Three-dimensional Temperature Research Articles

Orthogonal dual-channel single-camera spectral imaging for online measurement of three-dimensional space–time evolution of temperature field in laser melt pool

Current temperature measurement technology in laser manufacturing cannot obtain the internal three-dimensional (3D) temperature distribution of the melt pool. Necessary information for laser-manufacturing process optimization is lacking, including the melt pool depth and depth-to-width ratio. We propose a method for 3D temperature measurement based on orthogonal dual-channel single-camera spectral imaging. The 3D temperature field distribution of the melt pool can be obtained by collecting projected radiation data from two perpendicular angles. Use of a single monochrome camera for spectral imaging at three wavelengths ensures excellent spatial and temporal consistency during measurements. To verify the feasibility of the method, we measured the 3D temperature field in a melt pool of 304 stainless steel irradiated by a Gaussian laser beam (continuous laser, 500 W) with different irradiation times. The results indicate that the temperature field exhibits an approximately axisymmetric distribution on each cross-section at different depths. The temperature is highest in the center and gradually decreases around it. As the depth increases, the high-temperature area (>1730 K) gradually becomes smaller, and the temperature of each cross-section decreases. The maximum temperature, depth, width, and depth-to-width ratio of the melt pool at different times were obtained from the measured 3D temperature distributions. With an irradiation time of 0–80 s, the maximum temperature of the melt pool exhibited three stages: rapid increase (20–2230 K), slow increase (2230–2280 K), and stabilization. The growth of the width and depth of the melt pool indicated a similar process, increasing rapidly at first and gradually slowing. The depth-to-width ratio decreased rapidly at first and gradually stabilized. The proposed method for 3D temperature measurement has potential use in laser manufacturing for process control and quality improvement.

High-precision gaseous flame temperature field measurement based on quadriwave-lateral shearing interferometry

Quadriwave-lateral shearing interferometry (QLSI) has a broad utilization in quantitative phase imaging (QPI) for refraction-type objects due to its compact structure and stable performance against external disturbance. Here we propose to use the QLSI technique to image and measure the gaseous flame temperature field distribution in high precision. The quantitative phase image of an axisymmetric candle flame is firstly reconstructed from the wire-mesh-like QLSI interferogram, and then the three-dimensional temperature field distribution is calculated with the axisymmetric projection transform algorithm. Compared to the conventional digital holographic interferometry (DHI) based on Mach-Zehnder architecture, the proposed method possesses a high-precision measurement and better stability in disturbed environment, benefiting from the compact common-path structure of QLSI. The temperature measurement errors of the proposed QLSI method are ±5.0 K and ±5.3 K in the presence of airflow disturbance and mechanical vibration, respectively, while those of the DHI method are ±7.6 K and ±12.9 K, respectively.

Temperature Structures Associated with Different Components of the Atmospheric Circulation on Tidally Locked Exoplanets

Observations of time-resolved thermal emission from tidally locked exoplanets can tell us about their atmospheric temperature structure. Telescopes such as JWST and ARIEL will improve the quality and availability of these measurements. This motivates an improved understanding of the processes that determine atmospheric temperature structure, particularly atmospheric circulation. The circulation is important in determining atmospheric temperatures, not only through its ability to transport heat, but also because any circulation pattern needs to be balanced by horizontal pressure contrasts, therefore implying a particular temperature structure. In this work, we show how the global temperature field on a tidally locked planet can be decomposed into contributions that are balanced by different components of the atmospheric circulation. These are the superrotating jet, stationary Rossby waves, and the divergent circulation. To achieve this, we partition the geopotential field into components balanced by the divergent circulation and the rotational circulation, with the latter comprising the jet and Rossby waves. The partitioned geopotential then implies a corresponding partitioning of the temperature via the hydrostatic relation. We apply these diagnostics to idealized general circulation model simulations, to show how the separate rotational and divergent circulations together make up the total three-dimensional atmospheric temperature structure. We also show how each component contributes distinct signatures to the thermal phase curve of a tidally locked planet. We conclude that this decomposition is a physically meaningful separation of the temperature field that explains its global structure, and can be used to fit observations of thermal emission.

Simulation Research on Tightening Force and Temperature Distribution of Tension Clamps in Distribution Network

In order to study the effect of tightening torque on the temperature change of overhead line tension clamps and conductors, a structural model of NLL-4 tension clamps was established using COMSOL Multiphysics. Under the power frequency of 400-650A, the electromagnetic-thermal coupling finite element simulation analysis of the tension clamp was carried out by adjusting the tightening torque, and the three-dimensional temperature field distribution of the tension clamp and the wire was obtained. The results show that when 600A power frequency alternating current is applied, the tightening torque decreases continuously, and the overall temperature of the tension clamp and wire increases with the decrease of the torque. When the tightening torque is constant, different power frequency AC currents of 400-650A are applied, and the overall temperature of the tension clamp increases with the increase of the current; at the same time, no matter how the current and tightening torque change, the temperature of the extrusion part of the wire is always higher than the temperature of the unextruded part.

Study of the internal temperature of rigid polyurethane bodies using temperature sensors

This paper investigates the effect of filling polystyrene foam beads (EPS) on the foaming temperature regulation of rigid polyurethane (RPUF) composites and describes the temperature change process of the first 400 s of the foaming reaction for two systems with high foaming temperature and low foaming RPUF. Different contents of expandable EPS were used to regulate the foaming temperature of RPUF to reduce the internal structural defects of the composite foam material caused by excessive internal foaming temperature which is effectively optimized for its use and low cost. RPUF with HCFC-141B as the physical blowing agent and expandable EPS as the filler were studied. MATLAB software was used to simulate the foaming process of pure RPUF for both systems and to predict the foaming temperature. The comparison with experimental data was made, and it was concluded that the foaming temperature of pure RPUF was too high. In addition, the temperature of the EPS-doped PUF porous composites in the core region and the temperature variation of the upper and lower surfaces during the foaming process were measured using a probe temperature sensor. The internal temperature is represented by a three-dimensional temperature trapezoid. The maximum temperature of the foaming process decreases more rapidly with increasing EPS content. In addition, the high RPUF heat loss and the smaller EPS growth energy lead to an increase in the mass fraction.

Inversion of the Full-Depth Temperature Profile Based on Few Depth-Fixed Temperatures

Seawater temperature plays a key role in underwater acoustics and marine fishery, etc. In oceanographic surveys, it is often desirable to detect the temperature profile and obtain its spatio-temporal variation. The present study shows that the temperatures at the depths which are the three extreme points of the first two empirical orthogonal function (EOF) modes, contain the largest amount of information. Based on the back propagation (BP) neural network, a model for reconstructing the full-depth temperature profile using a few temperatures at fixed depth is established. The experimental result shows that the root mean square error (RMSE) of the temperature profile inversion in the test set is mostly less than 0.2 °C, and the three-dimensional temperature field obtained in this study is relatively reliable.

A semi-analytical approach for analysis of thermal behaviors coupling heat loss in powder bed fusion

The build-up of the heat losses induced by a high-temperature gradient during laser additive manufacturing process has a significant effect on the thermal behaviors and the formation of parts’ defect. In this paper, considering heat losses caused by conduction, convection and radiation, a semi-analytical model for predicting three-dimensional transient temperature field distributions is established, which is verified by comparison with results from the literature. The temperature distributions coupled with heat losses for typical surface and volumetric heat source models are obtained by using the separation of variables. The effect of process parameters and heat source model on peak temperature, temperature gradient, molten pool dimensions and heat losses is analyzed. In addition, the effect of the surface and volumetric heat source model on formation quality during the powder bed fusion (PBF) process is discussed in detail. The results show that higher average temperature and lower heat losses occur for the volumetric heat source model. Moreover, heat losses increase as the power, energy absorptivity and effective radius of the laser beam, while decrease with a decrease of scan speed. The results could be helpful to enable process optimization of the PBF to improve as-built parts quality.

Using infrared thermal imaging technology to estimate the transpiration rate of citrus trees and evaluate plant water status

Crop transpiration is the main dissipation way of agricultural water. Accurate and effective estimation of crop transpiration is of great significance for the study of the carbon-water cycle relationship and efficient water-saving irrigation. This study uses infrared thermal imaging technology to accurately extract the average temperature of the plant canopy as a key input for the new model (three-dimensional temperature (3D-3T) model), which is an extension of the three-temperature (3T) model and applied to estimate the canopy transpiration rate of typical citrus trees (variety named Guoqing No. 1) from 8:00 to 18:00 on May 7 to 11, 2021. And a processing method for extracting green plants in visible-light images based on the Normalized Difference Ratio Index (NDRI) is proposed for the first time, which can distinguish green plants from other ground objects, backgrounds, and shadows in the visible-light image, and then help to accurately extract the average canopy temperature from infrared thermal images. For this experiment, the canopy structure characteristics of the selected experimental subjects and the measurement methods used were considered, so the 3D-3T model was converted to a 5-point three-temperature model (5P-3T model) to estimate the canopy transpiration rate of citrus trees and evaluate the plant water status, and then the sap flow measurement was used for validation. The results showed that: (1) The 3T model overestimated the transpiration rate of the citrus tree, while the 5P-3T model underestimated it. The estimated values of the 5P-3T model have a good correlation with the measured values of the packaged stem sap flow gauge method, with a determination coefficient (R2) of 0.72 and root mean square error (RMSE) of 0.35 mm/d. (2) In this model, the plant transpiration transfer coefficient (hat) can evaluate the water shortage of plants, where the value of hat increased with the aggravation of plant water stress. (3) The citrus trees have lower transpiration rates under water stress, ranging from 0.06 to 0.12 mm/h in the daytime (from 8-10 May 2021). The model used in this study only needs the input of temperature information and net radiation, and would not depend on aerodynamic resistance. The method in this paper can realize the non-contact and non-invasive measurement of crop transpiration, and it provides a feasible way to use a portable thermal imager to accurately obtain the temperature for estimating plant canopy transpiration rate.

Wall-attached temperature structures in supersonic turbulent boundary layers

It is well known that low- and high-speed velocity streaks are statistically asymmetric. However, it is unclear how different the low- and high-temperature structures (T-structures) are even though they are strongly coupled with the streamwise velocity. Therefore, this paper identifies three-dimensional wall-attached temperature structures in supersonic turbulent boundary layers over cooled and heated walls (coming from direct numerical simulations) and separates them into positive and negative families. Wall-attached T-structures are self-similar; especially, the length and width of the positive family are linear functions of the height. The superposed temperature variance in both positive and negative families exhibits a logarithmic decay with the wall distance, while the superposed intensity of the wall-normal heat flux in the negative family shows a logarithmic growth. The modified strong Reynolds analogy proposed by Huang, Coleman, and Bradshaw [“Compressible turbulent channel flows: DNS results and modelling,” J. Fluid Mech. 305, 185–218 (1995)] is still valid in the negative family. The relative position between T-structures of opposite signs depends on the wall temperature and that in the cooled-wall case differs significantly from the relative position between low- and high-speed streaks, especially those tall ones. In the cooled-wall case, although positive temperature fluctuations below and above the maximum of the mean temperature can cluster to large-scale wall-attached structures, they are very likely dynamically unrelated.

Three-dimensional reconstruction of flame temperature and H2O concentration using water vapor integrated spectral band emission

Efficient and accurate reconstruction of flame temperature and species concentration is very useful for combustion monitoring. In this work, the integrated spectral band ratio (ISBR) method, which uses the ratio of two integrated spectral radiative intensities to infer temperature, is applied to reconstruct three-dimensional flame temperature and H2O concentration distributions. First, the ratio of two integrated spectral radiative intensities is justified by gas radiation theory to only depend on gas temperature, and the influence of gas concentration and pressure on the ratio is negligible. Then, a spectral band pair is carefully selected for the measurement with an atmospheric path between the detector and the flame. In the selected spectral bands, CO2 and CO emissions are negligible compared to H2O emission, and atmospheric absorption can be ignored. Meanwhile, gas temperature is monotonically related to the ratio of integrated spectral radiative intensities. When the uncertainty of the ratio is 2%, the error of reconstructed temperature is less than 38K with gas temperature close to 3000K, and the error decreases as the gas temperature goes down. Finally, numerical experiments on reconstruction of axisymmetric and non-axisymmetric flames are carried out. Results show that three-dimensional distributions of flame temperature and H2O concentration can be reconstructed with high accuracy.

Reconstruction Optimization Algorithm of 3D Temperature Distribution Based on Tucker Decomposition

For the purpose of solving the large temperature field reconstruction error caused by different measuring point arrangements and the problem that the prior dataset cannot be built due to data loss or distortion in actual measurement, a three-dimensional temperature profile reconstruction optimization algorithm is proposed to repair the empirical dataset and optimize the arrangement of temperature measuring points based on Tucker decomposition, the minimum condition number method, the greedy algorithm, and the hill climbing algorithm. We used the Tucker decomposition algorithm to repair the missing data and obtain the complete prior dataset and the core tensor. By optimizing the dimension of the core tensor and the number and position of the measuring points calculated by the minimum condition number method, the greedy algorithm, and the mountain climbing algorithm, the real-time three-dimensional distribution of the temperature field is reconstructed. The results show that the Tucker decomposition optimization algorithm could accurately complete the prior dataset, and compared with the original algorithm, the proposed optimal placement algorithm improves the reconstruction accuracy by more than 20%. At the same time, the algorithm has strong robustness and anti-noise, and the relative error is less than 4.0% and 6.0% with different signal-to-noise ratios. It indicates that the proposed method can solve the problem of building an empirical dataset and 3D temperature distribution reconstruction more accurately and stably in industry.

Comparison of Three Convolution Neural Network Schemes to Retrieve Temperature and Humidity Profiles from the FY4A GIIRS Observations

FY4A/GIIRS (Geostationary Interferometric Infrared Sounder) is the first infrared hyperspectral atmospheric vertical sounder onboard a geostationary satellite. It can achieve observations of atmospheric temperature and humidity profiles with high vertical and temporal resolutions. Presently, convolutional neural network algorithms are relatively less used in the field of atmospheric profile retrieval, and different convolutional neural network approaches have different characteristics. The one-dimensional convolutional neural network scheme 1D-Net and two three-dimensional retrieval schemes U-Net 1 and U-Net 2 are used to achieve atmospheric temperature and humidity profiles under all skies based on GIIRS-observed brightness temperatures in this paper. After validation with test training data, the retrievals of different schemes derived from actual GIIRS observations and level 2 operational products were verified with ERA5 reanalysis data and radiosonde measurements in summer and winter respectively. The retrieved three-dimensional temperature and humidity fields from U-Net 1 and U-Net 2 are closer to the ERA5 reanalysis field in both distribution and value than the retrievals from the 1D-Net scheme and level 2 operational products. In particular, the inversion field of the U-Net 2 scheme is more continuous in space. Compared with radiosonde observations, the accuracy of the level 2 temperature product is the highest when the field of view is completely clear both in winter and summer month. The root mean square error (RMSE) of temperature retrieval of the two U-Net schemes is the second highest, and the RMSE and bias of the 1D-Net scheme are both large. Two U-Net schemes overestimate the temperature and humidity slightly in winter and underestimate it in summer in both clear and all sky cases. Under all sky conditions, the temperature retrieval RMSE and bias of the two U-Net schemes above 800 hPa are lower than those of the level 2 products, especially the U-Net 2 scheme with an RMSE of approximately 2.5 K. The U-Net 2 scheme bias is the smallest, with a value of approximately 0.5 K in winter. Since the level 2 product only provides the atmospheric temperature above the cloud top, it indicates that its temperature product accuracy is very low when the field of view is influenced by clouds. The humidity retrieval RMSEs of the two U-Net schemes is within 2 g/kg, better than that of the 1D-Net scheme. The retrieval accuracy of the U-Net 2 scheme is approximately 0.3 g/kg better than that of the U-Net 1 scheme below 600 hPa in winter. Level 2 does not provide humidity products. The summer humidity retrieval is worse than in winter. In general, among the three deep machine learning algorithms, 1D-Net has a large retrieval error, and the temperature and humidity from U-Net 2 have the highest accuracy. The retrieval speeds of the two U-Net schemes are nearly the same, and both are faster than that of scheme 1D-Net.

Axial conduction in cross-flow heat exchangers: An analytical approach to the coupled heat transfer problem

Cross-flow heat exchangers are widely used in the process intensification and air separation industry. Its miniaturized versions are touted to be especially useful for aircraft heat exchange, portable cooling systems, and micro-combustion chambers for fuel cells. The desired thermal effect is often obtained in a cross-flow heat exchanger of a shorter length leading to a lower pressure drop penalty. Although miniaturization leads to high heat transfer to volume ratio, the low flow rates and large solid cross-section area to fluid free-flow area ratio might lead to intense axial conduction. Standard mathematical models for macro-scale exchangers neglect this effect and must be modified for micro-scale applications. While the analytical models are available for the counter-current exchanger, a similar analytical tool is missing for the cross-flow device. The present work attempts to develop such a tool, wherein, unlike previous attempts, a three-dimensional modelling approach is undertaken. The unique flow configuration in the cross-flow system necessitates this modification if both axial conduction and thermal resistance of the separating wall (missing in earlier two-dimensional attempts) are to be simultaneously tackled. The developed model can handle both balanced and unbalanced flows. Validations have been performed using conjugate computational studies (with exact geometry and solved in COMSOL), a simplified numerical model, and by comparison with some of the standard cross-flow expressions in the limit of no axial conduction. Results are presented in the form of three-dimensional temperature profiles, effectiveness-NTU (number of transfer units), and conduction effect factor curves for different flow and geometric configurations. It is found that the balanced cross-flow exchanger can experience performance deterioration of ∼45% at low flow rates. The fast convergence of the proposed theory allows it to be nested in heat exchanger optimization routines, where a detailed computational step would have led to prohibitive computational costs.

Reconstruction of ocean temperature and salinity profiles in the Northern South China Sea using satellite observations

Based on historical temperature and salinity (T–S) profiles, the correlation between the sea surface temperature (SST) anomaly, sea surface dynamic height (SSH) anomaly, and temperature profile anomaly is constructed by regression analysis. A three-dimensional temperature field is reconstructed in the northern South China Sea by satellite SST and SSH, with daily temporal and 0.25°×0.25° spatial resolutions. The three-dimensional salinity field is also reconstructed based on the correlation between salinity and temperature. Compared with the observational T–S profiles, the reconstructed T–S field reflects the characteristics and structure and accurately describes the mesoscale variability of the ocean temperature field. The new expanded T–S field can be used as the initial field in numerical models and be assimilated into numerical reanalysis and prediction systems, improving their output.

Efficiency analysis and heating structure design of high power electromagnetic thermal energy storage system

Based on the principle of electromagnetic induction, this paper proposes a new sleeve structure of electromagnetic induction heating energy storage system, which converts the electrical energy that cannot be consumed by wind power, solar power and other power grids into heat energy. The electromagnetic induction heating model of the eddy current field is established by Ansoft/Maxwell, and the magnetic induction intensity, current penetration depth and current frequency are analyzed. The three-dimensional fluid temperature field and its corresponding temperature characteristics of the system are analyzed by Ansys/Fluent. The temperature field cloud diagram of the sleeve is analyzed. It is concluded that with the increase of air thickness, the loss of the internal iron pipe increases, and the loss of the middle iron pipe decreases. The characteristic curve of the resonant circuit of the electromagnetic induction heating power supply is simulated and analyzed to determine the optimal parameters of the resonant circuit of the induction heating. A 100 kW electromagnetic energy storage system is developed, and the effectiveness and practicability of the method are verified, which can be applied to high power thermal energy storage.

Comparative Study on Water Temperature Stratified Flow under Different Vertical Coordinate Systems in Delft3D

Reservoirs often suffer from water blooms, which are likely related to the hydrodynamic and water temperature characteristics of the tributary bays. To obtain the detailed changing process of hydrodynamics and water temperature stratification, it is necessary to choose a suitable vertical coordinate system in order to achieve the required precision. Based on a physical model experiment of cold water flowing into the Generalized Reservoir Hydraulics (GRH) flume, both the σ-coordinate system model and the z-coordinate system model are built for comparison. For the z-coordinate system model, the influences of different grid resolutions and different bottom slopes on the simulation accuracy are also analyzed. The results show that the σ-coordinate system model can simulate cold-water underflow in a reservoir better than the z-coordinate system model, and the numerical errors of the z-coordinate system model can be reduced but not eliminated by increasing the horizontal grid resolution. When the bottom slope of the reservoir is less than 18‰, the z-coordinate system model can also be used to simulate cold-water underflow in a reservoir. The conclusions about vertical coordinate systems can be applied to the development of a three-dimensional hydrodynamic and water temperature model of reservoirs.

Adaptive digital twins of combustion systems using sparse sensing strategies

This work proposes to implement a sparse sensing framework to build a hybrid numerical-experimental Digital Twin of a practical combustion system. The goal is to find the optimal sensor placement that minimizes the prediction error, and to predict the distribution of reacting scalars using few measurements. Three-dimensional CFD simulations with detailed chemistry were used to build the design space by varying the fuel composition (from pure methane to pure hydrogen), the equivalence ratio (from 0.7 to 1) and the air velocity. The Proper Orthogonal Decomposition (POD) was applied to the numerical data to find a tailored basis for dimensionality reduction. Then, the QR decomposition with column pivoting was applied to the tailored basis to find the optimal sensor placement. Finally, the model was employed to predict the three-dimensional temperature distribution in the unexplored part of the design space, using the experimental samples as input. The optimal placement of the sensors provides valuable information on the key locations and features, which can then be used in the design of reactor network models, for example. Also, the results show that the hybrid Digital Twin could predict an adjusted temperature distribution which reduces the error with the experimental measurements, when compared to the original CFD temperature distribution.

Measuring Thermal Diffusivity of Orthotropic Materials by Multidimensional Constant-Temperature Boundary Method

A method for measuring thermal diffusivity of orthotropic materials by using multidimensional heat transfer model combined with parameter estimation is proposed. The unsteady mathematical model of three-dimensional temperature field is established by heat conductivity product method, the thermal diffusivity is calculated by random conjugate gradient method, and the thermophysical property testing system is developed. The constant-temperature boundary is constructed by using a constant-temperature water bath box combined with graphene stickers wrapped on the surface of the sample, the insulation material covers the upper surface of the sample to construct an insulating boundary, and thermocouples are arranged on the upper surface to monitor the temperature rise change. First, isotropic materials, such as acrylic plate and marble, were tested. Compared with a reference value, the maximum relative deviation of thermal conductivity was 3.72%, which verified the feasibility and accuracy of the test method. Furthermore, the orthotropic-material unidirectional carbon fiberboard was tested. Compared with the results measured by improved parallel hot-wire method, the relative deviations of thermal diffusivity, thermal conductivity, and specific heat capacity were 3.66, 1.59, and 2.15%, respectively, which indicate that this test method could meet the thermophysical testing requirements of orthotropic materials.

Experimental Study on the Fracture Toughness of Granite Affected by Coupled Mechanical-Thermo

Abstract Hot dry rock geothermal energy is deep geological energy. Its ability to resist fracture is an important basis for effective reconstruction and scientific evaluation of the stability of geothermal reservoirs. Hot dry rock is typically buried deeply, and the reservoir is often in a high-temperature and high stress environment. There have been limited studies conducted on the effect of different three-dimensional stress and temperature on granite fracture toughness. Thereby, herein an experimental study is conducted on the heat treatment of granite under different external loads and temperatures. The variation in fracture toughness of granite with temperature and pressure is studied using a three-point bending fracture mechanics experiment, scanning electron microscope (SEM) observation, and acoustic wave velocity measurement. The results show that under the joint influence of 25 MPa deviator stress and 200 °C temperature, the Mode I, Mixed mode (I + II), and Mode II fracture toughness of granite show a nonlinear change trend of decreasing and increasing. Among the three modes, the change range of Mode I fracture toughness is not more than 10% which is not significant. Contrarily, the degradation effect of rock mechanical properties caused by the joint action of stress and temperature in Mode II and Mixed mode (I + II) is predominant. The maximum range of Mode II fracture toughness is reduced by 22%, whereas the maximum range of Mixed mode (I + II) fracture toughness is reduced by 18%. However, the compression action of three-dimensional stress causes a slight enhancement in granite mechanical properties, wherein the maximum range of Mixed mode (I + II) fracture toughness is increased by 12%. Furthermore, the change of granite’s ability to resist tensile, shear, and composite (tensile + shear) fracture is not coordinated under the joint action of different temperatures and external loads. This may be due to the small deviator stress effect, which is similar to the early loading stage of uniaxial compression. External loads and thermal stress damage occur in the rock along with the compaction of pore cracks. These mechanisms have different dominant positions under varied temperature and three-dimensional stress coupling conditions, resulting in either the enhancement or weakening of the mechanical properties of granite. The results of this experimental study are conducive to gaining an in-depth understanding of the change law of deep rock mechanical properties and the exploration of hot dry rock reservoir reconstruction.

Fast prediction model of three-dimensional temperature field of commercial complex for entrance-atrium temperature regulation

Based on the status quo of poor winter thermal comfort of commercial complexes, we developed a three-dimensional temperature prediction model for the typical space of commercial buildings, the “Entrance-Atrium”. A database of 4500 samples was built by using computational fluid dynamics to simulate different spatial deformations and wind environments based on typical models. The simulation method was verified by on-site measurement. Two indicators, Cr (Compliance rate of temperature) and Tr (Temperature resistance index), were defined to evaluate the thermal environment performance of the spatial form. And S (spatial performance score) was used for the comparison of architectural design schemes. In order to achieve rapid temperature prediction, the simulation database was reconstructed and expanded by artificial neural network algorithm, and then the three-dimensional temperature prediction model was constructed. The prediction model may be applied for thermal environment prediction and architectural design optimization for key spaces. Meanwhile, we have expanded its application in air conditioning supply volume adjustment and verified its reliability through practical cases. This study may provide a reliable basis for architects and engineers to make critical decisions, helping optimize the thermal environment through a combination of active and passive methods in the entire process from building design to operation, and improve the utilization efficiency of building operation energy consumption.