On-line Temperature Monitoring Research Articles

Fundamental investigations on temperature development in ultra-precision turning

Ultra-precision machining represents a key technology for manufacturing optical components in medical, aerospace and automotive industry. Dedicated single crystal diamond tools enable the production of innovative optical surfaces and components with high dimensional accuracies and low surface roughness values in a wide range of airborne sensing and imaging applications concerning space telescopes, fast steering mirrors, laser communication and high-energy laser systems. Despite the high mechanical hardness of single crystal diamonds, temperature-induced wear of the diamond tools occurs during the process. In order to increase the economic efficiency of ultra-precision turning, the characterisation and interpretation of cutting temperatures are of utmost importance. According to the state-of-the-art, there are no precise methods for online temperature monitoring during the process at the cutting edge with regard to the requirements for resolution accuracy, response time and accessibility to the cutting edge. For this purpose, a dedicated cutting edge temperature measurement system based on ion-implanted boron-doped single crystal diamonds as a highly sensitive temperature sensor for ultra-precision turning was developed. To enable highly sensitive temperature measurements, ion implantation was used for partial and specific boron doping close to the cutting edge of single crystal diamond tools. Within the investigations, a resolution accuracy of 0.29 °C ≤ aR ≤ 0.39 °C could be proven for the developed cutting edge temperature measurement system. In addition, a total measurement uncertainty of uM = 0.098 °C was determined for the sensor accuracy aS in the investigated process area. For a rake angle range of 0° ≤ γ0 ≤ −30°, reaction times of 420 ms ≤ tR ≤ 440 ms were further determined. Using the developed cutting edge temperature measurement system enables a holistic view of the temperature development during ultra-precision machining, whereby a correlation between the measured cutting temperatures and the chip formation mechanisms depending on the applied process parameters could be identified. Within the investigations, the highest measured temperatures of ϑM = 50.18 °C and simulated maximum temperatures of ϑS,max = 183.12 °C were determined at a cutting speed of vc = 350 m/min, a cutting depth of ap = 35 µm as well as a feed of f = 35 µm using a rake angle of γ0 = −30°. The most uniform chips with the smoothest surfaces were identified within the chip analysis using a cutting speed of vc = 50 m/min, a cutting depth of ap = 5 µm and a feed of f = 35 µm with a measured temperature of ϑM = 21.30 °C and a simulated temperature of ϑS = 38.47 °C in the examined finishing area. According to the results, it was also shown that the cutting edge temperature measurement system with ion-implanted diamonds can be used for both electrically conductive and non-conductive materials. This provides the fundamentals for further research works to identify the complex temperature-induced wear behaviour of single crystal diamonds in ultra-precision turning and serves as the basis for self-optimising and self-learning ultra-precision machine tools.

A Study on the Effect of Cutting Temperature on CFRP Hole Wall Damage in Continuous Drilling Process

In the assembly process of aerospace parts, drilling is essential for carbon fiber-reinforced materials. However, due to the extreme thermal sensitivity of these composites, continuous drilling often leads to irreparable defects such as hole wall burns and exit delamination caused by concentrated cutting heat, resulting in the scrapping of parts. To address this issue, this paper explores the impact of temperature characteristics on drilling quality, providing guidance for optimizing the composite drilling process. A simulation model for single and continuous drilling was established to analyze the temperature distribution on the tool surface during drilling. A drilling temperature measurement system based on thin-film thermocouple technology was developed, enabling real-time online temperature monitoring. Continuous drilling experiments were conducted, analyzing the correlation between maximum drilling temperature and hole quality. Results show that temperatures from −25.75 °C to −9.75 °C and from 182 °C to 200.75 °C cause significant exit damage, while optimal hole quality is achieved between −1.25 °C and 168 °C.

Adhesive solid-state fermentation producing Aspergillus niger conidia on stainless-steel dixon ring supports.

An adhesive solid-state fermentation (adSSF) mode was developed to produce Aspergillus niger conidia, which used a stainless-steel Dixon ring as the support and water-retaining adhesive to load nutritional media on its surface. To obtain high conidia yields, the components of the water-retaining adhesive were screened, optimized by single-factor optimization and response surface methodology, and the optimal dosages of the main components were: wheat bran powder 0.023g·cm-3bed, cassava starch 0.0022g·cm-3bed, and xanthan gum 0.0083g·cm-3bed. The experimentally tested conidia yield was 4.2-fold that without water-retaining adhesive but was 3.7% lower than the maximum yield predicted by the model. The observed double-side growth of A. niger on the Dixon ring supports improved space utilization of the fermentation bed, and the void fraction can increase with the shrinkage of the gel layer. In 1.6L tray reactors with three-point online temperature monitoring, the inner-bed temperature of adSSF was at most 4°C lower than the adsorbed carrier solid-state fermentation (ACSSF) mode, and the conidia yield was 1.68 × 108 conidia.cm-3bed, 61.5% higher than that of the ACSSF bed at the same time, but when the fermentation time was extended to 168h, the conidia yield of the adSSF bed and ACSSF bed were close to each other. The results revealed that the high voidage of the adSSF bed was the main reason for low bed temperature, which can benefit the inner-bed natural convection and water evaporation.

Multi-color space features and data regression neural network-based method for molten salt temperature detection in rare earth electrolytic processes

To address the online monitoring of molten salt temperature in the rare earth electrolysis process, this paper proposes a rare earth molten salt temperature detection model (MSTDM) based on multi-color space features and data regression neural networks. The model initially preprocesses the collected molten salt temperature images using techniques such as the Gaussian Mixture Model (GMM) and median filtering, followed by color space transformation. Subsequently, 19 hue features used for temperature quantification are extracted, including the channel responses of RGB, HSV, Lab, and Gray color spaces. Finally, a novel data regression neural network (CNN-BiLSTM-Attention) is employed to learn the long-term dependencies between molten salt hue features and temperature, predicting future molten salt temperatures. Experimental results indicate that using the GMM algorithm to filter out flame interference, introducing novel temperature prediction features, and constructing the CNN-BiLSTM-Attention network all enhance the performance of MSTDM in molten salt temperature prediction tasks. The model achieves a mean absolute error of 3.16 °C in predicting molten salt temperatures at rare earth smelting sites. This research not only provides an effective solution for online monitoring of molten salt temperatures in the rare earth electrolysis process but also offers a reliable reference for temperature monitoring in other fields.

Fiber temperature sensor based on dual-wavelength emitting Mg0.388Al2.408O4: Mn2+/Mn4+ phosphors for real-time temperature monitoring

Single doped Mg0.388Al2O3.408O4 phosphor was prepared and multivalent Mn ion (Mn2+ and Mn4+) emission was achieved in a single host. The structure, morphology, and luminescence characteristics of Mn ions in Mg0.388Al2O3.408O4 were discussed in detail, especially the temperature dependent emission characteristics of Mn ions. Based on the fluorescence intensity ratio (FIR) of Mn2+versus Mn4+ and the decay lifetime of Mn4+ emission as the temperature readout, a dual-mode optical temperature-sensing mechanism was proposed and studied in the temperature range of 293–473 K. The maximum relative sensitivities (Sr) are derived as 2.83 % K−1 (at 373 K based on FIR) and 3.40 % K−1 (at 473 K based on decay lifetime), respectively. The temperature sensing characteristics of Mg0.388Al2.408O4: Mn2+/Mn4+ powders in a full fiber system were studied, which can provide thermal-sensitive emissions at dual-wavelengths for stable ratiometric temperature sensing with good precision and repeatability. The constructed all fiber temperature sensing system has been applied in the on-line monitoring of CPU temperature.

CFRTP single-lap adhesive bonding and its mechanical performance enhanced by laser surface treatment: Finite element simulation and experimental validation

The outstanding mechanical properties of carbon fiber reinforced thermoplastic polymer (CFRTP) have led to its widespread application in many industrial sectors. In response to the engineering challenge of repairing large non-critical CFRTP structural components in situ, an infrared fiber laser surface cleaning technology is proposed to treat the bonding interface and enhance the tensile strength of polypropylene (PP)-based CFRTP single-lap bonded joints. Specifically, through single-factor and orthogonal experiments, the impact of different process parameters on the properties of the bonded joints was identified first. Then, online temperature monitoring was performed to elucidate the laser treatment mechanism of the CFRTP sample interface. Surface morphology of the laser-treated samples further indicates that when the temperature of the sample surface surpasses the resin decomposition temperature with extended holding time, the resin could be removed from the surface more thoroughly. Additionally, a novel three-dimensional woven finite element (FE) model, accounting for anisotropic heat transfer, was established to predict the surface temperature and cleaning quality of CFRTP. The FE model incorporates the anisotropic heat transfer characteristics of carbon fibers, thus accurately simulating the heat transfer behaviors between carbon fibers and the resin matrix. The laser ablation mechanism is elucidated by examining the surface ablation morphologies and peak surface temperatures. A comparison between experimental results and FE simulations demonstrated a notable coherence in the trend of surface morphology variations, with discrepancies in peak surface temperatures ranging from 3.29 % to 24.63 %. The experimental tests proved that the shear strength of single-lap bonded joints reaches its maximum value when the laser power is 35 W, the scanning speed is 2500 mm/s, and the number of scans is four. The enhancement of the mechanical properties of bonded joints can be attributed to the improved wettability and higher surface free energy of the laser-treated samples.

Simulation and on-line monitoring using optical fiber Bragg grating sensors of temperature history during laser-assisted automated fiber placement

Automated fiber placement (AFP) in situ consolidation (ISC) of thermoplastic composite possess the potential to reduce manufacturing costs and improve manufacturing efficiency. The properties of composite manufactured by the ISC are affected by several mechanisms including polymer degradation, crystallization, intimate contact, polymer healing and void dynamics. All these mechanisms are directly affected by the temperature history. Consequently, the control and accurate measurement of temperature history during ISC are particularly important for improving the properties of composite. In this study, a simplified three-dimensional transient heat transfer model was established. The effect of tool temperature and placement speed on the temperature history and peak temperature were predicted. Simultaneously, an online temperature monitoring system was built and the optical Fiber Bragg Grating sensors (FBGS) was used to measure the temperature history. The results indicated that the predicted results of the model were consistent with the measured results, the error was below 8%. In addition, the temperature history of layers was significantly affected by the tool temperature and placement speed. The temperature of the layers decreased to near the tool temperature after cooling, and a higher tool temperature increasing its peak temperature because of the reduce of the cooling rate. On the contrary, an increase in placement speed will reduce the peak temperature of the layers.

A high‐precision voltage reference with a curvature‐compensated bandgap for fluorescence detection

SummaryFluorescent optical fiber temperature sensors require accurate online temperature monitoring in hazardous environments with strong electromagnetic fields, high voltages, flammability, or explosiveness. This imposes stringent requirements on the temperature coefficient stability of the bandgap reference (BGR) circuit. To address these challenges, this paper proposes a high‐order curvature compensation bandgap reference (HCC_BGR) circuit fabricated using a 0.18‐μm bipolar‐CMOS‐DMOS (BCD) process. A traditional first‐order bandgap reference (TRA_BGR) circuit is also fabricated for comparison. Experimental results demonstrate that the proposed HCC_BGR circuit generates a stable 1.22‐V reference voltage with a low‐temperature coefficient of 5.56 ppm/°C from −20°C to 85°C. Compared to the TRA_BGR circuit, the HCC_BGR reduces the temperature coefficient by 3.07 times. Furthermore, the low‐dropout regulator (LDO) using the proposed HCC_BGR exhibits excellent line sensitivity of 1.52%/V from 3.4 to 5 V.

Optimization and test of a ring-ring typed atmospheric pressure plasma jet for optical fabrication

In recent years, the atmospheric pressure plasma jet (APPJ) has gained considerable attention in the field of optical fabrication because the chemical etching approach offers the advantage of avoiding mechanical damage to workpieces. This paper presents the development of an atmospheric pressure plasma machining system with a ring-ring typed APPJ, which exhibits several favorable characteristics. It has a relatively low processing temperature, no electrode corrosion, no plasma contamination, and a long discharge plume, etc. Optimization of the dimensional parameters and analysis of reactive gas flow rate are conducted through experimental investigations. Comparative experiments are carried out with the commonly used needle-ring typed APPJ, revealing significant improvements of the ring-ring typed APPJ, i.e., a fourfold increase in machining distance, a tenfold increase in machining efficiency, and a 58% enhancement in the stability of the material volumetric removal rate. Furthermore, on-line temperature monitoring of the footprint has been achieved due to the specific traits of the extended discharge plume. Fabrication experiments are conducted to demonstrate the significant correlation between the temperature and material removal rate, which shows the possibility of improving the accuracy of optical fabrication based on the ring-ring typed APPJ.

Analysis of the Effect of Copper Doping on the Optoelectronic Properties of Indium Oxide Thin Films and the Thermoelectric Properties of an In2O3/Pt Thermocouple

The detection and real-time monitoring of temperature parameters are important, and indium oxide-based thin film thermocouples can be integrated on the surface of heaters because they operate normally under harsh conditions and provide accurate online temperature monitoring. The higher stability and appropriate optical and electrical properties of In2O3 make it very suitable as an electrode material for thermocouple sensors. This work demonstrates that copper doping can alter the optical and electrical properties of In2O3 films and regulate the output performance of thermocouples. Copper-doped In2O3 thin films were prepared using the magnetron co-sputtering method. The doping concentration of Cu was controlled using direct current (DC) power. An In2O3/Pt thermocouple sensor was prepared, and the optoelectronic and thermocouple properties were adjusted by changing the copper doping content. The thickness valve of the thin film sample was 300 nm. The results of the X-ray diffraction suggested that the structure of the doped In2O3 thin films was cubic. The results of the energy-dispersive X-ray analysis revealed that Cu was doped into the In2O3 thin films. All deposited films were n-type semiconductor materials according to Hall effect testing. The 4.09 at% Cu-doped thin films possessed the highest resistivity (30.2 × 10−3 Ω·cm), a larger carrier concentration (3.72 × 1020 cm−3), and the lowest carrier mobility (0.56 cm2V−1s−1). The optical band gap decreased from 3.76 to 2.71 eV with an increase in the doping concentration, and the transmittance of the film significantly reduced. When the DC power was increased, the variation range of Seebeck coefficient for the In2O3/Pt thermocouple was 152.1–170.5 μV/°C, and the range of thermal output value was 91.4–102.4 mV.

Retracted: On-Line Temperature Monitoring System of Electrical Equipment Based on Passive Wireless Sensor

Retracted: On-Line Temperature Monitoring System of Electrical Equipment Based on Passive Wireless Sensor

A Junction Temperature Online Monitoring Method for IGBTs Based on Turn-off Delay Time

A Junction Temperature Online Monitoring Method for IGBTs Based on Turn-off Delay Time

Analysis of Electromagnetic Interference for Anti-Medal UHF RFID Temperature Tag in High Power Electronic Equipment

Being inches from the rapid development of new energy technology, the capacity of high-power power electronic equipment is increasing rapidly, and the requirements for its safe and reliable operation are also rising. As a result, the demand for online temperature monitoring of such equipment is becoming increasingly urgent. RFID temperature measurement technology can be used for real-time monitoring of the temperature of powered operation equipment. However, the operation of high-power electronic equipment generates strong electromagnetic interference, which can seriously affect the normal operation of RFID temperature measurement systems. For applications involving the internal temperature measurement of high-power power electronic equipment, this paper employs an RFID anti-metal temperature tag antenna with a short-circuit cutoff structure. This structure was tested in an excitation switchgear cabinet. During the low-power operation of the cabinet, the temperature tag functioned normally. By combining an RFID antenna model with an electromagnetic interference simulation model of the main circuit of the excitation switchgear cabinet, this paper establishes an electromagnetic interference simulation model for an RFID temperature tag. It analyzes how the tag’s antenna performance parameters change when subjected to interference. Through simulation, the failure mechanism of the RFID temperature tag during the high-power operation of the excitation switchgear cabinet is clarified. The analysis found that there are both conductive electromagnetic interference and radiated electromagnetic interference in the excitation switchgear cabinet, with the conductive electromagnetic interference having a more significant effect. Conductive electromagnetic interference can seriously impact the performance of RFID temperature tags in the excitation switchgear cabinet, significantly degrading their performance. In contrast, the effect of radiated electromagnetic interference on the tags is relatively small. Therefore, this paper employs anti-metal RFID temperature tags and simulates and analyzes their electromagnetic interference characteristics.

Numerical and experimental research on electromagnetic-thermal and leakage defects characteristics of the high voltage cable terminal

Thermal and insulation performance of the High Voltage Cable Terminal (HVCT) could effectively improve the reliability and economy of power energy transmission. In this paper, a numerical model of the electromagnetic heat flow field was proposed to analyze the heat transfer and temperature characteristics of HVCT under oil leakage defects. This model was the first validated using operation data from the actual equipment and the relative error was less than 1.51%. The effects of oil leakage fault on the global and local temperature distribution of the HVCT were then investigated under different load currents. In addition, the local temperature rise effect of different ambient temperatures on the HVCT oil leakage defect was also considered. Finally, combined with reference indicators such as oil level, temperature, and temperature gradient, a qualitative and quantitative evaluation of the oil leakage fault of HVCT was performed. The results showed that the temperature of the core, surface, and their maximum temperature gradient were linearly related to the ambient temperature. However, the temperature of the core at the oil leak exceeded the normal temperature by up to 7.2 °C with 1000A load current, and the temperature gradient change reaches 681.3 °C/m, which indicated that the convection heat dissipation effect of the oil-deficient part was poor, and the heat accumulates near the cable core. Therefore, the numerical model and analytical results presented in this paper provided an important method for online temperature monitoring and fault analysis of HVCTs.

Fluorescent sensing probe based on heterovalent doped Lu2W2.5Mo0.5O12:Er3+/Yb3+ phosphor for real-time chip temperature monitoring

The influence of Li+/Zn2+ heterovalent doping on the structural change and upconversion luminescence properties of Lu2W2.5Mo0.5O12:Er3+/Yb3+ phosphors was investigated in details. The gradual substitution of Li+/Zn2+ ions for Lu3+ ions result in the evolution from orthorhombic Lu2W2.5Mo0.5O12 to monoclinic (LiZn)2W2.5Mo0.5O12, which bring the structural distortion, the reduction of local symmetry and the crystallite growth. The green upconversion intensity of Er3+ ions at 536 nm and 550 nm were enhanced significantly by a factor of 8000 and 4000. The temperature sensing characteristics of a single (LiZn)2W2.5Mo0.5O12:Er3+/Yb3+ particle in all-fiber structure was explored and the unusual thermally-enhanced upconversion luminescence was observed, which is beneficial for achieving high-precision temperature measurement based on the fluorescence intensity ratio technology. The absolute temperature sensitivity reached a maximum of 0.0095 K−1 at 423 K and the temperature deviation was less than 0.6 K. The as-built all-fiber temperature sensor was successfully applied in the on-line monitoring of CPU temperature.

Parallel Contactless Transmission of Power and Rotor Temperature of Electrical Machines via Magnetically-Coupled Resonance and Capacitive Radio Frequency

Over-temperature of the rotor may cause a series of insulation deterioration of electrical machines. In severe cases, it can lead to insulation failure and even faults, such as broken rotor bars and end ring fracture. The temperature online monitoring can effectively avoid the aforementioned insulation failure; however, the conventional temperature measurement by embedded sensors is difficult to utilize due to the power and data transmission of sensors at the rotor side. This paper proposes a contactless strategy to supply power and send rotor temperature data between the stator and rotor sides of electrical machines. With the proposed method, contactless power transfer is realized by means of magnetically-coupled resonance, while the data signal is transferred by capacitive radio frequency (RF) technology. An experimental prototype was developed and installed on a 22-kW induction motor. The results show that the embedded sensors are contactless powered effectively. At the same time clear temperature data signal can be received on the stator side without filtering, and rotor temperature can be monitored in real-time accurately.

Prediction model of transformer top oil temperature based on data quality enhancement.

Top oil temperature (TOT) is an important parameter to evaluate the running state of a transformer. According to the variation trend of TOT, the internal thermal state of transformers can be predicted so as to arrange operation and maintenance reasonably and prevent the occurrence of accidents. However, due to the complex working environment in the field, there are often a large number of missing values in online monitoring data, which seriously affects the prediction of TOT. At the same time, it is affected by various factors such as load, ambient temperature, wind speed, and solar radiation, which cause the information of different time scales to be mixed in its monitoring data. Therefore, it is difficult to achieve the desired accuracy with a single model. In this article, a model for predicting TOT based on data quality enhancement is proposed. First, the Markov model is used to complete the online monitoring data containing missing values to obtain a complete and continuous time series. Then, using the ensemble empirical modal decomposition method, the time series of TOT is decomposed into multiple time series components to eliminate the interaction between different time scales of information, thus reducing the prediction difficulty. Finally, the sub-prediction model of the extreme learning machine is constructed, and the prediction results of all the sub-models are reconstructed to obtain the final prediction results of TOT. In order to verify the effectiveness of the model, the TOT of an operating transformer for the next two days is predicted in the article, and its mean absolute percentage error (MAPE) is 5.27% and its root mean square error (RMSE) is 2.46. Compared with the BP neural network model and the support vector machines (SVM) model, the MAPE is reduced by 69.56% and 61.92%, respectively, and the RMSE is reduced by 67.02% and 59.87%. The results of this study will provide important support for the fault diagnosis of the top oil temperature online monitoring system.

Online Monitoring Method of P-I-N Diode Temperature Based on Maximum Recovery Current

The P-i-N diode is as important as insulated gate bipolar translators (IGBTs) in power electronic devices, and its junction temperature is a significant indicator when evaluating the reliability of power electronics. Thus, an online junction temperature monitoring method with the maximum recovery current for P-i-N diodes is proposed in this paper. Firstly, the relationship among maximum recovery current, on-state current and junction temperature of diode has been deduced in theory. The linear correlation among the maximum recovery current, temperature, and on-state current have been illustrated. Secondly, a sampling circuit based on a current transformer has been designed. And then, the mathematical model of junction temperature online monitoring based on the maximum recovery current and sampling circuit has been obtained. Finally, the experimental platform based on the DSP TMS320F28335 has been developed. The experimental results verify the correctness of the relationship among maximum recovery current, on-state current and junction temperature of the diode, and high accuracy of the proposed online monitoring method in practice application, where the maximum temperature error and error percentage are 4.7℃ and 4.49%, respectively. In addition, the proposed method has advantages of simplicity, small size, low cost, convenient installation, and high linearity.

Evolution of thermal cracking, temperature distribution and deformation at mineral scale of Beishan granite during heating and cooling

Thermo-mechanical property of rock is of great importance for the long-term safety of the high-level radioactive waste (HLW) geological disposal engineering. Thermal cracking, temperature and meso-deformation on the mineral grain size scale of Beishan granite were investigated during heating (160 °C ∼ 200 °C) and cooling process using online temperature, deformation and acoustic emission monitoring system. During the heating process, the temperature difference in different mineral grain was evident that the highest temperature was observed in feldspar while lower temperature in quartz and mica, and the temperature difference reached 20%. Meanwhile the feldspar expanded as the quartz and mica being compressed during heating. During the temperature holding and cooling process, the temperature difference between different mineral grain reduced and stabilized around 5%. The thermal induced expansion was recovered gradually but irreversible deformation was left, which also demonstrated by the nuclear magnetic resonance measurement that size and volume of large pore in granite both decreased after heated. The thermal cracking emerged from 25 °C ∼ 35 °C, and the thermal cracking activity was active once temperature changed during heating and cooling stage, which was calm during temperature holding stage. In addition, the cracking process was investigated by numerical modelling. The ‘confining pressure effect’ was observed during heating process, and the mechanism of thermal strengthening effect was discussed. Overall, the mild high temperature caused by decay heat of HLW could play positive role for the long-term safety of the repository, since the tightness and strength could be both enhanced by mild high temperature.

Experimental research on online monitoring of high temperature and high speed airflow ablation of quartz ceramic thermal protection structure using guided wave

Thermal protection structure (TPS) plays a key role in protecting hypersonic flight vehicles from harsh service environment and has been widely used. As a common ablative thermal protection material, quartz ceramic TPS realizes thermal insulation by generating ablation during the reentry phases. The structural state of quartz ceramic TPS therefore is of great importance to the service performance and safety of hypersonic flight vehicles, and shows an urgent need for structural health monitoring (SHM). However, the monitoring of real ablation of quartz ceramic structure is barely considered in the current study, let alone online monitoring under harsh service environment, which brings a great challenge to the implementation of reliable ablation monitoring. Aiming at online ablation monitoring of quartz ceramic structure, this paper performs experimental research by taking advantage of guided wave (GW)-based monitoring method. An ablation experiment and monitoring system is built to generate real ablation under high temperature and high speed airflow and perform GW monitoring. The maximal temperature of the system can reach about 2100 °C. The feasibility of ablation monitoring is verified by analyzing ablation-induced influence on GW signals. Gaussian mixture model (GMM) is adopted to combine with GW method to suppress the high temperature variation caused by uncertainty influence on GW signals during the ablation process, so that reliable monitoring of ablation can be realized. Experimental results show that online monitoring of ablation propagation of quartz ceramic structure under high temperature variation is achieved, which can be further used for ablation quantification evaluation.