Thermal Deviation Research Articles

Research and thermal comfort analysis of the air conditioning system of the Ferris wheel car based on thermoelectric cooling

To solve the problem of thermal discomfort caused by the lack of cooling facilities on the Ferris wheel and to investigate the effect of the coupling effect of thermoelectric modules on the thermoelectric cooling (TEC) system, this paper proposes a two-module thermoelectric cooling and air-conditioning system that can be applied to the Ferris wheel. Firstly, the experimental platform was established to test the performance parameters of the TEC system and reveal the influence of the thermoelectric module (TEM) coupling effect on the system performance. Then, the thermal environment inside the Ferris wheel was simulated using the CFD method and human thermal comfort was evaluated. The results show that when the voltage of TEM1 and TEM2 is 10V and 6V respectively, the thermoelectric cooling and air-conditioning system has the best working performance, and the coefficient of performance (COP) is 0.43. And the human thermal comfort deviation AEQT is 0.29, which is in a comfortable state under the action of the air-conditioning system.

Proactive Prevention Strategies for Grid Risk Scenarios Based on Pumped Storage Participation

Given the increasing importance of cascading trip prevention, this study presents the pumped storage characteristics to cooperate with thermal units and further ensure the safety of grid operation. The proposed model comprises two phases: the first phase is the day-ahead decision-making phase, which synergistically optimizes thermal units and pumped storage to improve the flexibility of grid operation; the second phase is the intra-day adjustment phase considering the uncertainty of the wind-photovoltaic and transmission line failure outage to enhance the robustness. Furthermore, this model employs a column and constraint generation algorithm to solve the two-phase, three-layer optimization problem, thereby minimizing the adjustment cost under the riskiest scenarios. The experimental results show that adding pumped storage reduces the total system operating cost by 3.99%, the renewable energy abandonment rate to 0.65%, and the thermal power unit output standard deviation to 74.13 MW.

Thermal deviation mechanisms for coupled heat transfer between the combustion side and the furnace tube side in the tubular heating furnace

Temperature deviation significantly affects the safe operation of tubular heating furnaces. This is attributed to the inevitable temperature difference between the flue gas and the working medium on the tube side. To date, little research has considered the dynamic heat transfer between the furnace body and the tubes in tube furnaces, and even less attention has been paid to the thermal deviation within tube furnaces. To optimize the operational parameters of the heating furnace, a comprehensive heat transfer model is established in this paper to numerically couple the heat transfer between the combustion side and the working medium on the tube side in tube furnaces. A hydrogenation feed heating furnace with a processing capacity of 600,000 tons per year in a chemical enterprise is selected as the subject of study. Using Fluent software, on the basis of coupled simulation, a non-uniformity coefficient of temperature distribution is introduced to characterize the thermal deviation within the furnace. The impact of the thermal load and hydrogen doping in the fuel gas on the thermal deviation within the furnace is analyzed. The numerical results demonstrate that with an increase in thermal load, the flame structure in the furnace gradually becomes concentrated, the average temperature of the flue gas increases, and the outlet temperature of the furnace chamber increases by 19%, with the thermal efficiency decreasing by 5.11%; at the same time, the overall non-uniformity coefficient of the temperature distribution in the furnace fluctuates irregularly, indicating a nonlinear relationship between the thermal load and the thermal deviation within the furnace. With an increase in the hydrogen content in the fuel gas, the flame structure in the furnace becomes more dispersed, the average temperature of the flue gas increases, but the combustion efficiency of the heating furnace exhibits irregular fluctuations; the thermal deviation within the furnace initially increases and then decreases, with a lower non-uniformity coefficient of temperature at 50% hydrogen content, which is 2.48% lower than at 40% hydrogen content. Under both conditions, the thermal deviation primarily leads to localized hot spots in the radiant furnace tubes and uneven temperature distribution in the convection section, with a minimal impact on the thermal efficiency of the heating furnace.

Thermodynamic and transport properties of binary mixtures containing 1,2-propanediol with 2-methoxyethanol and 2-ethoxyethanol at different temperatures

In the present investigation density, speed of sound, and viscosity have been reported for binary liquid mixtures of 1,2-propanediol (1,2-PD) with 2-methoxyethanol (2-ME) and 2-ethoxyethanol (2-EE) over the entire composition range at T= (298.15–323.15) K. From the experimental data, excess molar volume, (VmE), excess isentropic compressibility, (κsE), excess molar isentropic compressibility, (κs,mE), excess speed of sound, (uE), excess isobaric thermal expansion,αpE, and deviation in viscosity (Δη) of liquid mixtures have been calculated. The excess partial molar volume,V¯m,1E, V¯m,2E , excess partial molar isentropic compressibility, K¯s,m,1EK¯s,m,2E over the whole composition range together with partial molar volume,V¯m,10, V¯m,20, partial molar isentropic compressibility K¯s,m,10,K¯s,m,20, excess partial molar volume,V¯m,10E, V¯m,20E and excess partial molar isentropic compressibility, K¯s,m,10E,K¯s,m,20E at infinite dilution have also been calculated. All excess properties have been correlated using the Redlich-Kister smoothing polynomial equation. The VmE results are analysed in the light of Prigogine-Flory-Patterson theory. Analysis of each of the three contributions viz. interactional, free volume, and P* to VmE has shown that interactional contribution and free volume effect are negative for all the mixtures, and P* contribution is positive for the mixtures of 2-ME. The variations of these parameters with changes in composition and temperature have been discussed in terms of intermolecular interactions prevailing in these mixtures. Further, the viscosities of these binary mixtures were correlated theoretically by using various empirical and semi-empirical models and the results were compared with the experimental findings.

A quantification and classification framework for water temperature variation features induced by climate change and reservoir construction and operation: Application to the middle Yangtze River

AbstractRiverine water temperature (WT) is a crucial factor affecting habitat quality and ecological effect of aquatic ecosystems. To accurately quantify and classify WT variation features caused by climate change and reservoir construction and operation, a framework was developed that integrates multivariate vine copula model for accurately reconstructing the WT process and general evaluation indicators for comprehensively characterizing of WT variation. In this framework, month‐wise R‐vine copula models were employed to depict the multivariate dependence structure between WT and related hydrometeorological factors, and the change of WT process in the fluctuation range and thermal deviation was analogized as the change of simple harmonic wave in amplitude and phase. A testing‐oriented application of this framework in Yichang section of the Yangtze River highlighted that climate change and the Three Gorges Reservoir (TGR) dominated or participated in the fluctuation range changing and phase deviation of different monthly WT processes, as the ratios of affected months were 1.08:1 and 1.25:1 during the construction phase, and 1:2 and 1:1.28 during the operation phase. WT process also exhibited diverse monthly variation trends during construction and operation phases of the TGR. Therefore, it is inappropriate to neglect the impact of the TGR construction phase and climate change on WT variation. The proposed framework achieved systematic quantification and attribution analysis of WT variation, thereby providing an enhanced understanding of the variation characteristics of river thermal regimes under the individual and combined effects of climate change and artificial reservoir. Considering the significant influence of WT variation on aquatic organism reproduction, the identification of the sources and categories of monthly WT variation can also serve as a foundation for future targeted thermal and hydrological regime regulation, aiming to protecting aquatic species and preventing biodiversity loss.

Lithium-Ion Batteries (LIBs) Immersed in Fire Prevention Material for Fire Safety and Heat Management

Lithium-ion batteries (LIBs) have emerged as the most commercialized rechargeable battery technology. However, their inherent property, called thermal runaway, poses a high risk of fire. This article introduces the “Battery Immersed in Fire Prevention Material (BIF)”, the immersion-type battery in which all of the LIB cells are surrounded by a liquid agent. This structure and the agent enable active battery fire suppression under abusive conditions while facilitating improved thermal management during normal operation. Abuse tests involving a battery revealed that the LIB module experienced fire, explosions, and burnouts with the target cell reaching temperatures of 1405 °C and the side reaching 796 °C. Conversely, the BIF module exhibited a complete lack of fire propagation, with temperatures lower than those of LIBs, particularly 285 and 17 °C, respectively. Under normal operating conditions, the BIF module exhibited an average temperature rise ~8.6 times lower than that of a normal LIB. Furthermore, it reduced the uneven thermal deviation between the cells by ~5.3 times more than LIB. This study provides a detailed exploration of the BIF and covers everything from components to practical applications. With further improvements, this technology can significantly enhance fire safety and prevent the thermal degradation of batteries in the real world.

Thermal Management for a Stadium Power Supply Container Using a Rack-Level Air Cooling Strategy

This study investigates the airflow and thermal management of a compact electric energy storage system by using computational fluid dynamic (CFD) simulation. A porous medium model for predicting the flow resistance performance of the battery modules in a battery cabinet is developed. By studying the influence of rack shapes, the effects of heat exchanger arrangements and other parameters on the airflow and battery thermal distribution are analyzed. When applying a larger bottom air channel, the inlet flow uniformity of each battery cabin in the cabinet increases by 5%. Meanwhile, temperature standard deviation decreases by 0.18 while raising the flow rate from 3 m/s to 8 m/s, indicating better temperature uniformity in the battery cabin. When the charge–discharge ratio reaches 0.5 C, the temperature deviation of the entire cabinet significantly increases, reaching 8 K. Furthermore, a rack-level thermal management scheme is proposed to effectively reduce the thermal deviation of the container electric energy storage system and improve the overall temperature uniformity. Results reveal that the rack-level thermal management of the wavy cabinet in the electric storage container can effectively improve the thermal uniformity of the distributed battery cabin, and the overall thermal deviation is controlled within 1.0 K.

Numerical and Experimental Study on Nonlinear Phenomena and Thermal Deviation Control in a 1000 MW Tower-Type Boiler

Numerical and experimental studies were conducted to study the nonlinear phenomena of a 1000 MW ultra-supercritical four-corner tangential pulverized coal boiler. In this paper, (1) a 3D model of a furnace with a symmetrical structure was established to analyze the asymmetric flow phenomenon and multi-solution phenomenon of flow for multiple timepoints under the same boundary conditions. (2) The visual experiment verified that the flow in the furnace also behaved asymmetrically. (3) On the basis of correctly predicting the nonlinear law, the “diagonal start up” method and the “sequential start up” method are proposed. (4) An uneven coefficient of velocity distribution M, deviation coefficient of flue gas mass flow rate Eq and gas temperature deviation coefficient ET are proposed to quantitatively analyze the degree to which the actual tangent circle deviates from the ideal tangent circle. The tangent circle under the “sequential start up” method is the closest to the ideal, which can reduce the thermal deviation of the furnace outlet from 67 K under the “simultaneous start up” method to 41 K. In this paper, the initial steady-state flow field in the furnace is established by using the initial value sensitivity of the nonlinear system through different burner-opening methods, so as to reduce the thermal deviation at the furnace outlet and achieve the purpose of accurate control.

Characteristics analysis and structure optimization of a hybrid micro-jet impingement/micro-channel heat sink

To solve the heat dissipation problem of high-power electronics, a novel hybrid micro-jet impingement/micro-channel heat sink is proposed in this work. Different from the continuous and straight rectangular micro-channel, the inclined and interrupted channel walls (fins) are adopted to enhance the fluid disturbance inside the heat sink. To obtain the thermal–hydraulic performance of the hybrid heat sink, an overall 3D modeling and numerical simulations are conducted instead of local cell numerical simulation. In addition, to further improve the heat transfer and flow resistance performance, the effects of variation of structural parameters on heat transfer and flow resistance properties are investigated, including the fin inclination angle, fin length and fin height. The results of structural parametric analysis reveal that there are interactions between different structural parameters, but with different levels of significance for different evaluation indicators. Then, to obtain the optimal combinations of structural parameters for different applications, the multi-objective genetic algorithm coupled with artificial neural network (ANN) is utilized to search for the optimal value of each structural parameter. The heat transfer thermal resistance, pressure drop and mean absolute temperature deviation of the heated surface are utilized as the optimization objectives to evaluate the cooling and resistance characteristics. The optimization results obtained by three-objective optimization and two-objective optimization are analyzed and compared. Finally, seven optimal compromise solutions are selected from the Pareto front by using TOPSIS algorithm with different weight factor matrices. For the optimal compromise solutions, the maximum relative errors between the predicted values of the ANN and numerical simulation values are only 3%, which further demonstrates the accuracy of the artificial neural network model and the effectiveness of using multi-objective optimization to guide heat sink design.

Investigation of thermomagnetic convective flow in vertical layers between water and kerosene based magnetic fluids

In this article, the convective flow in a vertical layer subjected to a consistent magnetic field with nonzero gravity condition is investigated. One side of the vertical walls is heated, while the opposite side is cooling. The magnetic field strength, field orientation angle, magnetization effect, and thermal deviation of vertical walls play important roles as controlling parameters on the flow stabilization. The goal of this investigation is to analyze the flow characteristics and find out the significant distinction between water and kerosene based magnetic fluids under the variation of thermal and magnetic effects. The numerical results are obtained by the pseudo-spectral Chebyshev expansion method. The properties of all instability modes caused by three major mechanisms, namely; thermomagnetic, thermogravitational and magneto-gravitational are analyzed. In the normal magnetic field, the wave speed responds faster, and it is recognized by a relatively small wave number in water based fluid than that in kerosene based fluid. In oblique magnetic field, the waves propagate faster in both kerosene and water based fluids with the field inclination angle increases, but they still propagate slower in kerosene based fluid comparatively in water based fluid. According to the linear or non-linear magnetization law, both upward and downward propagating waves in kerosene based fluid propagate slower, and they are recognized by greater wave numbers than that in water based fluid. It is found that the basic flow in water based fluid is much more stable than in kerosene based fluid.

Numerical simulation and experimental application of a 300 MW boiler combustion system

In the actual operation of a 300 MW boiler, there are some problems such as unstable combustion, high combustible material of fly ash and slag, and large thermal deviation on both sides of steam. The Cooper method is used to divide the three parts of the furnace by a hexahedral structured grid, which can reduce the grid number and improve the numerical simulation calculation precision. The Realization k-ε turbulent model is used to simulate the gas-solid two-phase flow in the furnace before and after reconstruction. The boundary of the calculation model adopts the actual operating parameters, and the numerical calculation adopts the three-dimensional steady-state calculation - Simple algorithm. The conclusions are as follows: the amount of pulverized coal powder falling into the cold ash hopper is reduced from 0.077 kg/m3 before the reconstruction to 0.045 kg/m3 after the reconstruction, with a decrease of about 42%. The secondary air concentration arrangement in the lowest two layers strengthened the secondary air supporting capacity. The residence time of pulverized coal particles in the furnace is increased from 30.59 s before the reconstruction to 39.97 s after the reconstruction, and the time is extended by about 9.4 s, which is beneficial to the combustion of pulverized coal particles. The centralized arrangement of primary air in the lowest two layers is beneficial to the initial ignition and stable combustion of pulverized coal gas. The downdip of the tertiary air incidence angle reduces the rotational momentum of the tertiary airflow, and the increase of the rotational momentum of the over-fire air angle is conducive to weakening the residual rotation at the furnace outlet. After the implementation of the reconstruction measures, the boiler can be stably burned at 150 MW, the combustible material of fly ash and slag are reduced to the controllable range, the steam thermal deviation is significantly reduced, and the boiler operating parameters are stable.

Analyses and Research on a Model for Effective Thermal Conductivity of Laser-Clad Composite Materials

Composite materials prepared via laser cladding technology are widely used in die production and other fields. When a composite material is used for heat dissipation and heat transfer, thermal conductivity becomes an important parameter. However, obtaining effective thermal conductivity of composite materials prepared via laser cladding under different parameters requires a large number of samples and experiments. In order to improve the research efficiency of thermal conductivity of composite materials, a mathematical model of Cu/Ni composite materials was established to study the influence of cladding-layer parameters on the effective thermal conductivity of composite materials. The comparison between the model and the experiment shows that the model’s accuracy is 86.7%, and the error is due to the increase in thermal conductivity caused by the alloying of the joint, so the overall effective thermal conductivity deviation is small. This study provides a mathematical model method for studying the thermodynamic properties of laser cladding materials. It provides theoretical and practical guidance for subsequent research on the thermodynamic properties of materials during die production.

Laser induced graphene based high-accurate temperature sensor with thermal meta-shell encirclement

Accurate temperature measurement is critical in various fields, particularly in new energy vehicle power batteries and biomedicine. However, placing a temperature sensor in a thermal field can cause perturbations that lead to inaccuracies in measurement, which can have severe consequences. To address this issue, a Laser-induced graphene (LIG) based meta-shell encircled temperature sensor was proposed that takes advantage of the controllable thermal conductivity of LIG. The sensor's thermal measurement capabilities are theoretically analyzed, and the proposed approach is shown to eliminate thermal perturbations caused by the mismatch between the sensor and background, resulting in more accurate measurements. The effects of different laser processing parameters on the alteration and enhancement of LIG thermal conductivity have also been experimentally demonstrated for constructing the thermal meta-shell. The high-accuracy of the proposed sensor was experimentally verified by comparing the temperature differences with a bare sensor. The meta-shell encircled sensor showed a maximum thermal deviation of only 0.21 K, while the bare sensor produced a deviation of 1.55 K. Furthermore, the LIG-based sensor can maintain high accuracy in a high-temperature environment exceeding 410 K, and its stability and repeatability have been experimentally verified. The sensor also shows a fast response time of 1.15 s and can maintain accurate temperature measurement under large curvature (0.4 m−1), insensitive to humidity and vibration, proving its applicability in complex situations. The proposed LIG-based meta-shell encircled temperature sensor is manufactured through laser direct writing method and is easy to mass-produce, making it highly promising for high-accurate temperature monitoring applications.

Thermal environment evaluation and thermal comfort zone deviation ——a case study of Chinese seaweed house in summer

Renewing the vitality of traditional ecological dwellings in the context of global carbon peaking and carbon neutrality targets has become one of the important topics in today's building sustainability research, and the evaluation of thermal comfort in traditional dwellings is the key to it. In this paper, one of the most representative ecological dwellings in the world, the “Seaweed House”, was selected as the research object. Firstly, the physical environment of a seaweed house in Dazhuang Xujia Village was measured from July 29 to August 3, 2022. Secondly, a thermal comfort questionnaire was conducted to grasp the current information of the thermal comfort in seaweed house. The results show that:1. The humidity of seaweed houses in summer is too high. 2. Residents have a thermally neutral temperature of 26.9 °C, an acceptable temperature region of (24.8–29.1 °C), and a thermally desired temperature of 25.8 °C. 3. The adaptive predicted mean vote (APMV) model suitable for thermal comfort evaluation of seaweed houses was developed. The results of the study provide a precise theoretical guide for the study of thermal comfort evaluation models in this region, and a useful reference for the study of the renewal and renovation of the seaweed houses.

Optimal Power Flow for Hybrid AC/DC Electrical Networks Configured With VSC-MTDC Transmission Lines and Renewable Energy Sources

This article presents the single objective optimal power flow (OPF) formulation incorporating both renewable energy sources, and voltage source converter-based multiterminal direct current transmission lines, simultaneously. To solve the formulated OPF problem, powerful metaheuristic optimization algorithms including adaptive guided differential evolution, marine predators algorithm, atom search optimization, stochastic fractal search (SFS), and fitness-distance balance-based SFS (FDB-SFS) are employed. The performance of the algorithms is tested for the minimization of fuel cost, pollutant emissions of thermal generators, voltage deviation, and active power loss in a modified IEEE 30-bus power network. The simulation results give that FDB-SFS achieved the best results on the fuel cost (786.5361 $/h), the fuel cost with valve point effect (815.6644 $/h), and the fuel cost with emission-carbon tax (820.5991 $/h). In addition, FDB-SFS reduced voltage deviation and active power loss values by 14.2587% and 6.7438% compared to SFS. The nonparametric Wilcoxon and Friedman statistical test results confirmed that FDB-SFS is an effective and robust algorithm that can be used in the optimization of the introduced OPF problem.

Prediction of tube temperature distribution of boiler platen superheater by a coupled combustion and hydrodynamic model

The platen superheater of boiler is prone to tube overheating in comparison to other boiler heating surfaces. The resultant tube failures seriously affect the safe operation of boilers. The tube temperature of boiler is determined by the “heating” of the gas flow in the furnace and the “cooling” of the steam flow in the tubes. In order to incorporate the effects of both the gas and steam flows of boiler on tube temperature, this paper presented a coupled combustion and hydrodynamic model in which the gas flow in the furnace is simulated by a three-dimensional CFD model while the steam flow in the tubes is simulated by a one-dimensional hydrodynamic model. The two models are coupled by iteratively exchanging the data of boiler gas heat flux and steam temperature. This coupled model was applied to predict the tube temperature distributions of the platen superheater of a 600 MW boiler and investigate the effects of boiler load and superheater design on the tube temperature and overheated tube areas. The results showed close agreement with the measured values and incorporated the critical effects of both the gas thermal deviation and steam flow maldistribution on the tube overheating of the platen superheater.

Qualify a NIR camera to detect thermal deviation during aluminum WAAM

This paper proposes to qualify the minimal quality deviation that can be detected by a near-infrared camera during aluminum wire arc additive manufacturing. First, a review of the literature is done to highlight the interest in monitoring the melt pool in industrial condition for thermal management during manufacturing. It points out the relevance of the use of a near-infrared camera for steels, but it has to be demonstrated for aluminum alloys. Indeed, the melt pool of the aluminum is significantly dimmer and less distinct than the melt pool of the steels. An experimental design is proposed to qualify the minimal quality deviation that can be detected on a thin wall. The chosen default to correlate with the thermal deviation is the width of the wall. A method is proposed to extract a thermal metric from the camera image and to analyze its sensitivity to a width deviation of the wall. The paper shows the correlation between the width of the wall and the thermal metric for different heat conditions. Moreover, the thermal metric is sensitive to width deviation either on the wall scale or on the bead scale. It indicates the relevance of a near-infrared camera to detect heat accumulation-induced width deviation during wire arc additive manufacturing of aluminum alloy.

A quantitative evaluation model of outdoor dynamic thermal comfort and adaptation: A year-long longitudinal field study

The understanding of human outdoor thermal comfort demand and thermal adaptation contributes to sustainable urban design as well as city resilience in the context of human health and wellbeing. Humans' past thermal experience influence their outdoor thermal comfort. However, the quantitative relationship between the past thermal experience and outdoor thermal comfort is still not clear. This study aims to reveal quantitative relations of the impact of people's past thermal experience on adaptive thermal comfort and to develop a new outdoor adaptive thermal comfort model. A year-long longitudinal questionnaire survey along with a combination of outdoor thermal environment campaigns was carried out in Chongqing, China. It began on August 15, 2020, and finished on August 19, 2021. Through the analysis of 2240 valid responses to the questionnaire survey, the outdoor thermal adaptation characteristic and dynamic thermal comfort evaluation of the respondents were revealed. The results show that the quantified temperature of past outdoor thermal experience is the quadratic correlation with the thermal sensitivity coefficient and deviation constant, and the linear correlated with outdoor thermal demands. Based on the quantitative analysis, a new outdoor adaptive thermal comfort model has been developed as a function of the exponentially weighted sum of historical mean air temperature series (MeanTrm). The outdoor adaptive thermal comfort zones by 80% and 90% satisfactions thereby have been first drawn based on the Universal Thermal Climate Index (UTCI). The study developed a methodology for the evaluation of dynamic outdoor thermal comfort which can be used for different climate regions.

Computational Analysis of Tube Wall Temperature of Superheater in 1000 MW Ultra-Supercritical Boiler Based on the Inlet Thermal Deviation

Local over-temperature is one of the main reasons for boiler tube failures (BTF). By accurately monitoring and controlling tube wall temperature, local over-temperature can be avoided. Based on the measured flue gas parameters and numerical simulation, a method of thermal deviation calculation is proposed in this study for the on-line calculation of the tube wall temperature of boiler superheaters. The full-size three-dimensional numerical simulation was presented on the combustion in a pulverized coal-fired boiler of 1000 MW ultra-supercritical (USC) unit. A difference in the thermal deviation of the vertical direction was innovatively introduced into a segmented discrete model, and the thermal deviation condition conforming to reality was introduced into the calculation. An on-line calculation system developed based on the current calculation method was applied in a 1000 MW USC unit. The calculated local high-temperature zone was consistent with the actual over-temperature position and conformed to the law of the allowable metal temperature of the final superheater (FSH) serpentines segment. The comparison results showed that the calculated data by this method were more reflective of tube wall temperature change with boiler loads than the measured data. According to the calculated local over-temperature zone, the immediate warning response can effectively reduce the possibility of over-temperature BTF.

Role of brown adipose tissue in phlegm-dampness metabolic syndrome based on infrared thermal imaging

This study aimed to explore the infrared manifestation and role of brown adipose tissue(BAT) in phlegm-dampness me-tabolic syndrome(MS), and to provide objective basis for clinical diagnosis and treatment of phlegm-dampness MS. Subjects were selected from the department of endocrinology and ward in the South District of Guang'anmen Hospital, China Academy of Chinese Medical Sciences from August 2021 to April 2022, including 20 in healthy control group, 40 in non phlegm-dampness MS group and 40 in phlegm-dampness MS group. General information, height and weight of the subjects were collected and body mass index(BMI) was calculated. Waist circumference(WC), systolic blood pressure(SBP) and diastolic blood pressure(DBP) was measured. Triglyceride(TG), high density lipoprotein cholesterol(HDL-C), fasting blood glucose(FBG), fasting insulin(FINS), leptin(LP), adiponectin(ADP) and fibroblast growth factor-21(FGF-21) were detected. The infrared thermal image of the supraclavicular region(SCR) of the subjects before and after cold stimulation test was collected by infrared thermal imager and the changes of infrared thermal image in the three groups were observed. In addition, the differences in the average body surface temperature of SCR among the three groups were compared, and the changes of BAT in SCR were analyzed. The results showed compared with the conditions in healthy control group, the levels of WC, SBP, DBP, TG and FPG in MS groups were increased(P<0.01), and the HDL-C level was decreased(P<0.01). Compared with non phlegm-dampness MS group, phlegm-dampness MS group had higher conversion score of phlegm dampness physique(P<0.01). According to the infrared heat map, there was no difference in the average body surface temperature of SCR among the three groups before cold stimulation. while after cold stimulation, the average body surface temperature of SCR in MS groups was lower than that in healthy control group(P<0.05). After cold stimulation, the maximum temperature of SCR and its arrival time in the three groups were as follows: healthy control group(3 min)>non phlegm-dampness MS group(4 min)>phlegm-dampness MS group(5 min). The thermal deviation of SCR was increased and the average body surface temperature of left and right sides were higher(P<0.01) in healthy control group and non phlegm-dampness MS group, while the thermal deviation of SCR did not change significantly in the phlegm-dampness MS group. Compared with that in healthy control group, the elevated temperature between left and right sides was lower(P<0.01, P<0.05), and compared with that in non phlegm-dampness MS group, the elevated temperature of left side was lower(P<0.05). The changes of the average body surface temperature of SCR in the three groups were in the order of healthy control group>non phlegm-dampness MS group>phlegm-dampness MS group. Compared with the conditions in healthy control group and non phlegm-dampness MS group, FINS, BMI and FGF-21 levels were increased(P<0.01,P<0.05), while ADP level was decreased(P<0.01, P<0.05) in phlegm-dampness MS group. Moreover, the LP level in phlegm-dampness MS group was higher than that in non phlegm-dampness MS group(P<0.01). It was observed in clinical trials that after cold stimulation, the average body surface temperature of SCR in MS patients was lower than that of the healthy people; the thermal deviation of SCR did not change significantly in the phlegm-dampness MS patients, and the difference in their elevated temperature was lower than that in the other two groups. These characteristics provided objective basis for clinical diagnosis and treatment of phlegm-dampness MS. With abnormal BAT related indicators, it was inferred that the content or activity of BAT in SCR of phlegm-dampness MS patients were reduced. There was a high correlation between BAT and phlegm-dampness MS, and thus BAT might become an important potential target for the intervention in phlegm-dampness MS.