Small-flow controllable nozzle system

Abstract

The invention aims to provide a small-flow controllable nozzle system, which belongs to the field of marine salt spray environment simulation test devices, and comprises a liquid storage tank, a nozzle and a test cabin, the bottom of the liquid storage tank is connected with the nozzle through a spiral hose, the nozzle is connected with the test cabin through a flange, the flange is of a hollow structure, and liquid flows into the test cabin through the flange through the nozzle. A metal block supporting body is arranged in the nozzle, a metal block is installed on the metal block supporting body, a coil is wound on the metal block and connected with an electromagnetic control device, and a metal net is installed at the nozzle position of the nozzle. The nozzle is small enough, liquid drops in a vertical state cannot overcome surface tension to flow out, and outflow controllability is guaranteed. Liquid is extruded in the mode that the metal block is heated through eddy current to expand gas, the liquid drop outflow frequency is controlled by changing the heating frequency, the requirement for the salt mist concentration needed by an experiment is met, and environmental influence is avoided.

Description

Technical Field

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

[0002] Marine gas turbines work in the marine environment for a long time. There are a large number of salt spray particles in the ocean. These salt spray particles adhere to the compressor components for a long time. The salt will deposit on the compressor blades, resulting in the thickening of the blades, the reduction of the compressor flow area and the variation of the blade profile. The deposited salt spray particles will cause chemical corrosion of the blades. At the same time, the salt entering the engine combustion chamber will react with the sulfide in the fuel, evaporate in the combustion chamber, and deposit on the turbine blades and guide vanes in a liquid state, causing thermal corrosion of the exposed metal, thus shortening the service life of the engine.

[0003] When the salt-containing air enters the gas turbine, in order to evaluate the anti-corrosion ability of the unit in the marine environment, the mechanical durability of the coating and structure, and at the same time to extend the service life of the unit, it is necessary to conduct a salt spray test on the marine gas turbine. Salt spray environment simulation is an important part of the salt spray test. Through a special salt spray test chamber, a certain sodium chloride solution is used to simulate the marine salt spray environment.

[0004] However, the flow rate of the sodium chloride solution required to simulate the salt spray environment is extremely small, which means that a nozzle with a smaller diameter is needed for the solution to be ejected. Another problem brought by the small nozzle is the instability of the flow rate supply, that is, the nozzle needs to simultaneously meet the requirements of small-flow solution supply and continuous and controllable flow rate supply. Traditional nozzles basically cannot meet the above two points at the same time. Summary of the Invention

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

[0006] The purpose of the present invention is achieved as follows:

[0007] A small-flow controllable nozzle system of the present invention is 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 through a spiral hose. The nozzle is connected to the test chamber through a flange. The inside of the flange is a hollow structure. The liquid flows into the test chamber through the nozzle and the flange. A metal block support is arranged in the nozzle. A metal block is installed on the metal block support. A coil is wound around the metal block. The coil is connected to an electromagnetic control device. A metal mesh is installed at the nozzle head position.

[0008] The present invention may further include:

[0009] 1. The interior of the liquid storage tank includes an upper tank body and a lower tank body, which are separated and filled with liquid. A first connector, a second connector, and a third connector are respectively arranged outside the liquid storage tank. The upper end of the first connector is below the liquid level of the upper tank body, the lower end of the first connector is above the liquid level of the lower tank body, the upper end of the second connector is above the liquid level of the lower tank body, the lower end of the second connector is connected to the test chamber, the upper end of the third connector is above the liquid level of the upper tank body, and the lower end of the third connector is above the liquid level of the lower tank body.

[0010] 2. A first valve and a second valve are installed on the first connector; a third valve and a fourth valve are installed on the second connector; a fifth valve and a sixth valve are installed on the third connector.

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

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

[0013] 5. The aspect ratio of the nozzle is not less than 4:1.

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

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

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

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

[0018] The advantages of the present invention are as follows: The nozzle of the present invention is small enough, and the liquid droplets cannot flow out due to surface tension in the vertical state, ensuring controllable outflow. The liquid is extruded by the way of eddy current heating the metal block to expand the gas, and the outflow frequency of the liquid droplets is controlled by changing the heating frequency, meeting the requirements of the salt spray concentration required for the experiment and being not affected by the environment. Description of the Drawings

[0019] Figure 1 is the structural schematic diagram of the present invention;

[0020] Figure 2 is the enlarged view of the nozzle.

[0021] In the figure: water inlet 1, liquid storage tank 2, first liquid level 3, first communicating vessel 4, first valve 5, second valve 6, second liquid level 7, second communicating vessel 8, third valve 9, fourth valve 10, test chamber 11, water outlet 12, spiral hose 13-1, nozzle 13-2, metal block 13-3, coil 13-4, metal block support 13-5, 50μm aperture metal mesh 13-6, flange 13-7, fifth valve 14, third communicating vessel 15, sixth valve 16. Specific embodiments

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

[0023] Combined Figure 1-2 , as shown in the figure, the present invention includes a liquid storage tank 2, a communicating vessel, valves and a nozzle. The liquid storage tank is used to store the salt solution and supply liquid to the nozzle. The communicating vessel is used to balance the pressure of the upper and lower layers of the liquid storage tank, transport the 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 the liquid droplets from flowing out by themselves. 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 center of the liquid storage tank. The nozzle is made of ceramic or other non-metallic materials and is not corroded by brine. The total length range of the nozzle is 105-250mm, and the length-diameter ratio is not less than 4:1. The outside of the nozzle is wound with a coil, and the number of winding turns is 10-20 turns. The inside of the nozzle contains a finned metal block located at the center of the nozzle. The material of the metal block should be selected from materials with good corrosion resistance and strong magnetism, such as iron-chromium soft magnetic alloys (such as 1J16, 1J22) or iron-aluminum soft magnetic alloys (such as 1J12, 1J16). Considering continuous extrusion of liquid droplets, the space occupied by the metal block is not less than 1 / 4 of the entire nozzle. To ensure that the liquid droplets cannot flow out by themselves, a detachable metal mesh with a pore diameter of 50μm is installed at the nozzle. The nozzle is a detachable structure, and different flow rate controls can be achieved by replacing the nozzle and adjusting the control system. The coil is connected to the electromagnetic control and is heated by the electric control. Considering the need for rapid heat absorption and heat release of the metal block, the metal block is designed to be finned. Considering the need to balance the external pressure between the liquid storage tank and the nozzle each time the liquid is replenished, a hose is connected between the nozzle and the liquid storage tank and coiled into a spiral shape, which can balance the pressure and expand the use range of the nozzle. The total energization duration per time is not shorter than the liquid extrusion duration between the metal block and the nozzle. As mentioned above, the nozzle length range is 105mm≤L≤250mm, the nozzle volume is V1 = π(D / 2) 2 L, the volume of the metal block is estimated to be V2≈(30%-40%)V1. The resistivity of the metal block is ρ, the specific heat capacity is c, and the density is ρ2. The heat of vaporization of the liquid to be heated is L v, assuming the volume to be vaporized is approximately V3≈(70%-80%)V1, with a mass of m3, and the total heat required is Q3 = m3L v . The metal block is heated from room temperature to 280°C - 300°C, and the total heat combined with the heat of vaporization is Q total . The total heating time is t heat . Considering the fluid extrusion speed, it should be the ratio of the V3 evaporation steam volume to the nozzle cross-sectional area A and the heating time t heat , estimated as v = V3 / (A·t heat ). Considering heat loss and fluid viscous resistance, the actual heating and extrusion duration is approximately t total ≈2t heat , so the power-on duration is t≥t total ; After the liquid is extruded, the power supply is stopped, and when the liquid refills the nozzle again, eddy current heating is carried out. Considering the transmission of the spiral hose, the waiting duration t≥10 minutes; A spiral hose with an inner diameter of 20 - 22mm and an outer diameter of 26 - 28mm is connected between the liquid storage tank and the nozzle, which can not only expand the nozzle usage range but also serve as a communicating vessel between the liquid storage tank and the test chamber to ensure that the vaporized liquid flows out from the nozzle; Three communicating vessels are installed in the liquid storage tank, aiming to balance the pressure and supplement the liquid. The purpose of communicating vessel 1 is to balance the pressure of the upper and lower liquid storage tanks, ensuring that the pressure of the upper and lower liquid storage tanks is balanced when the water inlet supplements the liquid; Communicating vessel 2 serves as a liquid delivery pipe to supplement the liquid in the lower liquid storage tank; The purpose of communicating vessel 3 is to balance the pressure between the lower liquid storage tank and the test chamber, ensuring that the liquid droplets are extruded from the nozzle.

[0025] At the start of the experiment, close communicating vessel 8, open communicating vessels 4 and 15, open water inlet 1, and the salt solution is transported from the upper liquid storage tank to the lower layer. After the solution reaches the requirement, close communicating vessels 4 and 15, and open communicating vessel 8, aiming to balance the pressure between the lower liquid storage tank and test chamber 11, enabling nozzle 13 - 2 to smoothly extrude liquid droplets. Then turn on the electromagnetic control device, heat coil 13 - 4, and eddy current heat the internal metal block 13 - 3, control nozzle 13 - 2 to extrude liquid droplets into test chamber 11, adjust the heating frequency according to the required salt mist environment concentration, and adjust the liquid droplet outflow frequency to form a salt mist environment simulation.

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

[0027] Before the test starts, the nozzle is placed vertically naturally. The nozzle head is connected to the flange and leads to the lower test chamber. There is a metal block inside the nozzle. As mentioned before, the length-diameter ratio of the nozzle is not less than 4:1, and the length of the nozzle is not less than 105 mm. The specific heat capacity and density used are exemplified by iron-chromium soft magnetic alloys (such as 1J16, 1J22), and it is assumed that the temperature rise ΔT = 100 K and the heat absorption is 10 4 J. It is calculated that the volume of the metal block is greater than 26.5 cm 3 , accounting for about 20% of the total nozzle volume. Therefore, the volume of the metal block is very small. At this time, since the diameter of the nozzle head is only about 50 μm, the liquid cannot flow out naturally under capillary action. When the test starts, the electromagnetic control switch is turned on, the coil is energized, and eddy current is generated to heat the metal block inside the nozzle. The metal block heats up and evaporates the surrounding liquid. Due to the volume expansion of the liquid vaporization, the liquid below the metal block will be extruded. The liquid forms liquid drops through the nozzle head, simulating the salt spray environment. After the liquid drops, the liquid above the metal block flows down to supplement the space. However, due to the capillary phenomenon, the liquid drops cannot drip down by themselves, ensuring controllable outflow.

[0028] By changing the electric heating frequency, the heat generation amount and heat generation duration of the metal block are changed, thereby changing the dripping frequency of the liquid drops to achieve the control of the salt spray concentration. The eddy current heating power is calculated by the formula P = πfB 2 d 2 σ / ρ. The total efficiency of the system is controlled by the effective heating amount and the input electric 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 refers to the efficiency of general experimental devices and is considered to be 40%-60%. The electric heating frequency is controlled by the peak and trough. The voltage is similar to a square wave. The peak voltage is applied, and the trough is turned off. The coil is controlled by the control system. By changing the lengths of the peak and trough, the outflow frequency f is changed to meet the requirements of the experimental mass flow rate q. Assuming that the single-outflow mass flow rate is q1, the total mass flow rate q = f * q1. The eddy current heating amount is calculated by the formula Q = I 2 Rt. Generally, it is considered that the heat transfer efficiency of the experimental device is between 30%-60%, depending on the material and size of the device.

[0029] By controlling the single-time power-on duration, the extrusion duration of the liquid below the metal block is controlled. As mentioned before, to ensure that all the liquid below is extruded, the following estimations are made. The volume of the nozzle V1 = π(D / 2) 2 L = 61 cm 3 , the volume of the metal block V2 = 30%V1 = 18.3 cm 3 . The metal block material is exemplified by 1J12, the resistivity ρ = 0.27 μΩm, the specific heat capacity c = 500 J / (kg·K), and the density ρ2 = 8.1 g / cm 3 . The heat of vaporization of the liquid to be heated is L v = 2257 kJ / kg, and the volume to be vaporized V3 = 70%V1 = 42.7 cm3 , with a mass m3 = 43 g and a total heating quantity Q3 = m3L v = 98 kJ. The temperature rise of the metal block ΔT = 300 - 20 = 280 °C, and the superimposed total heat quantity Q total = 119 kJ, and the heating duration t heat = 280 s. The fluid extrusion speed v = V3 / (A·t heat ) = 7.5 mm / s. The total heating duration is t total = 2t heat = 560 s. Therefore, the power-on duration t ≥ t total = 560 s.

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

[0031] Applied to high-frequency micro-droplet 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 the generation of droplets of photosensitive resin or bio-ink.

[0032] Applied to medical atomization spray, by optimizing the nozzle pipeline, such as adding a converging-diverging channel and using air flow-assisted atomization, the uniformity of drug solution delivery is improved.

[0033] Applied to industrial nano-spraying equipment, by increasing the number of fin levels of the metal block and using a nozzle made of high-temperature resistant material, the nano-coating thickness can be controlled at the nano-level, and the effect is better than the traditional electrostatic spraying process.

Claims

1. A small-flow 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 through a spiral hose, and the nozzle is connected to the test chamber through a flange. The inside of the flange is a hollow structure, and the liquid flows into the test chamber through the nozzle and the flange. A metal block support is arranged in the nozzle, a metal block is installed on the metal block support, a coil is wound around the metal block, the coil is connected to an electromagnetic control device, and a metal mesh is installed at the nozzle head position.

2. The small-flow controllable nozzle system according to claim 1, characterized in that: The inside of the liquid storage tank includes an upper tank body and a lower tank body. The upper tank body and the lower tank body are separated and are both filled with liquid. A first connector, a second connector, and a third connector are respectively arranged outside the liquid storage tank. The upper end of the first connector is below the liquid level of the upper tank body, and the lower end of the first connector is above the liquid level of the lower tank body. The upper end of the second connector is above the liquid level of the lower tank body, and the lower end of the second connector is connected to the test chamber. The upper end of the third connector is above the liquid level of the upper tank body, and the lower end of the third connector is above the liquid level of the lower tank body.

3. The small-flow controllable nozzle system according to claim 2, characterized in that: A first valve and a second valve are installed on the first connector; a third valve and a fourth valve are installed on the second connector; a fifth valve and a sixth valve are installed on the third connector.

4. The small-flow controllable nozzle system according to claim 1, characterized in that: The diameter of the nozzle head is not less than 50 μm, and the liquid droplets cannot flow out naturally due to surface tension.

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

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

1.

7. The small-flow controllable nozzle system according to claim 1, characterized in that: The metal block is a metal block with fins.

8. A small-flow controllable nozzle system according to claim 1, characterized in that: The space occupied by the metal block is not less than 1 / 4 of the whole nozzle.

9. The small-flow controllable nozzle system according to claim 1, characterized in that: The metal mesh is a detachable metal mesh with a pore diameter of 50 μm.

10. A small-flow 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.

Images