Radiation Temperature Measurements Research Articles

Multi-Spectral Radiation Temperature Measurement: A High-Precision Method Based on Inversion Using an Enhanced Particle Swarm Optimization Algorithm with Multiple Strategies.

Multi-spectral temperature measurement technology has been found to have extensive applications in engineering practice. Addressing the challenges posed by unknown emissivity in multi-spectral temperature measurement data processing, this paper adds emissivity constraints to the objective function. It proposes a multi-spectral radiation temperature measurement data processing model realized through a particle swarm optimization algorithm improved based on multiple strategies. This paper simulates six material models with distinct emissivity trends. The simulation results indicate that the algorithm calculates an average relative temperature error of less than 0.3%, with an average computation time of merely 0.24 s. When applied to the temperature testing of silicon carbide and tungsten, experimental data further confirmed its accuracy: the absolute temperature error for silicon carbide (tungsten) is less than 4 K (7 K), and the average relative error is below 0.4% (0.3%), while two materials maintain an average computation time of 0.33 s. In summary, the improved particle swarm optimization algorithm demonstrates strong performance and high accuracy in multi-spectral radiation thermometry, making it a feasible solution for addressing multi-spectral temperature measurement challenges in practical engineering applications. Additionally, it can be extended to other multi-spectral systems.

Numerical study of a general criterion for divertor detachment control

Abstract The parameter R D = P rad / P cond , which measures the ratio of radiated power to conductive heat flux at downstream Scrape-Off-Layer (SOL), is proposed as a robust and practically useful figure of merit for divertor detachment control. The simulations performed using the SOLEDGE3X-EIRENE code predict that the instant where R D passes through unity (that is, when P rad ≈ P cond ) coincides with the detachment of the radiation front from the divertor target. Furthermore, as a function of R D , there is a decrease in target temperature and an increase in the distance at which the radiation front detaches from the target. These simulations cover scenarios in WEST and TCV with different levels of confinement, divertor closure, impurity concentration, and input power. The physical rationale underlying the above definition of R D is that when the divertor radiated power is comparable to the conductive heat flux, there will be a lack of energy reaching the target. Consequently, the radiation front detaches some distance from the divertor target. R D can thus be a good indicator for transitions to and from the detachment state. By monitoring R D , it becomes easier to maintain the heat flux deposition at the target at a manageable level. The evaluation of R D requires diagnostic measurement of downstream SOL radiation and upstream temperature which is feasible in tokamak devices. The robustness of this figure of merit is evaluated through realistic time-dependent numerical simulations for the WEST tokamak, as well as experimental data from WEST, TCV, and JT-60U cases. The results show that R D is capable of capturing the evolution of divertor plasma states, despite the different discharges and machines, suggesting that R D can serve as a valuable control variable for real-time experimental divertor detachment control.

Advances in the application of non-contact temperature measurement technology for aero-engine blade.

The advancement of the aviation sector has made the temperature measurement technology for aero-engine turbine blades essential for maintaining the engine's safe and steady performance. The non-contact temperature measurement technology is a trending research focus in turbine blade temperature measurement due to its benefits of not requiring direct touch with the object being measured and its suitability for high-temperature and high-speed conditions. This paper provides a concise overview of various key non-contact temperature measurement methods for aero-engines, such as fluorescence temperature measurement, fiber-optic temperature measurement, and radiation temperature measurement. It discusses the temperature measurement principle, technical characteristics, and the current research status both domestically and internationally. Based on this, this Review further discusses the main challenges faced by the non-contact temperature measurement technology and the development trend of the future.

Damage characteristic of electronic devices caused by products generated by Al/Ep/KMnO4/TiH2 active material projectile hypervelocity impacting on aluminum target

As the space environment becomes more competitive, space offense and defense are increasing every day. Projectiles made of reactive materials can achieve highly effective target destruction due to their good penetration, ignition and detonation capabilities as the kill element in space attacks. When a spacecraft encounters a hypervelocity impact from a projectile of active material, it will have a serious impact on the surface material and internal electronics (logic chips, super-capacitors, etc.), leading to anomalies in the spacecraft's on-orbit operation. In order to study the damage characteristics of internal typical logic chips and super-capacitor modules caused by the hypervelocity impact of active material projectiles on the surface of spacecraft, the simulated satellite experiment of Al/Ep/KMnO4/TiH2 active material projectiles hypervelocity impacting on aluminum target was performed. By using the self-built experimental loading system, plasma characteristic parameter diagnosis system, radiation temperature measurement system and electronic device function detection system, the characteristic parameters of plasma, light flash radiation temperature, temperature evolution process of logic chip and super-capacitor at specific position under different impact velocities are obtained. When the damage behavior of Al/Ep/KMnO4/TiH2 active material projectile impacts on the surface of simulated satellite, the main reasons affecting electronic devices and the damage characteristics of impact products on logic chip and super-capacitor are analyzed. The experimental results show that the plasma is the main reason for interfering with the operation of logic chips and super-capacitors. When the active material projectile impacts the simulated satellite at the speed of 1.26 km/s, 1.67 km/s and 2.13 km/s, the charge and discharge time of the super-capacitor increases by 3.28 times, 4.57 times and 6 times, respectively, and the maximum operating voltage performance decreases by 12.23%, 14.44% and 18.15%, respectively. When the impact velocities are 1.67 km/s and 2.13 km/s, the output signal of the CD74HC00 chip appears transient damage due to the injection of the plasma generated by the impact, which last 0.4 ms and 1.8 ms, respectively.

Increase in aerodynamic impedance and energy uptake in response to grazing prohibition in semi-arid grasslands during the beginning of the growing season

In Inner Mongolia, China, semi-arid grasslands have strong winds and radiation in spring, but it is unclear how grazing management influences the connections between aerodynamic and energy balance during this time. During spring, we conducted measurements of radiation, wind speed, and air temperature, for both grazed and grazing-prohibited grasslands. From these results it was found that the temperature gradient differential (ΔT = T0.4m-T2m) between the ground level (T0.4m) and the high height (T2m) is normally negative at night and positive during the day. Grazed grassland was found to have very few negative ΔT values. Albedo and ΔT were higher on the grazed grasslands, while net radiation and aerodynamic roughness (Z0) were lower on the grazed grasslands. According to structural equation modeling (SEM), the grazing prohibited and grazed had no effect on the relationship between surface albedo, air temperature, and humidity. Z0 in grazed grassland exhibited a substantial positive correlation with net radiation (Rn), but was not correlated with albedo. The Z0 of the grazing-prohibited grassland exhibited a substantial negative correlation with albedo, but not with Rn, and Z0 had a significant negative correlation with air temperature. These findings explain how grazing measures affect the vertical variations of surface heat in air.

Laser induced high temperature thermal-mechanical-oxygen coupling experimental system and method

In this paper, a thermal–mechanical–oxidation coupling experimental system based on laser heating is developed, containing two modes of Gaussian and flat-top lasers, which has a series of advantages such as high temperature range, rapid heating rate, and convenient observation. The system adopts active illumination and an optical filter to solve the problem where it is difficult for traditional digital-image correlation technology to image clearly under laser heating. A biaxial mechanical test machine is used to simulate the complex load by applying biaxial tension or compression loads on the material. Combined with the radiation temperature measurement and controllable flow field device, the thermal-mechanical-oxygen coupling experiment of high temperature resistant materials under aerobic environment can be carried out. The maximum uniform heat flux output density is 27.2 kW/cm2, and the maximum Gaussian heat flux output density is 105 kW/cm2. The thermal-mechanical-oxygen coupling experimental system and method are of great significance to the development of new high temperature resistant materials and thermal barrier coatings.

Investigating an accurate method for measuring the outdoor mean radiation temperature

Accurate measurement of mean radiation temperature (MRT), a main parameter affecting outdoor thermal comfort under sunlight conditions, is immensely important in improving the thermal environment of urban outdoor spaces and enhancing outdoor thermal comfort. In this study, four different surfaces (limestone, grass, concrete, and asphalt pavement) were selected and the experiments were set up under shading and no-shading conditions on four different surfaces. Based on the above conditions to analyze and compare three different MRT estimation methods, these include the black sphere thermometer measurement method under different wind speed measurement frequencies (0.1 and 10 Hz) and the six-way integrated radiation measurement method, and the outdoor wind speed (Va) of 10 Hz is the three-dimensional wind speed of the combined x-y-z three directions. The results showed that MRT was influenced by the long- and short-waves more in the vertical direction than in the horizontal direction, and the different solar radiation storage capacities of the lower cushion surfaces during the daytime led to different temperature change delays after sunset. The results shows that at the thermal comfort requirement of ±2 °C, and the acceptable error probability were 65.3% and 74.6% at 0.1 and 10 Hz, respectively. While at the thermal comfort requirement of ±5 °C, the acceptable error probability were 83.4% and 89.3% at 0.1 and 10 Hz, respectively. Noted that ±2 °C and ±5 °C as acceptable thresholds for MRT measurement accuracy are specified in ISO standard 7726:1985. Therefore, 10 Hz exhibited significantly better performance than that of 0.1 Hz for MRT estimation. Under the unshaded conditions, the MRT measurements obtained by black-sphere thermometer method is in most cases lower than obtained by six-way radiometry method, where the MRT obtained at 0.1HZ and 10HZ wind speed measurement frequencies are lower by about 5.8 and 4.2, respectively, compared to those obtained by six-way radiometry. However, due to the variation of the solar altitude angle, there is also a slightly higher phenomenon present. In addition, the results show that the RMSE of the estimated errors after correction for different cushion surfaces are lower than those before correction. Limestone is reduced by 22.15%. Concrete is reduced by 23.47%, Grassland by 28.38% and Asphalt road by 25.28%. And the correction effect is more obvious in the lower cushion surface with higher absorption rate. The conducting test that used an inexpensive black-sphere thermometer to measure outdoor MRT accurately improved the distinction between MRT estimation measurements under different conditions. It also refined the feasibility of changes in the wind speed measurement frequency to improve the accuracy of the traditional black-sphere thermometer measurements, thus, highlighting a new methodology for accurate outdoor MRT measurements that can in turn advance the improvement of outdoor thermal comfort.

Dual-Population Social Group Optimization Algorithm Based on Human Social Group Behavior Law

Inspired by the behavior law of human social groups, a new swarm intelligence algorithm named the dual-population social group optimization (DPSGO) algorithm is proposed in this article. Based on the primitive social group optimization (SGO) algorithm, dual-population grouping technology, reverse learning technology, immigration migration technology, and Gaussian mutation are introduced to further simulate the behavior law of actual human social groups. Experimental results and performance comparison show that the DPSGO algorithm has a better searchability and convergence rate. In addition, aiming at the socially hot issue of aviation safety, the simulation and experimental results show that the temperature measurement error can be reduced to less than 7.5 °C by using the DPSGO algorithm combined with reflected radiation correction to process the aeroengine multispectral radiation temperature measurement data. This article is of great significance to the design and optimization of swarm intelligence algorithms by using the behavior law of human social groups and provides valuable guidance for enhancing the safety monitoring of aeroengines.

Analysis of the Influencing Factors of Radiation Temperature Measurement Range of a Single Camera at a Certain Exposure

Analysis of the Influencing Factors of Radiation Temperature Measurement Range of a Single Camera at a Certain Exposure

Three-dimensional temperature field measurement method based on light field colorimetric thermometry

This paper proposes a novel method for three-dimensional (3D) temperature measurement using light field colorimetric thermometry, aiming to overcome the challenges associated with the intricate system structure and the limited availability of 3D information in traditional radiation temperature measurement methods. Firstly, the correlation between corresponding image points and the positions of 3D object in the light field image system is analyzed using the ray tracing method. The 3D position acquisition model and the light field colorimetric thermometry model are established, enabling simultaneous acquisition of the spatial coordinates and radiometric information of the 3D object. Then, the light field camera radiation calibration experiment was conducted, and the 3D temperature field will be obtained by employing colorimetric thermometry for each corresponding image point of the same object point. Finally, the experiment employed a light field camera for temperature measurement and reconstruction of candle flames. The accuracy of the temperature measurement is 3.31%, thus confirming the feasibility and effectiveness of the proposed method.

Radiation Temperature Measurement Method for Inner Surface of Cavity-Like Objects Based on Effective Emissivity Modeling

Radiation Temperature Measurement Method for Inner Surface of Cavity-Like Objects Based on Effective Emissivity Modeling

CMOS SPAD Imager Array for Wide Radiation Temperature Sensing and Thermal Imaging

We have demonstrated a wide radiation temperature measurement by using a single-photon avalanche diode (SPAD) image array that is analogous to a silicon photomultiplier with a time-gating technique and an adjustable summed output. The detection temperature window ranging from 280 °C to 1050 °C can be achieved with a noise equivalent temperature difference (NETD) value of below 1 °C. The thermal image with a high detection rate up to 1680 Hz is obtained at the same detection temperature as a commercial CMOS thermal camera. We further demonstrate a thermal image with a spatial resolution of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$80~\mu \text{m}$ </tex-math></inline-formula> .

Research on the correction method of reflected energy in radiation temperature measurement

Measure the target temperature with a radiation thermometer, the noise of the ambient radiance reflected by the target can cause measurement errors, especially when the ambient temperature is higher than the target temperature. In this paper, the one-point reflection correction method (OPRCM) is proposed based on the relationship between the band emissivity and the blackbody radiance corresponding to the target temperature. According to this method, the target's emissivity needs not be known, the instrument only needs to be calibrated in full-range at one ambient temperature, and the target temperature can be accurately measured under different ambient temperatures, with the measurement range being −10 °C ∼ 50 °C, the measurement accuracy is better than ±1 °C. Therefore, it is of great significance to improve the accuracy of radiation temperature measurement.

Multi-spectral radiation thermometry based on an Alpha spectrum-LM algorithm under the background of high temperature and intense reflection.

In order to meet the needs of multi-spectral radiation temperature measurement under high temperature background, this paper studies the problems of reflected radiation interference and spectral emissivity difficult to obtain in high temperature and intense reflection environment. First, using discrete triangular surface elements and radiation angle coefficients, an analysis model of high temperature background reflected radiation is constructed to describe the variation characteristics of high temperature background reflected radiation. Secondly, the least squares support vector machine (LSSVM) is optimized by particle swarm optimization (PSO) algorithm, and an emissivity model identification algorithm based on Alpha spectrum-Levenberg Marquarelt (LM) algorithm is proposed, which has stronger applicability and accuracy than existing emissivity model identification methods. Finally, the high temperature background radiation and the emissivity model are combined to construct and solve the multi-spectral target equation, so as to realize the reflected radiation error correction and radiation temperature measurement under the high temperature and intense reflection background. The simulation and experimental comparison with the existing methods show that the temperature measurement error of the radiation temperature measurement method proposed in this paper is below 9.5K, which can effectively correct the reflected radiation error and further improve the temperature measurement accuracy.

Comparison research on spectral emissivity of three copper alloys during oxidation

Accurate temperature measurement plays an important role in improving quality, saving energy and reducing consumption in the hot rolling. The crucial part of temperature measurement is the reliable data of spectral emissivity whose precise measurement can improve the accuracy of the radiation temperature measurement. In this work, the spectral emissivity of red copper, brass and cupronickel alloy at four oxidation temperatures (673, 773, 873 and 973 K) heating for 120 min is measured in the wavelength range of 2–20 μm. The dependency on wavelength, temperature, composition and oxidation of the emissivity for three copper alloy samples is investigated contrastively. The results show that the oscillation phenomenon exists in the emissivity distributions of three copper alloy samples, but the temperature at which the most violent oscillation occurs is different. The perspective of sample composition is accounted for the discrepancies in oxidation progress and degree of three copper alloy samples at the same temperature. Finally, the thickness of oxide film calculated based on the principle of thin film interference is compared with that measured by observing the cross-section of sample using scanning electron microscope (SEM), which is in accordance with the experimental results.

A Comparative Review of Thermocouple and Infrared Radiation Temperature Measurement Methods during the Machining of Metals.

During the machining process, substantial thermal loads are generated due to tribological factors and plastic deformation. The increase in temperature during the cutting process can lead to accelerated tool wear, reducing the tool’s lifespan; the degradation of machining accuracy in the form of dimensional inaccuracies; and thermally induced defects affecting the metallurgical properties of the machined component. These effects can lead to a significant increase in operational costs and waste which deviate from the sustainability goals of Industry 4.0. Temperature is an important machining response; however, it is one of the most difficult factors to monitor, especially in high-speed machining applications such as drilling and milling, because of the high rotational speeds of the cutting tool and the aggressive machining environments. In this article, thermocouple and infrared radiation temperature measurement methods used by researchers to monitor temperature during turning, drilling and milling operations are reviewed. The major merits and limitations of each temperature measurement methodology are discussed and evaluated. Thermocouples offer a relatively inexpensive solution; however, they are prone to calibration drifts and their response times are insufficient to capture rapid temperature changes in high-speed operations. Fibre optic infrared thermometers have very fast response times; however, they can be relatively expensive and require a more robust implementation. It was found that no one temperature measurement methodology is ideal for all machining operations. The most suitable temperature measurement method can be selected by individual researchers based upon their experimental requirements using critical criteria, which include the expected temperature range, the sensor sensitivity to noise, responsiveness and cost.

Supersonic–subsonic transition region in radiative heat flow via self-similar solutions

We study the radiative hydrodynamics flow of radiation-driven heat waves in hot dense plasmas, using approximate self-similar solutions. Specifically, we have focused on the intermediate regime between the pure radiative supersonic flow and the pure subsonic regime. These two regimes were investigated using both exact self-similar solutions and numerical simulations; however, most of the study used numerical simulations, mainly because the radiative heat wave and the shock regions are not self-similar altogether. In a milestone work [Garnier et al., “Self-similar solutions for a nonlinear radiation diffusion equation,” Phys. Plasmas 13, 092703 (2006)], it was found that for a specific power law dependency temperature profile, a unique exact self-similar solution exists that is valid for all physical regimes. In this work, we approximate Garnier's exact solution for a general power-law temperature-dependency, using simple analytical considerations. This approximate solution yields a good agreement compared to numerical simulations for the different thermodynamic profiles within the expected range of validity. In addition, we offer an approximate solution for the energies absorbed in the matter, again, for a general power-law temperature profile. Our approximate self-similar solution for the energy yields very good results compared to exact numerical simulations for both gold and Ta2O5. We also set a comparison of our self-similar solutions with the results of an experiment for radiation temperature measurement in a Hohlraum in low-density foams that is addressed directly to the intermediate regime, yielding a good agreement and similar trends. The different models as well as the numerical simulations are powerful tools to analyze the supersonic–subsonic transition region.

Feasibility of surface dielectric barrier discharge in wastewater treatment: Spectroscopic modeling, diagnostic, and dye mineralization

The paper investigates the ability of a surface dielectric barrier discharge (SDBD) based reactor to mineralize complex organic molecules such as azo dyes in water. The high operational flexibility, low maintenance, and energy efficiency of SDBD over most of the other plasma systems motivated its selection. Also, SDBD produces even discharge over a relatively large surface area. This could enhance plasma-liquid interaction and the production of reactive chemical species. Optical emission spectroscopy coupled with the collision radiative model and temperature measurements reveals the non-equilibrium nature of the plasma. Through plasma diagnostics, the study established the ability of SDBD to generate high energetic electrons with an electron temperature of 1.6 eV at a moderate sample temperature. The data supports the effective generation of reactive chemical species by SDBD reactor and its suitability for wastewater treatment with less energy consumption. The enhanced ability of the SDBD to mineralize azo dye (Brilliant Red 5B) in water is demonstrated under ambient conditions. The reactor is operated as a function of initial dye concentration, pH, and background salts such as NaCl, Na2SO4, and Na2CO3 to understand their effect on dye degradation. Faster degradation and mineralization of Brilliant Red 5B were observed due to the enhanced generation of •OH and H2O2 in the liquid medium. The degradation and complete mineralization of 50 mg/L of dye was achieved at hydraulic retention times of 20 min and 72 min, respectively. Compared to other plasma reactors reported, the present system showed a high energy yield of 247 mg/kWh at an operating power of 60 W and initial dye concentration of 50 mg/L. In short, the studies address two significant challenges of using plasma in wastewater treatment, i.e., energy efficiency and scalability.

Radiation Properties of Cement Clinker Fine Particles for Radiation Temperature Measurements

Radiation Properties of Cement Clinker Fine Particles for Radiation Temperature Measurements

A biosensor based on a thermal camera using infrared radiance as the signal probe

Flexible-type signal probes and their detection methods are increasingly being applied in biosensors. Among these, temperature-based signal probes represent a novel research direction. These sensors convert immunoassay signals into temperature signals, which are then detected using a thermometer or thermal infrared reader. However, from a physical viewpoint, we know that the temperature measured directly using a thermal infrared camera is the infrared radiance temperature, which is proportional to both the true temperature and emissivity. Herein, we design a novel sensing method that uses infrared radiance rather than true temperature as the signal probe. We convert the immunoassay to an infrared radiation temperature measurement by controlling an aluminum plate in constant temperature whose infrared radiation temperature varied significantly with immunoassay-based the amount of the target. We then develop two readout systems: one is based on a scientific-grade infrared camera, and the other uses a smartphone-based thermal camera, which is more portable, flexible, and can be used as an in-pocket sensor. The sensors are verified via detecting exemplary biomarker human IgG, and show excellent quantitative model performances in 0–100 ng mL−1 concentration range with the detection limit estimated as low as 0.54 ng mL−1. The excellent quantitative results demonstrate the powerful detection performance of this sensing method.