmission conductor, testing the aerodynamic force of the power transmission conductor and recording the data until all wind direction angles are tested;
(7) changing the wind speed of the wind tunnel incoming flow, testing the aerodynamic force of the transmission conductor again and recording data after the wind speed reaches the test simulation wind speed until all wind direction angles are tested;
(8) repeating the step (7) until all the test simulation wind speeds are tested, and sequentially closing the wind tunnel and the six-component balance test system;
(9) sequentially adding designed grids into the wind tunnel, repeating the steps (6) to (8), and obtaining the aerodynamic force of the transmission conductor in the corresponding grid turbulent flow field until all grid flow field tests are completed;
(10) changing the balance measuring position of the wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, mounting the sub-conductors in the power transmission conductor model on a six-component balance, and repeating the steps (6) to (9) until the aerodynamic characteristics of all the sub-conductors are tested, and obtaining the aerodynamic characteristics of the split sub-conductors in the corresponding grid turbulent flow field until all the grid flow field tests are completed;
(11) and comparing the aerodynamic force data under various working conditions, analyzing the aerodynamic force change rule, and completing the aerodynamic characteristic test of the power transmission conductor.
As a further improvement of the present invention, the grid flow field test described in step 3) and step 4) specifically includes the following steps:
(1) wind tunnel safety inspection, whether the connecting bolt is loosened or not; checking whether the connection of electric equipment such as a wind tunnel power end motor, a relay, a frequency converter and the like is normal and can normally run; checking whether foreign matters exist in the wind tunnel pipeline;
(2) determining a grid placement range according to the actual condition of the wind tunnel, determining the position of a measurement flow field according to the position of a measurement device in the wind tunnel, installing and fixing a movable support on the ground of the wind tunnel, and installing and fixing a hot wire probe test rack on the support;
(3) the hot-wire anemoscope is provided with three probes and is started, the sampling frequency and the sampling time of the hot-wire anemoscope are set, the three probes of the hot-wire anemoscope are calibrated, a linear curve of wind speed and voltage is fitted, and the hot-wire probes are installed and fixed on a hot-wire probe test rack after calibration is completed;
(4) starting the wind tunnel, and starting measurement by a hot-wire anemoscope by taking the wind speed measured by a pitot tube in the wind tunnel as reference when the wind speed is stabilized;
(5) and after the test is finished, moving the support, respectively testing five groups of instantaneous wind speeds with different heights, changing the wind speed to measure again after all the measurement points are tested, measuring all the measurement points under all the incoming flow wind speeds, and closing the wind tunnel.
(6) And (5) adding a grid used for the experiment, repeating the step (4) and the step (5), processing the experimental data, and comparing a design formula with the experiment to measure the forward turbulence intensity to finish the flow field test.
As a further improvement of the invention, the experimental grid is assembled by alloy steel, a movable grid for wind tunnel experiment is designed and manufactured according to the formula (1),
wherein: i isu1For the expected value of the downstream turbulence intensity, x is the distance between the measuring point of the hot wire probe and the grid, and M is the size of the grid hole
In the formula, the longitudinal width of the grid bars is a, the transverse width of the grid bars is c, the interval width is b, the height is d, and y is the grid porosity.
As a further improvement of the present invention, during data processing in the grid flow field measurement, the turbulence intensity in data processing in the flow field measurement is calculated according to equation (2):
wherein: l is 1, 2, 3 represents three directions of forward direction, transverse direction and vertical direction, N is the number of sampling data points, uliDiscrete sequence of samples representing turbulent wind velocity, e.g. u1iRepresenting the difference between the instantaneous sampled wind speed downstream and the average wind speed downstream of the sampled data,
representing the average wind speed of the sampled data, K is 1 to 15, representing 15 tests arranged on each sectionPoint;
calculating and processing the turbulence integral scale in data processing in flow field measurement according to the formula (3):
in formula (3), ui+τExpressed as u in a discrete sequence of samples and downstream fluctuating wind speediThe interval is the pulsating wind speed value of tau, tau takes the positive integer value from 1 to N-1, i takes the positive integer value from 1 to N-tau,
representing the average wind speed of the sampled discrete data, N representing the number of sampled data points, σuRepresents the root mean square value of the forward turbulent wind velocity pulsating component.
The object of the invention is achieved in another aspect by: the utility model provides a transmission line aerodynamic characteristic wind-tunnel measuring device, the device includes six weight balances and transmission line model, still includes the steel drum, the drum apron, pi shape fixed connector, transmission line fixed connector, steel drum bottom is fixed on the wind-tunnel wall, the drum apron is fixed at steel drum top, pi shape fixed connector sets up in the steel drum, pi shape fixed connector bottom is fixed on wind-tunnel bottom wall, and the top is connected with six weight balances, six weight balances tops are connected with transmission line fixed connector, and transmission line model utilizes bolt fastener and transmission line fixed connector fixed.
As a further improvement of the invention, the steel cylinder comprises a cylinder body and flange discs welded at two ends of the cylinder body, a plurality of through holes are formed in the flange discs, the bottom flange disc is fixed on the wall surface of the wind tunnel through bolts and metal gaskets, the top flange disc is connected with a cylinder cover plate through bolts and metal gaskets, a rectangular groove is formed in the steel cylinder body, the center position of the rectangular groove is the same as the center height of the six-component balance used for measurement, and a signal line of the six-component balance used for measurement is connected with an external acquisition system through the rectangular groove in the steel cylinder body.
As a further improvement of the invention, the cylinder cover plate is a steel circular plate, a through hole corresponding to the position of the through hole of the flange disc at the top of the steel cylinder is formed in the cylinder cover plate, and an up-and-down straight-through rounded rectangular groove is formed in the center of the steel circular plate to ensure that a power transmission lead model passes through.
As a further improvement of the wind tunnel fixing device, the Pi-shaped fixing connecting piece comprises a top steel plate, two steel plates are welded in the vertical direction below the top steel plate, the bottoms of the two steel plates in the vertical direction are respectively welded in the horizontal direction of the outer side, a plurality of through holes are formed in the top steel plate, the top steel plate is connected with the six-component balance through bolt fasteners, the through holes are formed in the steel plate in the horizontal direction of the bottom, and the steel plate in the horizontal direction of the bottom is fixed.
As a further improvement of the invention, the power transmission lead fixing connecting piece comprises two steel plates which are arranged perpendicular to each other, namely a vertically-arranged steel plate and a horizontally-arranged steel plate, four vertically-through rounded rectangle grooves are formed in the two steel plates, two connecting pieces perpendicular to the vertically-arranged steel plates are arranged on two sides below the vertically-arranged steel plates, the vertically-arranged steel plates are connected with the rounded rectangle grooves in the horizontally-arranged steel plates through connecting pieces through bolt fasteners, the power transmission lead model and the rounded rectangle grooves in the vertically-arranged steel plates are fixed through the bolt fasteners, and the six-component balance is connected with the rounded rectangle grooves in the horizontally-arranged steel plates through the bolt fasteners.
As a further improvement of the invention, a model top cover plate is arranged on the upper part of the power transmission wire model, the model top cover plate is a steel round plate, and a gap is left between the top of the power transmission wire model and the model top cover plate.
Compared with the prior art, the technical scheme adopted by the invention has the beneficial effects that: the invention determines a flow field measurement scheme of the aerodynamic characteristics of the transmission conductor, designs a device which comprehensively considers the wind tunnel environment, is simple and convenient in the installation and disassembly process, improves the test efficiency, and ensures the accuracy of the flow field measurement by comparing an empirical formula and experimental measurement turbulence parameters with the empirical formula for quantifying the turbulence intensity of the flow field; the wind tunnel measuring device for the aerodynamic characteristics of the transmission conductors is designed, safe and reliable operation of a six-component balance in the experimental process is guaranteed, external interference is small, denoising processing is conducted on the acquired original discrete signals, acquisition precision is improved, and the wind tunnel measuring device has high engineering value and practical significance.
Drawings
FIG. 1 is a schematic view of a wind tunnel measuring device for aerodynamic characteristics of a power transmission conductor provided by the present invention;
the device comprises a steel cylinder 1, a cylinder cover plate 2, a 3 pi-shaped fixed connecting piece, a transmission conductor fixed connecting piece 4, a transmission conductor model 5, a six-component balance 6 and a model top cover plate 7.
FIG. 2 is a steel cylinder structure diagram of the wind tunnel measuring device for aerodynamic characteristics of power transmission line provided by the present invention; wherein, 11 cylinder bodies, 111 rectangular grooves, 12 top flange discs, 13 bottom flange discs and 121 and 131 pass through holes.
FIG. 3 is a structural diagram of a cylinder cover plate in the wind tunnel measuring device for aerodynamic characteristics of a power transmission line according to the present invention; wherein, 21 the via hole, 22 the fillet rectangle recess.
FIG. 4 is a structural diagram of a pi-shaped fixed connecting piece in the wind tunnel measuring device for aerodynamic characteristics of a power transmission conductor provided by the invention;
wherein, 31 top steel plate, 311 through holes, 32 vertical steel plate, 33 horizontal steel plate, 331 through holes.
Fig. 5 is a structural diagram of a power transmission conductor fixing connector in the wind tunnel measuring device for aerodynamic characteristics of a power transmission conductor provided by the invention;
wherein, 41 vertically place the steel sheet, 412 connecting piece, 42 horizontally place the steel sheet, 411, 421 fillet rectangle's recess, 43 bolt fastener.
Fig. 6 is a schematic diagram of a grid flow field test provided by the present invention.
Fig. 7 is a comparison graph of the turbulence intensity empirical formula and the experimentally measured turbulence provided by the present invention.
FIG. 8 is a comparison graph before and after denoising processing of the original signal of the six-component balance provided by the invention.
Detailed Description
The first embodiment of the present invention will be further explained with reference to the drawings and the embodiments, taking the example of measuring two split conductors LGJ-400/35, as shown in fig. 1, a wind tunnel measuring device for aerodynamic characteristics of a transmission conductor comprises a six-component balance 6 and a transmission conductor model 5, and further comprises a steel cylinder 1, a cylinder cover plate 2, a pi-shaped fixed connector 3, a transmission conductor fixed connector 4, wherein the bottom of the steel cylinder 1 is fixed on the wall surface of the wind tunnel, the cylinder cover plate 2 is fixed at the top of the steel cylinder 2, the pi-shaped fixed connector 3 is arranged in the steel cylinder 1, the bottom of the pi-shaped fixed connector 3 is fixed on the wall surface of the bottom of the wind tunnel, the top of the pi-shaped fixed connector is connected with the six-component balance 6, the upper part of the six-component balance 6 is connected with the transmission conductor fixed connector 4, and the.
As shown in figure 2, considering that a six-component balance 6 is susceptible to wind tunnel incoming flow, and avoiding the influence of the balance from the incoming flow, a steel cylinder 1 comprises a cylinder body 11 and flange discs welded at two ends of the cylinder body, the inner diameter of the cylinder is 30cm, the wall thickness is 0.5cm, the height of the cylinder is 30cm, a plurality of through holes 121 and 131 with the inner diameter of 1cm are arranged on the flange discs, a bottom flange disc 13 is fixed on the wall surface of the wind tunnel through bolts and metal gaskets, a top flange disc 12 is connected with a cylinder cover plate 2 through bolts and metal gaskets, a rectangular groove 111 with the diameter of 5cm and 3cm is formed in the steel cylinder body 11, the center position of the rectangular groove 111 is the same as the center height of the six-component balance used for measurement, and a signal line of the six-component balance used for measurement is connected with an external acquisition system through.
As shown in fig. 3, the cylinder cover plate 2 is a steel circular plate with a radius of 35cm, a through hole 21 with an inner diameter of 1cm is formed in the cylinder cover plate, the through hole corresponds to the through hole of the flange disc at the top of the steel cylinder, an upper straight-through rounded rectangular groove 22 and a lower straight-through rounded rectangular groove 22 are formed in the center of the steel circular plate, the rectangular length is 20cm, the rectangular width is 3cm, the transmission conductor model is guaranteed to pass through, and the gap is covered by adhesive tape.
As shown in fig. 4, pi shape fixed connector 3 length is 12cm, width 8cm, thickness 1 cm's top steel sheet 31, the welding of the vertical direction in top steel sheet below has two highly be 5cm, thickness is 1 cm's steel sheet 32, two steel sheet interval 8cm, two steel sheet bottoms of vertical direction have the welding of outside horizontal direction respectively and have length to be 5cm, thickness is 1 cm's steel sheet 33, 8 via holes 311 have been arranged to top steel sheet 31, the top steel sheet is connected with six weight balances through bolt fastening spare, be provided with 2 internal diameters on bottom horizontal direction's the steel sheet 331 and be 1 cm's via hole, bottom horizontal direction's steel sheet passes through bolt fastening spare to be fixed on wind-tunnel bottom wall.
As shown in fig. 5, the power transmission line fixed connector 4 comprises two mutually perpendicular placed steel plates, the length and width of the two steel plates are 15cm, the thickness of the two steel plates is 1cm, the two steel plates are respectively a vertically placed steel plate 41 and a horizontally placed steel plate 42, aerodynamic force tests are performed for models of different sizes, the position is convenient to adjust and place, four grooves 411 of vertically straight round rectangles are formed in the two steel plates, 421, the width of each groove, namely the diameter of a round corner, is 1cm, two connecting pieces 412 perpendicular to the two steel plates are arranged on the two sides below the vertically placed steel plate, the vertically placed steel plate 41 is connected with the round rectangular groove 421 on the horizontally placed steel plate 42 through the connecting piece 412 through the bolt fastener 43, the two steel plates are fixed, the power transmission line model 5 and the groove 411 of the round rectangular of the vertically placed steel plate 41 are fixed through the bolt fastener, and the six-component balance.
When the wind tunnel measuring device for the aerodynamic characteristics of the power transmission wire is built, a tunnel wall effect of a wind tunnel is considered at the same time, a model top cover plate 7 is arranged at a position 75cm above a power transmission wire model 5, the model top cover plate 7 is a steel round plate with the radius of 35cm, a gap of 1 cm-2 cm is reserved between the top of the power transmission wire model 5 and the model top cover plate 7, the two-dimensional flow characteristics flowing around the wire model are guaranteed by the structure, the power transmission wire model 5 adopts a rigid model, the length of the power transmission wire model 5 is 95cm, and the power transmission wire is made of materials which need to have certain rigidity and good plasticity, so that metal strips are wound on the outer surface of the power transmission wire in an.
On the six weight balance fixed connection spare that guarantee that the balance can be firm through above-mentioned structure places, can not produce obvious vibration because of the effect of coming the stream down, lead to the data measurement deviation to appear.
A wind tunnel measurement method for aerodynamic characteristics of power transmission conductors comprises the following steps:
(1) the method for determining the type and the test working condition of the wire used in the aerodynamic characteristic wind tunnel experiment specifically comprises the following steps: testing simulation wind speed, testing simulation turbulence intensity and testing simulation wind direction angle;
(2) designing the size of a grid for an experiment according to the size of the wind tunnel and the condition of turbulence intensity required to be simulated in the experiment, and assembling and manufacturing a movable grid for the wind tunnel experiment by using steel;
(3) electrifying to start the wind tunnel, measuring the speed distribution of a power transmission conductor model test area by using a hot wire anemometer after the wind speed reaches the test simulation wind speed, closing the wind tunnel, and processing data to obtain corresponding turbulence characteristic parameters and flow speed distribution;
(4) sequentially adding the designed grids into the wind tunnel, repeating the step (3) to obtain turbulence characteristic parameters and flow velocity distribution corresponding to the grid turbulence field until all grid flow field tests are completed, and moving the test instrument and the grids out of the wind tunnel;
(5) designing a wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, installing and debugging the wind tunnel, and integrally installing a power transmission conductor model on a six-component balance to ensure that test equipment is firm and reliable;
(6) sequentially powering on and starting a six-component balance test system, powering on and starting a wind tunnel, testing the aerodynamic force of a power transmission conductor and recording data after the wind speed reaches the test simulation wind speed, changing the inflow wind direction angle of the power transmission conductor, testing the aerodynamic force of the power transmission conductor and recording the data until all wind direction angles are tested;
(7) changing the wind speed of the wind tunnel incoming flow, testing the aerodynamic force of the transmission conductor again and recording data after the wind speed reaches the test simulation wind speed until all wind direction angles are tested;
(8) repeating the step (7) until all the test simulation wind speeds are tested, and sequentially closing the wind tunnel and the six-component balance test system;
(9) sequentially adding designed grids into the wind tunnel, repeating the steps (6) to (8), and obtaining the aerodynamic force of the transmission conductor in the corresponding grid turbulent flow field until all grid flow field tests are completed;
(10) changing the balance measuring position of the wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, mounting the sub-conductors in the power transmission conductor model on a six-component balance, and repeating the steps (6) to (9) until the aerodynamic characteristics of all the sub-conductors are tested, and obtaining the aerodynamic characteristics of the split sub-conductors in the corresponding grid turbulent flow field until all the grid flow field tests are completed;
(11) comparing aerodynamic force data under various working conditions, analyzing the aerodynamic force change rule, and completing the aerodynamic characteristic test of the power transmission conductor;
specifically, the method comprises the following steps: the wind tunnel test section of the test site has the dimensions of 3.0m long, 3.0m wide and 1.5m high, and the types of the measuring wires are as follows: LGJ-400/35 two split wires, test wind speed: 7m/s, 10m/s, 15m/s, 20m/s, 25m/s, 30m/s, test turbulence intensity: 0.2%, 10.5%, 19%, test wind direction angle: the method takes the condition that two split conductors are not shielded as the wind direction angle zero degree, and tests are carried out once every 15 degrees, namely: 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °, -15 °, -30 °, -45 °, -60 °, -75 °, -90 °.
The design of the grating, the grating used in the test is assembled by adopting alloy steel with a cross section of 3cm multiplied by 3cm, the grating strips are fixedly connected through angle aluminum, the connecting mode of the grating and the wind tunnel is that a foot-padding bolt is additionally arranged at the bottom of the grating to support the grating on the top wall of the wind tunnel, and a rubber pad is additionally arranged between the top of the grating and the tunnel wall to increase the friction force. Two specific dimensions of the grid were designed: in the first scheme, the width of the longitudinal grid bars is 3cm, the width of the transverse grid bars is 3cm, the interval width is 34cm, and the height is 32cm, in the second scheme, the width of the longitudinal grid bars is 6cm, the width of the transverse grid bars is 6cm, the interval width is 31.4cm, and the height is 29.8 cm;
as shown in fig. 6, the grid flow field test schematic diagram provided by the present invention, the grid flow field test described in step 3) and step 4) specifically includes the following steps: (1) wind tunnel safety inspection, whether the connecting bolt is loosened or not; checking whether the connection of electric equipment such as a wind tunnel power end motor, a relay, a frequency converter and the like is normal and can normally run; checking whether foreign matters exist in the wind tunnel pipeline; (2) a movable support is fixedly arranged on the ground of the wind tunnel, and a hot wire probe test rack is fixedly arranged on the support; according to the actual situation of the wind tunnel, determining that a grid is placed 1.6m in front of the position of an experimental platform, determining the position of a measuring point of a measuring flow field, wherein the position is the center position of the cross section of the wind tunnel, the distance between the horizontal direction and the vertical direction of a probe is 10cm, and the measuring height is 35-75 cm; (3) the hot wire anemoscope is provided with three probes and is started, the sampling frequency of the hot wire anemoscope is set to be 5kHz, the sampling time is set to be 10s, the three probes of the hot wire anemoscope are calibrated, a linear curve of wind speed and voltage is fitted, and the hot wire probes are installed and fixed on a hot wire probe test frame after calibration is completed; (4) starting the wind tunnel, and starting measurement by a hot-wire anemoscope by taking the wind speed measured by a pitot tube in the wind tunnel as reference when the wind speed is stabilized to 7 m/s; (5) and after the wind tunnel is tested, moving the support, respectively testing five groups of instantaneous wind speeds with different heights from 35cm to 75cm, changing the wind speed to measure again until all the measuring points measure the wind speed at the incoming wind speeds of 10m/s, 15m/s, 20m/s, 25m/s and 30m/s, and closing the wind tunnel. (6) And (5) adding a grid used in the experiment, repeating the step (4) and the step (5), processing the experimental data, and comparing a design formula, namely a turbulence intensity empirical formula (1), with the experiment measured downstream turbulence intensity to finish the flow field test.
Wherein: i isu1For the expected value of the downstream turbulence intensity, x is the distance between the measuring point of the hot wire probe and the grid, and M is the size of the grid hole
In the formula, the longitudinal width of the grid bars is a, the transverse width of the grid bars is c, the interval width is b, the height is d, and y is the grid porosity;
during data processing in grid flow field measurement, the experimental measurement downstream turbulence intensity is calculated by the formula (2) and the formula (3), and the turbulence intensity in data processing in the grid flow field measurement is calculated and processed according to the formula (2):
wherein: l is 1, 2, 3 represents three directions of a forward direction, a transverse direction and a vertical direction, N is the number of sampling data points, and the value is 50000 and uliDiscrete sequence of samples representing turbulent wind velocity, e.g. u1iRepresenting the difference between the instantaneous sampled wind speed downstream and the average wind speed downstream of the sampled data,
representing the average wind speed of the sampled data, wherein the value of K is 1 to 15, and representing that 15 test points are arranged on each section;
calculating and processing the turbulence integral scale in data processing in flow field measurement according to the formula (3):
in formula (3), ui+τExpressed as u in a discrete sequence of samples and downstream fluctuating wind speediThe interval is the pulsating wind speed value of tau, tau is a positive integer and is 1 to 49999, i is a positive integer from 1 to 50000-tau,
mean wind speed, σ, representing sampled discrete datauA root mean square value representing a forward turbulent wind velocity pulsation component;
FIG. 7 is a comparison graph of the empirical formula of turbulence intensity and the experimentally measured turbulence, showing that the fitting formula is more consistent with a plurality of groups of measured values, and the goodness of fit R of data2Is 0.961, close to 1, indicating the correctness of the flow field measurement.
During measurement, the six-component balance testing system collects and analyzes experimental data by adopting SCXI series products of NI company, and integrates data collection and signal analysis. The test system comprises: the upper computer comprises a collection card with the model of PCI-6221, a slot collection box with the model of SCXI-1000, a 32-channel input module with the model of SCXI-1102, a 32-channel junction box with the model of SCXI-1303 and a signal wire for electric connection. When the six-component balance is used, preheating is carried out for 40 minutes before measurement, then zero clearing is carried out, meanwhile, a test system correspondingly amplifies and conditions the acquired electric signals through equipment such as an input module, an acquisition box and the like, then data are transmitted to a data acquisition card, the electric signals are converted into digital signals and input to an upper computer, the force and the moment of the six-component balance are calculated by adopting a formula (4), and the sampling frequency is 1 kHz;
wherein: i, j is a positive integer from 1 to 6, which represents a forward load, a cross wind load, a vertical load, a forward rotating moment, a cross wind rotating moment, and a vertical rotating moment, respectively, and i and j are different from each other in the formula, for example: when i is 1, j takes values of 2, 3, 4, 5 and 6; fiActual measurement of load size, k, for six componentsi1Is a principal coefficient of six components, ki2Is the coefficient of the square term of six components, kj1First order interference coefficient, k, of six componentsj2The square interference coefficient of six components, the coefficients of all components of the balance adopt factory calibration values, NiThe value is the balance reading in the i direction;
six-component actual measurement load size F obtained by collectioniAnd then the lifting force coefficients C of the whole power transmission conductor and the single conductor are calculated by using the formula (5) and the formula (6)L(theta), coefficient of resistance CD(θ)；
In formula (5): d is the measured outer diameter length of the wire model, and the value is 0.0266 m; h is the test length of the model, and the value is 0.75m, and the distance between the cylinder cover plate and the top cover plate of the model is taken asPreparing; ptTotal pressure of incoming flow, P, measured for pitot tube0The incoming hydrostatic pressure measured for the pitot tube; p in formula (5)t-P0The difference value of the wind speed difference value is the dynamic pressure of the incoming flow, theta is defined as the included angle between the incoming flow wind and the X direction of the six-component balance, when the theta is 180 degrees, the X direction of the six-component balance is the incoming flow direction of the wind tunnel,
the discrete signal processed by the formula (6) is the measured value in the X direction measured by the six-component balance,
the method is a discrete signal obtained by processing a measured value in the Y direction by a six-component balance through a formula (6), wherein the formula (6) is a discrete transfer function of a power frequency 50Hz wave trap which is designed to be eliminated after z-function transformation, Y (Z) is a discrete output quantity after z-function transformation, and U (Z) is a discrete input quantity of the z-function transformation; the specific design is as follows: the wave trap of the invention adopts a typical second-order wave trap, and the frequency domain transfer function is as follows:
in the formula: omeganThe value of the harmonic frequency is 50Hz, Q is a quality factor, the value of the harmonic frequency is 10, the sampling frequency T of a balance acquisition system is 1kHz, and a bilinear method is adopted to perform z transformation on the balance acquisition system, namely:
and (3) substituting an equation (7) to obtain an equation (6), taking a wind direction angle of 0 degree and an incoming flow wind speed of 25m/s as an example, fig. 7 is a comparison graph before and after denoising processing of the original signals of the six-component balance provided by the invention, the upper part of fig. 8 is a downstream load obtained by directly substituting the acquired original data into an equation (5) for calculation, and the lower part of fig. 8 is load data obtained by eliminating power frequency interference after the data pass through a designed power frequency wave trap. After the upper and lower pictures are compared, the method of the invention is adopted to realize the accurate reduction of data.
The present invention is not limited to the above-mentioned embodiments, and based on the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some technical features without creative efforts according to the disclosed technical contents, and these substitutions and modifications are all within the protection scope of the present invention.
Claims (10)
1. A wind tunnel measurement method for aerodynamic characteristics of a power transmission conductor is characterized by comprising the following steps:
(1) the method for determining the type and the test working condition of the wire used in the aerodynamic characteristic wind tunnel experiment specifically comprises the following steps: testing simulation wind speed, testing simulation turbulence intensity and testing simulation wind direction angle;
(2) designing the size of a grid for an experiment according to the size of the wind tunnel and the condition of turbulence intensity required to be simulated in the experiment, and assembling and manufacturing a movable grid for the wind tunnel experiment by using steel;
(3) electrifying to start the wind tunnel, measuring the speed distribution of a power transmission conductor model test area by using a hot wire anemometer after the wind speed reaches the test simulation wind speed, closing the wind tunnel, and processing data to obtain corresponding turbulence characteristic parameters and flow speed distribution;
(4) sequentially adding the designed grids into the wind tunnel, repeating the step (3) to obtain turbulence characteristic parameters and flow velocity distribution corresponding to the grid turbulence field until all grid flow field tests are completed, and moving the test instrument and the grids out of the wind tunnel;
(5) designing a wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, installing and debugging the wind tunnel, and integrally installing a power transmission conductor model on a six-component balance to ensure that test equipment is firm and reliable;
(6) sequentially powering on and starting a six-component balance test system, powering on and starting a wind tunnel, testing the aerodynamic force of a power transmission conductor and recording data after the wind speed reaches the test simulation wind speed, changing the inflow wind direction angle of the power transmission conductor, testing the aerodynamic force of the power transmission conductor and recording the data until all wind direction angles are tested;
(7) changing the wind speed of the wind tunnel incoming flow, testing the aerodynamic force of the transmission conductor again and recording data after the wind speed reaches the test simulation wind speed until all wind direction angles are tested;
(8) repeating the step (7) until all the test simulation wind speeds are tested, and sequentially closing the wind tunnel and the six-component balance test system;
(9) sequentially adding designed grids into the wind tunnel, repeating the steps (6) to (8), and obtaining the aerodynamic force of the transmission conductor in the corresponding grid turbulent flow field until all grid flow field tests are completed;
(10) changing the balance measuring position of the wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor, mounting the sub-conductors in the power transmission conductor model on a six-component balance, and repeating the steps (6) to (9) until the aerodynamic characteristics of all the sub-conductors are tested, and obtaining the aerodynamic characteristics of the split sub-conductors in the corresponding grid turbulent flow field until all the grid flow field tests are completed;
(11) and comparing the aerodynamic force data under various working conditions, analyzing the aerodynamic force change rule, and completing the aerodynamic characteristic test of the power transmission conductor.
2. The wind tunnel measurement method for aerodynamic characteristics of power transmission conductors according to claim 1, wherein the grid flow field test in step 3) and step 4) specifically comprises the following steps:
(1) wind tunnel safety inspection, whether the connecting bolt is loosened or not; checking whether the connection of electric equipment such as a wind tunnel power end motor, a relay, a frequency converter and the like is normal and can normally run; checking whether foreign matters exist in the wind tunnel pipeline;
(2) determining a grid placement range according to the actual condition of the wind tunnel, determining the position of a measurement flow field according to the position of a measurement device in the wind tunnel, installing and fixing a movable support on the ground of the wind tunnel, and installing and fixing a hot wire probe test rack on the support;
(3) the hot-wire anemoscope is provided with three probes and is started, the sampling frequency and the sampling time of the hot-wire anemoscope are set, the three probes of the hot-wire anemoscope are calibrated, a linear curve of wind speed and voltage is fitted, and the hot-wire probes are installed and fixed on a hot-wire probe test rack after calibration is completed;
(4) starting the wind tunnel, and starting measurement by a hot-wire anemoscope by taking the wind speed measured by a pitot tube in the wind tunnel as reference when the wind speed is stabilized;
(5) after the test is finished, moving the bracket, respectively testing five groups of instantaneous wind speeds with different heights, changing the wind speed to measure again after all the measurement points are tested, and closing the wind tunnel until all the measurement points under the incoming flow wind speed measure;
(6) and (5) adding a grid used for the experiment, repeating the step (4) and the step (5), processing the experimental data, and comparing a design formula with the experiment to measure the forward turbulence intensity to finish the flow field test.
3. The wind tunnel measurement method for the aerodynamic characteristics of the power transmission conductor according to claim 1 or 2, characterized in that the experimental grid is assembled by alloy steel, a movable grid for wind tunnel experiment is designed and manufactured, and the design is carried out according to formula (1),
wherein: i isu1For the expected value of the downstream turbulence intensity, x is the distance between the measuring point of the hot wire probe and the grid, and M is the size of the grid hole
In the formula, the longitudinal width of the grid bars is a, the transverse width of the grid bars is c, the interval width is b, the height is d, and y is the grid porosity.
4. The wind tunnel measurement device and method for aerodynamic characteristics of power transmission conductors according to claim 2, wherein during data processing in grid flow field measurement, turbulence intensity in data processing in flow field measurement is calculated and processed according to formula (2):
wherein: l is 1, 2, 3 represents three directions of forward direction, transverse direction and vertical direction, N is the number of sampling data points, uliTo representDiscrete sequence of samples of turbulent wind velocity, e.g. u1iRepresenting the difference between the instantaneous sampled wind speed downstream and the average wind speed downstream of the sampled data,
representing the average wind speed of the sampled data, wherein the value of K is 1 to 15, and representing that 15 test points are arranged on each section;
calculating and processing the turbulence integral scale in data processing in flow field measurement according to the formula (3):
in formula (3), ui+τExpressed as u in a discrete sequence of samples and downstream fluctuating wind speediThe interval is the pulsating wind speed value of tau, tau takes the positive integer value from 1 to N-1, i takes the positive integer value from 1 to N-tau,
representing the average wind speed of the sampled discrete data, N representing the number of sampled data points, σuRepresents the root mean square value of the forward turbulent wind velocity pulsating component.
5. The utility model provides a transmission line aerodynamic characteristic wind-tunnel measuring device, the device includes six weight balances and transmission line model, its characterized in that still includes steel drum, drum apron, pi shape fixed connector and transmission line fixed connector, steel drum bottom is fixed on the wind-tunnel wall, the drum apron is fixed at steel drum top, pi shape fixed connector sets up in the steel drum, pi shape fixed connector bottom is fixed on the wind-tunnel wall, and pi shape fixed connector top is connected with six weight balances, six weight balances tops are connected with transmission line fixed connector, and transmission line model utilizes bolt fastener and transmission line fixed connector fixed.
6. The wind tunnel measuring device for the aerodynamic characteristics of the transmission line according to claim 5, wherein the steel cylinder comprises a cylinder body and flange discs welded at two ends of the cylinder body, a plurality of through holes are formed in the flange discs, the bottom flange disc is fixed on the wall surface of the wind tunnel through bolts and metal gaskets, the top flange disc is connected with the cylinder cover plate through bolts and metal gaskets, a rectangular groove is formed in the steel cylinder body, the central position of the rectangular groove is equal to the central height of the six-component balance used for measurement, and signal wires of the six-component balance used for measurement are connected with an external acquisition system through the rectangular groove in the steel cylinder body.
7. The wind tunnel measuring device for the aerodynamic characteristics of the transmission conductor according to claim 5, wherein the cylinder cover plate is a steel circular plate, a through hole corresponding to the position of the through hole of the flange disc at the top of the steel cylinder is formed in the cylinder cover plate, and an up-and-down straight-through rounded rectangular groove is formed in the center of the steel circular plate to ensure that a transmission conductor model passes through.
8. The wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor according to claim 5, wherein the pi-shaped fixed connecting piece comprises a top steel plate, two steel plates are welded in the vertical direction below the top steel plate, the bottoms of the two steel plates in the vertical direction are respectively welded in the horizontal direction towards the outside, a plurality of through holes are formed in the top steel plate, the top steel plate is connected with a six-component balance through bolt fasteners, through holes are formed in the steel plate in the horizontal direction towards the bottom, and the steel plate in the horizontal direction towards the bottom is fixed on the wall surface at the bottom of the wind tunnel through the bolt fasteners.
9. The wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor according to claim 5, wherein the power transmission conductor fixing and connecting piece comprises two steel plates which are arranged perpendicular to each other and are respectively a vertically-arranged steel plate and a horizontally-arranged steel plate, four vertically-straight-through grooves of the rounded rectangles are formed in each of the two steel plates, two connecting pieces perpendicular to the vertically-arranged steel plates are arranged on two sides below the vertically-arranged steel plates, the vertically-arranged steel plates are connected with the rounded rectangle grooves in the horizontally-arranged steel plates through bolt fasteners through connecting pieces, the power transmission conductor model and the grooves of the rounded rectangles of the vertically-arranged steel plates are fixed through the bolt fasteners, and the six-component balance is connected with the grooves of the rounded rectangles of the horizontally-arranged steel plates through the.
10. The wind tunnel measuring device for the aerodynamic characteristics of the power transmission conductor according to claim 5, wherein a model top cover plate is arranged on the upper portion of the power transmission conductor model, the model top cover plate is a steel round plate, and a gap is reserved between the top of the power transmission conductor model and the model top cover plate.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112464589A (en) * | 2020-12-11 | 2021-03-09 | 国网新疆电力有限公司电力科学研究院 | Simplified numerical simulation method for aerodynamic resistance of power transmission conductor |
| CN113670565A (en) * | 2021-08-12 | 2021-11-19 | 同济大学 | Wind field measuring device and measuring method for wind power generation high tower model test |
| CN115901162A (en) * | 2023-03-02 | 2023-04-04 | 中国电建集团西北勘测设计研究院有限公司 | Wind and snow environment wind tunnel simulation device for green development of urban and rural construction |
| CN117909659A (en) * | 2024-03-20 | 2024-04-19 | 中国空气动力研究与发展中心超高速空气动力研究所 | Method and device for processing aerodynamic force signals of balance in wind tunnel dynamic test of variant aircraft |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000019193A (en) * | 1998-06-29 | 2000-01-21 | Toyota Central Res & Dev Lab Inc | Method for measuring non-steady flow field |
| CN104596727A (en) * | 2014-12-08 | 2015-05-06 | 华北电力大学 | High-voltage transmission conductor aerodynamic characteristic experiment device with artificial rivulet |
| CN104764579A (en) * | 2015-04-15 | 2015-07-08 | 浙江大学 | Wind tunnel test device for three-freedom-degree waving of multi-bundle iced conductor |
| CN105910793A (en) * | 2016-06-12 | 2016-08-31 | 哈尔滨工业大学深圳研究生院 | Active vibration grating capable of increasing atmosphere boundary layer wind tunnel turbulence level |
| CN106872140A (en) * | 2017-03-06 | 2017-06-20 | 西北工业大学 | The method that different wind speed downstream turbulivitys are measured based on cylinder model |
| CN110361155A (en) * | 2019-06-13 | 2019-10-22 | 浙江大学 | A kind of air tunnel testing device of arc conducting wire wind load |
-
2020
- 2020-05-29 CN CN202010473064.9A patent/CN111579196B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000019193A (en) * | 1998-06-29 | 2000-01-21 | Toyota Central Res & Dev Lab Inc | Method for measuring non-steady flow field |
| CN104596727A (en) * | 2014-12-08 | 2015-05-06 | 华北电力大学 | High-voltage transmission conductor aerodynamic characteristic experiment device with artificial rivulet |
| CN104764579A (en) * | 2015-04-15 | 2015-07-08 | 浙江大学 | Wind tunnel test device for three-freedom-degree waving of multi-bundle iced conductor |
| CN105910793A (en) * | 2016-06-12 | 2016-08-31 | 哈尔滨工业大学深圳研究生院 | Active vibration grating capable of increasing atmosphere boundary layer wind tunnel turbulence level |
| CN106872140A (en) * | 2017-03-06 | 2017-06-20 | 西北工业大学 | The method that different wind speed downstream turbulivitys are measured based on cylinder model |
| CN110361155A (en) * | 2019-06-13 | 2019-10-22 | 浙江大学 | A kind of air tunnel testing device of arc conducting wire wind load |
Non-Patent Citations (1)
| Title |
|---|
| 左太辉等: "分裂导线平均风荷载阻力系数干扰效应研究", 《实验流体力学》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112464589A (en) * | 2020-12-11 | 2021-03-09 | 国网新疆电力有限公司电力科学研究院 | Simplified numerical simulation method for aerodynamic resistance of power transmission conductor |
| CN112464589B (en) * | 2020-12-11 | 2023-02-03 | 国网新疆电力有限公司电力科学研究院 | Simplified numerical simulation method for aerodynamic resistance of power transmission conductor |
| CN113670565A (en) * | 2021-08-12 | 2021-11-19 | 同济大学 | Wind field measuring device and measuring method for wind power generation high tower model test |
| CN113670565B (en) * | 2021-08-12 | 2022-06-07 | 同济大学 | Wind field measuring device and measuring method for wind power generation high tower model test |
| CN115901162A (en) * | 2023-03-02 | 2023-04-04 | 中国电建集团西北勘测设计研究院有限公司 | Wind and snow environment wind tunnel simulation device for green development of urban and rural construction |
| CN115901162B (en) * | 2023-03-02 | 2023-06-13 | 中国电建集团西北勘测设计研究院有限公司 | Wind and snow environment wind tunnel simulation device |
| CN117909659A (en) * | 2024-03-20 | 2024-04-19 | 中国空气动力研究与发展中心超高速空气动力研究所 | Method and device for processing aerodynamic force signals of balance in wind tunnel dynamic test of variant aircraft |
| CN117909659B (en) * | 2024-03-20 | 2024-05-14 | 中国空气动力研究与发展中心超高速空气动力研究所 | Method and device for processing aerodynamic force signals of balance in wind tunnel dynamic test of variant aircraft |
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