Bird droppings simulant with controllable rheological property and preparation method of bird droppings simulant

Abstract

The invention discloses a bird droppings simulant with controllable rheological properties and a preparation method thereof. The bird droppings simulant comprises the following components: 4%-6% of sodium chloride, 8%-9% of uric acid, 10%-13% of flour, 0.5%-1% of K-type carrageenan, 1%-2% of hydroxypropyl guar gum and water. The invention focuses on improving the rheological property of the bird droppings simulant and obviously enhancing the thixotropy and wire drawing capability of the simulant, so that the bird droppings simulant can keep higher viscosity under low shear force, can quickly flow at high shear rate (such as wind blowing and gravity traction), and can be naturally thinned and extended until fracture in the drying process; and the method is closer to the form change process of real bird droppings in a natural environment.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission line maintenance, and in particular to a guano simulant with controllable rheological properties and a preparation method thereof. Background Art

[0002] High-voltage transmission lines in Inner Mongolia are exposed to extreme climate conditions all year round, with strong sandstorms, low humidity, and frequent bird activity. Bird droppings not only affect the insulation performance of insulators, but may also form wire-like conductive channels under certain conditions, increasing the risk of flashover. Normally, bird droppings contain a certain amount of moisture after excretion and gradually dry over time, but in dry climates, moisture evaporates faster, and bird droppings may begin to fall in a semi-fluid state, appearing in wire-like, elongated strips, or even broken shapes, which may cause premature discharge before it touches the wire.

[0003] Experimental studies have shown that under the action of a high-voltage electric field, wet or semi-dry bird droppings may be drawn into filaments, and when close to a conductor, the electric field causes local air ionization. Even if the bird droppings have not yet touched the conductor, air gap discharge may occur. This phenomenon is particularly evident in dry environments such as Inner Mongolia, because the water in the bird droppings evaporates quickly and easily forms a slender high-conductivity liquid bridge, which makes the flashover occur farther than in humid areas, up to 10 cm or even farther. However, most existing bird droppings simulants use a single consistency formula and lack wire drawing properties, making it difficult to accurately simulate the discharge behavior of bird droppings in actual environments, resulting in a large gap between experimental data and actual conditions. Although some conventional thickeners (e.g., xanthan gum, sodium carboxymethyl cellulose) can increase viscosity, they have limitations in simulating the wire drawing of bird droppings and the rheological behavior affected by wind force changes, making it difficult to fully reproduce the dynamic changes of bird droppings under the influence of multiple factors such as wind speed, gravity, and humidity. This results in a large gap between the experimental data based on these simulants and the actual impact of guano on transmission lines, which cannot provide accurate and reliable reference for power system operation and maintenance personnel, thus affecting the effective prevention and control of guano flashover faults in transmission lines and the formulation of countermeasures. Therefore, the development of a guano simulant that can accurately simulate the wire drawing characteristics of guano in the actual environment is of great practical significance and is crucial to improving the operational safety and stability of transmission lines. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention optimizes the rheological properties of the bird droppings mimetic, adopts a composite thickening system of K-carrageenan and hydroxypropyl guar gum (HPG), and improves the controllable rheological properties of the mimetic at different shear rates. By adjusting the ratio of water to thickener, the mimetic has a high viscosity under static conditions, exhibits excellent shear thinning when subjected to the action of wind speed, gravity or electric field, and at the same time has good wire drawing and fracture characteristics, so as to more realistically reproduce the flow, stretching and deposition behaviors of bird droppings in the actual environment. The present invention introduces uric acid components to simulate the main organic metabolites in real bird droppings, which not only improves the component simulation degree of the mimetic, but also promotes the wire drawing ability and overall rheology of the composite thickening system of K-carrageenan and hydroxypropyl guar gum. The bird droppings mimetic of the present invention is not only applicable to the study of the pollution flashover mechanism in the state of bird droppings wire drawing, but also can be used to systematically evaluate the pollution flashover risk of transmission lines under different wind speeds, humidities and electric field conditions, providing a more accurate and real experimental basis for formulating anti-pollution flashover measures for the power grid.

[0005] The technical solution of the present invention is as follows: A bird droppings mimetic with controllable rheological properties, by mass fraction, comprises the following components: sodium chloride 4% - 6%, uric acid 8% - 9%, flour 10% - 13%, K-carrageenan 0.5% - 1%, hydroxypropyl guar gum 1% - 2% and water.

[0006] Preferably, the bird droppings mimetic with controllable rheological properties, by mass fraction, comprises the following components: sodium chloride 4.5%, uric acid 8.5%, flour 10.5%, K-carrageenan 0.5%, hydroxypropyl guar gum 1.0% and water.

[0007] Preferably, the bird droppings mimetic with controllable rheological properties, by mass fraction, comprises the following components: sodium chloride 4.8%, uric acid 8.5%, flour 11%, K-carrageenan 0.8%, hydroxypropyl guar gum 1.5% and water.

[0008] Preferably, the bird droppings mimetic with controllable rheological properties, by mass fraction, comprises the following components: sodium chloride 5.2%, uric acid 8.5%, flour 12.2%, K-carrageenan 1%, hydroxypropyl guar gum 2% and water.

[0009] The preparation method of the bird droppings mimetic with controllable rheological properties comprises the following steps: The first step: Add water to a beaker, add sodium chloride and stir until completely dissolved to obtain a main solution; The second step: Take hydroxypropyl guar gum, pre-dissolve it with warm water first, and then slowly pour it into the main solution and stir, continuously stir for 10 - 15 minutes to ensure uniform dispersion; The third step: Add uric acid and continuously stir to obtain a mixed solution; Step 4: Take K-carrageenan, disperse it in warm water, and then add it to the mixture; gradually add flour and stir with a high-speed stirrer to make the rheological properties uniform and stable. Step 5: Place it in a sealed container and let it stand for 3 - 5 hours.

[0010] Preferably, the warm water is water at 50 °C.

[0011] Preferably, in Step 3, the stirring time is 15 - 20 minutes.

[0012] Preferably, in Step 2, the stirring time is 10 - 15 minutes.

[0013] Preferably, in Step 4, the stirring time is 15 - 20 minutes.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention innovatively adopts a composite thickening system of K-carrageenan and hydroxypropyl guar gum (HPG). Through synergistic effects, the thixotropy and drawing ability of the mimic are significantly enhanced, enabling the bird droppings mimic to maintain a high viscosity under low shear forces, flow rapidly under high shear rates (such as wind blowing, gravity traction), and naturally thin and extend until it breaks during the drying process, which is closer to the morphological change process of real bird droppings in the natural environment.

[0015] The bird droppings mimic of the present invention has the following technical breakthroughs: 1). Enhanced thixotropy: By introducing HPG as the main rheology control agent, the mimic maintains a high viscosity at low shear, rapidly reduces viscosity and resumes fluidity under external force, simulating the real deposition and change process of bird droppings under different wind speeds. Compared with the conventional xanthan gum / CMC system, the shear response speed is faster and the recovery is better.

[0016] 2). Improved drawing characteristics: K-carrageenan forms a controllable weak gel network in a sodium chloride environment, enabling the bird droppings mimic to continuously draw and gradually thin until it breaks during the drying process, greatly enhancing the ability to restore the dynamic drawing characteristics of bird droppings, and significantly superior to the problem of easy breakage and brittleness of the traditional xanthan gum / CMC system.

[0017] 3). Improved experimental adaptability: The new compound thickening system endows the mimic with a wider range of applications, and it can work stably under various extreme environmental conditions such as wind tunnel experiments, corona discharge experiments, and high-voltage insulator pollution flashover tests, significantly improving the authenticity and reliability of experimental results, and providing more accurate basic data support for formulating anti-bird-dropping pollution measures for high-voltage transmission lines. Detailed implementation manners

[0018] To better understand the technical content of the present invention, the following further illustrates the present invention in combination with specific embodiments.

[0019] Example 1: Controllable Rheological Property Guano Simulant and Its Preparation Method By mass fraction, the formula of the guano simulant is as follows: Sodium chloride 4.5%, uric acid 8.5%, flour 10.5%, K-carrageenan 0.5%, hydroxypropyl guar gum 1.0%, water 75%.

[0020] The water in the above guano simulant is divided into three parts and used in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the mass of deionized water in the first step, warm water in the second step, and warm water in the fourth step accounts for 75% of the formula.

[0021] The preparation method of the guano simulant is as follows: First step: Add deionized water to a beaker, add sodium chloride and stir until completely dissolved.

[0022] Second step: Take hydroxypropyl guar gum, pre-dissolve it with warm water (50°C) first, and then slowly pour it into the main solution and stir. Keep stirring for 10 - 15 minutes to ensure uniform dispersion.

[0023] Third step: Add uric acid and keep stirring for 15 - 20 minutes.

[0024] Fourth step: Take K-carrageenan, disperse it in warm water, and then add it to the mixture. Gradually add flour and use a high-speed stirrer to stir for 15 - 20 minutes to make the rheological properties uniform and stable.

[0025] Fifth step: Place it in a sealed container and let it stand for 3 - 5 hours to improve the rheological stability.

[0026] Example 2: Controllable Rheological Property Guano Simulant and Its Preparation Method By mass fraction, the formula of the guano simulant is as follows: Sodium chloride 4.8%, uric acid 8.5%, flour 11.0%, K-carrageenan 0.8%, hydroxypropyl guar gum 1.5%, water 73.4%.

[0027] The water in the above guano simulant is divided into three parts and used in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the mass of deionized water in the first step, warm water in the second step, and warm water in the fourth step accounts for 73.4% of the formula.

[0028] The preparation method of the guano simulant is the same as that of Example 1.

[0029] Example 3: Controllable Rheological Property Guano Simulant and Its Preparation Method By mass fraction, the formula of the guano simulant is as follows: Sodium chloride 5.2%, uric acid 8.5%, flour 12.2%, K-carrageenan 1.0%, hydroxypropyl guar gum 2.0%, water 71.1%.

[0030] The water in the above guano mimetic is divided into three parts and used in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the masses of deionized water in the first step, warm water in the second step, and warm water in the fourth step accounts for 71.1% of the formula.

[0031] The preparation method of the guano mimetic is the same as that of Example 1.

[0032] Test Example 1) Rheological property test In order to verify the rheological properties of guano mimetics made with different thickener systems at different shear rates, based on the combination of sodium carboxymethyl cellulose (CMC) and xanthan gum commonly used in the prior art, three comparative samples were prepared according to the above configuration steps, numbered A1, B1, and C1 respectively. The three groups of samples have different initial viscosity levels, among which sample A1 has the lowest viscosity, sample B1 has a moderate viscosity, and sample C1 has the highest viscosity. Through the rheological property tests of these samples, it serves as the basis for comparing with the performance of the innovative formulation (K-carrageenan + hydroxypropyl guar gum system) of the present invention. Using the above configuration steps, three samples were made with the K-carrageenan + HPG thickening system. The three samples have different initial viscosities. Among them, sample A2 has the lowest viscosity, sample B2 has a moderate viscosity, and sample C2 has the highest viscosity.

[0033] Table 1

[0034] Table 2

[0035] The experiment used a coaxial cylinder rotational rheometer with a coaxial cylinder having a diameter of 50 mm and a gap of 1 mm. The experiment was carried out at an indoor ambient temperature of 25°C.

[0036] Experimental steps: First step: Fill samples A, B, and C into the coaxial cylinder gap in sequence, avoiding air residue.

[0037] Second step: Set a stepped shear rate scan, and the shear rates are set to 0.1 cm / s, 1 cm / s, 10 cm / s, 30 cm / s, 50 cm / s, 80 cm / s, and 100 cm / s respectively.

[0038] Third step: Record the relationship between torque and shear rate, and automatically calculate the viscosity through software (viscosity = torque / shear rate).

[0039] Table 3

[0040] 2) Drawing ability test The drawing ability test uses the same sample as for the rheological property experiment, and is carried out at a controlled room temperature of 25 °C. A self-made parallel plate fixture is used (the middle gap is 5 cm long, 1 cm wide, and 1 cm high, and the surface in contact with the simulation object is roughened to enhance the adhesion between the sample and the fixture and prevent the sample from falling off the fixture). A ruler is used as the measuring tool, and the drawing length is observed with the naked eye. First step: Apply vaseline to the glass tabletop to prevent the sample from sticking to the tabletop during subsequent operations and affecting the experiment. Shape the sample into a 1×1×15 cm long strip and cover it with plastic wrap to keep it moist.

[0041] Second step: Clamp the sample with the parallel plate fixture, and set the length of the sample between the two fixtures to 5 cm. Ensure good contact between the sample and the fixture to prevent it from falling off during the experiment.

[0042] Third step: Fix one end and slowly and uniformly pull the other end. Stop stretching when the sample breaks, measure the distance between the two fixtures and the distance at the break of the sample, and calculate the total length of the stretched sample and the stretching length.

[0043] Table 4

[0044] The experimental results show that all samples exhibit typical shear thinning characteristics, that is, as the shear rate increases, the viscosity gradually decreases, indicating that the simulation object has high viscosity under static conditions and enhanced fluidity when subjected to external forces. Compared with samples A1, B1, and C1 prepared with the traditional formula (using a sodium carboxymethyl cellulose and xanthan gum thickener system), samples A2, B2, and C2 prepared with the innovative formula (K-carrageenan and hydroxypropyl guar gum composite system) adopted in the present invention exhibit higher initial viscosities and better shear thinning characteristics at each shear rate, and can better simulate the flow and deposition behavior of bird droppings in the natural environment. At the same time, in the drawing performance test, the drawing lengths of samples A2, B2, and C2 prepared with the innovative formula are significantly better than those of the traditional formula, indicating that by adjusting the content of K-carrageenan and HPG, the drawing ability and overall rheological properties of the simulation object can be effectively improved, thus more realistically reproducing the dynamic process of bird droppings drying, drawing, and breaking.

[0045] Comparative Example 1 Controllable rheological property bird dropping simulation object and its preparation method By mass fraction, the formula of the bird dropping simulation object is as follows: Sodium chloride 5.2%, uric acid 8.5%, flour 12.2%, CMC 1.0%, hydroxypropyl guar gum 2.0%, water 71.1%.

[0046] Divide the water in the above guano mimetic into three parts and use them in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the masses of the deionized water in the first step, the warm water in the second step, and the warm water in the fourth step accounts for 71.1% of the formula.

[0047] The preparation method of the guano mimetic is the same as that of Example 1.

[0048] For Comparative Example 2, by mass fraction, the formula of the guano mimetic is as follows: Sodium chloride 5.2%, uric acid 8.5%, flour 12.2%, K-carrageenan 1.0%, xanthan gum 2.0%, water 71.1%.

[0049] Divide the water in the above guano mimetic into three parts and use them in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the masses of the deionized water in the first step, the warm water in the second step, and the warm water in the fourth step accounts for 71.1% of the formula.

[0050] The preparation method of the guano mimetic is the same as that of Example 1.

[0051] In Comparative Example 1 and Comparative Example 2, CMC and xanthan gum were used to replace K-carrageenan and hydroxypropyl guar gum in Example 3 respectively. The results showed that the viscosities were 307 - 324 mPa·s at a shear rate of 100 cm / s, and the tensile lengths were 4.3 - 4.8 cm. Comparing the results of Comparative Example 1 and Comparative Example 2 with those of Example 3 (i.e., sample C3), it can be seen that the wire-drawing ability and overall rheological properties of the K-carrageenan and hydroxypropyl guar gum composite system are significantly better, indicating that there is a certain synergistic effect between the two.

[0052] Comparative Example 3 Controllable rheological property guano mimetic and its preparation method By mass fraction, the formula of the guano mimetic is as follows: Sodium chloride 5.2%, uric acid 0%, flour 12.2%, K-carrageenan 1.0%, hydroxypropyl guar gum 2.0%, water 79.6%.

[0053] Divide the water in the above guano mimetic into three parts and use them in the first, second, and fourth steps of the following preparation method respectively. That is, the sum of the masses of the deionized water in the first step, the warm water in the second step, and the warm water in the fourth step accounts for 79.6% of the formula.

[0054] The preparation method of the guano mimetic is the same as that of Example 1.

[0055] In Comparative Example 3, uric acid was not added. The results showed that the viscosity was 330 mPa·s at a shear rate of 100 cm / s, and the stretching length was 5.1 cm. By comparing the results of Comparative Example 3 with those of Example 3 (i.e., sample C3), it can be seen that uric acid plays a certain promoting role in the wire-drawing ability and overall rheological properties of the composite system of κ-carrageenan and hydroxypropyl guar gum.

[0056] Example 4: Controllable Rheological Properties of Bird Dropping Simulant and Its Preparation Method By mass fraction, the formula of the bird dropping simulant is as follows: Sodium chloride 4.0%, uric acid 8.0%, flour 10.0%, κ-carrageenan 0.8%, hydroxypropyl guar gum 1.5%, water 75.7%.

[0057] The water in the above bird dropping simulant is divided into three parts and used in the first step, the second step, and the fourth step of the following preparation method respectively. That is, the sum of the masses of deionized water in the first step, warm water in the second step, and warm water in the fourth step accounts for 75.7% of the formula.

[0058] The preparation method of the bird dropping simulant is the same as that of Example 1.

[0059] Example 5: Controllable Rheological Properties of Bird Dropping Simulant and Its Preparation Method By mass fraction, the formula of the bird dropping simulant is as follows: Sodium chloride 6.0%, uric acid 9.0%, flour 13.0%, κ-carrageenan 0.8%, hydroxypropyl guar gum 1.5%, water 69.7%.

[0060] The water in the above bird dropping simulant is divided into three parts and used in the first step, the second step, and the fourth step of the following preparation method respectively. That is, the sum of the masses of deionized water in the first step, warm water in the second step, and warm water in the fourth step accounts for 69.7% of the formula.

[0061] The preparation method of the bird dropping simulant is the same as that of Example 1.

[0062] Example 4 and Example 5 have similar effects to the aforementioned samples A2, B2, and C2. The viscosity is 340 mPa·s at a shear rate of 100 cm / s. The stretching length is 5.5 cm.

[0063] The above are only some embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A bird droppings mimetic with controllable rheological properties, characterized in that, By mass fraction, it includes the following components: sodium chloride 4% - 6%, uric acid 8% - 9%, flour 10% - 13%, K-carrageenan 0.5% - 1%, hydroxypropyl guar gum 1% - 2% and water.

2. The bird droppings mimetic with controllable rheological properties according to claim 1, characterized in that, By mass fraction, it includes the following components: sodium chloride 4.5%, uric acid 8.5%, flour 10.5%, K-carrageenan 0.5%, hydroxypropyl guar gum 1.0% and water.

3. The bird droppings mimetic with controllable rheological properties according to claim 1, characterized in that, By mass fraction, it includes the following components: sodium chloride 4.8%, uric acid 8.5%, flour 11%, K-carrageenan 0.8%, hydroxypropyl guar gum 1.5% and water.

4. The bird droppings mimetic with controllable rheological properties according to claim 1, characterized in that, By mass fraction, it includes the following components: sodium chloride 5.2%, uric acid 8.5%, flour 12.2%, K-carrageenan 1%, hydroxypropyl guar gum 2% and water.

5. A preparation method of the bird droppings mimetic with controllable rheological properties according to any one of claims 1 to 4, characterized in that, It includes the following steps: The first step: Add water into a beaker, add sodium chloride and stir until completely dissolved to obtain a main solution. The second step: Take hydroxypropyl guar gum, pre-dissolve it with warm water first, and then slowly pour it into the main solution and stir. Keep stirring to ensure uniform dispersion. The third step: Add uric acid and keep stirring to obtain a mixed solution. The fourth step: Take K-carrageenan, disperse it in warm water, and then add it into the mixed solution; gradually add flour and use a high-speed stirrer to stir to make the rheological properties uniform and stable. The fifth step: Place it in a sealed container and let it stand for 3 - 5 hours.

6. The preparation method according to claim 5, characterized in that, The warm water is water at 50°C.

7. The preparation method according to claim 5, characterized in that, In the third step, the stirring time is 15 - 20 minutes.

8. The preparation method according to claim 5, characterized in that, In the second step, the stirring time is 10 - 15 minutes.

9. The preparation method according to claim 5, characterized in that, In the fourth step, the stirring time is 15 - 20 minutes.

Images