Ignition method for combustion experiment in falling tower microgravity environment

Abstract

The invention discloses an ignition method for a combustion experiment in a falling tower microgravity environment, and relates to the technical field of combustion ignition, and the ignition method comprises the following steps: setting a fuel and air flow controller; after the experiment module is hoisted, fuel and air are introduced, the electric heating wire is electrified and ignited, and the electric heating wire is powered off after successful ignition; the experiment module is released to enter a free falling state, and the heating wire carries flames to enter a microgravity environment; after the microgravity indicator lamp is lightened for a preset time, the heating wire is controlled to evacuate from the combustion flow field; and when the free falling state is finished, the experiment module is connected to the network, and the fuel and air flow controller is closed. The heating wire carries flames to enter the microgravity environment, the risk that the flames are extinguished in the sudden change process of the gravity environment is effectively avoided, and the experiment success rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion ignition, and in particular to an ignition method for a combustion experiment in a drop tower microgravity environment. Background Art

[0002] When conducting normal-pressure combustion experiments in a normal-gravity environment on the ground, experimenters usually use ignition devices such as ignition guns to ignite, and immediately remove the ignition device after successful ignition. A drop tower is a ground-based facility that can provide a microgravity environment. The microgravity level can reach a lower gravity level, and the available microgravity time is generally in the order of seconds. When conducting combustion experiments in a drop tower, it is generally necessary to go through stages such as sealing, hoisting, releasing, and recovering. Among them, the drop capsule is released in a normal-gravity environment and performs free fall. After a period of time, it enters a microgravity environment (i.e., the experimental stage). After maintaining this stage for a few seconds, it enters the deceleration and recovery stage, during which the drop capsule will experience a sudden change in gravity.

[0003] If the ignition method used in a normal gravity environment is still used in the drop tower microgravity environment, there is a risk that the flame will be extinguished due to the sudden change in gravity at the moment of release, especially when the flame itself is easily affected by environmental conditions, such as the propulsion flame (referring to the flame root being stabilized at a certain position downstream of the burner nozzle). This flame extinction problem not only leads to experimental failure, but also causes high economic losses, as the cost of microgravity experiments is generally high. Therefore, there is an urgent need for an ignition scheme that can effectively avoid the risk of flame extinction caused by sudden changes in the gravity environment, ensuring that the flame can smoothly pass the environmental mutation stage and stably enter the microgravity experiment stage. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the present invention provides an ignition method for a combustion experiment in a drop tower microgravity environment, which can solve the problems mentioned in the background technology.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: an ignition method for a combustion experiment in a drop tower microgravity environment, comprising: setting fuel and air flow controllers; after the experimental cabin is hoisted, introducing fuel and air and energizing the heating wire for ignition, and after successful ignition, the heating wire is powered off; releasing the experimental cabin to enter a free fall state, and the heating wire carries the flame into the microgravity environment; a predetermined time after the microgravity indicator light is lit, controlling the heating wire to evacuate the combustion flow field; at the end of the free fall state, the experimental cabin is connected to the network, and the fuel and air flow controllers are turned off.

[0007] As a preferred embodiment of the ignition method for the drop tower microgravity combustion experiment described herein, controlling the heating wire's withdrawal from the combustion flow field includes: detecting the illumination of the microgravity indicator light; timing to a predetermined time; and controlling the drive device to operate so that the heating wire withdraws from the combustion flow field. This preferred technical solution advantageously achieves precise withdrawal of the heating wire at the optimal time, through the microgravity indicator light illumination signal and the predetermined time timing control, ensuring stable combustion of the flame in the microgravity environment.

[0008] As a preferred embodiment of the ignition method for the drop tower microgravity combustion experiment described herein, the method includes monitoring the flame morphology and determining flame stability after successful ignition. This preferred technical solution has the beneficial effect of determining flame stability by monitoring the flame morphology, providing an accurate time point for subsequent experimental chamber release, and reducing the risk of experimental failure.

[0009] As a preferred embodiment of the ignition method for the drop tower microgravity combustion experiment described herein, releasing the experimental chamber into the free-fall state includes: controlling a release mechanism to release the lock on the experimental chamber; and maintaining the position of the heating wire, allowing the heating wire to carry the flame into the microgravity environment. This preferred technical solution has the beneficial effect of maintaining the position of the heating wire and carrying the flame into the microgravity environment, thereby resolving the technical problem of flame extinction caused by sudden gravity changes and improving the stability and reliability of the experiment.

[0010] As a preferred embodiment of the ignition method for the drop tower microgravity combustion experiment described herein, the ignition device includes: the heating wire; a drive device connected to the heating wire; a fixing device for fixing the heating wire to the drive device; and a control system for controlling the heating of the heating wire and the operation of the drive device. The beneficial effect of this preferred technical solution is that, by integrating the heating wire, drive device, fixing device, and control system into the ignition device, the heating wire can be precisely positioned and controlled, ensuring the stability and controllability of the flame during the ignition process.

[0011] As a preferred solution of the ignition method for the combustion experiment in the drop tower microgravity environment described in the present invention, wherein: the heating wire has a coil structure; the driving device is a screw motor, and the screw motor has a predetermined rotational speed; the fixing device includes a support rod and a clamp; the control system includes a programmable logic controller, and the programmable logic controller sends a control signal to the screw motor at the predetermined time after the microgravity indicator light is turned on; the control system also includes a temperature sensor, and the temperature sensor monitors the temperature of the heating wire and adjusts the current according to temperature feedback.

[0012] As a preferred solution of the ignition method for the combustion experiment in the drop tower microgravity environment described in the present invention, wherein: the ignition position of the heating wire has a predetermined axial height from the nozzle outlet; before sealing the cabin, the heating wire is rotated to the ignition position above the nozzle outlet; the control system also integrates an image recognition module, which analyzes the flame image and determines the flame state; the fuel and air flow controllers are shut down in a step-by-step manner, first reducing the flow and then completely shutting down.

[0013] As a preferred solution of the ignition method for the combustion experiment in the drop tower microgravity environment described in the present invention, the setting of the fuel and air flow controllers includes: measuring the physical parameters of the fuel and the air; calculating the flow requirements of the fuel and the air based on the average velocity of the jet outlet; converting the flow requirements into control parameters of the fuel and the air flow controllers; and adjusting the fuel and the air flow controllers to the control parameters before sealing the cabin.

[0014] As a preferred solution of the ignition method for the combustion experiment in the drop tower microgravity environment described in the present invention, it also includes: setting up a data acquisition system, the data acquisition system is electrically connected to the microgravity indicator light; the data acquisition system receives the status signal of the microgravity indicator light, marks the experimental stage according to the status signal; and performs segmented processing on the experimental data according to the experimental stage.

[0015] As a preferred solution of the ignition method for the combustion experiment in the drop tower microgravity environment described in the present invention, the structural parameters of the ignition device are pre-set according to the characteristics of the fuel before sealing the cabin, and the structural parameters include: the material and size of the heating wire; the speed and stroke of the driving device; and the position and angle of the fixing device.

[0016] The present invention has the following beneficial effects: First, the ignition method using a heating wire to carry the flame into the microgravity environment fundamentally avoids the risk of flame extinguishing during sudden changes in gravity environment in conventional ignition methods, which is particularly effective for environmentally sensitive propulsion flames; second, the timing of the heating wire's withdrawal is precisely coordinated with the microgravity indicator light lighting signal and the predetermined time, ensuring that the flame can be stably established in the microgravity environment; third, the introduction of a flame morphology monitoring mechanism to determine the flame stability state provides a reliable time node control reference for the experimental process; fourth, the designed ignition device structure achieves precise positioning and controllable withdrawal of the heating wire, ensuring the stability and reliability of the ignition process; fifth, the gas path is controlled by a step-by-step shutdown strategy, avoiding the interference of sudden airflow on experimental data. These technical innovations work together to form a complete solution, which improves the success rate of microgravity combustion experiments, reduces experimental costs, and solves the problem of flame extinguishing caused by sudden gravity changes that is difficult to overcome in existing technologies, providing a reliable experimental basis for the study of combustion mechanisms in microgravity environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of the overall process of an ignition method for a drop tower combustion experiment in a microgravity environment proposed by the present invention;

[0019] Figure 2 This is a comparison chart between the ignition method for a drop tower microgravity combustion experiment proposed by the present invention and a conventional ignition scheme. DETAILED DESCRIPTION

[0020] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Example 1, with reference to Figure 1 and Figure 2 , as one embodiment of the present invention, provides an ignition method for a combustion experiment in a drop tower microgravity environment, comprising:

[0023] S100: Setting fuel and air flow controllers;

[0024] S200: After the experimental cabin is hoisted, fuel and air are introduced and the heating wire is powered on and ignited. After the ignition is successful, the heating wire is powered off;

[0025] S300: Release the experimental cabin to enter a free-fall state, and the heating wire carries the flame into the microgravity environment;

[0026] S400: After the microgravity indicator light is on for a predetermined time, the heating wire is controlled to evacuate the combustion flow field;

[0027] S500: At the end of the free fall state, the experimental cabin enters the network and the fuel and air flow controllers are turned off.

[0028] It should be noted that in drop-tower microgravity experiments, the transition from normal gravity to microgravity involves a sudden change in gravity. This change significantly impacts flame stability, especially for propulsion flames (flames whose root stabilizes at a certain position downstream of the burner nozzle), which are particularly sensitive to environmental conditions. Conventional ignition methods can easily cause flame extinction in such sudden gravity changes, leading to experimental failure and wasting experimental resources while increasing costs.

[0029] Therefore, to address the aforementioned ignition stability issues, a novel ignition method has been implemented through steps S100-S500. In this method, a heating wire carries the flame into a microgravity environment and only leaves the combustion flow field after a predetermined period of time, thus avoiding the impact of sudden gravity changes on flame stability. Experiments have demonstrated that using this ignition method, the flame can reach a stable state in a microgravity environment, effectively avoiding the risk of flame extinction caused by sudden gravity changes and ensuring that the flame successfully survives the sudden environmental change phase. Furthermore, this ignition method avoids experimental failures due to ignition issues, significantly reducing experimental costs and increasing experimental success rates.

[0030] Example 2, reference Figure 1 , which is an embodiment of the present invention, provides an ignition method for a combustion experiment in a drop tower microgravity environment based on the above embodiment.

[0031] In an embodiment of the present invention, the fuel and air flow controllers are set in step S100 by calculating the required flow rates according to the average velocity of the jet outlet, and the setting is completed before the cabin is sealed.

[0032] In an optional embodiment, setting the fuel and air flow controllers in step S100 can also be achieved through an adaptive control system, which can automatically adjust the flow controller readings based on the real-time monitored environmental parameters in the drop tower (such as temperature and pressure) to ensure that the mixture ratio of fuel and air is in the optimal ignition state.

[0033] In another optional embodiment, the fuel and air flow controllers set in step S100 may also adopt a preset program control mode, and select corresponding flow control parameters based on a combustion characteristic database of different types of fuels.

[0034] In the embodiment of the present invention, after the experimental chamber is hoisted, in step S200, fuel and air are introduced and the heating wire is powered on and ignited. After the ignition is successful, the heating wire is powered off and the following steps A1-A4 are included:

[0035] A1: Confirm that the experimental cabin has been hoisted and is in a stable state;

[0036] A2: Turn on the fuel and air flow controllers to allow the mixed gas to enter the combustion chamber;

[0037] A3: Apply power to the heating wire to raise its temperature to the ignition temperature of the fuel;

[0038] A4: After observing the flame forming and burning stably, disconnect the power supply of the heating wire.

[0039] Specifically, confirmation of the completion of the hoisting of the experimental cabin in A1 is achieved through position sensors and stability monitoring systems to ensure that the experimental cabin is in a completely stationary state before ignition. After turning on the flow controller in A2, it is necessary to wait for about 5-10 seconds for the mixed gas to fill the combustion chamber and reach a stable flow state. After the heating wire in A3 is energized, its temperature will rise to 600-800°C within 1-2 seconds, which is enough to ignite most fuels. The criterion for stable flame combustion in A4 is that the flame morphology parameters (such as height, width, brightness) do not change by more than 5% within 3 consecutive seconds.

[0040] In an optional embodiment, step S200 may also employ a multi-ignition source coordinated ignition technique, i.e., multiple heating wires are placed within the combustion chamber and energized simultaneously or in a specific sequence to increase the ignition success rate. This method is particularly suitable for experimental conditions where the fuel concentration is close to the flammable limit or the flow rate is high.

[0041] In another optional embodiment, step S200 can also be combined with preheating technology to preheat the mixed gas before ignition, reducing the ignition energy required and improving the ignition success rate. Preheating can be achieved using a low-power heating wire or auxiliary heating device to raise the temperature of the mixed gas to a temperature close to but below its auto-ignition point.

[0042] In an embodiment of the present invention, releasing the experimental chamber in step S300 to enter a free-fall state, and allowing the heating wire to carry the flame into the microgravity environment includes the following steps B1-B3:

[0043] B1: Confirm that the flame has reached a stable state under normal gravity;

[0044] B2: Trigger the release mechanism to release the mechanical lock of the experimental chamber;

[0045] B3: Keep the heating wire in position and allow it to carry the flame into the microgravity environment.

[0046] Specifically, confirmation of flame stability in B1 is accomplished through a real-time image analysis system, which analyzes time series data of flame morphology parameters to determine whether the flame has reached stability. The release mechanism in B2 typically utilizes an electromagnetic lock or hydraulic system design, which unlocks within milliseconds after receiving the release signal. Maintaining the position of the heating wire in B3 is achieved through a rigid bracket and fixture, ensuring that the position of the heating wire relative to the burner does not change during the initial drop phase (approximately 0.1-0.2 seconds).

[0047] In an optional embodiment, step S300 may also include a release process vibration suppression system, which uses active or passive vibration reduction devices to reduce mechanical vibrations at the moment of release, further improving flame stability during the transition period. This system may be composed of a spring-damper combination, an air cushion, or a magnetic suspension buffer device.

[0048] In another optional embodiment, step S300 can also adopt a gradual release strategy. The experimental chamber is not completely released instantly, but a gradual release is achieved in a short period of time (about 0.05-0.1 seconds) through the control system to reduce the initial acceleration change rate and reduce the impact on flame stability.

[0049] In an embodiment of the present invention, in step S400, controlling the heating wire to withdraw from the combustion flow field a predetermined time after the microgravity indicator light is turned on includes the following steps C1-C3:

[0050] C1: The microgravity indicator light is on;

[0051] C2: count down to the scheduled time;

[0052] C3: Control the driving device to operate so that the heating wire is withdrawn from the combustion flow field.

[0053] Specifically, the microgravity indicator light in C1 is connected to an accelerometer and illuminates when the acceleration of the experimental chamber reaches the preset microgravity condition (usually less than 10^-4g). The predetermined time in C2 is typically set to 0.6 seconds, a value determined through extensive experimental data analysis to ensure that the flame reaches an initial stable state in the microgravity environment. The drive unit in C3 uses a precision screw motor design with a speed of approximately 27rpm, ensuring that the heating wire is evacuated at a steady speed to avoid airflow disturbances that affect the flame.

[0054] In an alternative embodiment, step S400 can also employ an adaptive evacuation time control system, which dynamically determines the optimal evacuation time by analyzing the flame's morphological changes in a microgravity environment in real time, rather than using a fixed, predetermined time. This system requires a high-speed camera and a real-time image processing unit to automatically adjust the evacuation time based on flame stability indicators.

[0055] In another optional embodiment, step S400 can also adopt a segmented evacuation strategy. The heating wire is not completely evacuated at one time, but is gradually moved away from the flame area in 2-3 stages. There is a short pause (about 0.1-0.2 seconds) between each stage, so that the flame can gradually adapt to the change in the position of the heating wire, further reducing the disturbance of the flame during the evacuation process.

[0056] In an embodiment of the present invention, at the end of the free fall state in step S500, the experimental cabin is connected to the network, and the fuel and air flow controllers are turned off, which includes the following steps D1-D3:

[0057] D1: monitor the falling distance or time of the experimental cabin;

[0058] D2: When the experimental cabin approaches the end of free fall, it enters the deceleration net;

[0059] D3: After the experimental chamber comes to a complete stop, a shutdown signal is sent to the fuel and air flow controllers, and the solenoid valve is activated to cut off the gas line.

[0060] Specifically, monitoring of the descent distance or time in D1 can be achieved using photoelectric sensors or precision timers. The deceleration net in D2, made of special materials, safely slows the descent of the experimental chamber over a short distance (approximately 1-2 meters) to prevent damage to experimental equipment. In D3, a shutdown signal is automatically sent by the control system, ensuring that the fuel and air supply are immediately stopped after the experiment concludes, preventing safety hazards.

[0061] In an optional embodiment, step S500 can also include automatic storage and transmission of experimental data. Before the experimental chamber enters the deceleration network, the system automatically transfers the data collected during the experiment to an external storage system, ensuring that even if the experimental chamber is impacted during the deceleration process, the data will not be lost. This is very important for ensuring the integrity and reliability of the experimental data.

[0062] In another alternative embodiment, step S500 can also employ a step-by-step shutdown strategy, first reducing the flow rate (to approximately 20% of the initial value) and maintaining it for a short period (approximately 0.5-1 second) before completely shutting down the flame. This prevents sudden changes in the flow rate from affecting the final data stage of the experiment. This gradual shutdown approach facilitates obtaining more complete experimental data, particularly for experiments studying the flame extinction process.

[0063] In this embodiment of the present invention, the heating wire has a coil structure with a coil diameter of 3 mm and a wire diameter of 0.35 mm. The drive device is a screw motor with a rotational speed of 27 rpm. The ignition position of the heating wire is approximately 60 mm axially above the nozzle outlet. These parameters are optimized through extensive experimentation to ensure ignition reliability and flame stability.

[0064] In summary, the ignition method for combustion experiments in a drop tower microgravity environment provided by this invention effectively addresses the technical problem of flame extinguishing easily under conditions of sudden gravity changes through a unique ignition strategy (a heating wire carries the flame into the microgravity environment and withdraws it at the appropriate time). This method meticulously designs and controls every key step, including flow rate setting, ignition process, chamber release, heating wire withdrawal, and safe experiment termination. This significantly improves the success rate of microgravity combustion experiments, reduces experimental costs, and provides reliable technical support for the study of combustion mechanisms in microgravity environments.

[0065] Example 3, reference Figure 1 , which is an embodiment of the present invention, provides an ignition method for a combustion experiment in a drop tower microgravity environment based on the previous two embodiments.

[0066] In an embodiment of the present invention, the ignition device used in the method of steps S100-S500 includes:

[0067] The heating wire;

[0068] a driving device connected to the heating wire;

[0069] a fixing device for fixing the heating wire to the driving device;

[0070] A control system controls the heating of the heating wire and the operation of the driving device.

[0071] Specifically, the ignition device is the core hardware device for implementing the method of the present invention. The heating wire is made of nickel-chromium alloy and has a coil structure, which can quickly heat up to the fuel ignition temperature after power is applied. The drive device uses a screw motor, which has precise position control capabilities and smooth motion characteristics. The fixing device includes a support rod made of high-temperature resistant material and a clamp that can firmly fix the heating wire and ensure its stability during the experiment. The control system consists of a programmable logic controller, a signal processing unit, and an execution module, which can control the entire ignition process according to preset programs or external signals.

[0072] In an alternative embodiment, the heating wire can also be designed with a multi-coil structure, where multiple coils of varying diameters are placed on the same support rod to accommodate ignition requirements under varying flow rates and mixing ratios. This multi-coil structure provides a larger thermal contact area, facilitating heat transfer during ignition and improving ignition success rates.

[0073] In another alternative embodiment, the drive device can also use a multi-degree-of-freedom robotic arm that can control the position and movement trajectory of the heating wire in three-dimensional space. This design allows the heating wire to evacuate the combustion flow field along the optimal path, minimizing disturbance to the formed flame.

[0074] In an embodiment of the present invention, the control system includes a programmable logic controller, and the programmable logic controller controls the operation of the screw motor for a predetermined time after the microgravity indicator light is turned on, comprising the following steps E1-E4:

[0075] E1: The programmable logic controller receives a signal that the microgravity indicator light is on;

[0076] E2: The programmable logic controller starts the internal timer;

[0077] E3: After the timing reaches the predetermined time, the programmable logic controller generates a control signal;

[0078] E4: The control signal is transmitted to the screw motor, causing it to operate according to preset parameters.

[0079] Specifically, the signal that turns on the microgravity indicator light in E1 is typically a voltage signal, transmitted to the programmable logic controller via a photoelectric sensor or direct electrical connection. The internal timer in E2 typically has millisecond accuracy, ensuring accurate timing control. The control signal generated in E3 contains motion parameter information such as speed and position. After receiving the control signal, the screw motor in E4 executes precise motion control through an internal closed-loop control system to ensure smooth removal of the heating wire.

[0080] In an optional embodiment, the control system can also integrate a real-time feedback mechanism, using sensors to monitor the actual position and motion of the heating wire, forming a closed-loop control system to improve the accuracy and reliability of the evacuation process. This feedback system can be composed of position sensors, speed sensors, and control algorithms, and can adjust the motor operating parameters in real time to address potential interference and deviations.

[0081] In another alternative embodiment, the control system can also adopt a distributed architecture, distributing signal acquisition, processing, and execution functions across multiple subsystems to improve the system's responsiveness and fault tolerance. This architecture is particularly suitable for complex experimental environments, as it can maintain basic functionality even if a subsystem fails.

[0082] In an embodiment of the present invention, the structural parameters of the ignition device include: the ignition position of the heating wire has a predetermined axial height from the nozzle outlet; before the cabin is sealed, the heating wire is rotated to the ignition position above the nozzle outlet, including the following steps F1-F3:

[0083] F1: Determine the optimal ignition position of the heating wire according to the fuel type and flow conditions;

[0084] F2: Before sealing the cabin, use the driving device to adjust the position of the heating wire;

[0085] F3: Lock the position of the heating wire to ensure stability during the cabin sealing and lifting process.

[0086] Specifically, the determination of the optimal ignition position in F1 is based on the combustion characteristics of the fuel and fluid dynamics analysis. For most common fuels, the ignition position is approximately 60mm axially from the nozzle outlet, a position that ensures stable flame formation and effective propagation. Position adjustment in F2 is usually completed during the experimental preparation phase, using a precise position control system to ensure that the heating wire is in the predetermined position. Position locking in F3 is usually achieved through a mechanical locking device or a high-holding torque motor brake system to ensure that the heating wire position does not shift during subsequent operations.

[0087] In an alternative embodiment, an automatic ignition position calibration system can be used. This system uses visual recognition or laser ranging technology to automatically detect the nozzle outlet position and calculate the ideal ignition position of the heating wire, reducing manual adjustment errors. This system is particularly suitable for precision experiments requiring high-precision positioning.

[0088] In another alternative implementation, a database of ignition positions can be created for different fuel and flow conditions. The optimal ignition position can be automatically determined by selecting the experimental conditions before the experiment, simplifying the experimental preparation process. The database can be built based on historical experimental data and theoretical analysis, and continuously optimized using machine learning algorithms.

[0089] This embodiment also provides a specific method for determining flame stability, including the following steps G1-G3:

[0090] G1: flame image sequence captured by high-speed camera;

[0091] G2: Use image processing algorithms to extract flame geometric characteristic parameters (such as height, width, area, etc.) and photometric characteristic parameters (such as brightness distribution, color distribution, etc.);

[0092] G3: Calculate the time rate of change of the characteristic parameters. When the rate of change is lower than the preset threshold and lasts for a certain period of time (usually 2-3 seconds), it is determined that the flame has reached a stable state.

[0093] This flame stability assessment method serves as a basis for determining whether the heating wire has been deenergized after successful ignition in step S200, and for confirming flame stability before releasing the experimental chamber in step S300. Compared to traditional visual observation or single-parameter monitoring methods, this multi-parameter quantitative analysis method can more accurately assess flame stability, reduce the influence of human factors, and improve experimental reliability and repeatability.

[0094] In this embodiment, the method for determining the predetermined time in step S400 is also described in detail. The predetermined time refers to the time interval between the lighting of the microgravity indicator light and the removal of the heating wire. Its value directly affects the stability of the flame in the microgravity environment. Through extensive experimental data analysis and microgravity flame dynamics simulation, it was found that for push-up flames, when the predetermined time is set to 0.6 seconds, the flame can reach an initial stable state in the microgravity environment, and the removal of the heating wire will not cause the flame to go out. For different types of fuels and flow conditions, the predetermined time may need to be adjusted appropriately, generally ranging from 0.4 to 0.8 seconds. Before the experiment, the optimal predetermined time can be determined through small-scale pilot experiments or theoretical model calculations.

[0095] In summary, this embodiment details the ignition device structure and control system for implementing the method of the present invention, as well as the specific implementation details of the key steps. By rationally designing the ignition device's structural parameters and control strategy, combined with precise methods for determining flame stability and pre-determining the predetermined time, the success rate and data quality of combustion experiments in drop-tower microgravity environments can be effectively improved. Compared to traditional ignition methods, the method of the present invention effectively addresses the problem of flame extinguishing under conditions of sudden gravity changes, providing reliable technical support for microgravity combustion research.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An ignition method for a combustion experiment in a drop tower microgravity environment, characterized in that: include: Set up fuel and air flow controllers; After the experimental cabin is hoisted, fuel and air are introduced and the heating wire is powered on and ignited. After the ignition is successful, the heating wire is powered off; releasing the experimental cabin to enter a free-fall state, and allowing the heating wire to carry the flame into the microgravity environment; controlling the heating wire to withdraw from the combustion flow field a predetermined time after the microgravity indicator light is turned on; At the end of the free fall state, the experimental cabin is connected to the net, and the fuel and air flow controllers are turned off.

2. The ignition method for a combustion experiment in a drop tower microgravity environment according to claim 1, characterized in that: The controlling the heating wire to evacuate the combustion flow field comprises: detecting that the microgravity indicator light is lit; Counting to the predetermined time; The driving device is controlled to operate so that the heating wire is withdrawn from the combustion flow field.

3. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 2, characterized in that: After the ignition is successful, the process includes monitoring the shape of the flame and determining whether the flame is stable.

4. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 3, characterized in that: include: Releasing the experimental cabin to enter the free-fall state includes: Controlling the release mechanism to release the lock on the experimental cabin; The heating wire is kept in a constant position so that the heating wire carries the flame into the microgravity environment.

5. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 4, characterized in that: The ignition devices used include: The heating wire; a driving device connected to the heating wire; a fixing device for fixing the heating wire to the driving device; A control system controls the heating of the heating wire and the operation of the driving device.

6. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 5, characterized in that: The heating wire has a coil structure; the driving device is a screw motor, which has a predetermined rotational speed; the fixing device includes a support rod and a clamp; the control system includes a programmable logic controller, which sends a control signal to the screw motor at a predetermined time after the microgravity indicator light is turned on; the control system also includes a temperature sensor, which monitors the temperature of the heating wire and adjusts the current according to temperature feedback.

7. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 6, characterized in that: The ignition position of the heating wire has a predetermined axial height from the nozzle outlet; before sealing the cabin, the heating wire is rotated to the ignition position above the nozzle outlet; the control system also integrates an image recognition module, which analyzes the flame image and determines the flame state; the fuel and air flow controllers are shut down in a step-by-step manner, first reducing the flow and then completely shutting down.

8. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 7, characterized in that: The fuel and air flow controllers are provided as follows: measuring physical parameters of the fuel and the air; Calculating the flow requirements of the fuel and the air based on the average jet outlet velocity; converting the flow requirements into control parameters of the fuel and air flow controllers; The fuel and air flow controllers are adjusted to the control parameters before sealing the cabin.

9. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 8, characterized in that: Also includes: Setting a data acquisition system, wherein the data acquisition system is electrically connected to the microgravity indicator light; The data acquisition system receives a status signal from the microgravity indicator light and marks an experiment phase according to the status signal; The experimental data are segmented according to the experimental stages.

10. The ignition method for a drop tower combustion experiment in a microgravity environment according to claim 9, characterized in that: The structural parameters of the ignition device are pre-set according to the characteristics of the fuel before the cabin is sealed. The structural parameters include: The material and size of the heating wire; the speed and stroke of the drive; The position and angle of the fixing device.

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