Device and method for detecting ignition delay of self-igniting propellant based on chemical titration

Abstract

The application discloses a device for detecting ignition delay of self-igniting propellant based on chemical titration method, which comprises a combustion chamber, the outer wall surface of the cylinder of which is uniformly provided with a window; an oxidant storage device for containing liquid oxidant; a sample injection system comprising a fuel tank and an environmental gas cylinder, the fuel tank being communicated with a sample injection pipe through a peristaltic pump, the outlet of the sample injection pipe being inserted into the combustion chamber through the top of the combustion chamber; and a gas extraction system comprising a vacuum pump, which is used for extracting the combustion chamber into a vacuum environment and also used for extracting 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 the oxidant in the oxidant storage device through the sample injection pipe in a titration manner, so as to realize ignition and observe the state of ignition delay of the self-igniting propellant. The device solves the problems of insufficient precision and safety of the existing ignition delay experiment system for studying the self-igniting propellant.

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] Currently, liquid propellants are the most widely used and consumed propellants in the world. They play a crucial role in all stages of spacecraft research, design, testing, and deployment. Liquid rockets powered by liquid propellants offer advantages such as high specific impulse, adjustable thrust, multiple ignition starts, and easily controllable thrust, making them uniquely advantageous in the aerospace field. Therefore, accurately measuring the ignition delay of these hypergolic propellants is of great significance and a key focus of basic research on new hypergolic propellants. Existing ignition devices for hypergolic propellants are mostly piston compression ignition devices, which cannot observe the evaporation and combustion process of the liquid propellant, making it almost impossible to accurately measure the ignition delay time, and thus lacking accuracy and safety. Existing chemical titration devices, on the other hand, often utilize gas to compress the liquid propellant, making it impossible to precisely control the combustion of individual droplets or their size. Alternatively, they are prefabricated as gel particles, making it impossible to study liquid combustion in its natural form. Summary of the Invention

[0003] In response to the above-mentioned 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. By using a peristaltic pump and changing the inner diameter of the syringe, the droplet size of the hypergolic propellant can be precisely controlled, 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 objectives, 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 with a hollow cylindrical structure and a viewing window on the outer wall;

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

[0008] 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 combustion chamber with environmental gas to control the pressure in the combustion chamber;

[0011] An air extraction system includes a vacuum pump, wherein an air extraction pipe 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, comprising:

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

[0014] - Vacuum gauge, installed on the combustion chamber, used to monitor the vacuum degree inside the combustion chamber;

[0015] —A high-speed camera for recording the combustion of hypergolic propellants through a viewing window;

[0016] - An electronic computer, which is connected to the high-speed camera data and 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 thus 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 further provides 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, comprising:

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

[0025] Step 2: Open the ambient gas cylinder and fill the combustion chamber with ambient gas; when the pressure value displayed on the pressure gauge reaches the pressure required for the experiment, close the ambient 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 stabilizes, 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. This 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] This device sets the peristaltic pump and adjusts the dripping frequency and titration time according to different experimental requirements and propellant types. The ignition delay time can be calculated based on the pressure change. This method can measure the ignition delay more accurately.

[0031] This invention applies chemical titration to propellant ignition for the first time, providing a new approach and device for studying the collisional combustion of micronized droplets in liquid engines. Furthermore, the device uses a relatively small dose of hypergolic propellant, preventing large-scale explosions, and the titration method is immune to safety hazards such as flashback. With a pre-installed peristaltic pump, automated experiments can be performed at the ignition site without the need for human presence, addressing the safety concerns of existing devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a system structure diagram of a device for detecting ignition delay of hypergolic propellant based on chemical titration method according to 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, hollow cylindrical bomb with two symmetrically positioned viewing windows 2 on its outer wall. Quartz glass windows serve as viewing windows, allowing for data acquisition with the optical system during the experiment. In a preferred embodiment, a shield is provided outside the viewing window 2 to conceal it when not in use.

[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 is used to accommodate liquid oxidant.

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

[0039] The fuel tank 4 is used to accommodate 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. 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 fuel and oxidant 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. The length of the needle is adjustable, about 20 to 30 cm. The outlet end of the sampling tube 12 is located approximately 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. It is used to fill the combustion chamber 1 with ambient gas. The amount of ambient gas injected is controlled to control the pressure in the combustion chamber 1 to meet the experimental requirements.

[0041] Among them, the exhaust system includes a vacuum pump 11, the exhaust pipe of the vacuum pump 11 is connected to the combustion chamber 1, 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, peristaltic pump 5 was used to control the flow of fuel from fuel tank 4 through inlet tube 12, titrating the fuel into the oxidizer in oxidizer storage device 3 to achieve ignition and observe the ignition delay of the hypergolic propellant. The titration ratio of oxidizer to fuel was selected based on 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] A pressure gauge 7 is mounted on combustion chamber 1 to monitor the pressure within combustion chamber 1. A vacuum gauge 8 is mounted on combustion chamber 1 to monitor the vacuum level within combustion chamber 1 to ensure a vacuum condition after the vacuum pump completes evacuation. A high-speed camera 9 records the combustion state of the hypergolic propellant at different angles through window 2, thereby obtaining more accurate combustion data. A computer 10 is connected to the high-speed camera 9 and receives data on the combustion process of the hypergolic propellant uploaded by the camera 9. The computer 10 is also used to analyze the propagation characteristics of the combustion flame.

[0045] In some embodiments, the two viewing windows 2 are positioned directly above the oxidizer storage device 3 and at the outlet end of the sample injection tube 12. This positioning ensures 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 that the vacuum condition is reached through the pressure gauge 7.

[0048] Step 2: Open the ambient gas cylinder 6 and fill the combustion chamber 1 with ambient gas; when the pressure value displayed by the pressure gauge 7 reaches the pressure required for the experiment, close the ambient 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 stabilizes, 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 this 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, and a more accurate ignition delay time can be obtained by combining the results of multiple experiments. When using the LabF1 peristaltic pump for chemical titration experiments, first prepare the sample to be tested and the titrant, 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 a total of 10 times 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 end point 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. Using a Fastcam S9 camera, the system accurately captured subtle color changes in the reaction liquid, such as the transition from blue to green, ensuring that every detail was captured. The camera's sensitivity was set to 800 ISO, allowing even subtle color changes to be clearly discerned in low-light experimental environments. Furthermore, the camera's resolution of 1280 x 1280 pixels and a capture rate of 9000 frames per second enabled in-depth observation of detailed changes in each titration stage, capturing the dynamic process from start to finish. Images of the combustion process were 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, providing a new idea and device for studying the collision and combustion of micro-sized 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, solving the problem of unsafe existing devices.

[0054] It should be noted that the above-described embodiments are merely preferred embodiments of the present invention. Persons skilled in the art will appreciate that various modifications, improvements, and equivalent substitutions may be made to the present invention without departing from the principles of the present invention, and such modifications, improvements, and equivalent substitutions are deemed to fall within the scope of protection of the claims of the present invention.

Claims

1. A device for detecting ignition delay of 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), which is fixedly arranged at the bottom of the combustion chamber (1) and is used to accommodate liquid oxidant; Injection system, including: a fuel tank (4), the fuel tank (4) being connected to a sampling tube (12) via a peristaltic pump (5), the outlet of the sampling tube (12) being inserted into the combustion chamber (1) through the top of the combustion chamber (1), the outlet end of the sampling 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) via a gas pipeline and being used to fill the combustion chamber (1) with environmental gas to control the pressure in the combustion chamber (1); An air extraction system comprises a vacuum pump (11), wherein an air extraction pipe 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, comprising: a pressure gauge (7), arranged on the combustion chamber (1), 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 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 the ignition delay of the self-igniting propellant.

2. The device for detecting ignition delay of hypergolic propellant based on chemical titration 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 sampling tube (12), so that the complete oxidant storage device (3) and the end of the sampling 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 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 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 according to claim 1, characterized in that: The vacuum pump (11) is also used to remove 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 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: Turn on the vacuum pump (11) to evacuate the combustion chamber (1); turn off the vacuum pump (11) after observing that a vacuum condition is reached through the pressure gauge (7); Step 2: Open the ambient gas cylinder (6) and fill the combustion chamber (1) with ambient gas; when the pressure value displayed by the pressure gauge (7) reaches the pressure required for the experiment, close the ambient 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; 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 perform experiments according to different dripping frequencies and titration times.

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