Short time domain synchronized gated igniter temperature measurement device based on multispectral imaging

Abstract

The application provides a short-time domain synchronous gating igniter temperature measuring device based on multispectral imaging, which comprises a multispectral imaging module, a trigger detection module, a synchronous gating and timing control module and a temperature inversion module. The multispectral imaging module is used for collecting radiation signals of a target region at multiple wave bands in the range of 600nm-900nm during operation of an igniter; the trigger detection module is used for detecting an ignition event and outputting a trigger signal; the synchronous gating and timing control module controls the collection of the multispectral imaging module based on the trigger signal output by the trigger detection module, so that the radiation signals at different wave bands are collected at different delay points after ignition; and the temperature inversion module is used for solving the temperature of the collected radiation signals at different wave bands to obtain the temperature distribution of the target region of the igniter. The application can realize accurate measurement of the temperature of the target region of the igniter and the change process thereof with time, and provides a reliable temperature diagnosis means for research on the igniter.

Description

Technical Field

[0001] This invention relates to the field of igniter temperature measurement technology, and in particular to a short-time-domain synchronous gated igniter temperature measurement device based on multispectral imaging. Background Technology

[0002] Ignition systems enhance ignition and broaden the ignition limit through rapid heating and free radical generation by high-temperature plasma. Therefore, its temperature evolution is a key indicator for evaluating ignition energy, flame core formation, and ignition reliability. However, plasma ignition temperature measurement is very challenging: the discharge process is often transient, ranging from microseconds to milliseconds, with drastic temperature changes over time, requiring high temporal resolution diagnostics; simultaneously, high-voltage discharge introduces strong electromagnetic interference, easily contaminating the measurement link; furthermore, plasma radiation exhibits strong spectral lines and non-equilibrium characteristics, resulting in spatially inhomogeneous temperature fields. This makes traditional contact-based or single-band radiation temperature measurements susceptible to large errors due to unknown emissivity, spectral interference, and line-of-sight integration effects. Therefore, developing a short-time-domain synchronous gated ignition temperature measurement device based on multispectral imaging is of great significance. Summary of the Invention

[0003] To address the shortcomings or deficiencies of the existing technologies, this invention provides a short-time-domain synchronous gated igniter temperature measurement device based on multispectral imaging. This device can achieve high-time-resolution synchronous acquisition of multi-band radiation signals during the transient ignition process of the igniter, solving the problems of time alignment difficulties and insufficient response speed of existing temperature measurement technologies under transient ignition conditions.

[0004] The objective of this invention can be achieved through the following technical measures: a short-time-domain synchronous gated igniter temperature measurement device based on multispectral imaging, the device comprising:

[0005] Multispectral imaging module: Acquires radiation signals from the target area in multiple bands within the 600nm-900nm range during ignition operation;

[0006] Trigger detection module: detects ignition control command pulse signal, generates standard trigger pulse, and determines the time corresponding to the standard trigger pulse as the system time zero point. ;

[0007] Synchronous gating and timing control module: Receives the standard trigger pulse and sets the time zero point... A TTL trigger signal is generated as a reference for the externally triggered camera to control the multispectral imaging module to acquire radiation signals of multiple bands at different delay points after ignition.

[0008] Temperature inversion module: Based on Planck's law and emissivity model, the collected radiation signals of multiple bands are preprocessed and the temperature is solved to obtain the temperature distribution of the igniter target area.

[0009] The objective of this invention can also be achieved through the following technical measures:

[0010] The multispectral imaging module acquires radiation signals in no fewer than 16 bands within the 600nm-900nm wavelength range, and each band is a narrowband band.

[0011] The trigger detection module includes a Schmitt trigger structure for threshold discrimination of the ignition control command pulse signal; the trigger detection module also includes a monostable shaping circuit for pulse width shaping and level normalization of the ignition control command pulse signal, and outputting the standard trigger pulse with controlled pulse width and normalized level.

[0012] The TTL trigger signal generated by the synchronization gating and timing control module follows a preset delay sequence. Configure the settings; wherein the TTL trigger signal is output to the trigger port of the multispectral imaging module, and the rising edge of the TTL trigger pulse is used to trigger the multispectral imaging module to acquire radiation signals.

[0013] The synchronous gating and timing control module controls the exposure time of the multispectral imaging module to a preset value. The multispectral imaging module performs a duration of [duration missing] within the start time corresponding to the rising edge of each TTL trigger pulse. The exposure radiation signal was collected.

[0014] The temperature inversion module establishes a temperature inversion problem with the error between the radiation signals of multiple bands and the theoretical radiation signals output by the radiation model as the objective function, and uses the particle swarm optimization algorithm to optimize and solve the objective function in order to obtain the temperature distribution of the target region.

[0015] The radiation model of the temperature inversion module is as follows:

[0016] In the formula, The flame spectral radiance is expressed in W / m². 3 / sr;c1=3.742×10 -16 c2 = 1.4388 × 10 -2 ; Wavelength, in nm; Temperature, in Kelvin (K). These are parameters in the emissivity model.

[0017] The objective function of the temperature inversion module is expressed as:

[0018] In the formula, The radiation signal measured by the multispectral imaging module. This is the standard value.

[0019] This invention achieves short-time-domain temperature measurement of igniters based on a multispectral imaging system, synchronous gating, and timing control system. It enables high-time-resolution synchronous acquisition of multi-band radiation signals during the ignition transient process, solving the problems of time alignment difficulties and insufficient response speed of existing temperature measurement technologies under ignition transient conditions. At the same time, through joint inversion of multispectral radiation information, the influence of plasma radiation characteristics on temperature measurement accuracy is reduced, enabling accurate measurement of the temperature of the target area of ​​the igniter and its change over time. This provides a reliable temperature diagnostic method for igniter performance evaluation, structural optimization, and ignition mechanism research. Attached Figure Description

[0020] Figure 1 A schematic diagram of the structure of a short-time-domain synchronous gated igniter temperature measurement device based on multispectral imaging provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the shaping process of the ignition control command pulse by the trigger detection module provided in an embodiment of the present invention;

[0022] Figure 3 Signal diagram of the synchronization gating and timing control module provided in the embodiments of the present invention;

[0023] Figure 4 The distribution diagram of the transient ignition temperature of the igniter under different delays provided in the embodiments of the present invention. Detailed Implementation

[0024] The specific implementation method of the present invention will be described below with reference to the accompanying drawings.

[0025] This invention utilizes a multispectral imaging device, synchronous gating, and timing control system to measure the transient ignition temperature distribution of an igniter. The ignition command pulse signal is used as the time zero point, and the synchronous gating and timing control system is used to collect radiation signals from the target area in a short time domain. The transient temperature distribution of the igniter is then solved based on the radiation signals in multiple bands.

[0026] An embodiment of the present invention will now be described with reference to the accompanying drawings. This embodiment uses the ignition control command pulse of the igniter as the trigger reference, and achieves transient temperature distribution measurement of the igniter target area through trigger shaping, timing control, external camera trigger acquisition, and multispectral temperature inversion.

[0027] like Figure 1As shown, the short-time-domain synchronous gating igniter temperature measurement device based on multispectral imaging in this embodiment includes: a multispectral imaging module 13, a trigger detection module 11, a synchronous gating and timing control module 12, and a temperature inversion module 14. The trigger detection module 11 receives the ignition control command pulse output from the ignition control system, and its output is a standard trigger pulse (TTL), connected to the trigger in port of the synchronous gating and timing control module 12. The synchronous gating and timing control module 12 generates a TTL trigger output based on the trigger in signal, connected to the external trigger input terminal of the camera in the multispectral imaging module 13. The multispectral imaging module 13 acquires multi-band radiation images under external camera triggering and transmits the image data to the temperature inversion module 14 for temperature calculation.

[0028] Specifically, the multispectral imaging module 13 is used to acquire radiation signals from the target area of ​​the igniter during ignition operation. This module can form multiple spectral channels within a predetermined wavelength range, preferably dividing the 600nm-900nm wavelength range into no less than 16 narrowband bands to obtain multiband radiation information for temperature inversion.

[0029] The trigger detection module 11 is used to acquire the time reference of the ignition transient. This module detects the ignition control command pulse signal and determines the time corresponding to the detected ignition command pulse as the system's time zero point. A Schmitt trigger structure is used to perform threshold discrimination on the input ignition control command pulse to suppress the impact of noise, glitches, and electromagnetic interference on trigger accuracy. A monostable shaping circuit is used to perform pulse width shaping and level normalization on the trigger signal, thereby generating a standard trigger pulse with stable amplitude and controlled pulse width. This standard trigger pulse is output as a unified time reference signal for the system and sent to the synchronization gating and timing control module 12.

[0030] The synchronization gating and timing control module 12 is used at the zero time point Based on this, a timing control signal is generated for acquisition by the multispectral imaging module 13. This module receives a standard trigger pulse output by the trigger detection module 11 and uses the time corresponding to this pulse as the zero point of time. Generate a set of values ​​relative to time zero. The delayed trigger signal. In this invention, the synchronization gating and timing control module 12 preferably outputs a control signal to the multispectral imaging module in the form of a TTL trigger signal. The TTL trigger signal follows a preset delay sequence. Configure the settings. At each delayed trigger moment, the rising edge of the TTL trigger pulse triggers the multispectral imaging module to perform one radiation signal acquisition. The exposure time of the multispectral imaging module 13 is set to a predetermined value. This allows each image to correspond to a duration of The short time-domain sampling window.

[0031] The temperature inversion module 14 preprocesses and solves the temperature of the radiation signals of multiple bands acquired by the multispectral imaging module 13 based on Planck's law and emissivity model. The temperature inversion problem is established with the error between the radiation signals of multiple bands and the theoretical radiation signal output by the radiation model as the objective function. The particle swarm optimization algorithm is used to optimize and solve the objective function in order to obtain the temperature distribution of the target area.

[0032] The working process of the short-time-domain synchronous gated igniter temperature measurement device based on multispectral imaging of the present invention is as follows:

[0033] 1. The multispectral imaging module observes the target area of ​​the igniter, which is the jet region near the nozzle, through optical imaging components. Sixteen narrowband bands are formed in the 600nm-900nm range to obtain multispectral information for temperature inversion. The camera is set to external trigger acquisition mode, meaning one image is acquired for each rising edge of a TTL trigger pulse. The camera exposure time is set to 1 ms so that each image corresponds to an exposure integration process lasting 1 ms.

[0034] 2. The trigger detection module receives the ignition control command pulse signal output by the ignition control system. Because the ignition system may experience electromagnetic interference, glitches, and ringing during operation, the original input pulse may not be suitable as a reference signal for high-precision timing. For example... Figure 2 As shown, the trigger detection module first uses a Schmitt trigger structure to perform threshold discrimination on the input ignition control command pulse, with the upper and lower thresholds set to 2.5V and 1.5V respectively. The trigger detection module further shapes the Schmitt trigger output using a monostable shaping circuit: when a valid trigger edge is detected, the monostable circuit outputs a pulse with a fixed width of... The standard trigger pulse is used to normalize the output level to TTL level. The rising edge of the standard trigger pulse of the monostable shaped output is defined as the system time zero point. The standard trigger pulse is output as a unified time reference signal for the system and sent to the synchronization gating and timing control module (trigger in).

[0035] 3. The synchronous gating and timing control module receives the standard trigger pulse from the trigger detection module and uses the rising edge as the time zero point. .like Figure 3 As shown, the synchronous gating and timing control module generates a set of parameters relative to the preset parameters. m delayed trigger times:

[0036] in A time variable can be used to cover different stages of the ignition transient process.

[0037] 4. After acquiring ignition transient radiation signals in multiple bands within the 600nm-900nm range, the temperature calculation process in the temperature inversion module is as follows:

[0038] a) The transient radiation signal during ignition can be represented as:

[0039] In the above formula, The flame spectral radiance is expressed in W / m². 3 / sr;c1=3.742×10 -16 c2 = 1.4388 × 10 -2 ; Wavelength, in nm; Temperature, in Kelvin (K). These are parameters in the emissivity model.

[0040] b) The ignition transient temperature and emissivity coefficient can be calculated based on the particle swarm optimization algorithm. The initial iterative values ​​of the ignition transient temperature and emissivity coefficient are randomly set as follows:

[0041] in, It is the position of the nth population in the jth dimension. It is a random number in the range of 0 to 1. It is the lower bound of the initial iteration value. It is the upper limit of the initial iteration value.

[0042] c) The matrix of initial iteration values ​​is as follows:

[0043] d) The iterative steps for determining the ignition transient temperature and emissivity coefficient consist of step 1 and step 2:

[0044] in, Represented as Where dim is the dimension of the search space, which is 3 here, and randn is a random number that follows a standard normal distribution; It is the iteration order, P kThis is the position vector of temperature and emissivity coefficients corresponding to the k-th iteration; , These are the worst and best solutions for the transient temperature and emissivity coefficient of the fire, respectively, and their corresponding iteration order is as follows: .

[0045] in, , From The iteration order corresponding to the randomly selected different iterative solutions is as follows: .

[0046] e) Based on the iterative steps obtained from equations (4) and (5), the ignition transient temperature and emissivity coefficient can be calculated as follows:

[0047] f) To evaluate the consistency between the measured transient multispectral irradiance curve of the ignition system and the calculated curve, the standard can be defined as:

[0048] In the above formula, The radiation signal measured by the multispectral imaging module. This is the standard value. Figure 4 This refers to the transient temperature distribution of the ignition device under different time delay conditions, which is obtained by inversion calculation using this device.

[0049] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered to fall within the protection scope of the present invention.

Claims

1. A temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging, characterized in that, The device includes: Multispectral imaging module: Acquires radiation signals from the target area in multiple bands within the 600nm-900nm range during ignition operation; Trigger detection module: detects ignition control command pulse signal, generates standard trigger pulse, and determines the time corresponding to the standard trigger pulse as the system time zero point. ; Synchronous gating and timing control module: Receives the standard trigger pulse and sets the time zero point... A TTL trigger signal is generated as a reference for the externally triggered camera to control the multispectral imaging module to acquire radiation signals of multiple bands at different delay points after ignition. Temperature inversion module: Based on Planck's law and emissivity model, the collected radiation signals of multiple bands are preprocessed and the temperature is solved to obtain the temperature distribution of the igniter target area.

2. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 1, characterized in that, The multispectral imaging module acquires radiation signals in no fewer than 16 bands within the 600nm-900nm wavelength range, and each band is a narrowband band.

3. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 1, characterized in that, The trigger detection module includes a Schmitt trigger structure for threshold discrimination of the ignition control command pulse signal; the trigger detection module also includes a monostable shaping circuit for pulse width shaping and level normalization of the ignition control command pulse signal, and outputting the standard trigger pulse with controlled pulse width and normalized level.

4. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 1, characterized in that, The TTL trigger signal generated by the synchronization gating and timing control module follows a preset delay sequence. Configure the settings; wherein the TTL trigger signal is output to the trigger port of the multispectral imaging module, and the rising edge of the TTL trigger pulse is used to trigger the multispectral imaging module to acquire radiation signals.

5. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 4, characterized in that, The synchronous gating and timing control module controls the exposure time of the multispectral imaging module to a preset value. The multispectral imaging module performs a duration of [duration missing] within the start time corresponding to the rising edge of each TTL trigger pulse. The exposure radiation signal was collected.

6. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 1, characterized in that, The temperature inversion module establishes a temperature inversion problem with the error between the radiation signals of multiple bands and the theoretical radiation signals output by the radiation model as the objective function, and uses the particle swarm optimization algorithm to optimize and solve the objective function in order to obtain the temperature distribution of the target region.

7. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 6, characterized in that, The radiation model of the temperature inversion module is as follows: In the formula, The intensity of the flame spectrum is expressed in W / m². 3 / sr;c1=3.742×10 -16 c2 = 1.4388 × 10 -2 ; Wavelength, in nm; Temperature, in Kelvin (K). These are parameters in the emissivity model.

8. The temperature measurement device for a short-time-domain synchronous gated igniter based on multispectral imaging according to claim 7, characterized in that, The objective function of the temperature inversion module is expressed as: In the formula, The radiation signal measured by the multispectral imaging module. This is the standard value.

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