Preparation method of high-altitude water for ice wind tunnel simulation

Abstract

A method for preparing high-altitude water for ice wind tunnel simulation, comprising mixing tetrahydrofuran and matrix water in a mass ratio of 0% to 20%, to obtain high-altitude simulated water with a low freezing temperature for ice wind tunnel simulation. The present invention introduces a hydrogen bond acceptor into deionized water by adding tetrahydrofuran, so that the freezing temperature of the water can be regulated over a wide range without affecting the purity of the deionized water, thereby achieving the supercooled freezing temperature effect of high-altitude ultrapure water. The prepared water for ice wind tunnel high-altitude simulation has the advantages of stable physical form and no stratification, and the preparation process has the characteristics of simple operation and strong practicality. The invention solves the problem that the ground cannot simulate the supercooled state of high-altitude high-purity water, and provides a solution for ice wind tunnel simulation of high-altitude water and ground preparation of simulated supercooled ultrapure water.

Description

Technical Field

[0001] The present invention relates to a technology in the field of wind tunnel simulation, in particular to a method for preparing high-altitude water for ice wind tunnel simulation. Background Art

[0002] Icing wind tunnels are large, specialized wind tunnels with complex performance requirements. They serve as ground-based test facilities for studying ice formation patterns, ice tolerance, and anti-icing (de-icing) technologies on the windward surfaces of various aircraft components and the external sensing sections of detection instruments during flight in icing weather conditions. Because water at altitude is ultrapure water lacking condensation nuclei (most commonly compounds such as chlorine, nitrogen, carbon, magnesium, sodium, and calcium), the resulting supercooled water remains liquid even at temperatures between -15°C and -20°C without freezing. Therefore, simulating supercooled water at altitude in ground-based environments requires a higher purity level. However, the carbon dioxide concentration at ground level is high, and when the water is ultrapure (18.2 MΩ·cm), carbon dioxide readily dissolves in water, affecting its purity. This is because carbon dioxide is a weakly acidic gas. Dissolving in water forms carbonic acid, which degrades the water's purity and, in turn, affects the freezing temperature of the ultrapure water. Consequently, ground-based wind tunnel tests are unable to simulate the freezing conditions of water at altitude. Therefore, there is an urgent need to develop high-altitude water for ground ice wind tunnel simulation, that is, to simulate the supercooled temperature of high-altitude water on the ground. Summary of the Invention

[0003] In response to the aforementioned shortcomings of the prior art, the present invention proposes a method for preparing high-altitude water for ice wind tunnel simulation. By adding tetrahydrofuran to deionized water, a hydrogen bond acceptor is introduced. This allows the freezing temperature of the water to be controlled over a wide range without affecting the purity of the deionized water, thereby achieving the supercooled freezing temperature effect of high-altitude ultrapure water. The prepared water for ice wind tunnel high-altitude simulation has the advantages of stable physical form and no stratification. The preparation process is simple to operate and highly practical. This invention solves the problem of the inability to simulate the supercooled state of high-altitude high-purity water on the ground, providing a solution for ice wind tunnel simulation of high-altitude water and the preparation of simulated supercooled ultrapure water on the ground.

[0004] The present invention is achieved through the following technical solutions:

[0005] The invention relates to a method for preparing high-altitude water for ice wind tunnel simulation. The method comprises mixing tetrahydrofuran and matrix water in a mass ratio of 0.1% to 20% to obtain high-altitude simulated water with a low freezing temperature for ice wind tunnel simulation.

[0006] The mixing is preferably uniformly mixed under magnetic stirring and dispersion.

[0007] The matrix water is preferably deionized water.

[0008] Technical Effects

[0009] This invention utilizes a hydrogen bond control strategy to inhibit freezing, enabling wide-range control of the freezing temperature of water used in wind tunnel high-altitude simulations, reaching the freezing temperature of ultrapure water without compromising water purity. Compared to existing technologies, this invention maintains the purity of deionized water and enables deionized water to freeze at -15°C. The resulting water exhibits advantages such as stable physical form and lacks stratification. The preparation process is simple to operate and highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Figure 1 shows the resistance and conductivity test device (a), the freezing temperature test device (b), and the sample placement diagram during the freezing temperature test.

[0011] Figure 2 The conductivity and resistivity diagrams are for tap water, ultrapure water-0min and ultrapure water-10min;

[0012] Figure 3 The cooling process diagrams of tap water, ultrapure water-0min and ultrapure water-10min;

[0013] Figure 4 The actual picture of the prepared deionized water and the 0.1%-20% tetrahydrofuran / deionized water solution;

[0014] Figure 5 The conductivity and resistivity diagrams are for deionized water and 0.1%-20% tetrahydrofuran / deionized water solutions;

[0015] Figure 6 Freezing temperature diagram for deionized water and 0.1%-20% tetrahydrofuran / deionized water solution. DETAILED DESCRIPTION

[0016] Example 1

[0017] This example tests the purity (conductivity and resistivity) and freezing temperature of comparative tap water as follows:

[0018] Step 1: Add 20g of tap water into a container as a comparative example, and test the conductivity and resistivity of the tap water at 25°C;

[0019] Step 2: Add 10 g of tap water to a 20 mL container;

[0020] Step 3: Add 5 mL of paraffin oil to the container (to prevent air dust from entering during the freezing temperature test and thus affecting the test results);

[0021] Step 4: Test the freezing temperature of tap water;

[0022] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to measure the purity and freezing temperature of tap water respectively.

[0023] like Figure 1-Figure 3 As shown, after actual testing, the conductivity of tap water is 2.518μS / cm; the resistivity of tap water is 397kΩ·cm; and the freezing temperature of tap water is -7.3℃.

[0024] Example 2

[0025] This example tests the purity of ultrapure water prepared by the ultrapure water machine in the comparative example as follows: conductivity, resistivity and freezing temperature after being stored in air for different periods of time:

[0026] Step 1: Add 20 g of ultrapure water prepared by an ultrapure water machine to a container, record ultrapure water - 0 min (tetrahydrofuran accounts for 0% of the matrix water), and immediately test the conductivity and resistivity of the ultrapure water prepared by the ultrapure water machine at 25°C;

[0027] Step 2: Add 10 g of ultrapure water prepared by an ultrapure water machine into a 20 mL container;

[0028] Step 3: Add 5 mL of paraffin oil into the above container;

[0029] Step 4: Test the freezing temperature of the ultrapure water prepared by the ultrapure water machine;

[0030] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to measure the purity and freezing temperature of ultrapure water at -0 min, respectively.

[0031] like Figure 1-Figure 3 As shown, after actual testing, the ultrapure water machine showed an online water purity of 18.2 MΩ·cm; the conductivity of the ultrapure water prepared by the ultrapure water machine was 0.469 μS / cm; the resistivity of the ultrapure water prepared by the ultrapure water machine was 2130 kΩ·cm; and the freezing temperature of the ultrapure water prepared by the ultrapure water machine was -12.0°C. Therefore, the ultrapure water immediately came into contact with air upon collection, causing its purity to drop from 18.2 MΩ·cm to 2130 kΩ·cm (carbon dioxide in the air immediately dissolved into the ultrapure water). Compared with the results of Example 3, its freezing temperature also increased.

[0032] Example 3

[0033] This example tests the purity (conductivity and resistivity) and freezing temperature of ultrapure water prepared by the comparative example ultrapure water machine and placed in air for 10 minutes as follows:

[0034] Step 1: Add 20 g of ultrapure water that has been left for 10 minutes to a container, record it as ultrapure water-10 min (tetrahydrofuran accounts for 0% of the matrix water), and test the conductivity and resistivity of the ultrapure water that has been left for 10 minutes at 25°C;

[0035] Step 2: Add 10 g of ultrapure water that has been left for 10 minutes to a 20 mL container;

[0036] Step 3: Add 5 mL of paraffin oil into the above container;

[0037] Step 4: Test the freezing temperature of ultrapure water after it has been left for 10 minutes.

[0038] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to measure the purity and freezing temperature of ultrapure water -10 minutes respectively.

[0039] like Figure 1-Figure 3 As shown in the figure, actual tests show that the conductivity of ultrapure water after 10 minutes is 1.010 μS / cm; the resistivity of ultrapure water after 10 minutes is 990 kΩ·cm; and the freezing temperature of ultrapure water after 10 minutes is -11.0°C. In comparison with Example 2, the purity of the ultrapure water decreases due to the rapid absorption of carbon dioxide from the air during 10 minutes, and the freezing temperature increases by 1°C.

[0040] Example 4

[0041] This example tests the purity (conductivity and resistivity) and freezing temperature of the deionized water of the comparative example as follows:

[0042] Step 1: Add 20g of laboratory-prepared deionized water to the container, record it as deionized water, and test the conductivity and resistivity of the deionized water at 25°C;

[0043] Step 2: Add 10 g of deionized water to a 20 mL container;

[0044] Step 3: Add 5 mL of paraffin oil into the above container;

[0045] Step 4: Test the freezing temperature of deionized water;

[0046] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to measure the purity and freezing temperature of deionized water respectively.

[0047] like Figure 1 、 4 , 5 and Figure 6 As shown, after actual testing, the conductivity of deionized water is 2.985μS / cm; the resistivity of deionized water is 335kΩ·cm; and the freezing temperature of deionized water is -8.3℃.

[0048] Example 5

[0049] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 0.1% tetrahydrofuran / deionized water as follows:

[0050] Step 1: Add 20g of deionized water to a container, and then add 0.1% of tetrahydrofuran to the deionized water to simulate 0.1% of the high-altitude water. Then test the conductivity and resistivity of the high-altitude simulated water of 0.1% tetrahydrofuran / deionized water solution at 25°C;

[0051] Step 2: Add 10 g of the above 0.1% tetrahydrofuran / deionized water solution into a 20 mL container;

[0052] Step 3: Add 5 mL of paraffin oil into the above container;

[0053] Step 4: testing the freezing temperature of high-altitude simulated water without 0.1% tetrahydrofuran / deionized water solution;

[0054] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water in a 0.1% tetrahydrofuran / deionized water solution.

[0055] like Figure 1 、 4 , 5 and Figure 6 As shown, actual tests show that the conductivity of a 0.1% tetrahydrofuran / deionized water solution is 3.546 μS / cm; the resistivity of a 0.1% tetrahydrofuran / deionized water solution is 282 kΩ·cm; and the freezing temperature of a 0.1% tetrahydrofuran / deionized water solution is -12.5°C.

[0056] Example 6

[0057] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 0.5% tetrahydrofuran / deionized water as follows:

[0058] Step 1: Add 20g of deionized water to a container, and then add 0.5% of the mass of tetrahydrofuran to simulate high-altitude water (0.5%), and test the conductivity and resistivity of the high-altitude simulated water of the 0.5% tetrahydrofuran / deionized water solution at 25°C;

[0059] Step 2: Add 10 g of the above 0.5% tetrahydrofuran / deionized water solution into a 20 mL container;

[0060] Step 3: Add 5 mL of paraffin oil into the above container;

[0061] Step 4: testing the freezing temperature of high-altitude simulated water without 0.5% tetrahydrofuran / deionized water solution;

[0062] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water in a 0.5% tetrahydrofuran / deionized water solution.

[0063] like Figure 1 、 4 , 5 and Figure 6 As shown, actual tests show that the conductivity of a 0.5% tetrahydrofuran / deionized water solution is 2.985 μS / cm; the resistivity of a 0.5% tetrahydrofuran / deionized water solution is 335 kΩ·cm; and the freezing temperature of a 0.5% tetrahydrofuran / deionized water solution is -14.3°C.

[0064] Example 7

[0065] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 1% tetrahydrofuran / deionized water as follows:

[0066] Step 1: Add 20g of deionized water to a container, and then add 1% of the mass of tetrahydrofuran to simulate high-altitude water (recorded as 1%), and test the conductivity and resistivity of the high-altitude simulated water solution of 1% tetrahydrofuran / deionized water at 25°C;

[0067] Step 2: Add 10 g of the above 1% tetrahydrofuran / deionized water solution into a 20 mL container;

[0068] Step 3: Add 5 mL of paraffin oil into the above container;

[0069] Step 4: Testing the freezing temperature of high-altitude simulated water using a 1% tetrahydrofuran / deionized water solution;

[0070] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water of a 1% tetrahydrofuran / deionized water solution.

[0071] like Figure 1 、 4 , 5 and Figure 6 As shown in actual testing, the conductivity of a 1% THF / DI water solution is 2.906 μS / cm; the resistivity is 344 kΩ·cm; and the freezing point of a 1% THF / DI water solution is -15.0°C. Therefore, compared to deionized water, whose purity remains unchanged, the freezing point of pure DI water drops from -8.3°C to -15.0°C with just 1% THF, reaching the simulated temperature of supercooled large water droplets at high altitudes.

[0072] Example 8

[0073] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 2% tetrahydrofuran / deionized water as follows:

[0074] Step 1: Add 20g of deionized water to a container, and then add 2% of the mass of tetrahydrofuran to simulate the high-altitude water content. Test the conductivity and resistivity of the high-altitude simulated water solution of 2% tetrahydrofuran / deionized water at 25°C.

[0075] Step 2: Add 10 g of the above 2% tetrahydrofuran / deionized water solution into a 20 mL container;

[0076] Step 3: Add 5 mL of paraffin oil into the above container;

[0077] Step 4: Testing the freezing temperature of high-altitude simulated water using a 2% tetrahydrofuran / deionized water solution;

[0078] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water of a 2% tetrahydrofuran / deionized water solution.

[0079] like Figure 1 、 4 , 5 and Figure 6 As shown, actual tests show that the conductivity of a 2% tetrahydrofuran / deionized water solution is 2.890 μS / cm; the resistivity of a 2% tetrahydrofuran / deionized water solution is 346 kΩ·cm; and the freezing temperature of a 2% tetrahydrofuran / deionized water solution is -14.0°C.

[0080] Example 9

[0081] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 3% tetrahydrofuran / deionized water as follows:

[0082] Step 1: Add 20g of deionized water to a container, and then add 3% of the mass of tetrahydrofuran to simulate the high-altitude water content, and test the conductivity and resistivity of the high-altitude simulated water solution of 3% tetrahydrofuran / deionized water at 25°C;

[0083] Step 2: Add 10 g of the above 3% tetrahydrofuran / deionized water solution into a 20 mL container;

[0084] Step 3: Add 5 mL of paraffin oil into the above container;

[0085] Step 4: Testing the freezing temperature of high-altitude simulated water using a 3% tetrahydrofuran / deionized water solution;

[0086] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water in a 3% tetrahydrofuran / deionized water solution.

[0087] like Figure 1 、 4 , 5 and Figure 6 As shown, actual tests show that the conductivity of a 3% tetrahydrofuran / deionized water solution is 2.409 μS / cm; the resistivity of a 3% tetrahydrofuran / deionized water solution is 415 kΩ·cm; and the freezing temperature of a 3% tetrahydrofuran / deionized water solution is -11.7°C.

[0088] Example 10

[0089] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 10% tetrahydrofuran / deionized water as follows:

[0090] Step 1: Add 20g of deionized water to a container, and then add tetrahydrofuran (10% of the mass of the deionized water) to simulate high-altitude water (10%), and test the conductivity and resistivity of the high-altitude simulated water of the 10% tetrahydrofuran / deionized water solution at 25°C;

[0091] Step 2: Add 10 g of the above 10% tetrahydrofuran / deionized water solution into a 20 mL container;

[0092] Step 3: Add 5 mL of paraffin oil into the above container;

[0093] Step 4: testing the freezing temperature of high-altitude simulated water with a 10% tetrahydrofuran / deionized water solution;

[0094] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water of a 10% tetrahydrofuran / deionized water solution.

[0095] like Figure 1 、 4 , 5 and Figure 6 As shown, actual tests show that the conductivity of a 10% tetrahydrofuran / deionized water solution is 2.364 μS / cm; the resistivity of a 10% tetrahydrofuran / deionized water solution is 423 kΩ·cm; and the freezing temperature of a 10% tetrahydrofuran / deionized water solution is -12.3°C.

[0096] Example 11

[0097] This example prepares and tests the purity (conductivity and resistivity) and freezing temperature of high-altitude simulated water containing 20% ​​tetrahydrofuran / deionized water as follows:

[0098] Step 1: Add 20g of deionized water to a container, and then add 20% of the mass of tetrahydrofuran to simulate the high-altitude water (20%). Test the conductivity and resistivity of the high-altitude simulated water of the 20% tetrahydrofuran / deionized water solution at 25°C.

[0099] Step 2: Add 10 g of the above 20% tetrahydrofuran / deionized water solution into a 20 mL container;

[0100] Step 3: Add 5 mL of paraffin oil into the above container;

[0101] Step 4: testing the freezing temperature of high-altitude simulated water with a 20% tetrahydrofuran / deionized water solution;

[0102] This embodiment uses a water purity measuring instrument and a freezing temperature testing device to respectively measure the purity and freezing temperature of high-altitude simulated water of a 20% tetrahydrofuran / deionized water solution.

[0103] like Figure 1 、 4 , 5 and Figure 6 As shown, after actual testing, the conductivity of the 20% tetrahydrofuran / deionized water solution is 2.049 μS / cm; the resistivity of the 20% tetrahydrofuran / deionized water solution is 488 kΩ·cm; and the freezing temperature of the 20% tetrahydrofuran / deionized water solution is -14.0°C.

[0104] Compared to existing technologies, this method introduces hydrogen bond acceptors into deionized water, allowing them to form hydrogen bonds with water, ultimately generating a macromolecular microscopic superstructure of tetrahydrofuran and water composed of hydrogen bonds, thereby inhibiting the formation of ice nuclei and ordered ice crystal structures in the deionized water. By incorporating organic hydrogen bond acceptors into deionized water, the present invention, based on the structure of organic hydrogen bond acceptors, introduces unitized hydrogen bond acceptor elements, such as oxygen, into the deionized water, thereby enhancing the hydrogen bond-inhibiting effect of the organic hydrogen bond acceptors in the deionized water.

[0105] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principles and purpose of the present invention. The scope of protection of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. All implementation schemes within its scope shall be subject to the constraints of the present invention.

Claims

1. A method for preparing high-altitude water for ice wind tunnel simulation, characterized in that: By mixing tetrahydrofuran and matrix water in a mass ratio of 0.1% to 20%, high-altitude simulated water with a low freezing temperature for ice wind tunnel simulation is obtained; The matrix water is deionized water.

2. The method for preparing high-altitude water for ice wind tunnel simulation according to claim 1, characterized in that: The mixture is uniformly mixed under magnetic stirring and dispersion.

Images