Experimental test device and test method for the effect of wind and sand activities on heliostat focusing

Abstract

The present invention discloses an experimental test device and a test method for the influence of wind and sand activities on the focusing of heliostats, and belongs to the field of wind tunnel experiment technology. The experimental test device for the influence of wind and sand activities on the focusing of heliostats includes a test room and a heliostat test model, a sand leakage trough, a Lambertian target, a laser transmitter and a CCD camera arranged in the test room. The test room has a relatively arranged air inlet and an air outlet. The heliostat test model is arranged downstream, the sand leakage trough is arranged at the upstream top of the heliostat test model, and a plurality of sand leakage holes that can be opened and closed are evenly arranged at the bottom of the sand leakage trough. The Lambertian target is arranged upstream of the heliostat test model, and the CCD camera is used to continuously shoot the number of light spots on the Lambertian target. The experimental test device and the test method for the influence of wind and sand activities on the focusing of heliostats of the present invention can accurately predict the influence of wind and sand activities on the focusing efficiency of the heliostat field, and provide an accurate theoretical basis for the mirror field design.

Description

Technical Field

[0001] The invention relates to the technical field of wind tunnel experiments, and in particular to an experimental testing device and a testing method for the influence of wind and sand activities on the focusing of a heliostat. Background Art

[0002] Compared with fossil energy, solar energy has the unique advantages of wide distribution, sufficient reserves, clean and safe, and great market potential. In recent years, it has grown steadily both globally and in my country. Vigorously developing solar energy has become an important way to transform and upgrade energy. Among them, compared with solar photovoltaic power generation, solar thermal power generation does not have the phenomenon of "abandoning light", has the advantages of energy storage safety and peak-shifting power supply, and has developed rapidly.

[0003] The heliostat field is one of the key concentrating equipment in the tower solar thermal power station. It transmits sunlight through mirror reflection to the absorber of the central heat absorption tower to heat the molten salt and other heat transfer media and finally drive the steam turbine to generate electricity. Depending on the heat storage capacity, for example, a 100MW solar thermal power station is designed with about 1 million square meters of reflectors, and thousands to tens of thousands of heliostats are planned for reflection and concentration. However, in the actual operation of the power station, the heliostats are operated in the desert Gobi area for a long time to chase the sun, which makes the surface of the heliostats prone to dust accumulation under the influence of wind and sand. After long-term operation, the dust thickness of the mirror surface gradually increases, resulting in a decrease in the power of sunlight reflected to the mirror surface. In addition, the presence of dust increases the scattering of light, thereby reducing the focusing energy of the absorber, thereby affecting the power generation efficiency of the solar thermal power station.

[0004] At present, wind tunnel tests and CFD (Computational Fluid Dynamics) numerical simulation and prediction studies have been mainly carried out on the impact of wind and sand movement on the output performance of photovoltaic arrays. There is no test device for the impact of wind and sand activities on the concentrating efficiency of heliostats in solar thermal power plants. Since photovoltaic modules are mainly composed of glass cover plates, back plates and solar cells, and are installed on the ground of the Gobi Desert through photovoltaic brackets. However, the heliostat structure of a solar thermal power station is composed of columns, bracket structure systems, torque tubes and reflectors. It is mainly fixed to the ground surface through pile foundations through columns and bracket structure systems. The height of the columns is distributed in the range of 4 to 10 meters, and the area of ​​the reflectors is distributed in the range of 20 to 178 m 2 , and the height of the reflector from the ground is different at different working elevation angles, so there are significant differences between the heliostat structure and the photovoltaic module structure.

[0005] Therefore, the present invention proposes an experimental device for testing the influence of wind and sand activities on the focusing of heliostats in tower-type solar thermal power stations based on wind tunnel tests, so as to explore the causes of dust formation on the mirror surface of the heliostats, and provide important guarantees for the normal operation and maintenance of the heliostats and the high-efficiency operation of solar thermal power stations. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems in the prior art and provide an experimental test device and a test method for the influence of wind and sand activities on the focusing efficiency of heliostats, which can accurately predict the influence of wind and sand activities on the focusing efficiency of heliostats and provide an accurate theoretical basis for the design of heliostats.

[0007] The present invention provides a test device and a test method for the effect of wind and sand activities on heliostat focusing, comprising:

[0008] The test room has an air inlet and an air outlet arranged relatively to each other, the side close to the air inlet is the upstream, and the side close to the air outlet is the downstream, and also includes:

[0009] The heliostat test model is located downstream;

[0010] A sand leakage trough is arranged upstream of the heliostat test model and at the top of the test room, and a plurality of sand leakage holes that can be opened and closed are evenly arranged at the bottom of the sand leakage trough;

[0011] A laser transmitter for emitting light to the mirror surface of the heliostat test model;

[0012] A Lambertian target is disposed upstream of the heliostat test model so that the center of the Lambertian target can receive light reflected by the center of the mirror surface of the heliostat test model;

[0013] CCD (Charge coupled device) camera, used to continuously capture the number of light spots on the Lambertian target;

[0014] In this way, the influence of wind and sand activities on the focusing efficiency of the heliostat under different working conditions and wind field environments can be analyzed.

[0015] Preferably, the heliostat test model comprises a turntable, a column and a light-transmitting mirror, the turntable is rotatably arranged downstream of the bottom of the test room, and the center of rotation is arranged vertically, the bottom end of the column is fixedly connected to the center of the turntable, the middle part of the light-transmitting mirror is hinged to the top of the column, and multiple measuring points are arranged on both sides of the light-transmitting mirror, and the measuring points are connected to the electronic pressure scanning valve channel through rubber tubes, and the laser emitter is used to emit light to the center of the light-transmitting mirror, so that the center of the Lambertian target can receive the light reflected by the center of the mirror surface of the light-transmitting mirror, so that the action mechanism of wind pressure and wind suction on the distribution characteristics of sand particles on the surface of the heliostat can be analyzed.

[0016] Preferably, the test room is further provided with a rough element and a wedge and a plurality of wind speed meters, the rough element and the wedge are arranged upstream of the sand leakage trough, the wind speed meters are arranged upstream of the heliostat rigid model, each wind speed meter is arranged within the mirror height variation range of the heliostat test model, and the distance between adjacent wind speed meters is 9 mm to 11 mm, so that the actual wind field environment of the solar thermal power station can be simulated, and the wind speed meter is used to monitor the incoming wind speed at the height of the test reference point, so that the average wind profile, turbulence intensity profile and wind speed power spectrum are finally made to coincide with the theoretical curve, so as to simulate the wind field environment in the desert Gobi area and ensure the accuracy of the test.

[0017] Preferably, a gradient sand collector is provided below the sand leakage trough, the gradient sand collector is located downstream of the sand leakage trough and upstream of the heliostat test model, the gradient sand collector is provided with a plurality of sand collecting channels, the sand collecting channels are all arranged within the range of the mirror height variation of the heliostat test model, and the distance between adjacent sand collecting channels is 9 mm to 11 mm, so that it is convenient to test the sand concentration on the mirror surface of the heliostat under different working conditions.

[0018] Preferably, the heliostat test model is a rigid model, so that the heliostat test model remains stable under wind load.

[0019] The test method of any of the above-mentioned test devices for the effect of wind and sand activities on heliostat focusing comprises the following steps:

[0020] S1-1: The wind speed in the test room is stable;

[0021] S1-2: Open the sand leakage hole and start releasing sand and dust. Set the time as a sand activity collection condition. At the same time, use a CCD camera to take a picture of the light spot reflected from the mirror surface of the heliostat test model to the surface of the Lambertian target every other condition.

[0022] S1-3: Number the light spots in the order of appearance, n5, n6, n7, n8, n9...;

[0023] S1-4: Count the number of light spots m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25, m26, m27, m28, m29, m30, m31, 10 , and calculate the average value of the number of light spots for 10 times And the average value of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times

[0024] S1-5: Calculate the light collection efficiency to obtain

[0025] Preferably, the method further comprises the following steps:

[0026] S2-1: Close all sand leakage holes and wait for the wind speed in the test room to stabilize;

[0027] S2-2: The set time is used as a wind and sand activity collection condition. At the same time, a CCD camera is used to capture the light spot reflected from the mirror surface of the heliostat test model to the Lambertian target surface every other condition.

[0028] S2-3: Count the number of light spots reflected by the reflector to the Lambertian target surface during the 10-day test, and calculate the average value m′ of the number of light spots for 10 times, as well as the average value m′ of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times total ;

[0029] S2-4: Calculate the light collection efficiency to obtain

[0030] S2-5: Calculation

[0031] Preferably, a test method for the critical wind speed of sand particles at each reference height is also included. A gradient sand collector is provided in the test room. The gradient sand collector is located upstream of the heliostat test model. The gradient sand collector is located below the sand leakage trough and downstream of the sand leakage trough. The steps of the test method for the critical wind speed of sand particles at the start-up are as follows:

[0032] S3-1: The wind speed in the test room is stable;

[0033] S3-2: Open the sand leakage hole and start releasing sand and dust. Set the time as a sand activity collection condition. Collect the sand and dust in each sand collection channel of the gradient sand collector every other condition and weigh them separately.

[0034] S3-3: Calculate the average weight of each dust in 10 working conditions;

[0035] S3-4: Calculate dust concentration at each reference height in:

[0036] ρ 沙 ——Sand concentration, g / m 3 ;

[0037] Q——collected sand volume, g;

[0038] t——sand collection time, s;

[0039] A0——Opening area of ​​sand collection tester, m 2 ;

[0040] V H ——average wind speed at reference height, m / s;

[0041] S3-5: Calculate the critical wind speed for sand particles at each reference height

[0042]

[0043] in,

[0044] A——empirical coefficient, generally taken as 0.1;

[0045] ρ s ——Sand density, kg / m 3 ;

[0046] ρ——air density, kg / m 3 ;

[0047] d——sand particle diameter, mm;

[0048] g——acceleration due to gravity, m / s 2 ;

[0049] z——height, m;

[0050] z0——surface roughness.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] The test device for the effect of wind and sand activities on the focusing of heliostats of the present invention is provided with a sand leakage trough device with holes of different diameters at the bottom and a gradient sand collector, which are respectively installed on the top of the test room in the upstream area of ​​the model installation and on the bracket installed on the ground. At the same time, according to the optical incidence-reflection principle, a Lambert target is selected to replace the heat absorption at the top of the heat absorption tower. During the duration of the wind and sand activities of the test, a CCD camera is used to continuously shoot the number of light spots on the surface of the Lambert target and the number of overflow light spots, so as to calculate the focusing efficiency of the heliostat under the wind and sand activities. Secondly, the sand leakage trough device is closed, the sand collector is removed, and then other identical test devices are used to test the number of light spots reflected from the heliostat to the surface of the Lambert target, and the difference in the focusing efficiency of the Lambert target obtained by the two test tests is compared and analyzed, so as to accurately evaluate the influence of wind and sand activities on the focusing efficiency of the heliostats. On this basis, a statistical analysis is conducted on the influence of wind direction, wind speed and elevation angle on the concentrating efficiency of heliostats in a windy and sandy environment. The range of elevation angles for the optimal service state of heliostats is clarified from the perspective of optical technology. This provides a systematic statistical basis for the design of heliostat layout and structural transmission systems in actual solar thermal power station projects, thereby improving the heat absorption efficiency of the concentrating collector field and ultimately improving the power generation efficiency of tower solar thermal power stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of a wind tunnel test of the effect of wind and sand movement on heliostat focusing in the present invention;

[0054] Figure 2It is a schematic diagram of the arrangement structure of the gradient sand collector of the present invention;

[0055] Figure 3 It is a schematic diagram of the structure of the heliostat test model of the present invention;

[0056] Figure 4 It is a schematic diagram of the measurement point arrangement of the heliostat rigid model of the present invention;

[0057] Figure 5 It is a schematic diagram of wind-sand movement of the present invention;

[0058] Figure 6 Schematic diagram of average wind profile and turbulence intensity of the present invention;

[0059] Figure 7 It is a schematic diagram of the pulsating wind speed power spectrum of the present invention;

[0060] Figure 8 It is a schematic diagram of the light transmission path of the collector field of the present invention.

[0061] Description of reference numerals:

[0062] 1. Test room; 11. Air inlet; 12. Air outlet; 2. Heliostat test model; 21. Turntable; 22. Column; 23. Transparent mirror; 24. Gasket; 25. Universal bearing; 3. Sand trough 3; 4. Gradient sand collector; 5. Rough element and wedge; 6. Lambert target; 7. Laser transmitter; 8. CCD camera; 9. Pitot tube; 26. Heat absorber; 27. Heliostat; 28. Heat absorption tower; 29. ​​Sun. DETAILED DESCRIPTION

[0063] In December 2023, the country emphasized the need to accelerate the construction of a new energy system, vigorously improve the level of safe and reliable substitution of new energy, and focus on promoting the full use of solar concentrating and heat storage technology in Xinjiang, Qinghai, Gansu and other northwestern regions rich in solar energy resources. The new solar thermal power generation technology, due to its unique advantages, can effectively alleviate the dual crisis of the depletion of fossil energy and serious environmental pollution in countries around the world. Compared with fossil energy, solar energy has the unique advantages of wide distribution, sufficient reserves, clean and safe, and has broad commercial application prospects. In recent years, it has grown steadily both globally and in my country. According to statistics, the global cumulative installed capacity of solar thermal power generation will be 7550MW by the end of 2023, of which tower-type solar thermal power generation accounts for about 19.9%, and large-capacity solar thermal power stations have been widely used at home and abroad.

[0064] Three Gorges Energy's Golmud 100MW solar thermal + 1000MW photovoltaic project at the Haixi base, the Jixi base's Lugu DC Baicheng 1.4 million kilowatts transmission project (100MW solar thermal), Qinghai Hainan, Haixi base's Qingyu DC transmission solar thermal 100MW project and many other molten salt tower solar thermal power stations. This type of power station system can be divided into four major units: concentration, heat absorption, heat storage and exchange, and power generation. It is mainly composed of heliostats 27, heat absorption towers 28, absorbers 26, high and low temperature molten salt storage tanks, steam generators and steam turbine generator sets. The basic operating principle is as follows: Figure 8 As shown, the heliostats 27 are distributed in a circle with the heat absorbing tower 28 as the center. The azimuth and altitude angles of the heliostats 27 are adjusted and controlled to reflect the sunlight 29 and focus it on the heat absorber 26 at the top of the heat absorbing tower 28. The liquid binary nitrate low-temperature molten salt is driven by a cold salt pump and flows through the heat absorber 26 at the top of the heat absorbing tower 28 to absorb heat, and the temperature rises to 565°C. The heated molten salt flows into the high-temperature hot salt tank for storage. When power generation is needed, the high-temperature molten salt exchanges heat with water to generate high-temperature and high-pressure steam, which drives the steam turbine generator set to generate power.

[0065] A tower solar thermal power station consists of four major systems, of which the heliostat structure of the concentrating system accounts for more than 50% of the total investment of the power station. During long-term service, ensuring the safe, stable and efficient service of the heliostat structure in a certain windy and sandy environment is the key to the long-term operation of the current tower solar thermal power station.

[0066] However, due to the lightweight and flexible heliostat structure serving in the open and windy desert Gobi environment, the CSP station that has been serving in the desert environment for a long time is frequently disturbed by the characteristic product of the desert climate - wind and sand movement, which has a significant impact on its concentration and heat collection efficiency. Sand particles attached to the front and back of the reflector will not only damage the mirror and the protective paint on the back, but will also significantly affect the concentration rate and reflectivity of the heliostat field, resulting in the output power attenuation of the entire CSP station. According to statistics, during the entire service period of a 50MW CSP station, the direct economic loss is more than 70 million yuan for every 1% to 1.5% decrease in the reflectivity of the heliostat due to the impact of dust on the mirror surface. Moreover, during the operation and maintenance of the power station, the frequency of mirror cleaning needs to be increased, but the related costs will also increase. Therefore, it is urgent to clarify the law and degree of the impact of wind and sand activities on the concentration efficiency of heliostats, clarify the optimal service state of heliostats, and optimize the design of the heliostat structure transmission system and heliostat field layout based on existing technologies to reduce the damage of wind and sand activities to heliostats. However, at present, there are no reports on the impact of wind and sand activities on the damage of heliostats and the output rate of the entire CSP plant. Therefore, it is urgent to develop a wind tunnel test device that can accurately predict the impact of wind and sand activities on the concentration efficiency of heliostats and provide an accurate theoretical basis for the design of the field.

[0067] In summary, based on the research on the basic theory of wind-sand two-phase flow, the present invention designs an experimental test device for the influence of wind-sand activity on the focusing of heliostats, and tests the influence of wind-sand activity on the focusing of heliostats in tower-type solar thermal power stations. In the wind tunnel test design, the test device of the present invention is used to carry out wind tunnel tests on the influence of factors such as wind speed, wind direction and wind-sand particles under various spacings and various arrangements in the heliostat field, so as to obtain the law of wind-sand activity of heliostats under group interference conditions, thereby providing a theoretical basis for optimizing the arrangement of heliostats, formulating cleaning and maintenance strategies, improving power generation efficiency and reducing costs.

[0068] The following is combined with Figures 1 to 8 , the specific implementation of the present invention is described in detail, but it should be understood that the protection scope of the present invention is not limited by the specific implementation. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0069] The present invention provides an experimental test device and a test method for the influence of wind and sand activities on heliostat focusing, comprising a test room 1, wherein the test room 1 has an air inlet 11 and an air outlet 12 arranged relatively to each other, the side close to the air inlet 11 is the upstream, and the side close to the air outlet 12 is the downstream, and is characterized in that it also includes a heliostat test model 2, a sand leakage trough 3, a Lambertian target 6, a laser emitter 7 and a CCD camera 8 arranged in the test room 1, wherein the heliostat test model 2 is arranged at the downstream, the sand leakage trough 3 is arranged at the upstream top of the heliostat test model 2, a plurality of sand leakage holes that can be opened and closed are evenly arranged at the bottom of the sand leakage trough 3, the Lambertian target 6 is arranged upstream of the heliostat test model 2 and downstream of the sand leakage trough 3, the laser emitter 7 is used to emit light to the center of the mirror surface of the heliostat test model 2, and reflect the light spot to the center of the Lambertian target 6 through the center of the mirror surface of the heliostat test model 2, and the CCD camera 8 is used to continuously shoot the number of light spots on the Lambertian target 6.

[0070] Specifically, a sand leakage trough 3 is set at the top position of the upstream area of ​​the heliostat test model 2, and a plurality of sand leakage holes are evenly set at the bottom of the sand leakage trough 3. The test sand enters the test section through the opened sand leakage holes under the action of wind load. At the same time, the amount of sand entering the test section is controlled by adjusting the number of opened sand leakage holes during the test process, and finally the sand may adhere to the surface of the heliostat test model 2 through the action of wind pressure. In the upstream area of ​​the heliostat test model 2 and the downstream area of ​​the sand leakage trough 3, a Lambertian target with a length and width of 1m is arranged, and 4 blue reference points are set at the four corners of the square Lambertian target surface with a side length of 1m, and are numbered n1, n2, n3, and n4, respectively, so as to correct the target surface, and the corresponding two reference points of the diagonals are connected respectively, and the intersection of the two diagonals is taken as the center of the target surface, and then the laser transmitter fixed on the tripod pan head is adjusted. Based on the following Figure 8The light incident-reflection-focusing principle between the heliostat and the heat absorption tower shown is that according to the working state of the heliostat at different elevation angles, the laser transmitter is adjusted so that the light spot is reflected from the center of the mirror surface to the center O of the Lambertian target surface, and the MV-EM120M model CCD camera with a lens focal length of 12mm is selected, and the camera is fixed on a tripod platform on the ground to continuously shoot the number of light spots reflected from the heliostat to the Lambertian target under the influence of wind and sand activities, so as to analyze the influence of sand particle attachment on the focusing rate of the reflective mirror surface. In order to further quantitatively analyze the influence of sand particles on the focusing efficiency of the heliostat under the action of wind load, the sand leakage hole at the bottom of the sand leakage trough 3 is closed on the basis of the present invention, and the gradient sand collector is removed, and the rigid model pressure measurement test of the heliostat without sand particle activity is carried out, and the CCD camera is used to continuously shoot the number of light spots reflected from the heliostat to the Lambertian target, so as to quantitatively compare and analyze the influence of wind and sand activities on the focusing efficiency of the heliostat under different working conditions and wind field environments.

[0071] Preferably, the heliostat test model 2 includes a turntable 21, a column 22 and a light-transmitting mirror 23. The turntable 21 is rotatably arranged downstream of the bottom of the test room 1, and the center of rotation is arranged vertically. The bottom end of the column 22 is fixedly connected to the center of the turntable 21. The middle part of the light-transmitting mirror 23 is hinged to the top of the column 22. Both sides of the light-transmitting mirror 23 are provided with multiple measuring points to realize synchronous pressure measurement, which can facilitate the calculation of the net wind load. The measuring points are connected to the electronic pressure scanning valve channel through a rubber tube. The laser transmitter 7 It is used to emit light to the center of the light-transmitting mirror 23, and reflect the light spot to the center of the Lambert target 6 through the center of the light-transmitting mirror 23, wherein the light-transmitting mirror 23 is made of K9 optical glass, the column 22 is made of steel pipe, and a gasket 24 and a universal bearing 25 are arranged at the bottom center of the light-transmitting mirror 23. The light-transmitting mirror 23 is installed on the column 22 through the gasket 24 and the universal bearing 25, so as to be fixed on the turntable 21 on the ground of the wind tunnel test section, and the influence of different wind attack angles on the movement law of wind and sand is tested, such as Figure 3-5 As shown, and on this basis, the mechanism of wind pressure and wind suction on the distribution characteristics of sand particles on the surface of heliostat is analyzed.

[0072] Preferably, the test room 1 is further provided with a rough element and a wedge 5 and a plurality of wind speed measuring devices, the rough element and the wedge 5 are arranged upstream of the sand leakage trough 3, and the wind speed measuring devices are all arranged upstream of the heliostat rigid model 2 and downstream of the sand leakage trough 3. Specifically, the wind speed measuring device can select a hot wire anemometer, a pitot tube 9, etc. In this embodiment, the pitot tube 9 is used to measure the pulsating wind speed, and each pitot tube 9 is arranged within the mirror height variation range of the heliostat test model 2, and the height distance between the pitot tubes 9 is 10 mm. A reference point is selected in the upstream area of ​​the incoming flow according to the characteristic height of the heliostat, and a rough element and a wedge are arranged in the upstream area of ​​the sand leakage trough 3 to simulate the actual wind field environment of the solar thermal power station. At the same time, a wind speed measuring device is used to monitor the incoming flow wind speed at the height of the test reference point, so that the average wind profile, the turbulence intensity profile and the wind speed power spectrum are finally consistent with the theoretical curve, so as to simulate the wind field environment in the desert Gobi area. Figure 6 and Figure 7 As shown, ensure the accuracy of the test.

[0073] Preferably, a gradient sand collector 4 is provided below the sand drain trough 3, and the gradient sand collector 4 is provided with a plurality of sand collecting channels, and the sand collecting channels are all provided within the range of the mirror height variation of the heliostat test model 2, and the distance between adjacent sand collecting channels is 10 mm, so as to facilitate the testing of the sand concentration of the mirror surface of the heliostat under different working conditions, such as Figure 2 shown.

[0074] Preferably, the heliostat test model 2 is a rigid model so that the heliostat test model 2 will not vibrate under the action of wind load.

[0075] The test method of any of the above-mentioned test devices for testing the effect of wind and sand activities on heliostat focusing also includes the following steps:

[0076] S1-1: Wait for the wind speed in test room 1 to stabilize;

[0077] S1-2: Open the sand leakage hole to start releasing sand and dust, and count for 1 minute as one sand activity collection condition. At the same time, use the CCD camera 8 to take a picture of the light spot reflected by the mirror surface of the heliostat test model 2 onto the surface of the Lambertian target 6 every other condition;

[0078] S1-3: Number the light spots in the order of appearance, n5, n6, n7, n8, n9...;

[0079] S1-4: Count the number of light spots m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25, m26, m27, m28, m29, m30, m31, 10 , and calculate the average value of the number of light spots for 10 times And the average value of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times Specifically, is the total number of light spots inside and outside the Lambertian target 6 surface, is the total number of light spots reflected into the six surfaces of the Lambertian target;

[0080] S1-5: Calculate the light collection efficiency to obtain

[0081] The following steps are also included:

[0082] S2-1: Wait for the wind speed in test room 1 to stabilize;

[0083] S2-2: Close all the sand leakage holes and count for 1 minute as one wind sand activity collection condition. At the same time, use the CCD camera 8 to take a picture of the light spot reflected by the mirror surface of the heliostat test model 2 onto the surface of the Lambertian target 6 every other condition.

[0084] S2-3: Count the number of light spots reflected by the reflector to the Lambertian target surface during the 10-day test, and calculate the average value m′ of the number of light spots for 10 times, as well as the average value m of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times. t ' otal ;

[0085] S2-4: Calculate the light collection efficiency to obtain

[0086] S2-5: Calculation

[0087] Specifically, according to the test frequency of the rigid model of the heliostat structure, the following statistics are obtained: ① The variation law of the number of light spots on the surface of the Lambert target with time; ② The variation law of the number of light spots on the surface of the Lambert target with wind speed; ③ The variation law of the number of light spots on the surface of the Lambert target with wind direction angle; ④ The variation law of the number of light spots on the surface of the Lambert target with elevation angle. In order to investigate the influence of wind and sand particles attached to the surface of the reflector on its reflectivity and concentration rate, the optimal service elevation angle range of the heliostat under the combined action of wind and sand is clarified to improve the concentration efficiency of the heliostat field;

[0088] Furthermore, in order to compare and illustrate the influence of wind and sand activities on the concentrating and collecting efficiency of heliostats, by closing all the holes of the sand drain trough 3, the concentrating efficiency test of heliostats without sand particle movement was carried out under different elevation angles, wind speeds, wind directions and other combined working conditions, so as to quantitatively analyze the influence of wind and sand activities on the concentrating and collecting efficiency of heliostat structures. The differences between the Lambertian target focusing efficiencies η(t) and η′(t) of the heliostat in the rigid model test with and without the influence of sand particles are compared and analyzed. Combined with the sand particle size and the corresponding critical starting wind speed, the optimal elevation angle range for the heliostat to serve in a windy and sandy environment is clarified.

[0089] Specifically, the light-transmitting mirror surface 23 is rotated around the corresponding hinge to adjust the elevation angle of the light-transmitting mirror surface 23, so as to test the influence of different elevation angle working states on the focusing efficiency of the heliostat.

[0090] Specifically, the turntable 21 is rotated to change the wind direction received by the light-transmitting mirror surface 23, so as to test the influence of different wind directions on the focusing efficiency of the heliostat.

[0091] As a preferred method, the test method of the influence of wind and sand activities on the focusing of heliostats in tower-type solar thermal power stations also includes a test method for the critical wind speed of sand particles at each reference height. A gradient sand collector 4 is also provided in the test room 1. The gradient sand collector 4 is located upstream of the heliostat test model 2. The gradient sand collector 4 is located below the sand leakage trough 3 and downstream of the sand leakage trough 3. The steps of the test method for the critical wind speed of sand particles are as follows:

[0092] S3-1: Wait for the wind speed in test room 1 to stabilize;

[0093] S3-2: Open the sand leakage hole and start releasing sand and dust. 1 minute is counted as one sand activity collection condition. Every other condition, sand and dust in each sand collection channel of the gradient sand collector 4 are collected and weighed respectively;

[0094] S3-3: Calculate the average weight of each dust in 10 working conditions;

[0095] S3-4: Calculate dust concentration at each reference height in:

[0096] ρ 沙 ——Sand concentration, g / m 3 ;

[0097] Q——collected sand volume, g;

[0098] t——sand collection time, s;

[0099] A0——Opening area of ​​sand collection tester, m 2 ;

[0100] V H ——average wind speed at reference height, m / s;

[0101] S3-5: Calculate the critical wind speed for sand particles at each reference height

[0102]

[0103] Among them, A is the empirical coefficient, which is generally taken as 0.1;

[0104] ρ s - sand density;

[0105] ρ——air density;

[0106] d——sand particle diameter;

[0107] g——acceleration due to gravity;

[0108] z – height;

[0109] z0——surface roughness;

[0110] The above technical scheme is used to clarify the critical wind speed for sand particle startup and its relationship with particle size, and then evaluate the relationship between sand and fluid velocity around the heliostat.

[0111] In the description of the present invention, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0112] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect" and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0113] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An experimental test device for the effect of wind and sand activities on heliostat focusing, characterized in that: The invention comprises a test room (1), having an air inlet (11) and an air outlet (12) arranged opposite to each other, the side close to the air inlet (11) being the upstream side, and the side close to the air outlet (12) being the downstream side, and also comprising: Heliostat test model (2), located downstream; A sand leakage trough (3) is arranged upstream of the heliostat test model (2) and located at the top of the test room (1), and a plurality of sand leakage holes that can be opened and closed are evenly arranged at the bottom of the sand leakage trough (3); A laser emitter (7) for emitting light to the mirror surface of the heliostat test model (2); A Lambertian target (6) is arranged upstream of the heliostat test model (2) so that the center of the Lambertian target (6) can receive light reflected by the center of the mirror surface of the heliostat test model (2); A CCD camera (8) is used to continuously photograph the number of light spots on the Lambertian target (6); The heliostat test model (2) comprises a turntable (21), a column (22) and a light-transmitting mirror (23); the turntable (21) is rotatably arranged downstream of the bottom of the test room (1), and the center of rotation is arranged vertically; the bottom end of the column (22) is fixedly connected to the center of the turntable (21); the middle part of the light-transmitting mirror (23) is hinged to the top of the column (22); a plurality of measuring points are arranged on both sides of the light-transmitting mirror (23); the measuring points are connected to the electronic pressure scanning valve channel through a rubber tube; the laser emitter (7) is used to emit light to the center of the light-transmitting mirror (23), so that the center of the Lambertian target (6) can receive the light reflected by the center of the mirror surface of the light-transmitting mirror (23); The test room (1) is also provided with a rough element and a wedge (5) and a plurality of wind speed measuring devices. The rough element and the wedge (5) are arranged upstream of the sand leakage trough (3). The wind speed measuring devices are all arranged upstream of the heliostat test model (2). Each wind speed measuring device is arranged within the range of the mirror height variation of the heliostat test model (2), and the distance between adjacent wind speed measuring devices is 9 mm to 11 mm. A gradient sand collector (4) is provided below the sand leakage trough (3), the gradient sand collector (4) is located downstream of the sand leakage trough (3) and upstream of the heliostat test model (2), the gradient sand collector (4) is provided with a plurality of sand collection channels, the sand collection channels are all provided within the range of variation of the mirror surface height of the heliostat test model (2), and the distance between adjacent sand collection channels is 9 mm to 11 mm; The heliostat test model (2) is a rigid model.

2. The testing method of the test device for testing the effect of wind and sand activities on heliostat focusing as claimed in claim 1, comprising the following steps: S1-1: The wind speed in the test room (1) is stable; S1-2: Open the sand leakage hole to start releasing sand and dust, and set the time as a sand activity collection working condition. At the same time, use a CCD camera (8) to take a picture of the light spot reflected by the mirror surface of the heliostat test model (2) to the surface of the Lambertian target (6) every other working condition; S1-3: Number the light spots in the order of appearance, n5, n6, n7, n8, n9...; S1-4: Count the number of light spots m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25, m26, m27, m28, m29, m30, m31, m32, m33, m34, m35, m36, m37, m38, m39, m40, m41, m42, m43, m44, m45, m46, m47, m48, m49, m5 10 , and calculate the average value of the number of light spots for 10 times And the average value of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times S1-5: Calculate the light collection efficiency to obtain 3. The testing method of the test device for testing the effect of wind and sand activities on heliostat focusing as claimed in claim 2, characterized in that: The following steps are also included: S2-1: Close all sand leakage holes and wait for the wind speed in the test room (1) to stabilize; S2-2: taking a set time as a wind and sand activity collection working condition, and at the same time, using a CCD camera (8) to take a picture of a light spot reflected from the mirror surface of the heliostat test model (2) to the surface of the Lambertian target (6) every other working condition; S2-3: Count the number of light spots reflected by the reflector to the Lambertian target surface during the 10 continuous test conditions, and calculate the average value of the number of light spots for 10 times And the average value of the total number of light spot reflection points captured by the CCD camera for 10 consecutive times S2-4: Calculate the light collection efficiency to obtain S2-5: Calculation Among them, Δ is the influence of wind and sand activities on the concentration and heat collection efficiency of the heliostat structure, η is the concentration efficiency of the heliostat when there is wind and sand activity, and η′ is the concentration efficiency of the heliostat when there is no wind and sand activity.

4. The testing method of the test device for testing the effect of wind and sand activities on heliostat focusing as claimed in claim 2, characterized in that: The invention also includes a test method for the critical wind speed at which sand particles start at each reference height. A gradient sand collector (4) is also provided in the test room (1). The gradient sand collector (4) is located upstream of the heliostat test model (2). The gradient sand collector (4) is located below the sand leakage trough (3) and downstream of the sand leakage trough (3). The test method for the critical wind speed at which sand particles start is performed in the following steps: S3-1: The wind speed in the test room (1) is stable; S3-2: Open the sand leakage hole to start releasing sand and dust, and set the time as a sand activity collection working condition. Collect the sand and dust in each sand collection channel of the gradient sand collector (4) every other working condition and weigh them respectively; S3-3: Calculate the average weight of each dust in 10 working conditions; S3-4: Calculate the sand concentration at each reference height in: ρ 沙 ——Sand concentration, g / m 3 ; Q——collected sand volume, g; t——sand collection time, s; A0——Opening area of ​​sand collection tester, m 2 ; V H ——average wind speed at reference height, m / s; S5: Calculate the critical wind speed of sand particles at each reference height Among them, A is the empirical coefficient, with a value of 0.1; ρ s ——Sand density, kg / m 3 ; ρ——air density, kg / m 3 ; d——sand particle diameter, mm; g——acceleration due to gravity, m / s 2 ; z——height, m; z0——surface roughness.

Images