Intelligent fire prevention control method for goaf based on residual coal dynamic evaluation

Abstract

The application discloses a goaf intelligent fire prevention control method based on residual coal dynamic evaluation and relates to the technical field of mine fire prevention safety, and comprises the following steps: in the process of goaf intelligent fire prevention control, in view of the situation that the inert gas is prone to backflow due to temperature difference in a hot environment, a continuous temperature and pressure monitoring link is established, temperature, pressure and flow direction information of the inert gas in different channels are acquired in real time in a time sequence mode, and a continuous monitoring data set is formed. Through continuous monitoring and dynamic oriented control, stable forward flow of the inert gas in the goaf is realized, and backflow and cooling blind area are eliminated; through introduction of a periodic flow fluctuation and a dynamic compensation loop, a self-balancing state of the airflow and the temperature is maintained, a continuous cooling zone is formed, and therefore the real-time response capability and overall stability of the fire prevention process are improved.

Description

Technical Field

[0001] This invention relates to the field of mine fire prevention and safety technology, specifically to an intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal. Background Technology

[0002] Intelligent fire prevention and control in goaf areas based on dynamic assessment of residual coal refers to a technical approach that addresses the potential for spontaneous combustion due to oxidation and heating of residual coal in goaf areas (the voids formed after coal seam mining) after coal mining. This is achieved through the establishment of a dynamic monitoring and intelligent control mechanism to proactively prevent and precisely manage fire risks. Dynamic assessment of residual coal involves using multi-source sensor data, ventilation gas parameters, ground temperature distribution, and oxidation rates to continuously model and classify the quantity, distribution, oxidation activity, and heating trend of residual coal in the goaf, allowing for real-time assessment of the evolution of spontaneous combustion hazard zones. Intelligent fire prevention and control in goaf areas, driven by the dynamic assessment results, automatically selects and executes the optimal fire prevention strategy, such as intelligently controlling the injection volume of inerting gas, directional spray cooling, and adjusting airflow direction and flow rate, thus shifting from passive fire suppression to proactive prevention. The combination of these two approaches forms a closed-loop fire prevention system centered on data-driven, real-time sensing, and intelligent decision-making, significantly improving the accuracy and timeliness of goaf safety management.

[0003] The existing technology has the following shortcomings: In existing technologies, inerting control of the risk of spontaneous combustion of residual coal in goaf areas typically relies on the directional injection and natural diffusion of inerting agents to create a continuous cooling and oxygen-barrier environment. However, in the hot environment of goaf areas, due to the highly uneven internal temperature distribution, complex channel morphology, and significant thermal pressure differences, the inerting agent fluid often forms a significant temperature gradient driving effect between high and low temperature zones, leading to abnormal reversal of gas flow and the creation of reverse flow channels. This phenomenon prevents areas that should be stably cooled from receiving sufficient inerting gas coverage, creating cooling blind zones and causing localized heat accumulation. As the local temperature continues to rise, the oxidation rate of residual coal accelerates exponentially, inducing uncontrolled oxidation hotspots. In severe cases, this can disrupt the entire fire prevention and control balance, and even lead to high-temperature reignition or secondary fires within the goaf.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide an intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal, comprising the following steps: In the process of intelligent fire prevention and control in the goaf, in the case of inert gas being prone to backflow due to temperature differences in the hot environment, a continuous temperature and pressure monitoring link is established to acquire the temperature, pressure and flow direction information of inert gas in different channels in real time in a time sequence, forming a continuous monitoring dataset to provide a real-time basis for subsequent directional adjustment. Based on the continuous monitoring dataset, the flow state of inert gas between the high-temperature and low-temperature regions is analyzed in time segments to identify channel areas with obvious backflow, extract temperature difference driving parameters and flow direction offset amplitude, and construct a set of key control parameters for zoned regulation, providing a control basis for subsequent guidance control. Based on the set of key control parameters, airflow guidance control is implemented in the backflow region. By adjusting the direction and flow rate ratio of the inert gas injection port, a stable forward flow region is established, so that the inert gas can continue to move along the design direction under temperature and pressure changes, thereby achieving continuous cooling of the high-temperature region. After the stable forward flow region is established, the release rhythm of the inert gas is synchronously adjusted along the time sequence. Periodic flow fluctuations are introduced at the forefront of the high-temperature region to weaken the backflow effect caused by the temperature difference, so that the inert gas forms a continuous cooling zone in spatial distribution and maintains the stability of the forward flow. A dynamic compensation loop for temperature and pressure is established around the continuous cooling zone. The feedback information of periodic flow fluctuations is used as the input signal to correct the inert gas supply pressure and release time interval in real time, so as to maintain the stability of the inert gas flow and uniform cooling coverage throughout the fire prevention process, thereby preventing local overheating and high-temperature reignition caused by backflow.

[0007] Preferably, the steps for establishing a continuous temperature and pressure monitoring link are as follows: Within the goaf area, based on the goaf space structure, ventilation direction and residual coal distribution characteristics, temperature and pressure sampling points are arranged along the inert gas flow path to form a monitoring link that runs through the high-temperature zone and the low-temperature zone. After the monitoring link is established, the temperature, pressure and flow direction of the inert gas at different locations are continuously collected in a time sequence, so that the inert gas forms a continuous time series data at each collection point. The continuously collected temperature and pressure data are correlated and organized in chronological order to form a time-series data chain for inert gas, and the areas of change in airflow direction are identified based on the temperature and pressure change trends of adjacent collection points. After forming a continuous monitoring dataset, temperature and pressure information are continuously updated so that the state of the inert gas at any given time corresponds to a unified time series, providing a real-time basis for subsequent targeted regulation.

[0008] Preferably, after forming a continuous monitoring dataset, a time synchronization device is used to perform unified time reference correction on each temperature and pressure acquisition point, so that the monitoring data at different locations remain continuous and consistent in the time dimension, and the temperature and pressure signals are updated synchronously during the flow of inert gas, thereby ensuring that the monitoring link can reflect the real-time flow status and dynamic changes of inert gas in the goaf.

[0009] Preferably, the steps for time-segmented analysis based on continuous monitoring datasets are as follows: Based on the temperature and pressure information of the inert gas in the continuous monitoring dataset, the monitoring points at different locations are arranged in time sequence, and the monitoring data is divided into continuous time periods based on the time axis. After time segmentation, by comparing the rate of temperature change and the direction of pressure difference change of adjacent sampling points, the channel area with obvious backflow of airflow is identified, and its spatial location and temporal distribution characteristics are recorded. Within the identified channel area, temperature difference driving parameters are extracted based on the relationship between temperature difference and distance, and flow direction offset amplitude is extracted based on the change amplitude of airflow direction. By combining the temperature difference driving parameters with the flow direction offset amplitude and the time segmentation identification results, a set of key control parameters for zoned regulation is constructed, providing a control basis for subsequent airflow guidance control.

[0010] Preferably, during the construction of the key control parameter set, the temperature difference driving parameters and the flow direction offset amplitude are correlated in chronological order, and a continuous parameter chain is formed by combining the spatial distribution of the inert gas. The airflow state between the high-temperature zone and the low-temperature zone in the goaf is dynamically expressed through the parameter chain, so as to achieve accurate identification and control of the zoned adjustment area.

[0011] Preferably, the steps for implementing airflow guidance control based on the key control parameter set are as follows: Based on the temperature difference driving parameters and flow direction offset amplitude in the key control parameter set, the spatial distribution of the backflow area is divided, and the priority area for guidance adjustment is determined according to the characteristics of airflow backflow. Within the guide zone, adjust the direction of the inert gas injection port according to the magnitude of the flow direction offset, and adjust the flow rate ratio of the inert gas according to the backflow intensity to make the gas move in the designed direction; After adjusting the direction and flow rate ratio of the inert gas injection port, the airflow guidance control is corrected in real time by continuously monitoring temperature and pressure changes to keep the forward flow stable. After the forward flow region is established, the set of key control parameters is continuously updated to ensure that the inerting gas continues to move along the design direction and maintains the cooling effect under temperature and pressure changes.

[0012] Preferably, the steps for synchronously adjusting the release rhythm of the inert gas in chronological order are as follows: After the forward flow region is formed, the initial pattern of the release rhythm of the inert gas in the time dimension is determined according to the set of key control parameters, and the continuous time period is divided according to the temperature response time and the pressure equilibrium duration. Periodic flow fluctuations are introduced at the forefront of the high-temperature region. By setting up a mainstream release section and a compensation release section, the reverse flow effect of the airflow caused by the temperature difference is weakened, so that the inert gas keeps flowing in the forward direction. The distribution of inert gas in space is synchronized with the time rhythm to stagger the flow peaks of different channels and form a continuous cooling zone. After the cooling zone is formed, the release rhythm is adjusted synchronously according to the temperature and pressure changes, so that the inert gas maintains a continuous and balanced flow in time and space.

[0013] Preferably, the steps for establishing a dynamic temperature and pressure compensation loop are as follows: Under the condition of stable operation of continuous cooling zone, real-time temperature and pressure data of inert gas in high temperature region, transition region and low temperature region are collected in time sequence to form the input signal chain of dynamic compensation loop; Based on the feedback information of periodic flow fluctuations, the inerting gas supply pressure is initially compensated and adjusted to maintain the continuity of pressure distribution of the inerting gas in different temperature regions. After dynamic compensation of the supply pressure, the release time interval of the inert gas is synchronously corrected based on the feedback information, so that the release rhythm of the inert gas is dynamically coupled with the change of thermo-pressure. After compensating for the supply pressure and release time interval, a continuous operation mechanism is formed, which ensures that the inert gas maintains a stable flow direction and uniform cooling coverage throughout the fire prevention process.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention establishes a continuous temperature and pressure monitoring link and combines it with dynamic analysis of time sequence to achieve real-time monitoring of the inert gas flow state within the goaf, enabling the inert gas to continuously and stably advance along the designed direction under complex thermo-pressure conditions. By identifying and guiding the backflow areas of the airflow, the inert gas forms a stable forward flow zone in the high-temperature region, effectively avoiding backflow and cooling blind spots caused by thermal differences. This transforms the fire prevention process from static injection to dynamic guidance, improving the continuity of airflow distribution and the uniformity of cooling coverage.

[0015] This invention introduces a periodic flow fluctuation and dynamic temperature and pressure compensation loop, enabling the inerting gas to form a self-regulating cooling structure in high-temperature regions. This structure can adjust the gas supply pressure and release rhythm in real time according to changes in the ambient thermal state. This method maintains a stable flow direction and energy balance of the inerting gas in time and space, effectively weakening the back-push effect caused by thermal pressure difference, achieving a constant balance between continuous cooling and fire prevention. This keeps the temperature and flow fields inside the goaf in a long-term stable state, improving the response efficiency and safety reliability of fire control. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a flowchart of the intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal, as described in this invention. Detailed Implementation

[0018] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0019] This invention provides, for example Figure 1 The intelligent fire prevention and control method for goaf based on dynamic assessment of residual coal, as shown, includes the following steps: In the process of intelligent fire prevention and control in the goaf, in the case of inert gas being prone to backflow due to temperature differences in the hot environment, a continuous temperature and pressure monitoring link is established to acquire the temperature, pressure and flow direction information of inert gas in different channels in real time in a time sequence, forming a continuous monitoring dataset to provide a real-time basis for subsequent directional adjustment. To address the complex flow problem of inert gas in hot environments, where backflow due to temperature differences is common, a continuous temperature and pressure monitoring link needs to be established to continuously sense and collect data on the flow status of inert gas within the goaf. By forming a stable monitoring link and continuous data stream, the fire control system can obtain dynamic information on the temperature, pressure, and flow direction of the inert gas, thus providing a precise data foundation for subsequent directional adjustments. The specific steps are as follows: Within the goaf, based on the goaf's spatial structure, ventilation direction, and residual coal distribution characteristics, continuous temperature and pressure monitoring points are deployed along the possible flow paths of the inerting gas, forming a monitoring link spanning the high-temperature and low-temperature zones. The spatial spacing of each monitoring point needs to be determined according to the goaf's volumetric scale, channel extension direction, and temperature gradient, ensuring that temperature and pressure data cover the entire process of the inerting gas from injection to emission. Each monitoring point is equipped with both temperature and pressure monitoring units. These units are aligned with the gas flow direction via a closed airflow detection pipeline to ensure that the acquired data reflects the true state of the inerting gas. After the monitoring points are deployed, a time synchronization device is used to unify the time reference, ensuring that data from different locations remain continuous and consistent over time, thus forming a time-series monitoring link that reflects transient changes in gas flow. This continuous distributed deployment along the spatial path ensures that the temperature and pressure evolution of the inerting gas from the high-temperature to the low-temperature zone is fully captured under the goaf's thermal environment, providing a foundation for subsequent time-series data analysis.

[0020] After the monitoring link is established and operating stably, temperature and pressure signals of the inert gas at different locations are continuously acquired over time. Data acquisition is performed sequentially, with each acquisition point recording temperature, pressure, and flow direction in real time at the same sampling interval, ensuring a complete representation of the inert gas state at each moment. During sampling, the temperature signal primarily reflects the heat transfer of the inert gas in the channel, while the pressure signal reflects the flow trend of the inert gas in space. Once the acquired temperature and pressure data form a continuous time series, the airflow direction relationship between each acquisition point can be determined by data comparison. If the pressure at the downstream acquisition point is higher than that at the upstream acquisition point, accompanied by a reverse temperature increase, it indicates a backflow trend. To maintain the stability of the monitoring link, the time interval between acquisition points needs to be dynamically adjusted so that the sampling frequency can adapt to different stages of inert gas flow rate and temperature change rate, thereby continuously obtaining reliable monitoring datasets throughout the entire goaf fire prevention process.

[0021] After continuous acquisition of temperature, pressure, and flow direction data, the collected data is correlated and organized chronologically to form a time-series data chain for the inert gas. This time-series data chain provides a clear view of the flow evolution of the inert gas in different channels within the goaf. During the data processing, the temperature and pressure trends of adjacent acquisition points are compared longitudinally to identify areas with significant temperature gradients and pressure fluctuations. These areas are often locations where airflow direction is prone to change under hot conditions. This time-continuous comparison method allows for the construction of a dynamic curve of the inert gas flow direction, thereby determining the forward and reverse flow trends of the gas at different time periods. Areas with large temperature difference rates require focused adjustment in subsequent control. By transforming the continuous data from the monitoring chain into a time-series spatial state representation, the fire prevention control process can fully grasp the dynamic characteristics of the inert gas in complex thermal environments.

[0022] After establishing a complete continuous monitoring dataset, the temperature and pressure information acquired by the acquisition link needs to be updated in real time to ensure that the monitoring link reflects the actual state of the inerting gas in the goaf. To ensure accurate data support for subsequent directional adjustments, the monitoring link must continuously and synchronously acquire temperature and pressure during operation, so that the state of the inerting gas at different channel locations at any given time corresponds to a unified time series. By continuously supplementing the existing dataset with newly acquired data, the monitoring link can possess self-updating characteristics in the continuous time dimension. In this way, the temperature and pressure difference changes of the inerting gas in the high-temperature zone, transition zone, and low-temperature zone can be presented in the form of continuous curves, providing a direct basis for subsequent identification of airflow backflow areas and implementation of directional adjustments. Through this continuous, synchronous, and dynamic monitoring method, real-time capture of changes in the inerting gas flow direction can be achieved, providing a reliable time-series data foundation for subsequent fire prevention and control processes.

[0023] Based on the continuous monitoring dataset, the flow state of inert gas between the high-temperature and low-temperature regions is analyzed in time segments to identify channel areas with obvious backflow, extract temperature difference driving parameters and flow direction offset amplitude, and construct a set of key control parameters for zoned regulation, providing a control basis for subsequent guidance control. After establishing a continuous temperature and pressure monitoring link and forming a complete time-series monitoring dataset, it is necessary to use this continuous monitoring dataset to perform time-segmented analysis of the flow state of inert gas in different areas of the goaf. This is to identify channels where there is significant backflow between high-temperature and low-temperature zones, and further extract temperature difference driving parameters and flow direction offset amplitude. This allows for the construction of a set of key control parameters for zoned regulation, providing an operable control basis for subsequent airflow guidance control. The entire process focuses on the temporal changes of inert gas in a thermal environment, using segmented analysis and correlation extraction of continuous data to achieve dynamic determination of the airflow state. The specific implementation steps are as follows: In the acquired continuous monitoring dataset, the temperature and pressure information of the inert gas is used as the core basis. Monitoring points at different locations within the goaf are arranged chronologically, and the monitoring data is divided into several continuous time periods based on a time axis. The length of each time period is determined based on the flow velocity, temperature fluctuation range, and pressure difference change rate of the inert gas within the goaf, ensuring that each time period reflects both the stable phase characteristics of the airflow and the transition process of the gas flow state. During the segmentation process, the temperature, pressure, and flow direction information of each monitoring point within the same time period are horizontally correlated, forming a spatial distribution structure of the airflow state for each time period. Through this segmentation method, which prioritizes time and supplements it with space, the changing patterns of the inert gas flow state can be continuously described at different time levels, laying a data foundation for determining whether backflow occurs and its causes.

[0024] After time segmentation, the flow characteristics of inert gas between high-temperature and low-temperature zones are analyzed based on the temperature and pressure change trends within each time period. By comparing the rate of temperature change and the direction of pressure difference between adjacent sampling points, the continuity of inert gas flow within the same time period is determined. When the pressure value at the upstream sampling point is lower than that at the downstream sampling point and is accompanied by a reverse temperature increase, it can be determined that the airflow in that area has reversed. Based on this, the spatial locations of such phenomena within the goaf are marked, and their temporal distribution characteristics are recorded to form the identification results of backflow areas between high-temperature and low-temperature zones. In this way, it can be clearly identified which channels within the goaf exhibit backflow trends at different time periods, thereby transforming the spatial flow state of inert gas from a single static description into a dynamic distribution structure with temporal evolution patterns.

[0025] After identifying channels with significant backflow, the temperature and pressure data within these areas were analyzed in detail to extract the temperature difference driving parameters and the flow direction offset amplitude. The temperature difference driving parameters characterize the strength of the thermal buoyancy effect on the inerting gas between high-temperature and low-temperature zones. Their calculation is based on the temperature difference and distance relationship between adjacent monitoring points, reflecting the driving force characteristics of the airflow under thermal pressure difference conditions. The flow direction offset amplitude characterizes the degree to which the gas flow direction deviates from the design direction, determined by the magnitude of changes in the gas flow direction angle or pressure gradient direction within adjacent time periods. By continuously correlating the temperature difference driving parameters and the flow direction offset amplitude over time, the dynamic flow stability characteristics of the inerting gas in different channels can be obtained. Regions with large temperature difference driving parameters and frequent changes in flow direction offset amplitude are identified as high-risk areas for backflow, requiring focused control during subsequent adjustments. This extraction process not only reveals the formation mechanism of inerting gas backflow but also provides a quantifiable technical basis for subsequent zoned adjustments.

[0026] After extracting the temperature difference driving parameters and flow direction offset amplitude, these parameters are combined with the time-segmented identification results to construct a set of key control parameters for zoned regulation. This parameter set, centered on time series, links the temperature difference driving parameters, flow direction offset amplitudes, and corresponding spatial locations across different channels and time periods, forming a multi-dimensional correlation structure. This structure allows the dynamic flow state of inerting gas within the goaf to be expressed in parameterized form. The key control parameter set not only reflects the temperature gradient distribution and pressure difference changes of inerting gas in different areas but also includes the temporal pattern of airflow direction changes, which can be used to guide subsequent airflow guidance regulation. This parameter set enables effective integration of zone identification and zoned control, allowing the fire control process to dynamically adjust the inerting gas injection strategy based on the real-time status of the goaf.

[0027] Based on the set of key control parameters, airflow guidance control is implemented in the backflow region. By adjusting the direction and flow rate ratio of the inert gas injection port, a stable forward flow region is established, so that the inert gas can continue to move along the design direction under temperature and pressure changes, thereby achieving continuous cooling of the high-temperature region. After constructing the key control parameter set, in order to effectively suppress the backflow of inert gas caused by thermal differences in the goaf and to form a continuous and balanced cooling airflow in the high-temperature area, it is necessary to implement airflow guidance control in the backflow area based on the key control parameter set. This process adjusts the direction and flow rate ratio of the inert gas injection port to ensure that the inert gas can continuously move along the design direction under complex temperature and pressure environments, thereby forming a stable forward flow zone in the high-temperature area and achieving continuous cooling and fire prevention. The specific steps are as follows: Based on the temperature difference driving parameters and flow direction offset amplitude included in the key control parameter set, the spatial distribution of the backflow region is finely divided, and the priority area for guidance regulation is determined according to the strength of the backflow characteristics. When determining the region boundaries, the temperature and pressure time series data obtained in the previous stage should be combined to stratify the backflow region according to the rate of change of the temperature gradient, so that the guidance control targets of the high-temperature zone, transition zone, and low-temperature zone are clearly defined. In each stratified region, the injection direction offset angle of the inerting gas is calculated according to the magnitude of the temperature difference driving parameters, so that the injection direction is consistent with the expected forward flow direction or forms a reasonable angle, thereby realizing the redirection of local airflow. In this process, the arrangement of gas injection ports needs to be determined according to the spatial structure of the goaf, and the channel near the upstream of the backflow region is preferred as the injection point so that the inerting gas forms a downstream diffusion flow trend after injection, gradually replacing the reverse movement of the backflow gas.

[0028] After the guiding area is determined, the flow rate ratio of each injection port needs to be finely adjusted based on the flow direction offset information in the key control parameter set. The adjustment of the flow rate ratio is mainly based on the backflow intensity of the airflow. In areas with a large backflow amplitude, the inerting gas injection volume should be increased to form a stronger forward driving force; while in areas with a small backflow amplitude, a lower flow rate of inerting gas is continuously injected to maintain a stable pressure balance. During this process, to ensure that the gas flow direction remains in the designed direction under temperature and pressure fluctuations, the inerting gas injection rate needs to be dynamically adjusted so that the inerting gas density in the high-temperature zone is slightly higher than that in the low-temperature zone, utilizing the gas density difference to form a stable forward flow channel. To enhance the guiding effect of the airflow, intelligent grouting fire prevention control measures can be introduced at key locations in the high-temperature zone. By injecting inert grout with thermal conductivity and oxygen-barrier properties, an airtight layer structure is formed on the channel wall, thereby reducing the interference of thermal pressure difference on the gas flow direction. The inert slurry, through its dual effects of cooling and sealing, can reduce local high temperatures and limit the reverse reinjection path of backflowing gas, providing a stable channel environment for the forward diffusion of inert gas.

[0029] After adjusting the inert gas injection port direction and flow rate ratio to an initial stable state, it is necessary to dynamically monitor the airflow changes in the backflow area in a time-series manner and use key control parameter sets to make real-time corrections to the guiding control. By continuously comparing the temperature difference driving parameters and the flow direction offset amplitude, it can be determined whether the flow direction of the inert gas after guidance adjustment is consistent with the design target. If the temperature drop trend in the high-temperature zone tends to stabilize and the pressure difference between the upstream and downstream channels remains within the set range, it indicates that the guiding control has formed a relatively stable forward flow. At this time, the flow direction of the inert gas should be further consolidated. By making subtle angle corrections to the injection point at the leading edge of the high-temperature zone, the inert gas can be made to adhere to the inner wall of the channel to reduce the formation of eddies and backflow. At the same time, intelligent grouting fire prevention control can continue to be implemented in the boundary area of ​​the forward flow zone. By intermittently injecting curable inert grout, the edge area of ​​the airflow can be sealed and isolated to prevent hot gas in the high-temperature zone from seeping back from the boundary gaps, ensuring the overall stability and continuity of the forward flow.

[0030] After the forward flow region gradually stabilizes, a long-term equilibrium mechanism for inert gas guidance control needs to be established to ensure that the inert gas can continuously move along the designed direction and maintain a cooling effect under varying temperature and pressure conditions. To achieve this goal, the key control parameter set should be continuously updated, and new temperature and pressure monitoring data should be added to the existing dataset, allowing the flow rate ratio and injection direction of the guidance control to adaptively adjust according to time changes. During the long-term operation of the airflow guidance control, intelligent grouting for fire prevention should be periodically carried out at the boundary of the high-temperature zone. By injecting a small amount of inert grout, the airtightness of the channel is maintained, thereby further reducing the impact of thermal pressure difference on the gas flow direction. Through this combination of dynamic adjustment and spatial sealing, the inert gas forms a stable forward flow structure between the high-temperature and low-temperature zones, enabling the inert gas to achieve continuous cooling in the high-temperature zone and maintain a balanced state of airflow direction and pressure distribution over time. Ultimately, the entire guidance control process forms a stable airflow cooling zone in the high-temperature zone, which not only effectively suppresses the backflow of inert gas but also provides a durable and controllable gas flow basis for the oxidation inhibition and fire prevention control of residual coal inside the goaf.

[0031] After the stable forward flow region is established, the release rhythm of the inert gas is synchronously adjusted along the time sequence. Periodic flow fluctuations are introduced at the forefront of the high-temperature region to weaken the backflow effect caused by the temperature difference, so that the inert gas forms a continuous cooling zone in spatial distribution and maintains the stability of the forward flow. After the forward flow region is stabilized, to further enhance the continuity and cooling uniformity of the inert gas flow within the hot goaf, the release rhythm of the inert gas needs to be synchronously adjusted along a time sequence. This weakens the backflow effect caused by temperature differences, allowing the inert gas to form a continuous cooling zone with sustained cooling capacity in spatial distribution, thereby maintaining the stability of the forward flow in both time and space. This process, combining time-series release rhythm control with dynamic spatial distribution adjustment, effectively solves the problem of localized reverse airflow and cooling discontinuity caused by temperature fluctuations. The specific steps are as follows: After the stable forward flow region is formed, the initial pattern of the inerting gas release rhythm in the time dimension is determined based on the key control parameter set established in the previous stage and the temperature difference driving parameters and flow direction offset obtained during the airflow guidance control process. This initial pattern is mainly based on the temperature response time and pressure equilibrium duration of the inerting gas in different channels. By comparing the rate of change of the upstream and downstream temperature difference, the response delay of the airflow in the forward flow is determined, thus forming a time-series distribution pattern. According to this pattern, the inerting gas release process is divided into several continuous time periods, each corresponding to a specific release intensity and duration, ensuring that the airflow maintains regular fluctuations on the time axis. When formulating the release rhythm, the heat capacity and heat transfer rate of the high-temperature area in the goaf are considered as a key factor, ensuring that the inerting gas release cycle is basically matched with the heat transfer cycle, thereby forming a synchronous response relationship between airflow and temperature within the high-temperature area. Through this time-based rhythm planning, it can be ensured that the inerting gas is continuously distributed according to the temperature change pattern within the forward flow region, providing the foundation for the introduction of subsequent periodic flow fluctuations.

[0032] After determining the temporal distribution of the inerting gas release rhythm, periodic flow fluctuations need to be introduced at the leading edge of the high-temperature region to utilize the time-pulse effect of the flow to weaken the backflow caused by the temperature difference. Specifically, within each cycle of inerting gas release, two stages are set: a mainstream release stage and a compensation release stage. The mainstream release stage is used to maintain the continuous forward propulsion of the inerting gas, while the compensation release stage is used to apply a short-term flow increase when the mainstream airflow tends to stabilize, generating additional momentum impact to offset the local reverse pressure caused by the temperature gradient change. Due to the presence of thermal pressure difference in the high-temperature region, gas flow often tends to exhibit an upward or backward push-back trend. Periodic flow fluctuations can locally enhance the inerting gas velocity in a short period of time, thereby breaking the static equilibrium formed by thermal pressure and maintaining the inerting gas's continuous forward momentum. In addition, when setting flow fluctuations at the leading edge of the high-temperature region, it should be ensured that the fluctuation amplitude and period are within the stability range of the inerting gas flow, so that the flow fluctuations can generate a pressure regulation effect without disturbing the overall forward flow. By introducing periodic flow fluctuations, the inerted gas forms a dynamic equilibrium in the high-temperature region, effectively weakening the backflow caused by the temperature difference and stabilizing the forward flow structure.

[0033] After introducing periodic flow fluctuations, the spatial distribution of the inert gas needs to be synchronized with its temporal rhythm to create a continuous cooling zone. In this process, the release time of the inert gas in each channel is subdivided based on its thermal characteristics and flow resistance, causing the flow peaks in different channels to stagger, resulting in a wave-like spatial distribution. This phase difference control allows the inert gas to form a continuously covering cooling zone in the high-temperature area of ​​the goaf. The staggered gas release cycles of each channel avoid localized overcooling due to flow overlap and create overlapping cooling boundaries between adjacent areas, thus achieving continuous connection of the overall temperature field. Simultaneously, during the formation of the cooling zone, the direction of the inert gas injection port should be fine-tuned based on the guidance control results from the previous stage, allowing the airflow in different channels to gradually converge in space, forming a stable cooling ridge. This cooling ridge extends along the mainstream direction of the high-temperature zone, continuously transmitting the cooling effect of the inert gas in the depth direction, further consolidating the stable structure of the unidirectional flow region.

[0034] After the inerting gas forms a continuous cooling zone, its long-term stability requires time-synchronized adjustment of the release rhythm to achieve dynamic airflow balance. Specifically, the flow fluctuation amplitude and duration of each cycle should be fine-tuned based on real-time temperature and pressure changes to ensure a continuous offsetting relationship between the kinetic energy of the inerting gas and the thermal pressure difference. When the temperature change rate in the high-temperature region slows down, the duration of the mainstream release section should be appropriately extended to maintain the propulsion depth of the cooling airflow; when the temperature change rate accelerates or the pressure difference increases, the mainstream release section should be shortened and the frequency of the compensation release section increased to enhance the airflow's reverse thrust suppression capability. Simultaneously, in the boundary area of ​​the cooling zone, intelligent grouting fire prevention control technology can be combined to periodically spray inert grout to form a grout film layer with oxygen-barrier and thermally stable properties, suppressing the impact of edge hot air mass disturbances on the forward airflow. This grout film layer, together with the inerting gas cooling zone, constitutes a stable thermal protection barrier, ensuring the inerting gas maintains a continuously balanced flow state in time and space. By combining synchronous regulation with boundary constraints, the stability of forward flow can be maintained throughout the entire goaf area, preventing airflow reversal due to temperature gradient fluctuations, thereby achieving continuous cooling and fire control of high-temperature areas.

[0035] A dynamic compensation loop for temperature and pressure is established around the continuous cooling zone. The feedback information of periodic flow fluctuations is used as the input signal to correct the inert gas supply pressure and release time interval in real time, so as to maintain the stability of the inert gas flow and uniform cooling coverage throughout the fire prevention process, thereby preventing local overheating and high-temperature reignition caused by backflow. After the continuous cooling zone is formed and maintains a stable forward flow, a dynamic compensation loop for temperature and pressure needs to be established around the continuous cooling zone to ensure that the inerting gas maintains a stable flow direction and uniform cooling coverage throughout the entire fire control process. This dynamic compensation loop is based on feedback information generated by periodic flow fluctuations. Through real-time time-series responses, it continuously corrects the supply pressure and release time interval of the inerting gas, enabling the inerting gas to automatically balance airflow energy and temperature transfer rate under different thermal conditions. This effectively avoids backflow, overheating, and reignition caused by the accumulation of local thermal pressure differences. The specific steps are as follows: Under stable operation of the continuous cooling zone, real-time temperature and pressure data of the inerting gas in the high-temperature, transition, and low-temperature regions need to be collected sequentially over time to establish the input signal chain for the dynamic compensation loop. To ensure timely and continuous response of the compensation process, temperature and pressure monitoring points should be distributed longitudinally along the cooling zone and aligned with the inerting gas flow direction, so that data changes can reflect energy loss and flow resistance changes during gas propulsion. When periodic flow fluctuations occur, the airflow state at different locations in the cooling zone exhibits time-delay characteristics. By analyzing the temporal differences in temperature and pressure between upstream and downstream, the inertia and thermal pressure accumulation trends of the airflow in the current operating stage can be obtained. Temperature information mainly reflects the heat exchange rate between the gas and the coal body, while pressure information reflects the intensity of energy transfer in the channel. By continuously recording and synchronizing these signals, comprehensive feedback data containing temporal variations, spatial distribution, and flow direction is formed, providing the basic input conditions for the operation of the dynamic compensation loop.

[0036] After obtaining real-time input data on temperature and pressure, the initial compensation of the inerting gas supply pressure needs to be adjusted based on feedback information from periodic flow fluctuations. The core objective of the compensation adjustment is to maintain the continuity of the pressure distribution of the inerting gas in different temperature regions, avoiding the formation of low-pressure traps in high-temperature areas or high-pressure accumulation in low-temperature areas. To achieve this objective, the peak moment of the periodic flow fluctuation should be used as the adjustment reference point, comparing the pressure output at the upstream gas supply end with the downstream feedback signal. When the temperature at the leading edge of the cooling zone rises, leading to increased airflow resistance, the pressure output at the inerting gas supply end should be appropriately increased to allow gas energy to compensate for the back pressure caused by thermal pressure, thereby maintaining the continuity of forward flow. Conversely, when the temperature at the rear of the cooling zone drops, leading to increased airflow density, the supply pressure should be reduced to prevent excessive gas accumulation in local areas from disrupting the continuity of the cooling zone. Through this supply pressure adjustment based on periodic flow fluctuation feedback, the energy distribution of the inerting gas in the continuous cooling zone is adaptively balanced, ensuring that the kinetic energy output of the airflow along the depth direction matches the thermal conditions, providing a stable airflow basis for subsequent release time control.

[0037] After dynamic compensation of the gas supply pressure is completed, the release time interval of the inerting gas needs to be synchronously corrected to ensure the continuity of the airflow pulse in the time dimension and the uniform distribution of the cooling effect. The core of this process is to utilize the feedback characteristics of periodic flow fluctuations to dynamically couple the release rhythm of the inerting gas with the thermal pressure changes in the goaf. When the temperature rise rate at the leading edge of the cooling zone is fast, the release time interval of the inerting gas should be shortened to increase the airflow replenishment frequency and enhance the cooling coverage of the local high-temperature area. When the temperature change slows down or the pressure tends to be balanced, the release time interval should be appropriately extended to avoid disturbances or reverse accumulation caused by excessive airflow. In this process, the adjustment of the release time interval not only affects the local stability of the cooling zone but also directly determines the energy transfer efficiency of the airflow in the depth direction. To achieve balance, the correction of the release time should be linked with the trend of gas supply pressure changes to form a synchronous compensation relationship between pressure and release cycle. Through this synchronous adjustment method, the release of inerting gas maintains a time correspondence with the changes in ambient thermal pressure, thereby forming a dynamic balance of heat and airflow between high-temperature and low-temperature areas, maintaining the temperature equilibrium and airflow continuity of the cooling zone.

[0038] After completing the dynamic compensation of gas supply pressure and release time interval, the entire compensation loop needs to be established as a continuous operating mechanism to ensure that the inerting gas maintains a stable flow direction and uniform cooling coverage throughout the entire fire prevention process. This continuous operating mechanism relies on the continuous collection and real-time updating of the aforementioned feedback data, enabling the dynamic compensation loop to automatically adjust the pressure and rhythm according to the actual operating state of the inerting gas. During the long-term compensation operation, the fluctuation range of temperature and pressure should be continuously observed. When a new heat accumulation trend appears in the high-temperature area, the dynamic compensation loop should respond immediately, achieving rapid thermal pressure suppression by increasing the gas supply pressure and shortening the release interval. When the airflow tends to stabilize in the depth direction, the compensation loop automatically reduces the pressure output and extends the release cycle to maintain the flexible propagation of the cooling airflow. Furthermore, to enhance the thermal stability of the cooling zone, intelligent grouting fire prevention control can be combined with periodic injection of inert grout around the cooling zone to form an additional thermal insulation barrier, reducing the thermal disturbance experienced by the compensation loop during operation. After solidification, the inert slurry forms a thermal resistance layer, further reducing the interference of external heat on the internal flow field of the cooling zone. This allows the compensation loop to maintain stable flow of the inert gas and uniform cooling coverage even under complex thermal conditions. Through the synergistic effect of this dynamic compensation and structural sealing, the inert gas can maintain continuous flow balance in both time and space, preventing local overheating and high-temperature reignition caused by backflow, and ensuring that the goaf remains in a stable and controllable safe state throughout the entire fire prevention process.

[0039] This invention establishes a continuous temperature and pressure monitoring link and combines it with dynamic analysis of time sequence to achieve real-time monitoring of the inert gas flow state within the goaf, enabling the inert gas to continuously and stably advance along the designed direction under complex thermo-pressure conditions. By identifying and guiding the backflow areas of the airflow, the inert gas forms a stable forward flow zone in the high-temperature region, effectively avoiding backflow and cooling blind spots caused by thermal differences. This transforms the fire prevention process from static injection to dynamic guidance, improving the continuity of airflow distribution and the uniformity of cooling coverage.

[0040] This invention introduces a periodic flow fluctuation and dynamic temperature and pressure compensation loop, enabling the inerting gas to form a self-regulating cooling structure in high-temperature regions. This structure can adjust the gas supply pressure and release rhythm in real time according to changes in the ambient thermal state. This method maintains a stable flow direction and energy balance of the inerting gas in time and space, effectively weakening the back-push effect caused by thermal pressure difference, achieving a constant balance between continuous cooling and fire prevention. This keeps the temperature and flow fields inside the goaf in a long-term stable state, improving the response efficiency and safety reliability of fire control.

[0041] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for intelligent fire prevention and control in goaf areas based on dynamic assessment of residual coal, characterized in that, Includes the following steps: In the process of intelligent fire prevention and control in the goaf, in the case of inert gas being prone to backflow due to temperature differences in the hot environment, a continuous temperature and pressure monitoring link is established to obtain the temperature, pressure and flow direction information of inert gas in different channels in real time in a time sequence, forming a continuous monitoring dataset. Based on the continuous monitoring dataset, the flow state of inert gas between the high-temperature and low-temperature regions is analyzed in time segments to identify channel areas with obvious backflow, extract temperature difference driving parameters and flow direction offset amplitude, and construct a set of key control parameters. Based on the set of key control parameters, airflow guidance control is implemented in the backflow region. By adjusting the direction and flow rate ratio of the inert gas injection port, a stable forward flow region is established, so that the inert gas can continue to move along the design direction under the conditions of temperature and pressure changes. After the stable forward flow region is established, the release rhythm of the inert gas is synchronously adjusted along the time sequence, and periodic flow fluctuations are introduced at the forefront of the high temperature region to weaken the backflow effect caused by the temperature difference, so that the inert gas forms a continuous cooling zone in spatial distribution. A dynamic compensation loop for temperature and pressure is established around the continuous cooling zone. The feedback information of periodic flow fluctuations is used as the input signal to correct the inerting gas supply pressure and release time interval in real time, so as to maintain the stability of the inerting gas flow and uniform cooling coverage throughout the fire prevention process.

2. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 1, characterized in that, The steps to establish a continuous temperature and pressure monitoring link are as follows: Within the goaf area, based on the goaf space structure, ventilation direction and residual coal distribution characteristics, temperature and pressure sampling points are arranged along the inert gas flow path to form a monitoring link that runs through the high-temperature zone and the low-temperature zone. After the monitoring link is established, the temperature, pressure and flow direction of the inert gas at different locations are continuously collected in a time sequence, so that the inert gas forms a continuous time series data at each collection point. The continuously collected temperature and pressure data are correlated and organized in chronological order to form a time-series data chain for inert gas, and the areas of change in airflow direction are identified based on the temperature and pressure change trends of adjacent collection points. After forming a continuous monitoring dataset, temperature and pressure information are continuously updated so that the state of the inert gas at any given time corresponds to a unified time series.

3. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 2, characterized in that, After the continuous monitoring dataset is formed, the temperature and pressure acquisition points are uniformly time-referenced and calibrated using a time synchronization device, so that the monitoring data at different locations remain continuous and consistent in the time dimension, and the temperature and pressure signals are updated synchronously during the inert gas flow process.

4. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 2, characterized in that, The steps for time-segmented analysis based on continuous monitoring datasets are as follows: Based on the temperature and pressure information of the inert gas in the continuous monitoring dataset, the monitoring points at different locations are arranged in time sequence, and the monitoring data is divided into continuous time periods based on the time axis. After time segmentation, by comparing the rate of temperature change and the direction of pressure difference change of adjacent sampling points, the channel area with obvious backflow of airflow is identified, and its spatial location and temporal distribution characteristics are recorded. Within the identified channel area, temperature difference driving parameters are extracted based on the relationship between temperature difference and distance, and flow direction offset amplitude is extracted based on the change amplitude of airflow direction. By combining the temperature difference driving parameters with the flow direction offset amplitude and the time segmentation identification results, a set of key control parameters for zoned regulation is constructed.

5. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 4, characterized in that, In the process of constructing the key control parameter set, the temperature difference driving parameters and the flow direction offset amplitude are correlated in time sequence, and combined with the spatial distribution of the inert gas to form a continuous parameter chain. The airflow state between the high-temperature zone and the low-temperature zone in the goaf is dynamically expressed through the parameter chain.

6. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 4, characterized in that, The steps for implementing airflow guidance control based on the key control parameter set are as follows: Based on the temperature difference driving parameters and flow direction offset amplitude in the key control parameter set, the spatial distribution of the backflow area is divided, and the priority area for guidance adjustment is determined according to the characteristics of airflow backflow. Within the guide zone, adjust the direction of the inert gas injection port according to the magnitude of the flow direction offset, and adjust the flow rate ratio of the inert gas according to the backflow intensity to make the gas move in the designed direction; After adjusting the direction and flow rate ratio of the inert gas injection port, the airflow guidance control is corrected in real time by continuously monitoring temperature and pressure changes to keep the forward flow stable. After the forward flow region is established, the set of key control parameters is continuously updated to ensure that the inerting gas continues to move along the design direction and maintains the cooling effect under temperature and pressure changes.

7. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 6, characterized in that, The steps for synchronously adjusting the release rhythm of inert gas in chronological order are as follows: After the forward flow region is formed, the initial pattern of the release rhythm of the inert gas in the time dimension is determined according to the set of key control parameters, and the continuous time period is divided according to the temperature response time and the pressure equilibrium duration. Periodic flow fluctuations are introduced at the forefront of the high-temperature region. By setting up a mainstream release section and a compensation release section, the reverse flow effect of the airflow caused by the temperature difference is weakened, so that the inert gas keeps flowing in the forward direction. The distribution of inert gas in space is synchronized with the time rhythm to stagger the flow peaks of different channels and form a continuous cooling zone. After the cooling zone is formed, the release rhythm is adjusted synchronously according to the temperature and pressure changes, so that the inert gas maintains a continuous and balanced flow in time and space.

8. The intelligent fire prevention and control method for goaf areas based on dynamic assessment of residual coal as described in claim 7, characterized in that, The steps to establish a dynamic temperature and pressure compensation loop are as follows: Under the condition of stable operation of continuous cooling zone, real-time temperature and pressure data of inert gas in high temperature region, transition region and low temperature region are collected in time sequence to form the input signal chain of dynamic compensation loop; Based on the feedback information of periodic flow fluctuations, the inerting gas supply pressure is initially compensated and adjusted to maintain the continuity of pressure distribution of the inerting gas in different temperature regions. After dynamic compensation of the supply pressure, the release time interval of the inert gas is synchronously corrected based on the feedback information, so that the release rhythm of the inert gas is dynamically coupled with the change of thermo-pressure. After compensating for the supply pressure and release time interval, a continuous operation mechanism is formed, which ensures that the inert gas maintains a stable flow direction and uniform cooling coverage throughout the fire prevention process.

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