System for testing ignition of fuel liquid drops on high-temperature hot surface

Abstract

The utility model discloses a system for testing ignition of fuel liquid drops on a high-temperature hot surface, and belongs to the field of combustion science. A system for testing ignition of fuel liquid drops on a high-temperature hot surface comprises a working box and an injection pump fixedly connected to the top of the working box, the output end of the injection pump is connected with a discharging pipe through an injector, and the discharging pipe extends into a cavity of the working box and is provided with a control valve; the platform is connected to the interior of the cavity of the working box in a lifting mode, a heating table is arranged on the platform, and the discharging end of the discharging pipe faces the top of the heating table; according to the utility model, the high-speed camera can be used for recording the phenomenon that liquid drops drop on a high-temperature hot surface in real time, and then the infrared thermal imager is used for recording the temperature of the hot surface and the flame combustion distribution condition in real time, so that the hot ignition process is realized, the experiment can be repeated, and the ignition probabilities of different fuels are allowed to be quantitatively analyzed; the accuracy of ignition characteristics is improved, and liquid drops can drop from different heights so as to explore the fire phenomenon at different impact rates.

Description

TECHNICAL FIELD

[0001] The utility model relates to combustion technology field especially relates to a fuel droplet is in high temperature hot surface fire test system. BACKGROUND

[0002] In the field of aerospace, the safety of aircraft engine is very important. The leakage of aviation kerosene and other fuels in the internal pipeline of the aircraft engine is a serious safety hazard. The liquid fuel that leaks or overflows may catch fire when it contacts a hot surface. This type of fire is commonly found in the engine compartment of an aircraft, and is usually caused by fuel droplets leaking onto a high-temperature hot wall. The high-temperature area of a turbofan engine is mainly in the combustion chamber to the tail nozzle, and the temperature can reach about 500-800℃. Under normal conditions, aviation kerosene is the main fuel for aircraft, and during transportation, storage and use, fuel leakage may occur due to factors such as pipeline aging, poor construction quality, external forces, etc. When the leaked aviation kerosene comes into contact with the high-temperature components of the aircraft engine or other hot surfaces, it will quickly catch fire, exacerbating the severity of the accident and seriously threatening the safety of passengers and crew members.

[0003] In order for the various components of the turbofan engine to withstand different temperatures, materials that can withstand ultra-high temperatures must be used to manufacture them. The combustion chamber and tail nozzle must withstand high-temperature gas flow, and are generally made of fire-resistant titanium alloy. Titanium alloy is widely used in the field of aerospace. In order to minimize weight, the tail nozzle and other parts have increasingly adopted fire-resistant titanium alloy materials that are lightweight, strong, corrosion-resistant, and have a high-temperature resistance of over 600℃. This material is particularly suitable for high-temperature components of aircraft and structural components that withstand high stress. Therefore, before use, a hot ignition test device is needed to test the various components of the turbofan engine.

[0004] However, the traditional hot ignition test device cannot accurately control the fuel droplet addition amount and droplet addition speed, which limits the repeatability and accuracy of the experimental results, and generally cannot maintain a uniform hot surface temperature over a wide temperature range, affecting the accurate measurement of ignition characteristics. UTILITY MODEL CONTENTS

[0005] The utility model discloses a fuel droplet is in high temperature hot surface fire test system to solve the problem that the prior art cannot accurately control the fuel droplet addition amount and droplet addition speed, which limits the repeatability and accuracy of the experimental results.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0007] The system for testing the ignition of fuel droplets on a high-temperature hot surface comprises a working box, and further comprises: an injection pump fixedly connected to the top of the working box, wherein the output end of the injection pump is connected with a discharge pipe through a syringe, and the discharge pipe extends into the cavity of the working box and is provided with a control valve; a platform which is connected to the cavity of the working box in a lifting manner, wherein the platform is provided with a heating table, the discharge end of the discharge pipe faces the top of the heating table, and the heating table is provided with a cleaning mechanism, and the cleaning end of the cleaning mechanism abuts against the surface of the heating table.

[0008] In order to facilitate the lifting movement of the platform, preferably, a main lead screw is rotatably connected in the cavity of the working box, a first movable block is threadedly connected to the main lead screw, a limiting rod is fixedly connected to the working box, the first movable block is slidably connected to the limiting rod, and the platform is fixedly connected to the first movable block.

[0009] In order to facilitate the rotation of the lead screw, further, a motor is fixedly connected to the outer wall of the working box, and the main lead screw is fixedly connected to the output end of the motor.

[0010] In order to facilitate the scraping of the residues on the surface of the heating table, preferably, the cleaning mechanism comprises a scraper, an installation box is fixedly connected to the platform, an auxiliary lead screw is rotatably connected in the installation box, a second movable block is threadedly connected to the auxiliary lead screw, the second movable block is in abutment with the inner wall of the installation box, the scraper is fixedly connected to the second movable block, and the tip of the scraper abuts against the top of the heating table.

[0011] In order to facilitate the blocking of the fuel liquid, preferably, a shielding frame is arranged on the platform, and the heating table is arranged in the shielding frame.

[0012] In order to facilitate the shooting of the fuel liquid, preferably, a detection camera is arranged on the platform, and the shooting end of the detection camera faces the heating table.

[0013] In order to facilitate the recording of the fuel liquid, preferably, a detection recorder is arranged on the working box.

[0014] Compared with the prior art, the system for testing the ignition of fuel droplets on a high-temperature hot surface has the following beneficial effects:

[0015] 1. The system for testing the ignition of fuel droplets on a high-temperature hot surface can record the phenomenon of the liquid droplets dropping onto the high-temperature hot surface in real time by using a high-speed camera, record the temperature of the hot surface and the distribution of the flame in real time by using an infrared thermal imager, realize the hot ignition process, allow quantitative analysis of the ignition probability of different fuels, improve the accuracy of the ignition characteristics, and enable the liquid droplets to drop from different heights to explore the ignition phenomenon under different impact rates.

[0016] 2. The fuel droplet on high temperature hot surface fire test system, through the auxiliary lead screw driven by the servo motor, make its second movable block drive the scraper to move, and then drive the scraper to clean the heating table surface, reduce the combustion residue, improve the detection accuracy of subsequent.

[0017] The part not involved in the device is the same as or can be realized by the prior art, the utility model can use high speed camera to record the phenomenon that liquid drop drops on high temperature hot surface in real time, then use infrared thermal imaging machine to record the temperature of hot surface and flame combustion distribution in real time, and then realize hot ignition process, can repeat experiment, and allow to carry out quantitative analysis to ignition probability of different fuels, improve the accuracy of ignition characteristic, liquid drop can also be dropped from different height to explore the ignition phenomenon under different impact rate. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A fuel droplet on high temperature hot surface fire test system first visual angle schematic view is proposed for the utility model;

[0019] Figure 2 A fuel droplet on high temperature hot surface fire test system second visual angle schematic view is proposed for the utility model;

[0020] Figure 3 A fuel droplet on high temperature hot surface fire test system cut structure schematic view is proposed for the utility model;

[0021] Figure 4 A fuel droplet on high temperature hot surface fire test system local structure schematic view is proposed for the utility model.

[0022] In the drawing: 1, work tank;2, injection pump;3, syringe;4, discharge pipe;5, main lead screw;6, limit rod;7, first movable block;8, motor;9, platform;10, heating table;11, shielding frame;12, detection camera;13, mounting box;14, auxiliary lead screw;15, second movable block;16, scraper;17, detection recorder. DETAILED DESCRIPTION

[0023] The technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model, obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.

[0024] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0025] Embodiments:

[0026] Referring to Figures 1-4 A fuel droplet on high-temperature hot surface ignition test system, including work tank 1, mainly used for measuring the hot ignition temperature of flammable liquid fuel, simulating the process of fuel contacting, evaporating, mixing and self-sustaining exothermic reaction with hot surface under actual working condition, injection pump 2 is also installed at the top of work tank 1, the output end of injection pump 2 is connected with discharge pipe 4 through injector 3, and control valve is arranged in the cavity of work tank 1, and the discharge pipe 4 extends to the cavity of work tank 1, the injection pump 2 is a kind of high-precision push-pull injection pump 2, it realizes operation by mirror surface stainless steel machine shell and 4.3 inch color touch screen in combination with pure imported mechanical button, the pump adopts graphical interface and animation to display working state, can display filling parameter and running state on screen, provide good user experience, its working principle is based on the push-pull action of injection pump 3 to realize the accurate delivery of liquid.

[0027] The above-mentioned injection pump 2 device is a kind of high-precision programmable equipment, its core structure includes foot pedal interface, 9-hole interface (supporting RS-232 and RS-485 communication), 15-pin interface (for external input and output) and grounding column, start-stop key, stop key, fast-forward key and fast-backward key on operation panel are used to control the running state of pump.This injection pump 2 supports multiple working modes, including perfusion, extraction, first perfusion and then extraction, first extraction and then perfusion, and is suitable for different application scenarios.By accurately controlling the inner diameter and stroke of injector 3, injection pump 2 can realize accurate control of fuel delivery, ensure that fuel is added uniformly and stably on hot surface.In addition, injection pump 2 also has calibration and online fine adjustment function, allows to optimize the accuracy of liquid volume control to meet the demand of high-precision delivery.The moving speed of injection pump 2 can be from 1 micrometer / minute to 130 millimeter / minute, that is, the physical moving speed of injection pump 2 when pushing injector 3.The flow rate of injection pump 2 is from 0.001 microliter / minute to 165 milliliter / minute, which refers to the volume of liquid passing through injection pump 2 per unit time, that is, the rate of liquid flow.

[0028] The discharge pipe 4 connected to the injector 3 is made of curved stainless steel, which can make the fuel droplets fall freely from a certain height without being damaged by the flame, and the capacity range is 10ul-200ml, and the inner diameter range is 0.1mm-50mm.

[0029] In addition, the platform 9 can be lifted in the cavity of the working box 1, the main lead screw 5 is rotatably connected in the cavity of the working box 1, the first movable block 7 is threadedly connected on the main lead screw 5, the limiting rod 6 is fixedly connected on the working box 1, the first movable block 7 is slidably connected on the limiting rod 6, and the platform 9 is fixedly connected on the first movable block 7. The motor 8 is fixedly connected on the outer wall of the working box 1, and the main lead screw 5 is fixedly connected on the output end of the motor 8. The motor 8 drives the main lead screw 5 to rotate, so that the first movable block 7 moves up and down on the limiting rod 6, and the platform 9 moves up and down.

[0030] The heating table 10 is also provided on the platform 9, and the heating table 10 is made of titanium alloy, which has high thermal conductivity, fast heating and uniform heating. The principle is that 8 1cm round holes are punched on the side of the heating table 10, and 8 500W high-quality pure metal heating pipes are inserted side by side. These heating pipes can provide a power of up to 4000W, which can ensure that the heating table can quickly reach the required high temperature.

[0031] A digital temperature controller is also provided on the working box 1, which has high precision and can control the temperature more accurately. The digital temperature controller is internally provided with a solid-state relay (SSR) and a temperature controller, which can control a high temperature range of 0-800℃, and can meet the needs of various industrial heating.

[0032] In addition, the shielding frame 11 is provided on the platform 9, and the heating table 10 is arranged in the shielding frame 11. The shielding frame 11 is made of high-temperature-resistant and heat-insulating glass fiber to minimize heat loss caused by convection and radiation.

[0033] In order to improve the cleanliness of the surface of the heating table 10, a cleaning mechanism is provided on the platform 9 to clean the surface of the heating table 10. The cleaning mechanism includes a scraper 16, an installation box 13 is fixedly connected on the platform 9, an auxiliary lead screw 14 is rotatably connected in the installation box 13, a second movable block 15 is threadedly connected on the auxiliary lead screw 14, the second movable block 15 is in close contact with the inner wall of the installation box 13, the scraper 16 is fixedly connected on the second movable block 15, and the tip of the scraper 16 abuts against the top of the heating table 10. The auxiliary lead screw 14 is driven to rotate by a servo motor, so that the second movable block 15 drives the scraper 16 to move, and the scraper 16 cleans the surface of the heating table 10, reduces the burning residue, and improves the subsequent detection accuracy.

[0034] And in the middle of the heating table 10 is also provided with a thermocouple for real-time temperature monitoring of the center hot surface of the heating table 10, the hot end of the thermocouple can be directly contacted with the heating table 10, and the cold end is connected to the detection recorder 17, which can detect the temperature of 0-1200℃, the detection recorder 17 measures the electromotive force generated by the thermocouple through the built-in circuit, then converts the electromotive force into temperature reading according to the scale of the thermocouple, and displays or stores these data on the screen.

[0035] Wherein, the thermocouple is based on the Seebeck effect, when there is a temperature difference between the two junctions of two different metal conductors, an electromotive force will be generated between the two junctions. This electromotive force can be used to measure temperature. The thermocouple is composed of two different metal wires (called thermoelectric electrodes), one end is welded together and exposed to the heat source (working end or hot end), the other end (cold end or free end) is kept at a known temperature. When there is a temperature difference between the hot end and the cold end, an electromotive force will be generated in the loop, which is proportional to the temperature difference between the two ends.

[0036] The detection recorder 17 can perform automatic monitoring of data acquisition, processing and storage, which is composed of industrial special microprocessor, A / D converter, read-only memory ROM, random access memory RAM, display controller, liquid crystal display, keyboard controller, alarm circuit and clock circuit, etc. Through the A / D converter, the analog signal (such as the electromotive force generated by the thermocouple) is converted into a digital signal, which is then processed and stored by the microprocessor. These data can be displayed on the liquid crystal display, or stored in the RAM for subsequent analysis and processing. When operating, the instructions are input through physical buttons, and the microprocessor controls the collection, processing and display of data according to these instructions.

[0037] A detection camera 12 is arranged on the platform 9, and the shooting end of the detection camera 12 faces the heating table 10. The detection camera 12 is mainly composed of a high-speed camera and an infrared thermal imaging machine.

[0038] In the experiment of the device, a high-speed camera is used to capture images, which can capture images at a speed of 5000 frames per second, with an accuracy of 0.2 milliseconds per frame. It captures the falling liquid drops and the evaporation behavior of the liquid drops on the hot surface by fast exposure and continuous shooting, which is recorded by a charge-coupled device (CCD) image sensor to convert optical images into electrical signals output to a computer for processing; the lens is used to capture the imaging part of the reflected light of the scene or object; the objective lens group is used to converge and split the light to produce clear image points and form the magnification effect; the color filter is used to eliminate stray light and interfering light beams; the lighting system and LED light source are lamp equipment and its driving circuit used for the uniformity of picture brightness; the power supply provides the energy source for the entire system; the control unit CPU is responsible for monitoring the running state of the entire device and the function module of collecting data information; the storage card is used as a temporary storage carrier for data.

[0039] In addition, the temperature distribution when the liquid drop contacts the hot surface and the temperature change of the flame burning are monitored and recorded in real time by an infrared thermal imager. It converts the infrared radiation emitted by the object into a visible thermal image by detecting the infrared radiation emitted by the object, mainly composed of an infrared lens, an infrared detector, a signal processing circuit and a display, etc. The infrared lens is responsible for focusing the infrared radiation emitted by the measured object, the infrared detector converts these radiations into electrical signals, then the signal processing circuit processes the electrical signals, and finally generates a thermal image on the display, showing the color distribution of different temperature regions. The temperature measurement range of such equipment is usually between -20℃ and +1200℃, and the temperature resolution can reach 0.1℃, which can accurately capture the temperature change after the liquid drop contacts the hot surface and the burning condition of the flame.

[0040] The working principle is as follows:

[0041] I. First, turn on the power supply of the heating table 10, turn on the "power switch", at this time the red "power indicator" is always on, indicating that the device has been powered on, then turn on the "temperature rising switch" and the device starts to run, set the temperature to be reached, the yellow "temperature rising indicator" is always on, indicating that the workbench is continuously rising, and the flashing indicates that it is in a constant temperature state. At this time, the surface workbench is intermittently heated;

[0042] II. Place the thermocouple at the center of the heating table 10, connect the detection recorder 17 to measure and record the temperature of the hot surface in real time.

[0043] Three, the combustible liquid fuel to be measured is put into the syringe pump 2, the model of the syringe 3 is selected according to the flow and the amount in the system setting interface, and the specific liquid amount, the running time and the flow (speed) are set according to the working mode (such as perfusion, extraction, perfusion first and then extraction, extraction first and then perfusion) in the parameter setting interface; in addition, the actual flow is calibrated through the flow calibration interface to ensure accurate control of the liquid amount; in addition, the commonly used parameters can be saved as a commonly used mode for convenient and rapid calling; the liquid amount can also be fine-tuned through the online fine-tuning function; if the syringe pump 2 is connected to an external control system, the speed and the amount can be controlled by receiving external signals through the communication setting interface; finally, the start and stop of the syringe pump 2 can be controlled through the external control setting interface, such as a foot switch or an external input and output signal, so as to indirectly control the speed and the amount.

[0044] Four, by lifting and moving the platform 9, the liquid droplets can be dropped from different heights to explore the ignition phenomenon under different impact rates.

[0045] Five, real-time recording is realized by using the detection camera 12, first, the high-speed camera is used to record the phenomenon that the liquid droplets drop onto the high-temperature hot surface in real time, and then the infrared thermal imaging machine is used to record the temperature of the hot surface and the distribution of the flame combustion in real time, so that the hot ignition process is realized, the experiment can be repeated, and the ignition probability of different fuels can be quantitatively analyzed.

[0046] The above only describes the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any skilled person in the technical field according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application can make equivalent replacement or change, which should be covered in the protection scope of the present application.

Claims

1. A fuel droplet ignition on hot surface test system comprising a work chamber (1), characterized in that, Also include: The injection pump (2) is fixedly connected to the top of the working box (1), Wherein, the output end of the injection pump (2) is connected with the discharge pipe (4) through the syringe (3), and the discharge pipe (4) extends to the control valve arranged in the cavity of the working box (1); The platform (9) is connected in the cavity of the working box (1), Wherein, the heating table (10) is arranged on the platform (9), the discharge end of the discharge pipe (4) faces the top of the heating table (10), and the cleaning mechanism is arranged on the heating table (10), and the cleaning end of the cleaning mechanism abuts against the surface of the heating table (10).

2. A fuel droplet ignition on hot surface test system according to claim 1, wherein, The main lead screw (5) is rotatably connected in the cavity of the working box (1), the first movable block (7) is threadedly connected on the main lead screw (5), the limiting rod (6) is fixedly connected on the working box (1), the first movable block (7) is slidably connected on the limiting rod (6), and the platform (9) is fixedly connected on the first movable block (7).

3. A fuel droplet ignition on hot surface test system according to claim 2, wherein, The motor (8) is fixedly connected on the outer wall of the working box (1), and the main lead screw (5) is fixedly connected on the output end of the motor (8).

4. The fuel droplet ignition test system on hot surface at high temperature according to claim 1, wherein, The cleaning mechanism comprises a scraper (16), the mounting box (13) is fixedly connected on the platform (9), the auxiliary lead screw (14) is rotatably connected in the mounting box (13), the second movable block (15) is threadedly connected on the auxiliary lead screw (14), the second movable block (15) is attached to the inner wall of the mounting box (13), the scraper (16) is fixedly connected on the second movable block (15), and the tip of the scraper (16) abuts against the top of the heating table (10).

5. A fuel droplet ignition on hot surface test system according to claim 4, wherein, The shielding frame (11) is arranged on the platform (9), and the heating table (10) is arranged in the shielding frame (11).

6. The fuel droplet ignition on hot surface test system of claim 1, wherein, The detection camera (12) is arranged on the platform (9), and the shooting end of the detection camera (12) faces the heating table (10).

7. The fuel droplet ignition on hot surface test system of claim 1, wherein, The detection recorder (17) is arranged on the working box (1).

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