Surface Temperature Measurements Research Articles

3D infrared temperature maps measurements of ablative materials during plasma wind tunnel experiments

Accurate surface temperature and recession measurements are crucial experimental data for plasma wind tunnel testing of ablative thermal protection materials. In this work we propose a novel methodology to reconstruct infrared temperature maps on 3D geometries undergoing surface recession. An optical calibration technique is used to extract 3D metric information from the 2D thermal images, thanks to a specific calibration target with control points. The evolution of the sample shape during the experiment is tracked from a side view, using a visual-range camera with dedicated image processing, and reconstructed in 3D under the assumption of axisymmetry. The surface temperature is projected on the time-varying 3D geometry from the calibrated thermograms. The technique is demonstrated on a graphite ablation experiment in air plasma. The reconstructed maps provide detailed multidimensional information about the transient temperature evolution, overcoming traditional approaches that are limited around the stagnation point. The technique allows to study ablation mechanisms with further detail, improving experimental data for material qualification and validation of simulation codes.

Global and Regional Discrepancies between Early-Twentieth-Century Coastal Air and Sea Surface Temperature Detected by a Coupled Energy-Balance Analysis

Abstract A major uncertainty in reconstructing historical sea surface temperature (SST) before the 1990s involves correcting for systematic offsets associated with bucket and engine-room intake temperature measurements. A recent study used a linear scaling of coastal station-based air temperatures (SATs) to infer nearby SSTs, but the physics in the coupling between SATs and SSTs generally gives rise to more complex regional air–sea temperature differences. In this study, an energy-balance model (EBM) of air–sea thermal coupling is adapted for predicting near-coast SSTs from coastal SATs. The model is shown to be more skillful than linear-scaling approaches through cross-validation analyses using instrumental records after the 1960s and CMIP6 simulations between 1880 and 2020. Improved skill primarily comes from capturing features reflecting air–sea heat fluxes dominating temperature variability at high latitudes, including damping high-frequency wintertime SAT variability and reproducing the phase lag between SSTs and SATs. Inferred near-coast SSTs allow for intercalibrating coastal SAT and SST measurements at a variety of spatial scales. The 1900–40 mean offset between the latest SST estimates available from the Met Office (HadSST4) and SAT-inferred SSTs range between −1.6°C (95% confidence interval: [−1.7°, −1.4°C]) and 1.2°C ([0.8°, 1.6°C]) across 10° × 10° grids. When further averaged along the global coastline, HadSST4 is significantly colder than SAT-inferred SSTs by 0.20°C ([0.07°, 0.35°C]) over 1900–40. These results indicate that historical SATs and SSTs involve substantial inconsistencies at both regional and global scales. Major outstanding questions involve the distribution of errors between our intercalibration model and instrumental records of SAT and SST as well as the degree to which coastal intercalibrations are informative of global trends. Significance Statement To evaluate the consistency of instrumental surface temperature estimates before the 1990s, we develop a coupled energy-balance model to intercalibrate measurements of sea surface temperature (SST) and station-based air temperature (SAT) near global coasts. Our model captures geographically varying physical regimes of air–sea coupling and outperforms existing methods in inferring regional SSTs from SAT measurements. When applied to historical temperature records, the model indicates significant discrepancies between inferred and observed SSTs at both global and regional scales before the 1960s. Our findings suggest remaining data issues in historical temperature archives and opportunities for further improvements.

Temperature Distribution Analysis on the Surface of the Radiator: Infrared Camera and Thermocouples Results Comparison

The experiments conducted in a didactic laboratory of the Kielce University of Technology involved temperature distribution measurements on the outer surface of a steel radiator using a thermal imaging camera and thermocouples to compare both investigation methods. The research included registering the parameters for a specific period for each of the four different medium flows. Graphs present the results with the division of the radiator into eight thermal fields. The results present the differences in temperatures between 1.78°C to 3.65°C. The non-contact method with an infrared camera seems more accurate since it is precise for surface temperature measurement.

Messung der Körpertemperatur beim Schwein: Können Infrarotthermometer eine Alternative sein?

Internal body temperature is an essential parameter in evaluation an animal's general health status. The rectal temperature as 'gold standard' requires restraining of the animal which may cause stress especially when not accustomed to handling procedures. Stress on the other hand should whenever possible be avoided as it negatively affects animal welfare and may increase body temperature. The present study evaluated whether measuring the body surface temperature with an infrared thermometer (IRT) may represent a stressless alternative method to rectal body temperature measurements. Twelve male fattening pigs were included in the study. Body temperature was measured once a week for 11 weeks. Body surface temperature measurements were performed in the areas of the forehead, caudal base of the ear and anus using two infrared thermometers (IRT1 and IRT2) each. Throughout the study, all pigs were clinically healthy. Best repeatability was found for the rectal thermometer and IRT1 in the anus region. Homogeneity of variance was not found for the measurements of the three thermometers. Mean values of body temperature were significantly different (p<0,05) between thermometers and measurement points. Thereby, the type of thermometer and measurement point possessed a moderate to strong effect. The Bland-Altman plot shows that differences in the values of the thermometers and measurement points are within the acceptable range of variation (95% interval). However, the range of variation is too substantial for clinical assessment of the body temperature. The repeatability of temperature data measured with IRT on the body surface of pigs is acceptable. For this procedure, restraining the animals is not necessary, therefore reducing the animal's stress level during the clinical examination. However, the correlation to the rectal body temperature is weak to moderate. In order to use IRT for health monitoring in animals, reference values for respective IRT and measurement points need to be established. In the current study no case of hyper- or hypothermia occurred. Further research is warrented to evaluate whether IRT reliably detect fever.

Heat transfer performance assessment for precise accelerated control cooling of the hot heavy clad plate

In this study, the heat transfer characteristics are estimated to determine the internal temperature distribution of the hot heavy clad plate from the measured surface temperature prior to the accelerated control cooling process. The temperature prediction accuracy is verified by the advanced inverse heat transfer method (A-IHTM). It is found that the plate temperature distribution can be considered with the quasi-equilibrium state within the temperature deviation rate of 0.1 °C/s. The results have been also verified through a comparison with an analytical method over time, using dimensionless surface temperature. The comparison yielded a standard deviation of 0.027 and root mean squared error (RMSE) of 0.0574 in dimensionless temperature, indicating that the numerical method is a viable option for accurately predicting the temperature distribution in the hot heavy clad plate during the accelerated control cooling process. The internal temperature distribution of the heavy plate changes non-linearly. This phenomenon is defined as the “heat capacity effect” considering the enthalpy change. With the heat transfer characteristics, the cooling process of heavy clad plate could be controlled within finish cooling temperature deviation of 14.7 °C, cooling rate deviation of 0.7 °C/s. Also, the cooling control accuracy for the finish cooling temperature can be improved by 12.6 % with the satisfied mechanical property of heavy clad plate for corrosion resistance.

A mixed model of heat exchange in stationary honeybee foragers

During foraging honeybees are always endothermic to stay ready for immediate flight and to promote fast exploitation of resources. This means high energetic costs. Since energy turnover of foragers may vary in a broad range, energetic estimations under field conditions have remained uncertain. We developed an advanced model, combining the benefits of mechanistic and correlative models, which enables estimation of the energy turnover of stationary foragers from measurements of body surface temperature, ambient air temperature and global radiation. A comprehensive dataset of simultaneously measured energy turnover (ranging from 4 to 85 mW) and body surface temperature (thorax surface temperature ranging from 33.3 to 45 °C) allowed the direct verification of model accuracy. The model variants enable estimation of the energy turnover of stationary honeybee foragers with high accuracy both in shade and in sunshine, with SD of residuals = 5.7 mW and R2 = 0.89. Its prediction accuracy is similar throughout the main range of environmental conditions foragers usually experience, covering any combination of ambient air temperature of 14–38 °C and global radiation of 3–1000 W m−2.

A compact LWIR borescope sensor for 2D engine component surface temperature measurement

A compact long-wavelength infrared (LWIR) borescope imaging sensor operating in the wavelength range of 8–14 μm is designed and developed for non-contact two-dimensional (2D) surface temperature measurements in gas-turbine engines. The LWIR detection minimizes optical interferences from hot combustion gases and soot (emission within UV–mid IR region). Using simulations, the system is optimized for improving the signal collection efficiency and minimize image aberrations. The LWIR borescope probe is shielded by the custom-build compact water-cooled probe housing (outer diamter (OD) 19 mm, inner diameter (ID) 10 mm), which can sustain flame temperature up to 2400 K at a pressure of 50 bar. It facilitates long-term optical diagnostics inside the actual high-pressure combustion facilities where extreme thermal acoustic perturbation and intense heat fluxes are encountered. The design, construction, and characterization of the LWIR borescope sensor are discussed in detail. We present the 2D surface temperature measurements of a V-gutter bluff-body with simple nitrogen gas cooling in a laboratory testbed. The results indicate the sensor’s ability to accurately measure surface temperature with low background noise and to track transient cooling effect. The water-cooled probe housing was tested to verify the effectiveness of fast heat dissipation in high-temperature combustion environment to avoid unwanted thermal signals from the LWIR probe window. The developed LWIR sensor suite has promising applications in surface temperature measurements of engine components. The findings of this study may aid propulsion system engineers and researchers in designing thermal management systems and optimizing operation.

Challenges and opportunities in quantitative aerial thermography of building envelopes

The use of small unmanned aerial vehicles (UAVs) equipped with an infrared (IR) camera has created opportunities for qualitative and quantitative thermal assessments of building envelopes. However, it is currently unclear how successful this method is at quantifying heat losses through the building envelope. The inconsistency in findings indicates that sources of error that affect the accuracy of surface temperature measurements are not well understood by thermographers and that recommendations to minimize the errors in aerial thermography measurements have yet to be determined. In this study, laboratory and field experiments were conducted to investigate the scientific reasons for discrepancies between aerial (i.e. dynamic) and conventional stationary infrared thermography (IRT) observations. A set of practical approaches were presented to minimize the sources of error in UAV-IRT measurement. The results of field experiments showed a non-linear and dramatic variation of measured surface temperature during flight, where the deviations of results between dynamic and stationary thermography were beyond the manufacturer-reported accuracy of ±5 °C. Additionally, the results indicated that induced convection from drone propellers affects microbolometer stabilization with surrounding environmental conditions, which significantly influences the IR camera measurement accuracy. Finally, subsequent investigations utilized a shield around the camera to minimize the convective turbulence on the lens and thermal sensors, successfully achieving temperature deviations of less than 1 °C. These findings may inform manufacturers about the limitations of current IR camera technology during aerial surveys and therefore provide opportunities to define a more robust thermal imaging protocol for the quantification of building envelope thermal performance.

Body surface temperature of rats reveals both magnitude and sex differences in the acute stress response

Understanding how biological markers of stress relate to stressor magnitude is much needed and can be used in welfare assessment. Changes in body surface temperature can be measured using infrared thermography (IRT) as a marker of a physiological response to acute stress. While an avian study has shown that changes in body surface temperature can reflect the intensity of acute stress, little is known about surface temperature responses to stressors of different magnitudes and its sex-specificity in mammals, and how they correlate with hormonal and behavioural responses. We used IRT to collect continuous surface temperature measurements of tail and eye of adult male and female rats (Rattus norvegicus), for 30 minutes after exposure to one of three stressors (small cage, encircling handling or rodent restraint cone) for one minute, and cross-validated the thermal response with plasma corticosterone (CORT) and behavioural assessment. To obtain individual baseline temperatures and thermal responses to stress, rats were imaged in a test arena (to which they were habituated) for 30 seconds before and 30 minutes after being exposed to the stressor. In response to the three stressors, tail temperature initially decreased and then recovered to, or overshot the baseline temperature. Tail temperature dynamics differed between stressors; being restrained in the small cage was associated with the smallest drop in temperature, in male rats, and the fastest thermal recovery, in both sexes. Increases in eye temperature only distinguished between stressors early in the response and only in females. The post stressor increase in eye temperature was greater in the right eye of males and the left eye of females. In both sexes encircling may have been associated with the fastest increase in CORT. These results were in line with observed behavioural changes, with greater movement in rats exposed to the small cage and higher immobility after encircling. The female tail and eye temperature, as well as the CORT concentrations did not return to pre-stressor levels in the observation period, in conjunction with the greater occurrence of escape-related behaviours in female rats. These results suggest that female rats are more vulnerable to acute restraint stress compared to male rats and emphasise the importance of using both sexes in future investigations of stressor magnitude. This study demonstrates that acute stress induced changes in mammalian surface temperature measured with IRT relate to the magnitude of restraint stress, indicate sex differences and correlate with hormonal and behavioural responses. Thus, IRT has the potential to become a non-invasive method of continuous welfare assessment in unrestrained mammals.

Thermoreflectance-based approach for surface temperature measurements of thin-film gold sensors.

A novel thermoreflectance-based diagnostic tool capable of visualizing spatial and temporal changes in surface temperature is presented. The method uses narrow spectral emission bands of blue [λ = 405nm with 10nm full-width-at-half-maximum (FWHM)] and green (λ = 532nm with 10nm FWHM) light to monitor the optical properties of gold and thin-film gold sensors, relating changes in reflectivity to temperature through a known calibration coefficient. The system is made robust to tilt and surface roughness variations through the simultaneous measurement of both probing channels with a single camera. Experimental validation is performed on two forms of gold materials heated from room temperature to 200 °C at a rate of ∼100 °C/min. Subsequent image analysis shows perceptible changes in reflectivity in the narrow band of green light, while the blue light remains temperature-insensitive. The reflectivity measurements are used to calibrate a predictive model with temperature-dependent parameters. The physical interpretation of the modeling results is given, and the strengths and limitations of the presented approach are discussed.

Satellite-Based Ocean Color and Thermal Signatures Defining Habitat Hotspots and the Movement Pattern for Commercial Skipjack Tuna in Indonesia Fisheries Management Area 713, Western Tropical Pacific

Understanding the mechanisms that determine the critical habitat of commercial species is one of the significant challenges in marine science, particularly for species that inhabit the vast ocean worldwide. Previous investigations primarily focused on determining skipjack habitats without considering the feasible size for sustainable fisheries. To define habitat hotspots and movement patterns for decently sized skipjack tuna (≥50 cm) in Indonesia Fisheries Management Area (IFMA) 713, Indonesia, we examined the remote sensing of synoptic sea surface temperature (SST) and chlorophyll-a concentration (Chl-a) measurements with catch data from 2007 to 2016. A new skipjack tuna habitat model was developed based on the link between the key satellite-based environmental data and the best tuna fishery performance using a combination of generalized additive models (GAMs) and kernel density estimates. The findings reveal that feasible skipjack catch sizes were found in approximately 27% of total fishing grounds and were significantly captured in areas with a Chl-a of 0.15–0.28 mg m−3 and an SST of 29.5–31.0 °C, corresponding with an elevated skipjack habitat index (SHI). The habitat hotspots for the commercial skipjack were particularly produced by favorable Chl-a and SST, in association with Chl-a front and anticyclonic and cyclonic eddies, especially in October, which coincided with the highest skipjack catch per unit effort (CPUE). Skipjack distributions were mostly found within 10 km of favorable feeding habitats. They used the hotspot area as an indicator of their dynamics and movement pattern in the environment. The observed CPUEs cross-validated the predicted SHI values, suggesting that the model provided a reliable proxy for defining the potential habitats and the spatial movement of mature skipjack schools. Our findings have global significance for locating ecological hotspots, monitoring sustainable skipjack fisheries, and tracking skipjack migration, especially within the western tropical Pacific.

Heat transfer and skin friction: Beyond the Reynolds analogy

This paper describes a variational method to determine a high-resolution skin friction field from a measured surface temperature field based on the exact relation between skin friction, surface temperature and heat flux in viscous flows. The focus is the application of this method to complex three-dimensional flows to explore the intrinsic relationship between skin friction and heat transfer beyond the Reynolds analogy. Further, the underlying condition for establishing the Reynolds analogy is examined in this general theoretical framework. Essentially, this method is considered as a global variational form of the Reynolds analogy. To demonstrate the application of this method, the skin friction fields are extracted from temperature sensitive paint measurements in normally and obliquely impinging jets, revealing complex flow structures in the impingement region where the Reynolds analogy does not hold.

Very High spatial Resolution IR thermography diagnostic positioning system upgrade in WEST Tokamak

The Very High spatial Resolution (VHR) infrared thermography diagnostic developed by CEA-IRFM is installed in the WEST tokamak to measure surface temperature of the actively cooled W-monoblocks (MB) of the Plasma Facing Units (PFUs), which are similar to the International Thermonuclear Experimental Reactor (ITER) ones. It is a major diagnostic to investigate the behavior of PFU during experimentation thanks to its very high spatial resolution (0.1 mm / pixel), movable field of view (FoV) and the wide-range temperature measurement. In particular, it can study the evolution of monoblocks mounted in the tokamak, the influence of the shaping of these components submitted to high heat load and the behavior of the leading edges regarding the assembling tolerances between adjacent monoblocks. Finally, such diagnostic directly contributes to the specification assessment of the ITER divertor units. This diagnostic was operational during the 2019 WEST experimentation and its enhanced design for the 2020 WEST experimentation campaign. In order to monitor 30 × 12 mm monoblocks temperature, the VHR IR diagnostic is able to move its narrow FoV (64 × 51 mm) to specific targets on the observable divertor area (360 × 420 mm). Position and focus steering are achieved through motor-controlled mirrors and lenses operated by a dedicated Labview application on a remote unit. Mirror positioning occurs between pulses under normal WEST operation conditions, and can withstand thermal radiation and disruptions during pulses. Repeatability, hysteresis, mechanical components reliability are critical parameters to provide accurate positioning (<1 mm) of the FoV. The tuning and calibration of these actuators in accordance with WEST environment is crucial to guarantee the best position of the FoV and optical performances. This paper gives the FoV positioning implementation details and performance of the VHR in WEST.

Flow and Convective Exchanges Study in Rotor-Stator System With Eccentric Impinging Jet

Abstract This paper investigates numerically and experimentally the flow structure and convective heat transfers in an unconfined air gap of a discoid technology rotor–stator system. The cavity between the interdisk is defined by dimensionless spacing varying between G = 0.02 (Haidar et al., 2020, “Numerical and Experimental Study of Flow and Convective Heat Transfer on a Rotor of a Discoidal Machine With Eccentric Impinging Jet,” J. Therm. Sci. Eng. Appl., 12(2), 021012) and G = 0.16. For experimental data, an infrared thermography is applied to obtain a measurement of the rotor surface temperatures and a steady-state energy equation is solved to evaluate the local convective coefficients. A numerical study is performed with a computational code ansys-fluent and based to apply two different turbulence models named the Reynolds stress model (RSM) and k–ε renormalization group (RNG). The results of the numerical simulation are compared with experimental results on heat transfer for the rotational Reynolds number ranging from 2.38×105 to 5.44×105, the jet Reynolds numbers varying from 16.6×103 to 49.6×103, and for dimensionless spacing G between 0.04 and 0.16. Three heat transfer zones on the rotating disk surface are identified. A good accord between a numerical result and experimental data was obtained. Finally, a correlation relating the Nusselt number to the rotational Reynolds number, jet Reynolds number, and dimensionless spacing varying from 0.02 to 0.16 is proposed.

Detection of Fever Using Continuous Skin Temperature Monitoring in Hospitalized Older Adults

The continuous monitoring of body surface temperature has been proven to help detect potential fever events in hospitalized patients. However, the efficacy of using body surface temperature to detect fever in older adults remains unclear due to the relatively low and slower-to-change body surface temperature in this population. This study was designed to investigate 1) the relationship between changes in body surface and routine tympanic temperatures, 2) the correlation between body surface temperature measurement frequency and detection of fever, and 3) the factors related to the incidence of fever in hospitalized older adults. A prospective study was conducted on 33 hospitalized older adults aged 65 years or older who were suspected to have or diagnosed with an infection in an infectious disease and medical ward at a medical center in southern Taiwan from March to November 2020. Demographic, routine tympanic temperature, and heart rate data were collected by reviewing the participants' medical records. Body surface temperatures were monitored continuously using HEARThermo every 10 seconds until one of the following conditions were met: hospital discharge, no fever for three continuous days, and HEARThermo was removed. Descriptive analysis was used to compare the variations in body surface temperature and routine tympanic temperature measurements. Pearson correlation was used to analyze the correlation between different measurement frequencies and fever events. Finally, mixed effects logistic regression was used to analyze the factors significantly related to fever events. Seven hundred and twenty routine body temperature measurements were taken, with 209 (29.0%) fever events detected in 23 (69.7%) of the participants. The body surface temperatures were more closely correlated with tympanic temperatures during fever events than non-fever events (r = .260, p < .001). More fever events were detected using body surface temperature monitoring frequencies of every 10 seconds and every 1 minute. After controlling for demographic factors, the results of the mixed effect model indicate that body surface temperature and heart rate are significant factors related to fever events in hospitalized older adults (odds ratio, OR: 1.74, p < .001; OR: 1.11, p < .001). The continuous monitoring of body surface temperature may improve the detection of fever events in hospitalized older adults. The application of wearable devices and cloud platforms may further facilitate the real-time assessment and care capabilities of nurses, thus reducing their workload and improving care quality.

Temperature measurement and error analysis of the transverse plane of oil-jet-lubrication herringbone gear with infrared pyrometers.

Frictional power losses of high-speed and heavy-load herringbone gearboxes increase the temperature of the gearbox. Thus, real-time surface temperature measurement is significant for evaluating the gearbox lubrication design. A rotating gear test rig with an infrared pyrometer is developed in this paper to conduct real-time and accurate temperature measurements of the transverse plane of the oil-jet-lubrication herringbone gear. First, the influencing factors and measuring errors of surface temperature are analyzed using the infrared pyrometer. The emissivity of the measured surface of a gear tooth painted with matte black is experimentally calibrated. Second, the temperature measurement tests of the oil-jet-lubrication herringbone gear under different conditions are carried out. Measurement errors resulting from purge air pressure, purge air temperature, and oil-jet temperature are also experimentally studied. The results indicate that the purge gas flow can reduce the measurement errors of the infrared pyrometer resulting from oil mist with an appropriate purge air pressure and purge air temperature. Finally, a mathematical curve-fitting of the measurement results between the infrared pyrometer and thermocouple is carried out. The calculated temperatures by the curve-fitting formula are compared with the measured thermocouple temperature, with the relative differences being less than 1 °C. Thus, the curve-fitting formula is credible for the real-time measurement of surface temperature, while the relevant measuring method is also valuable for engineering applications of high-speed gear systems under oil-jet-lubrication conditions.

Foundations of machine learning for low-temperature plasmas: methods and case studies

Machine learning (ML) and artificial intelligence have proven to be an invaluable tool in tackling a vast array of scientific, engineering, and societal problems. The main drivers behind the recent proliferation of ML in practically all aspects of science and technology can be attributed to: (a) improved data acquisition and inexpensive data storage; (b) exponential growth in computing power; and (c) availability of open-source software and resources that have made the use of state-of-the-art ML algorithms widely accessible. The impact of ML on the field of low-temperature plasmas (LTPs) could be particularly significant in the emerging applications that involve plasma treatment of complex interfaces in areas ranging from the manufacture of microelectronics and processing of quantum materials, to the LTP-driven electrification of the chemical industry, and to medicine and biotechnology. This is primarily due to the complex and poorly-understood nature of the plasma-surface interactions in these applications that pose unique challenges to the modeling, diagnostics, and predictive control of LTPs. As the use of ML is becoming more prevalent, it is increasingly paramount for the LTP community to be able to critically analyze and assess the concepts and techniques behind data-driven approaches. To this end, the goal of this paper is to provide a tutorial overview of some of the widely-used ML methods that can be useful, amongst others, for discovering and correlating patterns in the data that may be otherwise impractical to decipher by human intuition alone, for learning multivariable nonlinear data-driven prediction models that are capable of describing the complex behavior of plasma interacting with interfaces, and for guiding the design of experiments to explore the parameter space of plasma-assisted processes in a systematic and resource-efficient manner. We illustrate the utility of various supervised, unsupervised and active learning methods using LTP datasets consisting of commonly-available, information-rich measurements (e.g. optical emission spectra, current–voltage characteristics, scanning electron microscope images, infrared surface temperature measurements, Fourier transform infrared spectra). All the ML demonstrations presented in this paper are carried out using open-source software; the datasets and codes are made publicly available. The FAIR guiding principles for scientific data management and stewardship can accelerate the adoption and development of ML in the LTP community.

Calculation of internal heat source and thermal gradient of cylindrical traction battery with measured surface temperature and heat flux

In the process of charging and discharging, the traction battery not only experiences electrochemical reactions, but also includes many side reactions, the typical phenomenon of which is the rise of battery temperature. In order to study the characteristics of the internal heat source and the distribution of the temperature field of a cylindrical battery, a one-dimensional (radius direction) heat transfer model is established in this work. Then, the temperature and heat flux measured on the external surface of the battery is used to calculate the internal heat source and temperature distribution, so as to quantify the thermal gradient in the diameter direction. In order to verify the feasibility of the model, a small incision is cut at the bottom of the battery, a thermocouple is built in to measure the temperature of the central position inside the battery, and the measured temperature is compared with the calculated temperature. The results show that the calculated results of the model have high reliability. In addition, the proposed model is also used to calculate the temperature of its internal central position at a higher ambient temperature (40 °C) and a lower ambient temperature (−10 °C). It is found that the calculated results are very close to the measured results at the ambient temperature of 40 °C, but the difference between the two was large at the ambient temperature of −10 °C.

Heat Transfer Calculations during Flow in Mini-Channels with Estimation of Temperature Uncertainty Measurements

The main aim of this work was to provide heat transfer calculations of flow boiling in mini-channels with an application for the Trefftz functions. The test section comprised five parallel mini-channels with a depth of 1 mm, with a common heated wall. For the estimation of the temperature uncertainty, during the experiment the temperature measurement was performed with the use of K-type thermoelements and an infrared camera in two mini-channels simultaneously. According to the Guide to the Expression of Uncertainty in Measurement, the Monte Carlo method is a practical alternative to the GUM uncertainty framework. Since the uncertainty components are not approximately the same magnitude, the Monte Carlo method was indicated to estimate the uncertainty of the surface temperature measurement. The results obtained from this simulation method were compared with the results of the computation related to the uncertainty propagation method. The results of both methods of temperature measurement were found to be consistent. The results of the statistical analysis were used to describe heat transfer calculations. The heat transfer investigations concerning the subcooled boiling region were performed during the other experiment. The local heat transfer coefficients on the contact surface between the working fluid and the heated wall were calculated from the Robin boundary condition. The mathematical model described by the heat equation in the mini-channel wall and by the Fourier-Kirchhoff equation in a flowing fluid leads to an inverse heat transfer problem. This problem was solved using the FEM with the Trefftz-type basis functions. The estimation of temperature uncertainty measurements due to the Monte Carlo method was included in the final results of the heat transfer coefficient.

Optimized curing and coating of smart paints for surface temperature measurements

Optimized curing and coating of smart paints for surface temperature measurements