Temperature Calibration Method Research Articles

An Efficient Temperature Calibration Method Based on the Improved Infrared Forward Model and Bayesian Inference

An Efficient Temperature Calibration Method Based on the Improved Infrared Forward Model and Bayesian Inference

Novel Temperature Calibration Method of E-Mode and D-Mode GaN Power Modules Considering Dynamic ON-Resistance

This paper presents a method for measuring temperature using the temperature sensitive parameter (TSP) of a GaN power module. Current collapse occurs in GaN high electron mobility transistors (HEMTs). This results in dynamic on-resistance because of trapped electrons. Thus, dynamic conditions should be considered to accurately measure thermal characteristics. GaN HEMTs are operated in the enhanced mode (E-mode) and depletion mode (D-mode). In this study, E-mode and D-mode GaN power modules are designed to compare their thermal characteristics. Among three common temperature-measurement methods, this work employs the TSP-based approach in consideration of the device operation, instead of those using thermo-sensitive optical or material properties. The calibration is conducted in steady-state and dynamic-state. The ambient temperature is estimated using steady-state calibration data. Power cycling is examined for considering dynamic conditions. It is confirmed that dynamic on-resistance changes according to the cycle period, on time, and number of cycles. Experiments are conducted using different values of these parameters. Finally, an equation for temperature is obtained from the experimental results. The equation precisely estimates temperature with an error of 0.7%.

A simplified method for high temperature calibration in the visible light band

A simplified method for high temperature calibration in the visible light band

A Novel Distributed Optical Fiber Temperature Sensor Based on Raman anti-Stokes Scattering Light

In this paper, a novel distributed optical fiber temperature sensor based on Raman anti-Stokes scattering light is proposed and experimentally demonstrated. The Raman anti-Stokes scattering light is sensitive to temperature parameters that are detected by the fiber under test conditions (FUT), and this allowed the temperature demodulation algorithm to be obtained through the relationship between the temperature and the power of the back-scattered Raman anti-Stokes light. In addition, we propose a new temperature calibration method to ensure accurate temperature measurement, which is greatly affected by the stability of a pulse laser. The experimental system is constructed with an optical fiber length of approximately 3.5 km. The proposed system obtains a 24 dB dynamic range with a pulse width of 20 ns and temperature testing ranges of 30.0 °C to 80.0 °C. The results demonstrate that the maximum temperature deviation range is −1.5 °C to +1.6 °C and the root mean square (RMS) error of the whole temperature range is 0.3 °C, which means it has the potential for practical engineering applications. More importantly, it avoids the walk-off effect that must be corrected in commonly used temperature demodulation schemes adopting both Raman Stokes light and anti-Stokes light. It also saves a signal channel, which is more suitable for the integration of hybrid distributed optical fiber sensing systems for multi-parameter monitoring.

Over-the-Air Noise Temperature Measurement

Noise temperature is one of the key performances of RF components, such as the amplifiers in those receivers and transmitters. It is essential to measure the noise temperature accurately; however, the traditional conduction method is no longer suitable for those components with integrated antennas, e.g., antennas in packages (AiP) or antenna on chip (AoC). This paper proposes a solution for noise temperature measurement based on the over-the-air (OTA) method. First, the concept and the problem of noise temperature for those devices integrated with RF components and radiation elements are reviewed, the proposed OTA noise temperature measurement and calibration methods are presented, the measurement systems are set up and at both C band and millimeter-wave band with different measurement distances under both transmitting and receiving states are demonstrated in detail, and the measured results are compared and discussed which verifies that this proposed method is technically feasible for the OTA noise temperatures with high accuracy.

The spectral‐voltage calibration technology of multispectral pyrometers based on Gauss–Newton‐genetic algorithm method for nonsource temperature regions

AbstractTo improve the accuracy of the nonsource temperature calibration method, a new method based on a Gauss–Newton‐genetic algorithm (GN‐GA) for the nonsource calibration of a multispectral pyrometer is proposed. Based on Planck's law, a temperature–voltage power function model was established based on constraint optimization, and the temperature–voltage function relationship of each spectral channel was obtained using a GN‐GA algorithm. When the GN‐GA algorithm extrapolated at 1000°C with 3000°C as the starting point, theoretical simulation results showed that, compared with the derivative least squares method, when the wavelengths were 0.4, 0.6, 0.8, and 1.0 μm, the extrapolation accuracy increased by 54.35%, 63.96%, 51.99%, and 44.05%, respectively. The black‐body experiment results showed that this method was feasible in multispectral, pyrometer, extrapolation, temperature–calibration technology. Compared with the results obtained by the derivative least squares method, the accuracy was improved for a given extrapolation temperature region, and the extrapolation interval was longer under the same accuracy.

Precise temperature calibration for visualized high-thermal-conductivity PPS in injection molding during filling process

High-thermal-conductivity polyphenylene sulfide (PPS) is expected to be used to manufacture various products because of its light weight, strength, high heat dissipation, and low CO2 emissions during manufacturing compared with aluminum die casting. However, this has a unique filling behavior owing to rapid cooling during the filling process, and is likely to cause hesitation and short shots, which must be suppressed. To address this issue, simulations are used to accurately predict the filling behavior and optimize the product shape. However, the thermal behavior of the molten resin in the mold is complex and not yet fully understood, which limits the accuracy of the simulation. In previous research, we built a thermal imaging visualization system to understand thermal behavior. We selected sapphire glass as the transparent material for infrared transmittance, strength, and thermal conductivity. The sapphire glass was made thicker to withstand the high injection pressure and thermal stress during molding of the high-thermal-conductivity PPS, which resulted in a large interference due to infrared attenuation and radiation inside the sapphire glass, affecting the temperature measurement results. In addition, changes in reflectance caused by changes in the state of contact between the sapphire glass and resin due to shrinkage of the resin in the mold also affected the temperature measurement. In this study, we propose a new temperature calibration method to convert the radiance distribution acquired using the visualization system into an appropriate temperature distribution. The developed system successfully visualizes the temperature of the filling process. The temperature measurement results were verified by comparing with the results from thermocouple temperature measurements.

Dynamic Characterization of Thermocouples under Double-Pulse Laser-Induced Thermal Excitation.

This study investigated the dynamic characteristics of thermocouples by using double-pulse laser excitation for dynamic temperature calibration under extreme conditions. An experimental device was constructed for double-pulse laser calibration; the device uses a digital pulse delay trigger to precisely control the double-pulse laser to achieve sub-microsecond dual temperature excitation with adjustable time intervals. The time constants of thermocouples under single-pulse laser excitation and double-pulse laser excitation were evaluated. In addition, the variation trends of thermocouple time constants under different double-pulse laser time intervals were analyzed. The experimental results indicated that the time constant increases and then decreases with the decrease in the time interval of the double-pulse laser. A method for dynamic temperature calibration was established for the evaluation of the dynamic characteristics of temperature sensors.

Real-Time Battery Temperature Monitoring Using FBG Sensors: A Data-Driven Calibration Method

Battery storage has an important role to play in integrating large-scale renewable power generations and in transport decarbonization. Real-time monitoring of battery temperature profiles is indispensable for battery safety management. Due to the advantages of small size, resistance to corrosion, immunity to electromagnetic interference, and multiplexing, fiber Bragg-grating (FBG) sensing has received substantial interest in recent years for battery temperature measurement. However, traditional temperature calibration for FBG sensors often requires a high-standard reference and causes the sensors to fail to be consistent during the calibration or recalibration processes. To tackle the challenges, an ensemble data-driven calibration method is developed in this article for FBG sensors. The calibration model consists of a linear part and a nonlinear part. First, the fuzzy <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${C}$ </tex-math></inline-formula> -means (FCM) algorithm is used to extract the linear relationship between the measured FBG wavelength shift and temperature variation. Then, the empirical mode decomposition (EMD) technique is used to classify the intrinsic mode functions (IMFs) and the remainder of the unmodeled nonlinear information. The unmodeled nonlinear information is further compensated using battery state of charge (SOC) and cycle number information. The experimental results confirm that the proposed temperature calibration method achieves desirable accuracy and reliability, with both the mean absolute error (MAE) and root mean square error (RMSE) being around 0.2 °C, respectively. Compared with the traditional temperature calibration method, the proposed approach can be used online in real-life applications.

Effect of alloying elements on surface temperature field of aluminum piston in diesel engine

For three kinds of Aluminum-Silicon (Al-Si) alloy piston materials with different alloying element contents, the parameters such as thermal diffusion coefficient, specific heat capacity and thermal conductivity were measured, and the effects of Cu and Ni on the thermal properties of the materials were studied. Under the same processing conditions, three kinds of engine aluminum alloy pistons of different materials were manufactured. The piston surface temperature under the rated working condition of the diesel engine was measured by the hardness plug temperature calibration method. The distribution of piston surface temperature field was simulated by ANSYS finite element analysis, and the surface temperature analysis results of key parts of the piston were obtained. The results show that the finite element simulation results of piston surface temperature field are consistent with the temperature measurement results of hardness plug test, and the temperature change of key specific locations of piston possesses the similar trend. The thermal conductivity of aluminum alloy piston material increases with the increase of temperature. There is an obvious temperature gradient from the piston head to the piston skirt. High thermal conductivity can reduce the surface temperature of the piston head. The addition of alloying elements such as Cu and Ni will reduce the thermal conductivity of aluminum alloy materials and increase the surface temperature of piston. Therefore, proper controlling of the content of alloying elements can control the heat resistance and high temperature performance of piston materials.

Online Monitoring of Torpedo Car Shells Based on Equal Angle Scanning

Infrared sensors are being applied more and more widely in industrial production applications. Based on the theory of thermal radiation, this paper discusses the system design principle, temperature calibration method, and thermal image analysis method in detail. The system passed the measurement unit certification, showing that the field of view is 180°, the number of scanning points is 2048, the linear velocity is 10–100 Hz, the spatial resolution is 2.5 mrad, and the precision is ±1 °C. An online monitoring test of torpedo car was carried out in the steelmaking plant of Bao Steel. The results show that the system has strong anti-interference ability, stability, and reliability, and meets the application requirements of online monitoring.

The Study of Thermal process and Temperature Calibration for a Vacuum Drying Oven Based on Numerical Simulation

Vacuum drying technique is widely used in food a processing, pharmaceutical and other industry which needs to be calculated regularly. In order to establish temperature calibration method for vacuum drying oven, temperature profile needs to be studied. In this paper, a three-dimensional (3D) unsteady mathematical model has been developed to study heat transfer in a vacuum drying oven. Governing equations are discretized in implicit form by using the control volume method. PRESTO! scheme was used for the discretization of the pressure modified equation. SIMPLE algorithm is adopted to solve the coupling of pressure and velocity. The natural-convection flow forced by buoyancy force was numerically calculated based on Boussinesq assumption. Results of the model calculation showed that temperature distribution in the vacuum drying oven significantly changed when the pressure in the oven is close to vacuum. Temperature uniformity in the vacuum drying box increases with the increase of vacuum degree. It is not appropriate to directly investigate the temperature uniformity of the vacuum drying oven by using JJF 1101-2019. The results can be used to lay a theoretical foundation for the establishment of calibration method for vacuum drying oven.

A SiN Microcalorimeter and a Non-Contact Precision Method of Temperature Calibration

A dual-channel flow-through microcalorimeter device is presented along with a non-contact precision method of temperature calibration. A microfluidic channel with a volume of ≈550 pL in a spiral layout was fabricated from low-stress nitride suspended over a cavity in a silicon substrate. The thin-film heater and resistive temperature detector (RTD) on the channel were defined by a patterned Ti layer. The device exhibited a rapid thermal response with the following thermal characteristics: a time constant of ≈10.5 ms, a heat conductance of $\approx 152~\mu ~\text{W}\,\cdot ~{\mathrm {K}}^{-{1}} $ and a heat capacitance of $\approx 1.6~\mu \text{J}\,\cdot {\mathrm {K}}^{-{1}} $ on average based on the measurements of nine separate units fabricated on the same wafer. Further, the melting curve analysis (MCA) of a double-stranded DNA was proposed as a non-contact method of microcalorimeter RTD calibration. The method revealed that the measurement by the RTD underestimates the temperature of the channel interior by an amount of nearly 15%, at ≈ 9 mW. At this dissipated power level, the method also revealed a spatial nonuniformity of ≈ ± 0.8 °C across the microcalorimeter. [2020-0173]

Analysis and Research on the Centimeter Band Receiver Amplitude Calibration Method

The receiver is a signal receiving device in a radio telescope system. As an important parameter to characterize the receiver performance, noise temperature is very practical to calibrate accurately. The traditional receiver noise temperature calibration method is the cold and ambient load method. Through the establishment of K-band ambient receiver, and its amplitude calibration test platform of the cold and ambient load method, chopper wheel method, and ambient and hot load method, comparison and analysis of the above three methods were carried out. The test and calculation results show that the test accuracy of the cold and ambient load method is about 1.3%, that of the chopper wheel method (nonlow elevation) is about 3%, and that of the ambient and hot load method is about 9%. The test accuracy of the ambient and hot load method is slightly lower than that of the above two methods. The analysis is mainly due to the uncertainty of the hot load temperature and the small temperature difference between the two loads, which leads to the deterioration of the overall accuracy. But the advantage is that the method can perform real-time calibration in the process of observation, and it is easier to implement than the traditional cold and ambient load method. The results of noise temperature measurement are compared with those of theoretical calculation, the error is basically within 10%, and it can satisfy the demand of the noise temperature test. In the future, we expect that on the basis of increasing the hot load temperature, further experiments were carried out on the thermostatic treatment of hot load and the accuracy of temperature acquisition, and finally we hope that this method can better meet the testing requirements of receiver noise temperature and radio source amplitude calibration.

New method of temperature and conductivity sensor calibration with improved efficiency for screening SBE41 CTD on Argo floats

The global ocean monitoring system would benefit from improvements in the efficiency of Conductivity, Temperature, and Depth Device (CTD) sensor screening. Here, we describe the development of a new screening system, J-Calibration, for use with the SBE41 CTD sensor on the Argo float (Sea Bird Scientific). This new system has crucial advantages over the traditional SBE-Calibration system. First, J-Calibration does not require removal of the CTD sensor unit from the Argo float body to operate in a laboratory. This feature enables technicians or operators to more efficiently check the Argo target accuracies (± 0.005 °C for temperature and ± 0.01 PSS-78 for salinity) and allows the manufacturer’s warranty to remain intact. This also allows for a more efficient basic screening system which maintains screening accuracy without the need for specialized technicians. J-Calibration reduces the screening time to 1/6th that of SBE-Calibration and does not require the preparation of large amounts of artificial seawater. J-Calibration uses 1/23rd of the volume of seawater compared to SBE-Calibration by examining calibration at only 1 temperature point (22 °C), whereas SBE-Calibration requires 7 points to achieve calibration. The J-Calibration system does require careful temperature control of the artificial seawater as it is critical to maintain a uniform water temperature throughout the experiments. To satisfy this, using a vinyl greenhouse and covering sensors with adiabatic materials and cooling packs are effective. In comparison with the accuracy and system stability of SBE-Calibration, we show that the J-Calibration system is non-inferior and therefore is suitable for use in laboratory screening prior to deployment. Based on these advantages, the J-Calibration system will make a strong contribution to the deployment of healthy Argo fleets and to the maintenance of uniform data in the global ocean.

Stable temperature calibration method of fiber Bragg grating based on radial basis function neural network

A stable temperature calibration method based on radial basis function neural network (RBFNN) is proposed to obtain the complex relationship between the temperature and the center wavelength of fiber Bragg grating (FBG) with high accuracy and excellent stability. We introduce the regularized and generalized RBFNN, respectively, and test the accuracy of trained models. Experimental results demonstrate that the maximum absolute error (MAE) and root-mean-squared error (RMSE) of regularized RBFNN are 1.1098°C and 0.1982°C, respectively, in fitting and 1.0206°C and 0.1997°C, respectively, in testing, and the MAE and RMSE of generalized RBFNN are 1.1099°C and 0.1982°C, respectively, in fitting and 1.0209°C and 0.1997°C, respectively, in testing. Compared with existing methods, such as polynomial fitting and back propagation neural network, RBFNN has significantly improved the accuracy and stability of FBG temperature calibration and has considerable application prospect in FBG temperature measurement.

Temperature Assessment Of Microwave-Enhanced Heating Processes

In this study, real-time and in-situ permittivity measurements under intense microwave electromagnetic fields are proposed as a powerful technique for the study of microwave-enhanced thermal processes in materials. In order to draw reliable conclusions about the temperatures at which transformations occur, we address how to accurately measure the bulk temperature of the samples under microwave irradiation. A new temperature calibration method merging data from four independent techniques is developed to obtain the bulk temperature as a function of the surface temperature in thermal processes under microwave conditions. Additionally, other analysis techniques such as Differential Thermal Analysis (DTA) or Raman spectroscopy are correlated to dielectric permittivity measurements and the temperatures of thermal transitions observed using each technique are compared. Our findings reveal that the combination of all these procedures could help prove the existence of specific non-thermal microwave effects in a scientifically meaningful way.

Distributed Temperature Sensing Monitoring of Well Completion Processes in a CO₂ Geological Storage Demonstration Site.

The Distributed Temperature Sensing (DTS) profiles obtained during well completion of a CO2 monitoring well were analyzed to characterize each well completion process in terms of temperature anomalies. Before analysis, we corrected the depth by redistributing the discrepancy, and then explored three temperature calibration methods. Consequently, we confirmed the depth discrepancy could be well corrected with conventional error redistribution techniques. Among three temperature calibration methods, the conventional method shows the best results. However, pointwise methods using heat coil or in-well divers also showed reliable accuracy, which allows them to be alternatives when the conventional method is not affordable. The DTS data revealed that each well completion processes can be characterized by their own distinctive temperature anomaly patterns. During gravel packing, the sand progression was monitorable with clear step-like temperature change due to the thermal bridge effect of sand. The DTS data during the cementing operation, also, clearly showed the progression up of the cement slurry and the exothermic reaction associated with curing of cement. During gas lift operations, we could observe the effect of casing transition as well as typical highly oscillating thermal response to gas lifting.

Investigation on the Thermo-Optic Coefficient of Silica Fiber Within a Wide Temperature Range

In this paper, the thermo-optic coefficient of silica fiber is analyzed and measured within a wide temperature range of 0-1200 °C for the first time. To obtain the thermo-optic coefficient, experiments were carried out by using fiber optic extrinsic Fabry-Perot interferometers (EFPIs) embedded in silica fiber. The optical cavity lengths of the EFPIs were measured with white-light interferometry. The experimental results show that the first and second orders of the thermo-optic coefficient are 1.090 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> /°C and 1.611 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> /°C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively. The quadratic model for the temperature dependence of the basic optical parameter, the refractive index, is rigorous within a wide temperature range. Furthermore, this paper also provides a temperature calibration method for extrinsic Fabry-Perot interferometric temperature sensors. The temperatures measured by the sensors are in excellent agreement with those measured by the reference thermocouple. Hence, this calibration method is promising for temperature sensors with a wide working temperature range.

Experimental tests of an infrared video bolometer on Alcator C-Mod.

A prototype of an infrared imaging bolometer (IRVB) was successfully tested on the Alcator C-Mod tokamak at the end of its 2016 campaign. The IRVB method interprets the power radiated from the plasma by measuring the temperature rise of a thin, ∼2 μm, Pt absorber that is placed in the torus vacuum and exposed, using a pinhole camera, to the full-spectrum of plasma's photon emission. The IRVB installed on C-Mod viewed the poloidal cross section of the core plasma and observed Ohmic and ion cyclotron range of frequency (ICRF)-heated plasmas. Analysis of total radiated power and on-axis emissivity from IRVB is summarized, and quantitative comparisons made to data from both resistive bolometers and AXUV diodes. IRVB results are clearly within a factor of two, but additional effort is needed for it to be used to fully support power exhaust research. The IRVB is shown to be immune to electromagnetic interference from ICRF which strongly impacts C-Mod's resistive bolometers. Results of the bench-top calibration are summarized, including a novel temperature calibration method useful for IRVBs.