A small flow controllable nozzle system

Abstract

The purpose of this invention is to provide a small-flow-rate controllable nozzle system, belonging to the field of marine salt spray environment simulation testing devices. It includes a storage tank, a nozzle, and a test chamber. The bottom of the storage tank is connected to the nozzle via a spiral hose. The nozzle is connected to the test chamber via a flange. The flange has a hollow internal structure, allowing liquid to flow into the test chamber through the nozzle and flange. A metal block support is installed inside the nozzle, and a metal block is mounted on the support. A coil is wound around the metal block, and the coil is connected to an electromagnetic control device. A metal mesh is installed at the nozzle head. The nozzle of this invention is small enough that vertically positioned droplets cannot overcome surface tension to flow out, ensuring controllable outflow. Liquid is forced out by vortex heating of the metal block to expand gas. The outflow frequency of the droplets is controlled by changing the heating frequency, meeting the salt spray concentration requirements of the experiment, and is unaffected by environmental conditions.

Description

Technical Field

[0001] The present invention relates to a measuring device, specifically a marine salt spray environment simulation measuring device. Background Technology

[0002] Marine gas turbines operate in marine environments for extended periods, where salt spray particles accumulate. These particles adhere to compressor components, causing salt to deposit on compressor blades, leading to blade thickening, reduced compressor flow area, and blade shape variations. The deposited salt spray particles also cause chemical corrosion of the blades. Simultaneously, salt entering the engine combustion chamber reacts with sulfides in the fuel, evaporating and depositing as liquid on turbine blades and guide vanes, exposing the exposed metal to thermal corrosion and shortening engine lifespan.

[0003] When salt-containing air enters a gas turbine, salt spray testing is required to assess the unit's corrosion resistance, the mechanical durability of its coatings and structures in a marine environment, and to extend the unit's service life. Salt spray environment simulation is an important part of salt spray testing, using a specialized salt spray test chamber and a specific sodium chloride solution to simulate the marine salt spray environment.

[0004] However, the flow rate of sodium chloride solution required to simulate a salt spray environment is extremely small. This means that nozzles with smaller diameters are needed to spray the solution. Another problem with small nozzles is the instability of the flow rate supply. In other words, the nozzle needs to simultaneously meet the requirements of a small flow rate solution supply and a continuous, controllable flow rate supply. Traditional nozzles are basically unable to meet both of these requirements at the same time. Summary of the Invention

[0005] The purpose of this invention is to provide a low-flow-rate controllable nozzle system that can simulate marine salt spray environment and control the droplet supply frequency.

[0006] The objective of this invention is achieved as follows:

[0007] This invention discloses a small-flow controllable nozzle system, characterized by comprising a liquid storage tank, a nozzle, and a test chamber. The bottom of the liquid storage tank is connected to the nozzle via a spiral hose, and the nozzle is connected to the test chamber via a flange. The flange has a hollow internal structure, allowing liquid to flow into the test chamber through the nozzle and the flange. A metal block support is installed inside the nozzle, and a metal block is mounted on the metal block support. A coil is wound around the metal block, and the coil is connected to an electromagnetic control device. A metal mesh is installed at the nozzle head position.

[0008] The present invention may also include:

[0009] 1. The liquid storage tank includes an upper tank and a lower tank, which are separated and both are filled with liquid. The outside of the liquid storage tank is provided with a first communicating vessel, a second communicating vessel and a third communicating vessel. The upper end of the first communicating vessel is below the liquid surface of the upper tank and the lower end of the first communicating vessel is above the liquid surface of the lower tank. The upper end of the second communicating vessel is above the liquid surface of the lower tank and the lower end of the second communicating vessel is connected to the test chamber. The upper end of the third communicating vessel is above the liquid surface of the upper tank and the lower end of the third communicating vessel is above the liquid surface of the lower tank.

[0010] 2. The first communicating vessel is equipped with the first valve and the second valve; the second communicating vessel is equipped with the third valve and the fourth valve; and the third communicating vessel is equipped with the fifth valve and the sixth valve.

[0011] 3. The nozzle diameter is not less than 50μm, and the droplets cannot overcome the surface tension and flow out naturally.

[0012] 4. The nozzle is made of ceramic or other non-metallic materials.

[0013] 5. The length-to-diameter ratio of the nozzle shall not be less than 4:1.

[0014] 6. The metal block is a finned metal block.

[0015] 7. The space occupied by the metal block shall not be less than 1 / 4 of the entire nozzle.

[0016] 8. The metal mesh is a detachable metal mesh with a mesh size of 50μm.

[0017] 9. The inner diameter of the spiral hose is 20-22mm, and the outer diameter is 26-28mm.

[0018] The advantages of this invention are: the nozzle is small enough that vertically positioned droplets cannot overcome surface tension to flow out, ensuring controllable outflow. Liquid is extruded by heating a metal block with eddy currents to expand the gas, and the droplet outflow frequency is controlled by changing the heating frequency, meeting the salt spray concentration requirements of the experiment and unaffected by environmental factors. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is a magnified view of the nozzle.

[0021] In the diagram: 1. Inlet; 2. Storage tank; 3. First liquid level; 4. First communicating vessel; 5. First valve; 6. Second valve; 7. Second liquid level; 8. Second communicating vessel; 9. Third valve; 10. Fourth valve; 11. Test chamber; 12. Outlet; 13-1. Spiral hose; 13-2. Nozzle; 13-3. Metal block; 13-4. Coil; 13-5. Metal block support; 13-6. 50μm aperture metal mesh; 13-7. Flange; 14. Fifth valve; 15. Third communicating vessel; 16. Sixth valve. Detailed Implementation

[0022] The invention will now be described in more detail with reference to the accompanying drawings:

[0023] Combination Figure 1-2 As shown in the figure, the present invention includes a storage tank 2, a communicating vessel, a valve, and a nozzle. The storage tank is used to store salt solution and supply liquid to the nozzle. The communicating vessel is used to balance the pressure between the upper and lower layers of the storage tank, transport liquid, and balance the pressure between the nozzle and the test chamber. The spiral hose 13-1 is used to transport liquid to the nozzle 13-2. The metal block support 13-5 is used to support the metal block 13-3. The metal mesh 13-6 is used to prevent droplets from flowing out on their own. The flange 13-7 is connected to the nozzle and communicates with the test chamber 11.

[0024] Considering the overall size of the instrument, the nozzle should be located at the exact center of the liquid storage tank; the nozzle should be made of ceramic or other non-metallic materials and be resistant to salt water corrosion; the total length of the nozzle should be between 105 and 250 mm, with a length-to-diameter ratio of not less than 4:1; a coil should be wound around the outside of the nozzle, with 10 to 20 turns; the nozzle should contain a finned metal block located at the exact center; the metal block should be made of a material with good corrosion resistance and strong magnetism, such as an iron-chromium soft magnetic alloy (e.g., 1J16, 1J22) or an iron-aluminum soft magnetic alloy (e.g., 1J12, 1J16); considering the need for continuous droplet extrusion, the metal block should occupy at least 1 / 4 of the entire nozzle space; to ensure that the droplets cannot flow out on their own, the nozzle... The head is equipped with a detachable metal mesh with a mesh size of 50μm; the nozzle is detachable, allowing for different flow rates to be controlled by replacing the nozzle and adjusting the control system; the coil is connected to an electromagnetic control system, which controls the coil's heating; considering the need for rapid heat absorption and release from the metal block, the metal block is designed with fins; to balance the external pressure between the liquid storage tank and the nozzle each time liquid is replenished, a flexible hose is connected between the nozzle and the liquid storage tank and coiled into a spiral shape, which both balances the pressure and expands the nozzle's usability; the total energizing time for a single operation is not less than the liquid extrusion time between the metal block and the nozzle head; as mentioned earlier, the nozzle length range is 105mm ≤ L ≤ 250mm, and the nozzle volume is V1 = π(D / 2). 2 The volume of the metal block is estimated as V2≈(30%-40%)V1. The resistivity of the metal block is ρ, its specific heat capacity is c, and its density is ρ2. The heat of vaporization of the liquid to be heated is L. vAssuming the volume to be vaporized is approximately V3 ≈ (70% - 80%)V1, and the mass is m3, the total heat required is Q3 = m3L. v The total heat generated when a metal block heats up from room temperature to 280℃-300℃, combined with the heat of vaporization, is Q. total The total heating time is t. heat Considering the fluid extrusion velocity, it should be V3, the volume of evaporated steam, the nozzle interface area A, and the heating time t. heat The ratio is estimated as v = V³ / (A·t) heat Considering heat loss and fluid viscous resistance, the actual heating extrusion time is approximately t. total ≈2t heat Therefore, the energizing time is t≥t total After the liquid is extruded, the power is stopped, and the nozzle is refilled with liquid before vortex heating is resumed. This waiting time, taking into account the transmission of the spiral hose, is ≥10 minutes. A spiral hose with an inner diameter of 20-22mm and an outer diameter of 26-28mm is connected between the storage tank and the nozzle. This not only expands the application range of the nozzle but also serves as a connector between the storage tank and the test chamber, ensuring that the liquid flows out of the nozzle after vaporization. Three connectors are installed in the storage tank to balance pressure and replenish liquid. Connector 1 balances the pressure of the upper and lower storage tanks, ensuring pressure balance when replenishing liquid at the inlet. Connector 2 serves as a liquid delivery pipe to replenish the liquid in the lower storage tank. Connector 3 balances the pressure between the lower storage tank and the test chamber, ensuring that droplets are extruded from the nozzle.

[0025] At the start of the experiment, communication device 8 is closed, while communication devices 4 and 15 are opened. Inlet 1 is opened, and the salt solution is transported from the upper storage tank to the lower tank. Once the solution reaches the required concentration, communication devices 4 and 15 are closed, and communication device 8 is opened. This is to balance the pressure between the lower storage tank and the test chamber 11, allowing nozzle 13-2 to smoothly expel droplets. Then, the electromagnetic control device is activated, heating coil 13-4, which in turn heats the internal metal block 13-3 via eddy current heating. This controls nozzle 13-2 to expel droplets into the test chamber 11. The heating frequency and droplet outflow frequency are adjusted according to the desired salt spray concentration to simulate a salt spray environment.

[0026] When replenishing the solution at liquid level 7, keep communicating vessels 4, 8, and 15 open to ensure the same pressure. The solution at liquid level 3 flows through communicating vessel 4 to the lower layer of the storage tank. The height of liquid level 7 during replenishment must not exceed communicating vessels 4 and 8. After replenishment, close communicating vessels 4 and 15, keeping communicating vessel 8 open to maintain the same pressure between the lower layer of the storage tank and the test chamber. A new round of experiments can then begin.

[0027] Before the test begins, the nozzle is placed vertically, with the nozzle head connected to the flange and leading into the test chamber below. Inside the nozzle is a metal block. As mentioned earlier, the nozzle's length-to-diameter ratio is not less than 4:1, and the nozzle length is not less than 105mm. The specific heat capacity and density used are based on iron-chromium soft magnetic alloys (such as 1J16 and 1J22), and it is assumed that the temperature rise ΔT = 100K and the heat absorption is 10 4 J. calculated that the volume of the metal block is greater than 26.5 cm³. 3 The metal block, comprising approximately 20% of the total nozzle volume, is very small. At this point, with a nozzle diameter of only about 50 μm, the liquid cannot flow out naturally due to capillary action. At the start of the experiment, the electromagnetic control switch is turned on, energizing the coil and generating eddy currents that heat the metal block inside the nozzle. The heated metal block evaporates the surrounding liquid, causing it to expand and squeeze out liquid below the metal block. This liquid then forms droplets that fall through the nozzle, simulating a salt spray environment. After the droplets fall, liquid flows down from above the metal block to fill the space, but due to capillary action, the droplets cannot fall on their own, ensuring controllable outflow.

[0028] By changing the electric heating frequency, the heat generation and heating duration of the metal block are altered, thereby changing the frequency of droplet descent and controlling the salt spray concentration. The eddy current heating power is given by the formula P = πfB. 2 d 2 The overall system efficiency, calculated by σ / ρ, is controlled by the effective heating amount and input electrical energy. B is the magnetic induction intensity, d is the coil diameter, σ is the conductivity, and ρ is the resistivity. The eddy current heating efficiency of this device is considered to be 40%-60%, referencing the efficiency of general experimental devices. The electric heating frequency is controlled by wave crests and troughs; the voltage is similar to a square wave, with voltage applied at the crest and closed at the trough. The coil is controlled by a control system, which changes the outflow frequency f by altering the lengths of the crests and troughs to meet the experimental mass flow rate q. Assuming a single outflow mass flow rate of q1, the total mass flow rate q = f * q1. The eddy current heating amount is calculated using the formula Q = I... 2 Rt is calculated, and it is generally believed that the heat transfer efficiency of the experimental device is between 30% and 60%, depending on the material and size of the device.

[0029] The duration of liquid extrusion below the metal block is controlled by adjusting the duration of each energization cycle. As mentioned earlier, to ensure all liquid is extruded, the following estimation is made: Nozzle volume V1 = π(D / 2). 2 L = 61cm 3 The volume of the metal block is V2 = 30% V1 = 18.3 cm³. 3 Taking 1J12 as an example, the resistivity of the metal block material is ρ = 0.27 μΩm, the specific heat capacity is c = 500 J / (kg·K), and the density is ρ2 = 8.1 g / cm³. 3 The heat of vaporization of the liquid requiring heating is L. v =2257kJ / kg, required vaporization volume V3 = 70% V1 = 42.7cm³3 Mass m3 = 43g, total heating amount Q3 = m3L v =98kJ. Temperature rise of the metal block ΔT = 300 - 20 = 280℃, total heat Q total =119kJ, heating time t heat =280s. Fluid extrusion velocity v = V³ / (A·t) heat = 7.5 mm / s. Total heating time is t. total =2t heat =560s. Therefore, the energizing time t ≥ t total =560s.

[0030] In addition, by appropriately adjusting the nozzle size, the layout of the metal block fins, and changing the materials of the nozzle and the metal block, it can be applied to multiple scenarios, which are briefly listed below.

[0031] Applied to high-frequency microdroplet printing technology, by reducing the nozzle size and combining the high thermal conductivity of the finned metal block with the precise control of the eddy current frequency, it can be used for droplet generation of photosensitive resins or bio-inks.

[0032] Applied to medical atomizing sprays, by optimizing the nozzle and pipe, such as adding scaling channels, airflow-assisted atomization is used to improve the uniformity of drug delivery.

[0033] Applied to industrial nano-coating equipment, by increasing the number of metal block fins and using high-temperature resistant material nozzles, the thickness of the nano-coating can be controlled at the nanometer level, with better results than traditional electrostatic spraying processes.

Claims

1. A low-flow-rate controllable nozzle system, characterized in that: It includes a liquid storage tank, a nozzle, and a test chamber. The bottom of the liquid storage tank is connected to the nozzle via a spiral hose. The nozzle is connected to the test chamber via a flange. The flange has a hollow structure inside. Liquid flows into the test chamber through the nozzle and the flange. A metal block support is installed inside the nozzle. A metal block is installed on the metal block support. A coil is wound on the metal block. The coil is connected to an electromagnetic control device. A metal mesh is installed at the nozzle head position. The liquid storage tank includes an upper tank and a lower tank, which are separated and both are filled with liquid. The outside of the liquid storage tank is provided with a first communicating vessel, a second communicating vessel and a third communicating vessel. The upper end of the first communicating vessel is below the liquid surface of the upper tank and the lower end of the first communicating vessel is above the liquid surface of the lower tank. The upper end of the second communicating vessel is above the liquid surface of the lower tank and the lower end of the second communicating vessel is connected to the test chamber. The upper end of the third communicating vessel is above the liquid surface of the upper tank and the lower end of the third communicating vessel is above the liquid surface of the lower tank. The nozzle diameter is not less than 50μm, and the droplets cannot overcome the surface tension and flow out naturally.

2. The small flow rate controllable nozzle system according to claim 1, characterized in that: The first communicating vessel is equipped with the first valve and the second valve; the second communicating vessel is equipped with the third valve and the fourth valve; and the third communicating vessel is equipped with the fifth valve and the sixth valve.

3. The small flow rate controllable nozzle system according to claim 1, characterized in that: The nozzle is made of ceramic or other non-metallic materials.

4. The small flow rate controllable nozzle system according to claim 1, characterized in that: The length-to-diameter ratio of the nozzle is not less than 4:

1.

5. A small flow rate controllable nozzle system according to claim 1, characterized in that: The metal block is a finned metal block.

6. The small flow rate controllable nozzle system according to claim 1, characterized in that: The metal block occupies no less than 1 / 4 of the space of the entire nozzle.

7. A small flow rate controllable nozzle system according to claim 1, characterized in that: The metal mesh is a detachable metal mesh with a mesh size of 50μm.

8. A small flow rate controllable nozzle system according to claim 1, characterized in that: The inner diameter of the spiral hose is 20-22 mm, and the outer diameter is 26-28 mm.

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