Device and method for detecting ignition delay of spontaneous combustion type propellant based on chemical titration method

Abstract

The invention discloses a device for detecting ignition delay of a spontaneous combustion type propellant based on a chemical titration method, and the device comprises a combustion chamber which is uniformly provided with windows on the outer wall surface of a cylinder; the oxidant storage device is used for accommodating a liquid oxidant; the sample introduction system comprises a fuel tank and an environment gas cylinder, the fuel tank is communicated with a sample introduction pipe through a peristaltic pump, and an outlet of the sample introduction pipe is inserted into the combustion chamber through the top of the combustion chamber; the air pumping system comprises a vacuum pump and is used for pumping the interior of the combustion chamber into a vacuum environment and pumping waste gas generated in the combustion chamber after the experiment is finished; wherein the peristaltic pump is used for controlling fuel in the fuel tank to drop into an oxidant in the oxidant storage device in a titration manner through the sample injection pipe, so that ignition is realized, and the ignition delay state of the spontaneous combustion type propellant is observed. The device solves the problem that an existing ignition delay experiment system for researching the spontaneous combustion type propellant is insufficient in precision and safety.

Description

Technical Field

[0001] The invention belongs to the technical field of propellant ignition experimental systems, and in particular relates to a device for detecting the ignition delay of a self-igniting propellant based on a chemical titration method. Background Art

[0002] At present, liquid propellant is the most widely used and largest-volume propellant in the world. It occupies an important position in all stages of spacecraft research, design, testing and use. Liquid rockets using liquid propellant as a power source have the advantages of large specific impulse, adjustable thrust, multiple ignition and start-up, and easy thrust control. They have unique advantages in the field of aerospace. Therefore, accurately measuring the ignition delay time of related self-igniting propellants is of great significance and is one of the key points of basic research on new self-igniting propellants. Existing research on self-igniting propellant ignition devices are mostly piston compression ignition devices, which cannot observe the evaporation and combustion process of liquid propellants, and can hardly accurately measure the ignition delay time, and there are problems of insufficient accuracy and safety. Existing chemical titration devices mostly use gas to squeeze liquid propellants, which cannot accurately control the combustion of individual droplets and the size of droplets, or are made into gel particle suspension in advance, and cannot be studied in the form of liquid combustion. Summary of the invention

[0003] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a device for detecting the ignition delay of hypergolic propellant based on the chemical titration method. The droplet size of the hypergolic propellant can be accurately controlled by a peristaltic pump and changing the inner diameter of the needle tube, and the evaporation and combustion process of the liquid propellant droplets can be intuitively observed, thereby accurately measuring the ignition delay time.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions.

[0005] In one aspect, the present invention provides a device for detecting ignition delay of a hypergolic propellant based on a chemical titration method, comprising:

[0006] The combustion chamber is a constant volume bomb of a hollow cylindrical structure with a viewing window on the outer wall;

[0007] An oxidant storage device, which is fixedly arranged at the bottom of the combustion chamber and is used to accommodate liquid oxidant;

[0008] Sample injection system, including:

[0009] a fuel tank, the fuel tank being connected to a sampling tube via a peristaltic pump, the outlet of the sampling tube being inserted into the combustion chamber through the top of the combustion chamber, the outlet end of the sampling tube being located directly above the oxidant storage device and not in contact with the oxidant;

[0010] — an environmental gas cylinder, which is connected to the interior of the combustion chamber through a gas pipeline and is used to fill the environmental gas into the combustion chamber to control the pressure in the combustion chamber;

[0011] An air extraction system includes a vacuum pump, wherein an air extraction pipeline of the vacuum pump is connected to the combustion chamber, and the vacuum pump is used to extract the combustion chamber into a vacuum environment;

[0012] An information collection system, the information collection system comprising:

[0013] —Pressure gauge, installed on the combustion chamber, used to monitor the internal pressure of the combustion chamber;

[0014] —Vacuum gauge, which is installed on the combustion chamber and is used to monitor the vacuum degree inside the combustion chamber;

[0015] — a high-speed camera to record the combustion of the hypergolic propellant through a viewing window;

[0016] —An electronic computer, which is connected to the high-speed camera data, is used to receive the combustion process of the hypergolic propellant uploaded by the high-speed camera, and is also used to analyze the propagation characteristics of the combustion flame;

[0017] The peristaltic pump is used to control the fuel in the fuel tank to drip into the oxidant in the oxidant storage device through the sampling tube in a titration manner, so as to achieve ignition and observe the state of the ignition delay of the self-igniting propellant.

[0018] Furthermore, the viewing window is arranged above the oxidant storage device and at the outlet end of the sampling tube, so that the complete oxidant storage device and the end of the sampling tube can be seen through the viewing window, and the high-speed camera can thereby observe the complete experimental phenomenon.

[0019] Furthermore, the window is a quartz glass window.

[0020] Furthermore, the distance between the outlet end of the sample injection tube and the oxidant storage device is 2-3 cm.

[0021] Furthermore, the vacuum pump is also used to remove the exhaust gas generated in the combustion chamber after the experiment is completed.

[0022] Furthermore, the ambient gas is nitrogen or argon.

[0023] On the other hand, the present invention also provides a method for detecting the ignition delay of a self-igniting propellant using the device for detecting the ignition delay of a self-igniting propellant based on the chemical titration method, comprising:

[0024] Step 1: Turn on the vacuum pump to evacuate the combustion chamber; turn off the vacuum pump after reaching the vacuum condition through the pressure gauge;

[0025] Step 2: Open the environmental gas cylinder and fill the combustion chamber with environmental gas; when the pressure value displayed on the pressure gauge reaches the pressure required for the experiment, close the environmental gas cylinder;

[0026] Step 3: Turn on the high-speed camera to prepare for recording, and ensure that the camera is facing the window;

[0027] Step 4: Set the dripping frequency and titration time of the peristaltic pump according to different experimental requirements and propellant types; after the pressure gauge digital display is stable, turn on the peristaltic pump for titration, and when the titration time is reached, turn off the peristaltic pump; calculate the time interval from the end of titration to the moment when the pressure gauge starts to rise through the information acquisition system, and the time interval is the ignition delay time.

[0028] Furthermore, the peristaltic pump is set to perform experiments according to different dripping frequencies and titration times.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The device sets a peristaltic pump and sets the dripping frequency and titration time of the peristaltic pump according to different experimental requirements and propellant types. The ignition delay time can be calculated with the help of pressure changes. This method can measure the ignition delay more accurately.

[0031] The present invention applies the idea of ​​chemical titration to the ignition of propellants for the first time, providing a new idea and device for studying the collision and combustion of micro-droplets in liquid engines. In addition, the dosage of the self-igniting propellant used in the device of the present invention is small, which will not cause large-scale explosions, and the titration method will not cause safety accidents such as flashback. As long as the peristaltic pump is set in advance, automatic experiments can be carried out at the ignition site without the need for personnel to be present, solving the problem of unsafe existing devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The system structure diagram of the device for detecting the ignition delay of the hypergolic propellant based on the chemical titration method of the present invention.

[0033] Among them, 1. combustion chamber; 2. window; 3. oxidant storage device; 4. fuel tank; 5. peristaltic pump; 6. environmental gas cylinder; 7. pressure gauge; 8. vacuum gauge; 9. high-speed camera; 10. electronic computer; 11. vacuum pump; 12. sample injection tube. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

[0035] The present invention provides a device for detecting the ignition delay of a self-igniting propellant based on a chemical titration method, such as Figure 1As shown, the device includes a combustion chamber 1, an oxidant storage device 3, a sampling system and an exhaust system, and an information acquisition system.

[0036] The combustion chamber 1 is a constant volume bomb with a hollow cylindrical structure, and two viewing windows 2 are symmetrically provided on the outer wall of the cylinder; a quartz glass window is provided in the opening part as a viewing window, which can be used in conjunction with the optical system for data collection during the experiment. In a preferred embodiment, a mask component is provided outside the viewing window 2 for masking the viewing window 2 when the viewing window 2 is to be used.

[0037] The oxidant storage device 3 is a box body with an open top, fixedly disposed at the bottom of the combustion chamber 1, and used for accommodating liquid oxidant.

[0038] The sampling system includes a fuel tank 4 and an environmental gas cylinder 6:

[0039] The fuel tank 4 is used to hold the fuel, and the fuel tank 4 is connected to the sampling tube 12 via the peristaltic pump 5. Preferably, the distance from the fuel tank 4 to the peristaltic pump 5 is about 5 cm, and the length of the sampling tube 12 is about 30 cm. The overall position is required to be as short as possible. The outlet of the sampling tube 12 is inserted into the combustion chamber 1 through the top thereof, and the outlet end of the sampling tube 12 is located directly above the oxidant storage device 2 and does not contact the oxidant. The distance is selected according to different types of fuels and oxidants and different experimental requirements. Preferably, the outlet of the sampling tube 12 is a special needle inserted into the combustion chamber 1 through the top of the combustion chamber 1, and the length of the needle is adjustable, about 20 to 30 cm, and the outlet end of the sampling tube 12 is located about 2 to 3 cm directly above the oxidant storage device 2.

[0040] The ambient gas cylinder 6 is used to contain ambient gas, which can be nitrogen or argon. The ambient gas cylinder 6 is connected to the interior of the combustion chamber 1 through a gas pipeline, and is used to fill the ambient gas into the combustion chamber 1. The pressure in the combustion chamber 1 is controlled to meet the experimental requirements by the amount of ambient gas injected.

[0041] The exhaust system includes a vacuum pump 11, an exhaust pipe of the vacuum pump 11 is connected to the combustion chamber 1, and the vacuum pump 11 is used to evacuate the combustion chamber 1 to a vacuum environment, and is also used to remove the exhaust gas generated in the combustion chamber 1 after the experiment is completed.

[0042] During the experiment, the peristaltic pump 5 is used to control the fuel in the fuel tank 4 to drip into the oxidant in the oxidant storage device 3 through the sampling tube 12 in a titration manner to achieve ignition and observe the state of the ignition delay of the self-igniting propellant. The titration ratio of the oxidant and the fuel is selected according to the experimental requirements.

[0043] The device for detecting the ignition delay of a hypergolic propellant based on the chemical titration method of the present invention further comprises an information acquisition system, including a pressure gauge 7 , a vacuum gauge 8 , a high-speed camera 9 and an electronic computer 10 .

[0044] Wherein: the pressure gauge 7 is arranged on the combustion chamber 1, and is used to monitor the pressure inside the combustion chamber 1. The vacuum gauge 8 is arranged on the combustion chamber 1, and is used to monitor the vacuum degree inside the combustion chamber 1, so as to ensure that the combustion chamber is vacuum after the vacuum pump is exhausted. The high-speed camera 9 is used to record the combustion state of the self-igniting propellant at different angles through the window 2, so as to obtain more accurate combustion data. The electronic computer 10 is connected to the high-speed camera 9 in data connection, and the electronic computer 10 is used to receive the combustion process of the self-igniting propellant uploaded by the high-speed camera 9, and is also used to analyze the propagation characteristics of the combustion flame.

[0045] In some embodiments, the two viewing windows 2 are located directly above the oxidant storage device 3 and at the outlet end of the sample injection tube 12. This position setting can ensure that the camera can accurately observe the combustion process of the hypergolic propellant, providing an accurate data source for subsequent experiments.

[0046] The present invention also provides a method for detecting the ignition delay of a hypergolic propellant based on a chemical titration method. The device for detecting the ignition delay of a hypergolic propellant based on a chemical titration method comprises the following contents:

[0047] Step 1, turn on the vacuum pump 11 to evacuate the combustion chamber 1; and turn off the vacuum pump 11 after observing through the pressure gauge 7 that the vacuum condition is reached.

[0048] Step 2, open the environmental gas cylinder 6, and fill the combustion chamber 1 with environmental gas; when the pressure value displayed by the pressure gauge 7 reaches the pressure required for the experiment, close the environmental gas cylinder 6.

[0049] Step 3: Turn on the high-speed camera 9 to prepare for recording, and ensure that the camera is facing the window 2.

[0050] Step 4, set the dripping frequency and titration time of the peristaltic pump 5 according to different experimental requirements and propellant types; after the digital display of the pressure gauge 7 is stable, turn on the peristaltic pump 5 for titration, and when the titration time is reached, turn off the peristaltic pump 5; calculate the time interval from the end of titration to the moment when the pressure gauge 7 starts to rise through the information acquisition system, and the time interval is the ignition delay time.

[0051] Set the peristaltic pump 5 to conduct experiments according to different dripping frequencies and titration times. Multiple ignition delay times can be measured. Combining multiple experimental results can obtain a more accurate ignition delay time. When using the LabF1 peristaltic pump for chemical titration experiments, first prepare the sample and titrant to be tested, and add the indicator. Set the flow rate of the peristaltic pump to 0.1mL / min, the speed to 10rpm, and the amount of liquid dispensed each time to 0.5mL. Titrate 10 times in total to obtain 5mL of titrant. During the titration process, record the time and amount of liquid added each time, and slow down the flow rate to 0.05mL / min when approaching the endpoint to ensure accuracy. After completion, turn off the pump and clean the equipment. Finally, organize the experimental data and calculate the sample concentration.

[0052] The combustion process was recorded using a high-speed camera 9. The Fastcam S9 camera was used to accurately capture the subtle color changes of the reaction liquid, such as the transition from blue to green, ensuring that every detail of the change was not missed. The camera sensitivity was set to 800ISO, so even in a weak light experimental environment, the slight changes in color could still be clearly identified. In addition, the camera has a resolution of 1280*1280 pixels and a shooting speed of 9000 frames per second, which can deeply observe the detailed changes in each titration stage and record the dynamic process from the start to the end point. The images of the combustion process are used for post-experimental analysis and research.

[0053] The device for detecting the ignition delay of a self-igniting propellant based on the chemical titration method of the present invention sets a peristaltic pump, and sets the dripping frequency and titration time of the peristaltic pump according to different experimental requirements and propellant types. The ignition delay time can be calculated with the help of pressure changes. This method can measure the ignition delay more accurately. The present invention applies the idea of ​​chemical titration to propellant ignition for the first time, and provides a new idea and device for studying the collision and combustion of micro-sized small droplets in liquid engines. In addition, the dosage of the self-igniting propellant used in the device of the present invention is small, and will not cause large-scale explosions, and the titration method will not cause safety accidents such as backfire. As long as the peristaltic pump is set in advance, automatic experiments can be carried out at the ignition site without the need for personnel to be present, which solves the problem of unsafe existing devices.

[0054] It should be noted that the above-described embodiments are only preferred embodiments of the present invention. For those skilled in the art, without departing from the principles of the present invention, the present invention may be modified, improved and replaced with equivalents, and these modifications, improvements and equivalents are also considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A device for detecting the ignition delay of a hypergolic propellant based on chemical titration, characterized in that: include: The combustion chamber (1) is a constant volume bomb with a hollow cylindrical structure, and a viewing window (2) is provided on the outer wall; An oxidant storage device (3) is fixedly arranged at the bottom of the combustion chamber (1) and is used to accommodate liquid oxidant; Sample injection system, including: a fuel tank (4), the fuel tank (4) being connected to a sample injection tube (12) via a peristaltic pump (5), the outlet of the sample injection tube (12) being inserted into the combustion chamber (1) via the top of the combustion chamber (1), the outlet end of the sample injection tube (12) being located directly above the oxidant storage device (2) and not in contact with the oxidant; - an environmental gas cylinder (6), the environmental gas cylinder (6) being connected to the interior of the combustion chamber (1) through a gas pipeline and being used to fill the environmental gas into the combustion chamber (1) so as to control the pressure in the combustion chamber (1); An air extraction system, comprising a vacuum pump (11), wherein an air extraction pipeline of the vacuum pump (11) is connected to the combustion chamber (1), and the vacuum pump (11) is used to extract the combustion chamber (1) into a vacuum environment; An information collection system, the information collection system comprising: a pressure gauge (7), arranged on the combustion chamber (1) and used for monitoring the internal pressure of the combustion chamber; a vacuum gauge (8), arranged on the combustion chamber (1) and used for monitoring the vacuum degree inside the combustion chamber; a high-speed camera (9) for recording the combustion state of the hypergolic propellant through the viewing window (2); an electronic computer (10), which is data-connected to the high-speed camera (9) and is used to receive the combustion process of the hypergolic propellant uploaded by the high-speed camera (9) and is also used to analyze the propagation characteristics of the combustion flame; The peristaltic pump (5) is used to control the fuel in the fuel tank (4) to drip into the oxidant in the oxidant storage device (3) through the sampling tube (12) in a titration manner, so as to achieve ignition and observe the state of ignition delay of the self-igniting propellant.

2. The device for detecting ignition delay of hypergolic propellant based on chemical titration method according to claim 1, characterized in that: The viewing window (2) is arranged above the oxidant storage device (3) and at the outlet end of the sample injection tube (12), so that the complete oxidant storage device (3) and the end of the sample injection tube (12) can be seen through the viewing window (2), and the high-speed camera (9) can thus observe the complete experimental phenomenon.

3. The device for detecting ignition delay of hypergolic propellant based on chemical titration method according to claim 1, characterized in that: The viewing window (2) is a quartz glass viewing window.

4. The device for detecting ignition delay of hypergolic propellant based on chemical titration method according to claim 1, characterized in that: The distance between the outlet end of the sample injection tube (12) and the oxidant storage device (2) is 2-3 cm.

5. The device for detecting ignition delay of hypergolic propellant based on chemical titration method according to claim 1, characterized in that: The vacuum pump (11) is also used to extract the waste gas generated in the combustion chamber (1) after the experiment is completed.

6. The device for detecting ignition delay of hypergolic propellant based on chemical titration method according to claim 1, characterized in that: The ambient gas is nitrogen or argon.

7. A method for detecting the ignition delay of a hypergolic propellant using the device for detecting the ignition delay of a hypergolic propellant based on the chemical titration method according to claim 1, characterized in that: include: Step 1: turning on the vacuum pump (11) to evacuate the combustion chamber (1); and turning off the vacuum pump (11) after observing through the pressure gauge (7) that a vacuum condition has been reached; Step 2: Open the environmental gas cylinder (6) and fill the combustion chamber (1) with environmental gas; when the pressure value displayed by the pressure gauge (7) reaches the pressure required for the experiment, close the environmental gas cylinder (6); Step 3: Turn on the high-speed camera (9) to prepare for recording, and ensure that the camera is facing the window (2); Step 4: The dripping frequency and titration time of the peristaltic pump (5) are set according to different experimental requirements and propellant types; after the digital display of the pressure gauge (7) is stable, the peristaltic pump (5) is turned on for titration, and when the titration time is reached, the peristaltic pump (5) is turned off; and the time interval from the end of the titration to the moment when the pressure gauge (7) starts to rise is calculated by the information acquisition system, and the time interval is the ignition delay time.

8. The method according to claim 7, characterized in that The peristaltic pump (5) is set to carry out experiments according to different dripping frequencies and titration times.

Images