Combustion experiment machine

Abstract

The invention relates to a combustion experiment machine, and relates to the technical field of material performance detection, and the combustion experiment machine comprises a combustion chamber used for accommodating a to-be-detected material; a heating system associated with the combustion chamber; the multi-mode sensing system is used for monitoring one or more performance parameters of the to-be-tested material in the combustion process; the data processing unit is connected with the heating system and the multi-mode sensing system; the heating system is configured to apply a composite heat flow comprising a reference heat flow and a periodically changing disturbance heat flow to the material to be tested. According to the method, traditional static measurement is converted into active dynamic diagnosis, parameters such as dynamic mechanical properties, chemical reaction kinetics and mass transfer characteristics in the combustion process can be quantitatively obtained, thermal-mechanical-chemical multi-physical field concurrent events are effectively decoupled by comparing phase information of multi-modal response, and the combustion performance of the combustion system is improved. And a brand new technical means is provided for deeply revealing a material combustion mechanism.

Description

Technical Field

[0001] This application relates to the field of material performance testing technology, and in particular to a combustion testing machine. Background Technology

[0002] The combustion behavior of materials is a complex phenomenon involving the close coupling of multiple physical and chemical processes, including heat transfer, mass transfer, chemical reaction kinetics, and the evolution of mechanical properties. Accurately understanding and characterizing the behavior of materials during combustion is crucial for fire science research, the development of novel flame-retardant materials, and the establishment of a scientific fire safety evaluation system.

[0003] In existing technologies, various experimental methods and equipment have been developed for evaluating the combustion performance of materials. For example, the cone calorimeter is widely used to measure macroscopic combustion parameters such as ignition time, heat release rate, mass loss rate, and smoke generation, providing important basis for the fire hazard classification of materials. Meanwhile, thermal analysis techniques such as thermogravimetric analysis (TGA) are also used to study the thermal stability and pyrolysis kinetics of materials under programmed temperature conditions. These conventional testing methods provide indispensable means for evaluating the combustion characteristics of materials at the macroscopic level.

[0004] However, most of these existing mainstream testing techniques are essentially passive observations of the combustion process and records of quasi-static responses. The parameters they measure, such as total heat release or final char residue, are often the final result or a slowly changing phenomenon resulting from the combined effects of multiple physicochemical phenomena during combustion. The highly dynamic internal evolution information contained in the combustion process itself, such as the breaking / formation rate of specific chemical bonds, the viscoelastic transition of materials at high temperatures, and the formation sequence of the mechanical properties of the protective char layer, are difficult to capture and quantify directly.

[0005] Furthermore, due to the lack of proactive, system-applied detection methods, traditional measurement methods struggle to effectively decouple these temporally related and mechanistically coupled subprocesses when multiple phenomena occur concurrently during material combustion—such as the pyrolysis of the polymer matrix, the decomposition of flame retardants, the release of gaseous products, and the foaming, cross-linking, and embrittlement of the condensed-phase char layer. Researchers therefore find it difficult to clearly identify the key physical or chemical steps that dominate at a specific stage, and cannot accurately establish the intrinsic causal relationships between the evolution of different physical fields (such as chemical and mechanical fields). This limitation restricts a deeper understanding of the profound combustion mechanisms of materials and poses challenges to the refined and functional design of high-performance flame-retardant materials. Therefore, there is an urgent need in this field for a technical solution that can transcend traditional passive, macroscopic measurements to achieve proactive diagnosis of the material combustion process and simultaneous characterization of multi-dimensional dynamic performance. Summary of the Invention

[0006] The purpose of this application is to provide a combustion testing machine that solves the problem that traditional combustion testing techniques cannot simultaneously acquire multi-dimensional parameters such as dynamic mechanical and chemical kinetics during the material combustion process, and it is difficult to effectively decouple these concurrent physicochemical events.

[0007] In a first aspect, this application provides a combustion testing machine, which adopts the following technical solution: including: a combustion chamber for containing a material to be tested; a heating system associated with the combustion chamber; a multimodal sensing system for monitoring one or more performance parameters of the material to be tested during combustion; and a data processing unit connected to the heating system and the multimodal sensing system;

[0008] The heating system is configured to apply a composite heat flux to the material under test, comprising a reference heat flux and a periodically varying perturbation heat flux.

[0009] The multimodal sensing system is configured to simultaneously acquire multiple response signals of the material under test under the action of the composite heat flow;

[0010] The data processing unit is configured to perform phase-locked analysis on the various response signals using the disturbed heat flow as a reference signal, so as to determine the phase delay and response amplitude of each response signal relative to the disturbed heat flow.

[0011] Preferably, the heating system includes a programmable power source that can precisely control the power applied to the heating element to generate the periodic perturbation heat flow in the form of a sine wave or square wave.

[0012] Preferably, the multimodal sensing system includes an acoustic-mechanical composite probe, which serves as a support for the material under test and is configured to simultaneously monitor the acoustic emission signal generated by the material due to cracking, as well as the dynamic mechanical response of the material when a weak vibration is actively applied.

[0013] Preferably, the data processing unit is further configured to determine the energy storage modulus and loss modulus of the material under test during the combustion process by performing phase-locked loop analysis on the dynamic mechanical response.

[0014] Preferably, the multimodal sensing system includes a hyperspectral imaging probe configured to acquire, in a non-contact manner, two-dimensional spatial information of the chemical composition distribution on the surface of the material under test during combustion.

[0015] Preferably, the multimodal sensing system includes a microelectromechanical system (MEMS) gas sensor array configured to measure the spatial concentration distribution of various gaseous products in the combustion chamber in an in-situ, distributed manner.

[0016] Preferably, the data processing unit is further configured to distinguish between processes controlled by surface chemical reactions and combustion events controlled by internal heat or mass transfer processes by comparing phase delays obtained from different sensor channels.

[0017] Preferably, the combustion test machine also includes a synchronization control unit, which can add a unified synchronization timestamp to all response signals acquired by the multimodal sensing system to ensure that the time base for phase-locked analysis is accurate and consistent.

[0018] Preferably, the data processing unit employs a digital lock-in amplifier algorithm to calculate the phase delay and response amplitude by performing cross-correlation operations between the response signal and in-phase and quadrature reference signals.

[0019] Secondly, the material combustion performance analysis method for a combustion testing machine provided in this application adopts the following technical solution, including the following steps:

[0020] S1. Place the material to be tested in the combustion test chamber;

[0021] S2. Start the heating system and apply a composite heat flow, including a reference heat flow and a periodic perturbation heat flow, to the material under test;

[0022] S3. Activate the multimodal sensing system to simultaneously acquire multiple response signals of the material under test to the composite heat flux;

[0023] S4. Using the data processing unit, with the disturbed heat flow as a reference, perform phase-locked analysis on the various response signals collected in step S3, thereby obtaining the phase delay and response amplitude parameters characterizing the combustion dynamics of the material under test.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. This invention enables the acquisition of dynamic performance parameters during material combustion, greatly enriching the dimensions of detection information. By applying a composite heat flux containing a reference heat flux and a periodically perturbed heat flux to the material, and performing phase-locked loop analysis on the multimodal response signal, this invention can quantitatively characterize properties that traditional static or slowly varying measurements cannot reach, such as the characteristic time constant of chemical reactions, the thermoviscoelasticity of materials at high temperatures, and the generation / diffusion mechanism of gaseous products, thus providing a new and deeper criterion for material performance evaluation.

[0026] 2. Significantly improves the detection signal-to-noise ratio and effectively decouples complex concurrent combustion processes. This invention utilizes the principle of phase-locked loop analysis to accurately separate the weak portion of the response signal acquired by the sensor that is strictly synchronized with the active perturbation frequency from strong combustion background noise and unrelated thermal events. This highly selective detection method makes it possible to identify and analyze subtle dynamic changes that are easily obscured by traditional measurement methods, thereby improving the sensitivity and accuracy of the analysis.

[0027] 3. This invention provides a novel approach to revealing the multi-physics coupling mechanism during material combustion. By simultaneously acquiring and analyzing response phase and amplitude information from different dimensions such as chemistry, mechanics, and mass transfer under the same perturbation excitation, this invention can establish the intrinsic correlation and time series relationship between these different physical processes. For example, it can directly link the evolution of the mechanical properties of the char layer with specific surface chemical reactions, thereby constructing a more comprehensive and profound combustion behavior model. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the combustion test machine system provided in an embodiment of the present invention;

[0029] Figure 2 This is a flowchart of the material combustion performance analysis method provided in the embodiments of the present invention;

[0030] Figure 3 This is a schematic diagram illustrating the principle of active perturbation-response analysis in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the acoustic-mechanical composite probe structure in an embodiment of the present invention. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1 -Appendix Figure 4 This application will be described in further detail below.

[0033] Example 1: A combustion testing machine, comprising: a combustion chamber for containing a material to be tested; a heating system associated with the combustion chamber; a multimodal sensing system for monitoring one or more performance parameters of the material to be tested during combustion; and a data processing unit connected to the heating system and the multimodal sensing system.

[0034] The heating system is configured to apply a composite heat flux to the material under test, which includes a reference heat flux and a periodically varying perturbation heat flux.

[0035] The multimodal sensing system is configured to simultaneously acquire multiple response signals of the material under test under the action of combined heat flow;

[0036] The data processing unit is configured to perform phase-locked analysis on multiple response signals using the perturbed heat flow as a reference signal, in order to determine the phase delay and response amplitude of each response signal relative to the perturbed heat flow.

[0037] See attached document Figure 1 The present invention provides a combustion testing machine with an innovative structural design to achieve dynamic performance characterization of the material combustion process.

[0038] The combustion test machine includes a combustion reaction system, a dynamic disturbance heating unit 20 associated with the combustion reaction system, a multimodal sensing system 30 for monitoring the response of the test material, a synchronous control and data acquisition unit 40, and a data processing unit 50.

[0039] The combustion reaction system includes a combustion chamber 10. This combustion chamber 10 is made of a high-temperature resistant and high-transmittance material such as quartz glass, and its geometry is suitable for external optical observation. The opening of the combustion chamber 10 is equipped with a sealing structure to form a closed or semi-closed reaction space. The combustion chamber 10 is connected to an atmosphere control module via piping. The atmosphere control module includes a gas mass flow meter for precisely delivering specific components and flow rates of gas into the combustion chamber 10 to establish and maintain the required experimental atmosphere.

[0040] The dynamic perturbation heating unit 20 is thermally coupled to the combustion chamber 10 to apply a controlled heat flux to the test material within the combustion chamber 10. The dynamic perturbation heating unit 20 includes a heating element and a high-frequency programmable power source. The heating element is, for example, an infrared lamp array or a resistance wire heater, arranged to uniformly heat the sample area. The high-frequency programmable power source is configured to output a precisely controlled power, causing the heating element to generate a composite heat flux. The composite heat flow is applied to the material under test. Expressed by the following formula:

[0041] ;

[0042] in, It represents the baseline heat flow, and its value can be constant or change slowly over time according to a preset program to drive the material to burn or pyrolyze. This represents the periodic disturbance heat flow, which is superimposed on the reference heat flow. Disturbance heat flow The specific form can be a sine wave:

[0043] ;

[0044] in, The amplitude of the disturbance heat flow, For time, Let ω be the angular frequency of the disturbance. and All values ​​can be preset and adjusted using a high-frequency programmable power source.

[0045] The multimodal sensing system 30 is configured to simultaneously monitor and acquire response signals generated by the material under test from different physical dimensions under the action of combined heat flux. In one specific embodiment, the multimodal sensing system 30 includes one or more probes:

[0046] Acoustic-mechanical composite probe 31. (See attached document) Figure 4 The probe 31 is designed as a sample holder within the combustion chamber 10, with a piezoelectric ceramic sensor integrated internally or attached to its surface. The probe 31 has two operating modes: in passive mode, the piezoelectric ceramic sensor monitors the acoustic emission signals released when the material under test undergoes internal microcrack propagation or bursting due to thermal stress; in active mode, the probe 31 is configured to apply a preset frequency and amplitude of mechanical micro-vibration to the material under test and simultaneously detect the vibration response signal of the material, which characterizes changes in the material's dynamic mechanical properties.

[0047] Hyperspectral imaging probe 32. This probe 32 is positioned outside the combustion chamber 10, with its optical axis aligned with the material under test through the light-transmitting area of ​​the combustion chamber 10. Structurally, the probe 32 includes an objective lens, a grating as a spectroscopic element, and a two-dimensional detector array. Its function is to acquire hyperspectral image data of a specific area on the surface of the material under test during the combustion process; this data includes spatial and spectral dimensional information.

[0048] Microelectromechanical systems (MEMS) gas sensor array 33. This array 33 is arranged within the combustion chamber 10, above the material to be measured. The array 33 consists of multiple MEMS sensor units targeting different target gases (e.g., CO, CO2, HCN, O2). The sensor units are connected to the gas environment near the material to be measured through a microfluidic sampling system, and are used for in-situ, distributed measurement of the spatial concentration distribution of gaseous products generated by pyrolysis and combustion.

[0049] The synchronous control and data acquisition unit 40 is a key component in realizing the technical solution of this invention. In terms of hardware, this unit 40 can be constructed using a field-programmable gate array (FPGA) or a dedicated digital signal processor (DSP). The control output of this unit 40 is connected to the high-frequency programmable power source of the dynamic disturbance heating unit 20, used to generate and output disturbance signals. Its data input is connected to various probes in the multimodal sensing system 30 (acoustic-mechanical composite probe 31, hyperspectral imaging probe 32, MEMS gas sensor array 33) and other sensors (such as a thermal balance and temperature sensor) located within the combustion chamber 10.

[0050] The synchronization control and data acquisition unit 40 incorporates a high-frequency master clock. This unit 40 is configured to append a synchronization timestamp from the high-frequency master clock to each acquired data point when receiving continuous data streams from all sensor channels at its data input terminal. This structure ensures that all acquired response signals are recorded under a unified, high-precision time reference, providing a foundation for accurate phase-locked loop analysis by the subsequent data processing unit 50.

[0051] The data processing unit 50 is connected to the synchronization control and data acquisition unit 40 and is used to receive multi-channel data with synchronization timestamps and perform subsequent analysis and calculations.

[0052] Example 2: A method for analyzing the combustion performance of materials using a combustion testing machine, as shown in the attached document. Figure 2 The analytical method of this invention, through specific design of the system workflow and application of core data processing algorithms, achieves accurate characterization of the dynamic performance of material combustion. The method specifically includes the following steps:

[0053] Step S201: Perform experimental preparation and system initialization. Place the material to be tested on the acoustic-mechanical composite probe 31 and position the probe at a predetermined location in the combustion chamber 10. Seal the combustion chamber 10 and introduce a gas of specific composition and flow rate into it through the atmosphere control module to establish a stable initial atmosphere environment. Set the reference heat flux of the dynamic disturbance heating unit 20 through the software interface of the data processing unit 50. The program curve, and set the disturbance heat flow. The parameters include the perturbation angular frequency. and disturbance amplitude .

[0054] Step S202: Monitor the reference combustion process. Activate the dynamic disturbance heating unit 20, initially applying only the reference heat flux. The material to be tested is heated. During this stage, the synchronous control and data acquisition unit 40 begins to acquire background response signals from the multimodal sensing system 30 and other sensors (such as a thermal balance and a temperature sensor) to obtain basic combustion behavior data of the material under undisturbed conditions.

[0055] Step S203: Apply active perturbation and perform synchronous data acquisition. When the combustion process of the material under test meets one or more preset triggering conditions, such as when the temperature reaches a specific threshold or the mass loss rate reaches a peak, the synchronous control and data acquisition unit 40 sends a command to the dynamic perturbation heating unit 20 to maintain the original reference heat flux. Based on this, periodic perturbation heat flow is then applied. During this period, the synchronization control and data acquisition unit 40 continuously records the dynamic response data stream from all sensor channels in a synchronized timestamp manner.

[0056] Step S204: Perform phase-locked analysis and dynamic parameter extraction. At the end of the disturbance application phase or after the entire experiment, the data processing unit 50 executes the core analysis algorithm on the multi-channel data stream with synchronization timestamps acquired in step S203. The core of this algorithm is multi-channel digital phase-locked analysis, the purpose of which is to accurately decouple the heat flow from the disturbance from the composite response signals acquired by each sensor. Response components of the same frequency.

[0057] For the response signal acquired by any sensor channel It can be expressed as:

[0058] ;

[0059] in, This refers to the slowly varying component of the signal, i.e., the basic measurement value under undisturbed conditions; The amplitude of the portion of the response signal that has the same frequency as the disturbance frequency; The phase delay of the response signal relative to the active thermal flow disturbance; This represents the frequency of the disturbance. Irrelevant noise and other interference signals.

[0060] To solve and The data processing unit 50 first internally generates two digital reference signals orthogonal to the active disturbance signal: an in-phase reference signal and a non-in-phase reference signal. and quadrature reference signals Subsequently, by responding to the signal Multiply each of the two reference signals point by point over one or more complete disturbance cycles. Integral operations are performed on the above to calculate its in-phase components. and orthogonal components :

[0061] ;

[0062] ;

[0063] in, The number of disturbance cycles included in the integral is a positive integer; This is the starting time of the integration. Through this integration process, the frequency of the disturbance is independent of the integration frequency. and Items will be effectively filtered out.

[0064] In obtaining and Then, the data processing unit 50 calculates the final response amplitude using the following formula. and phase delay :

[0065] ;

[0066] ;

[0067] in, It is a bivariate arctangent function, which can be based on and The algebraic symbols are used to determine the phase angle. The correct quadrant it belongs to.

[0068] Step S205 involves the collaborative interpretation of multimodal dynamic performance parameters. The data processing unit 50 will decouple the response amplitudes from different sensor channels. and phase delay This is transformed into dynamic performance parameters with clear physical meaning, and correlation analysis is performed. For example, when the response signal... When the absorbance originates from a specific chemical bond in the hyperspectral imaging probe 32, its phase retardation It is related to the characteristic time constant of the chemical bond formation or breaking reaction. When the response signal... When the dynamic mechanical response originates from the acoustic-mechanical composite probe 31, its in-phase component Related to the storage modulus of the material, its orthogonal components Related to the loss modulus of the material. When the response signal The phase delay is derived from the concentration of a specific gas in the MEMS gas sensor array 33. The magnitude of the phase delay parameter can be used to distinguish whether the gas generation process is directly controlled by surface chemical reactions or dominated by heat and mass transfer processes within the material. By comparing phase delay parameters obtained from different physical dimensions at the same time point, the temporal relationships and causal connections between thermal, chemical, and mechanical events during combustion can be established.

Claims

1. A combustion testing machine, comprising: A combustion chamber for containing the test material; a heating system associated with the combustion chamber; a multimodal sensing system for monitoring one or more performance parameters of the test material during combustion; and a data processing unit connected to the heating system and the multimodal sensing system; characterized in that, The heating system is configured to apply a composite heat flux to the material under test, comprising a reference heat flux and a periodically varying perturbation heat flux. The multimodal sensing system is configured to simultaneously acquire multiple response signals of the material under test under the action of the composite heat flow; The data processing unit is configured to perform phase-locked analysis on the various response signals using the disturbed heat flow as a reference signal, so as to determine the phase delay and response amplitude of each response signal relative to the disturbed heat flow.

2. The combustion testing machine according to claim 1, characterized in that, The heating system includes a programmable power source that can precisely control the power applied to the heating element to generate a periodic perturbation heat flow in the form of a sine wave or square wave.

3. The combustion testing machine according to claim 1, characterized in that, The multimodal sensing system includes an acoustic-mechanical composite probe, which serves as a support for the material under test and is configured to simultaneously monitor the acoustic emission signals generated by the material due to cracking, as well as the dynamic mechanical response of the material when a weak vibration is actively applied.

4. A combustion testing machine according to claim 3, characterized in that, The data processing unit is further configured to determine the energy storage modulus and loss modulus of the material under test during the combustion process by performing phase-locked analysis on the dynamic mechanical response.

5. A combustion testing machine according to claim 1, characterized in that, The multimodal sensing system includes a hyperspectral imaging probe configured to acquire, in a non-contact manner, two-dimensional spatial information of the chemical composition distribution on the surface of the material under test during combustion.

6. A combustion testing machine according to claim 1, characterized in that, The multimodal sensing system includes a microelectromechanical system (MEMS) gas sensor array configured to measure the spatial concentration distribution of various gaseous products in the combustion chamber in an in-situ, distributed manner.

7. A combustion testing machine according to claim 1, characterized in that, The data processing unit is further configured to distinguish between processes controlled by surface chemical reactions and combustion events controlled by internal heat or mass transfer processes by comparing phase delays obtained from different sensor channels.

8. A combustion testing machine according to claim 1, characterized in that, The combustion test chamber also includes a synchronization control unit, which can add a unified synchronization timestamp to all response signals acquired by the multimodal sensing system to ensure that the time base for phase-locked analysis is accurate and consistent.

9. A combustion testing machine according to claim 1, characterized in that, The data processing unit employs a digital lock-in amplifier algorithm to calculate the phase delay and response amplitude by performing cross-correlation operations between the response signal and in-phase and quadrature reference signals.

10. A method for analyzing the combustion performance of materials using a combustion testing machine, characterized in that, The method applied to the combustion testing machine according to any one of claims 1-9 includes the following steps: S1. Place the material to be tested in the combustion test chamber; S2. Start the heating system to apply a composite heat flow, including a reference heat flow and a periodic disturbance heat flow, to the material under test; S3. Start the multimodal sensing system and simultaneously collect multiple response signals of the material under test to the composite heat flux; S4. Using the data processing unit, with the disturbed heat flow as a reference, perform phase-locked analysis on the various response signals collected in step S3 to obtain the phase delay and response amplitude parameters characterizing the combustion dynamics of the material under test.

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