Temperature Heat Research Articles

Optimisation of dry heat treatment conditions for modification of faba bean (Vicia faba L.) starch

Faba bean is a protein-rich starchy grain that is underutilised in the UK. The starch of faba bean can be modified using environmentally friendly methods like dry heat treatment (DHT) to enhance functional and its physicochemical properties. This study investigated the impact of dry heat temperature and time on the structure, functional and physicochemical properties of faba bean starch (FBS) using a two-factor central composite rotatable design. Factors (DHT temperature:100–150 °C and DHT time:0.5–5 h) with their respective α mid-point values led to 13 experimental runs. Selected pasting and functional properties were measured as response variables. Corn starch was included as a reference and compared with the FBS modified using the optimized conditions. DHT increased peak (approx. 2205–2267 cP), final (approx. 3525–3642 cP) and setback (approx. 1887–1993 cP) viscosities but decreased the amylose content of FBS. Colour, as measured by lightness value, morphology and crystalline type were not altered but the starches showed a loss of order and an increase in crystallinity after DHT. FBS appeared resilient to DHT but showed higher swelling power and pasting properties compared to the corn starch control. The optimum DHT conditions to produce starch with desirable properties are a temperature of 100 °C for 0.1716 h, with a desirability factor of 66 %.

A fast and high-fidelity multi-parameter thermal-field prediction system based on CFD and POD coupling: Application to the RPV insulation structure

The thermal performance of the reactor pressure vessel (RPV) insulation structure plays a crucial role in ensuring the operational safety of the reactor. In this study, a fast and high-fidelity prediction system is proposed, which is based on the snapshot ensemble generated by the computational fluid dynamics (CFD) method and incorporates proper orthogonal decomposition (POD) as its core component to predict the heat transfer performance of the RPV insulation structure. The proposed thermal-field prediction system is employed to examine the impacts of air inlet temperature, mass flow rate, and RPV outer wall temperature on the thermal performance parameters: average heat flux qout and temperature Tout of the RPV insulation outer wall, as well as the maximum local temperature Tmax of the concrete pit inner wall. The POD predictive results showcase that the maximum relative deviations of qout, Tout and Tmax for eight sets of off-design cases are 2.25 %, 3.04 %, and 2.37 %, respectively. Meanwhile, the maximum values of qout, Tout and Tmax are 90.13 W·m−2, 44.69 ℃, and 87.51 ℃, respectively. They are all less than their prescribed limits. The field distributions of heat flux and temperature in off-design cases exhibit consistency between the CFD and POD methods. Notably, in comparison to the CFD simulation method, the POD method capturing more than 99.9 % energy demonstrates significant computational time savings for 99.87 %. Moreover, a multivariate linear regression (MLR) model for thermal performance parameters is established based on the POD prediction datasets. The results indicate that the maximum relative deviations between the POD and MLR methods in predicting qout, Tout and Tmax for the 72 sets of test cases are 5.1 %, 7.9 % and 7.1 %, respectively. Meanwhile, 99.99 % CPU time is reduced for MLR model compared with CFD method. Obviously, the predictive system showcases excellent accuracy and efficiency in forecasting.

MHD-driven thermal dynamics of bionanofluid flow on stretching porous media and the critical impact of multiple slip effects

Incorporating slip conditions into computational fluid dynamics (CFD) simulations and experiments helps engineers predict and improve the effectiveness of superhydrophobic surfaces in reducing drag. This optimization approach leads to significant enhancements in fuel efficiency and performance across a range of fluid-flow systems, including marine vessels and aircraft. This study models the phenomena of velocity and temperature slip, coupled with MHD, within the context of nanofluid flow undergoing bioconvection over a stretching sheet. Subsequently, the study seeks to analyze the resulting effects on heat and mass kinematics. The bvp4c solver effectively calculates analytical solutions for the reduced problem obtained through similarity transformation from the underlying partial differential equations. Velocity and temperature slip both impact temperature, with velocity slip increasing heat transfer rates and temperature slip decreasing them. The thermal radiation parameter enhances nanoparticle concentration, although it’s offset by an increased Lewis number. Brownian motion amplifies mass transfer, but the thermal radiation parameter hampers it. The escalation in the microorganism density profile correlates with the increase in both the Bioconvection Lewis number and the Peclet number. Likewise, as thermophoresis parameters and the bioconvection constant increase, the microorganism density along the profile also rises.

Machine Learning Investigation For Tri-Magnetized Sutterby Nanofluidic Model with Joule Heating In Agrivoltaics Technology

This paper aims to establish a panoramic foundation for investigating the impact of sunlight on a recently formulated water-based tri-nano hybrid Sutterby liquid (TNHF) under provided magnetic field, directed through photovoltaic solar panels by exploiting the knacks of machine intelligent computing paradigm. The comparative performance of hybrid and tri-nano fluidic system with water as a base fluid is exhaustively analyzed and discussed. This research is unique, as it has a distinguished figurative comparison analysis between two different types of nanofluidic materials, which helps to choose the best one for use in agrivoltaics systems, and replace the materials already in use to enhance the efficiency and performance coefficients. Furthermore, the description of the composition scheme makes this research more feasible and applicable. A numerical dataset of nonlinear mathematical model is generated by employing finite difference scheme in the recently introduced Python bvp-solver algorithm, then it is embedded into artificial intelligence (AI)-based Levenberg Marquardt neural network algorithm (LMNNA). A significant outcome of the research indicates that the integration TNHF results in a notably faster enhancement of heat transfer rate and temperature framework as compared to traditional hybrid fluid. It is observed that introducing three distinct nanomaterials of specific thermophysical characteristics enhances the thermal exchanging profile and faces an obvious flow rate dissipation in solar plate channels. The standard numerical and AI-generated results are documented to portray the stability, accuracy and efficacy of scheme in terms of iterative learning curves on MSE, error analysis, histograms and regression statistics. Additional perquisites of the methodology include cost effectiveness, time-saving ability, robustness, stability and its extendibility.

Effect of Disinfection on Tensile Strength and Rupture Elongation of Maxillofacial Silicone Reinforced with Nano-Filler Particles.

Objectives: Compare the tensile strength and rupture elongation of room temperature vulcanizing silicone (RTV), heat temperature vulcanizing silicone (HTV) and 3% SiO2 reinforced RTV and HTV following disinfection with various agents. Materials and Methods: According to ASTM D412, 384 samples were fabricated using HTV, RTV, RTV and HTV reinforced with 3% SiO2 nanoparticles. The control group received no disinfection treatment, while the other samples were disinfected for 10 minutes using neutral soap, 4% chlorhexidine, and ozone water, three times a day for 60 days. Additionally, accelerated aging was carried out for 252,504,1008 hours. Tensile strength and rupture elongation were assessed using a universal testing machine at 500 mm/min speed, and the mean values were analyzed using two-way ANOVA and Tukey HSD test (P<0.05). Results: The mean value of tensile strength of RTV (2.96 ± 0.41), 3%SiO2 RTV (3.26 ±0.33), HTV (3.30 ±0.36),3% SiO2 HTV (4.07 ±0.85) MPa which was statistically significant for control, neutral soap and 4% chlorhexidine at 252,504 ,1008 hours of aging. (P <0.05). The percentage of elongation of RTV (545 ±29.2),3%SiO2 RTV (617 ±30.5), HTV (735 ±48.7),3% SiO2 HTV (801 ±55.7) which was statically significant for control, neutral soap, 4% chlorhexidine and Ozone water for 252, 504 ,1008 hours of aging. (P <0.05). Conclusion: The HTV silicone showed more tensile strength and rupture elongation compared to HTV, RTV and RTV silicones reinforced with 3% SiO2 nanoparticles. Ozone water disinfection had least effect on tensile strength and rupture elongation of maxillo-facial silicone compared to other disinfectant.

Unsteady flow past an impulsively started infinite vertical plate in presence of thermal stratification and chemical reaction

AbstractThe purpose of this study is to analyze how thermal stratification affects fluid movement past an impulsively initiated infinite upright plate when first‐order chemical reactions are present. Laplace's transform method is applied to achieve a closed‐form solution for the nondimensional governing equations when . The formula , where t is the time and s is a parameter, can be used to obtain the Laplace transform of an exponentially ordered piece‐wise continuous function . The unstable flow past an infinite vertical plate, starting abruptly in the presence of heat stratification and chemical reactions, has never been studied before. The research focuses on the combined impact of thermal stratification and chemical processes on the flow of an incompressible viscous fluid over an indefinitely tall plate. In this study, the significant findings that resulted from heat stratification are compared to the condition in which heat stratification is absent. The impacts of a number of parameters, such as are investigated and visually displayed with respect to the following variables: concentration, velocity, shear stress, rate of heat transfer, temperature, and rate of mass transfer. It is demonstrated that applying stratification increases the frequency of oscillation in shear stress and heat transfer rate. The results obtained can be useful in the design of heat exchangers and other engineering applications.

A comprehensive ab-initio study of Cs3Sb2X9 (X= Cl, Br) novel halide perovskites for solar cell applications

Two-dimensional perovskite materials have recently attracted significant interest in solar cell applications. This study employed DFT calculations to investigate the structural, electronic, optical, magnetic, thermal properties and spectroscopic limited maximum efficiency (SLME) of Cs3Sb2X9 (X = Cl, Br) perovskites. The dynamic vibrational stability was calculated using the phonon energy dispersion curve; results show that Cs3Sb2X9 (X = Cl, Br) is dynamically stable. The electronic band structure revealed that these materials exhibit semiconductor behavior with energy bandgaps of 2.41 eV and 1.77 eV for Cs3Sb2Cl9 and Cs3Sb2Br9, respectively. The Cs3Sb2Br9 shows higher absorption and conductivity at comparatively lower frequencies of absorbed light. Furthermore, the magnetic characteristics of the investigated compounds demonstrate that there are no net magnetic moments. The thermodynamic properties analysis indicated a strong correlation between heat capacity and temperature. We have used SLME analysis to determine the theoretical power conversion efficiency for Cs3Sb2X9 (X = Cl, Br) perovskites. The determined results of SLME show that Cs3Sb2Cl9 and Cs3Sb2Br9 exhibit SLME values of 12.63 % and 26.40 %, respectively, at 298.15 K, suggesting that both compounds can be used in solar cells.

Self-powered, multifunctional, and skin-compatible electronic-tattoos based on hybrid bio-nanomaterials as electrically functionalized skins

Electronic tattoos (E-tattoos), imparting electrical functions to skin imperceptibly, are attractive for future biomedical engineering applications. However, it is still challenging to implement all requirements such as biocompatibility, skin-adhesion, breathability, self-powering, etc. in a single E-tattoo for a seamless human–device interface. Here, we report hybrid biomaterial-based E-tattoos fabricated by incorporating graphene with silk sericin (SS)-loaded cellulose nanofibers (CNFs), leveraging each other’s strengths for skin-compatible and multifunctional operations. Graphene/SS/CNF E-tattoos show stable and high electrical conductivities under mechanical deformations, along with breathability. Due to SS, strong skin-adhesion is possible without skin irritation. The broadband optical absorption and temperature-dependent conductivity of graphene facilitate optically and electrically stimulated heat patches and temperature sensors. Furthermore, skin-compatibility enables skin-activated self-powering operation via triboelectricity. A substantial open circuit voltage of 320 ± 20 V and power density of 7.2 mW/cm2, sufficient to turn-on light-emitting diodes, are achieved, and self-powered sensory systems can be developed owing to flexible and porous traits of the E-tattoo. The E-tattoo platform, serving as a proof of concept, demonstrates its utility in healthcare and secure communications by enabling Morse code transmission and biomechanical movement detection. This innovative hybrid biomaterial-based E-tattoo can significantly boost healthcare monitoring and secure communication.

Optimization of synthesis parameters for polyamide 610: Strategic tailoring for superior latent heat performance

The study systematically optimizes the synthesis of polyamide 610 with the aim of improving latent heat and melting temperature to meet the demanding requirements of high-temperature heat storage applications using Response Surface Methodology (RSM). The results clarify the critical impact of reaction times, washing solvents, and molar ratios on these vital thermal characteristics. Samples exhibiting exceptional latent heat capacities at various mole ratios were further analyzed using Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD). The TGA assessments were instrumental in determining the thermal degradation behaviors of the materials. At the same time, The DSC analysis was used for the determination of thermal properties of the materials, FTIR provided detailed insights into their molecular structures, and XRD elucidated the crystalline structure of the materials. The findings reveal that a specific mole ratio is essential for achieving superior thermal properties, indicative of the polymer's resilience and structural stability. It was evident that samples with a balanced molar ratio (1:1) and specific reaction time (60 min) showed the best latent heat, surpassing 80 J g-1, and melting temperatures up to 210 °C. A notable aspect of this research is the use of Sebacic Acid instead of the conventional Sebacoyl Chloride for synthesizing polyamide 610. The choice of Sebacic Acid was made due to its lower toxicity and the fact that its byproducts are easier to remove than those from sebacoyl chloride, which produces hydrochloric acid as a byproduct. The presence of HCL can lead to side reactions and negatively impact the reaction process. By using Sebacic Acid, we reduce the risk of such contaminants, thereby enhancing the thermal stability and performance of polyamide 610. This greener approach not only aligns with sustainable practices but also has significant implications for the performance of the polymer. In addition, the integration of RSM with comprehensive characterization techniques has been pivotal in elucidating the critical influence of synthesis parameters on material properties. This enhanced understanding holds the potential for significant contributions to the development of advanced materials for latent heat storage applications, combining sustainability with high performance.

Computational analysis of spray cooling heat transfer and Influential factors during glass tempering

The spray cooling and tempering technology has a series of advantages, such as improving the tempering quality and reducing energy consumption. In order to optimize the tempering technological parameters, it is necessary to accurately control the thermal history and temperature distribution of a hot glass surface during spray cooling. However, measuring the inner temperature of tempered glass proved challenging. The Euler-Lagrangian approach was utilized for simulating the process of spray cooling the glass surface. To validate the accuracy of model predictions, experimental studies were conducted on the tempering of glass by a single nozzle. The numerical outcomes exhibit strong correspondence with the experimental findings. Building upon the foundation, the study analyzed the heat transfer mechanisms in different states including film boiling, nucleate boiling, and forced convection. Subsequently, the effects of spray distance, spray loading fraction, spray pressure, and final cooling temperature on the heat transfer rate and temperature homogeneity were discussed. The results revealed that reducing the spray distance, increasing the spray loading fraction and spray pressure can improve the cooling rate and reduce energy consumption, but it aggravated the uneven distribution of temperature over the glass surface. Moderately increasing the final cooling temperature had little effect on the tempering quality of glass, but it significantly reduced the energy consumption for spray cooling. Within the experimental range, the optimal final cooling temperature was 573.15 K.

Multi-U-Style micro-channel in liquid cooling plate for thermal management of power batteries

In order to cope with the problem of the shortening of automotive power battery life and the reduction of occupant safety due to the large amount of heat generated by automotive power batteries of high-energy–density at high discharge rates, this paper proposes a Multi-U-Style micro-channel in the liquid-cooled plate (Multi-U), based on the heat generation characteristics and temperature distribution of automotive power batteries. The impact of different Multi-U arrangements on the cooling performance of the batteries is explored, and the results indicate that the cooling performance is better with the side face arrangement. Compared to main face 1, the maximum temperature (Tmax) and maximum temperature difference (ΔTmax) of the batteries decrease by 2.40 K and 2.50 K, respectively. In addition, through a comparative analysis with typical serpentine micro-channel chilled plate (SMCP) and parallel micro-channel chilled plate (PMCP), Multi-U exhibits superior overall performance. Furthermore, the influence of equally incremental and decreasing channel width of Multi-U from the center to the periphery on cooling performance of the batteries is explored. It turns out that when the channel width is equally decreasing 1 mm Multi-U (D 1 mm), the heat dissipation is most effective. Finally, the critical parameters of the Multi-U are optimized to improve the power density of batteries. The impact of critical parameters of the Multi-U on the cooling performance of the batteries is studied through orthogonal experiments. The optimal parameter combination is found to be a channel width (W) = 12 mm, channel thickness (H) = 6 mm, inlet mass flow rate (F) = 0.02 kg∙s−1, and inlet coolant temperature (T) = 292.15 K. Compared to the original Multi-U, the Tmax and ΔTmax of batteries decrease by 5.83 K and 0.06 K, respectively, while the pressure drops decrease by 89 %.

Joule heat induced ultrafine ZrO2/C composites for enhanced microwave absorption

Lightweight absorbers with effective broad absorption and high thermal stability are highly desirable in the field of electromagnetic wave absorption. In this work, we introduce a facile carbon thermal shock method to prepare ZrO2/C composites using UIO 66 (Zr) as the precursor. The instant heating and cooling process ensures the uniform deposition of nano-sized ZrO2 (ca. 5–15 nm) on graphene, exhibiting an ultrahigh interfacial number density of ca. 1015 m−2 that favors polarization loss. Due to the synergetic effect of dielectric loss and impedance matching, the prepared ZrO2/graphene composites show tunable wide-microwave absorption performance by adjusting the heat temperature, and possess a wide absorption band covering the entire X and Ku band. Notably, the ZrO2/graphene composites show high thermal stability up to 1000 °C, which presents great potential for microwave absorption applications.

Numerical investigation of the transient fluid flow and heat transfer behavior in self-driven natural circulation cooling loop

An innovative open natural circulation system is proposed in this work, which utilizes the difference of the heat flux loaded on different parts of the pipe to form a self-circulation flow of working fluid. Via CFD simulation established by embedding self-programmed code into commercial software, the transient performance of a three-dimensional natural circulation loop is studied. The results indicate that: applying uniform heat flux on the wall of the loop, the fluid flow state successively experiences three stages, i.e., liquid expansion, partial circulation, and phase change, and finally a vapor plunger blocks the pipe, leading to local heat transfer deterioration and temperature increase; applying non-uniform heat flux, the fluid can be driven to form self-circulation flow, which can not only cool the structure via convection, but also prevent bubbles from accumulating, stabilizing the maximum temperature of the system around the boiling point; further for the loop with a more complex configuration, the self-circulation can be also started but with different start modes. Therefore, the new natural circulation system can achieve effective and adaptive cooling according to the external thermal environment, avoid fluctuation and vapor block phenomenon caused by violent phase change, and reduce the driving equipment and control unit. This work provides a reference for the design of the natural circulation system applied in a non-uniform heating environment. Through transient numerical simulation of the start-up stage, the fluid flow, phase change, and heat transfer characteristics in the natural circulation loop are studied, and the start mode and mechanism are analyzed.

Association of ambient temperature on acute ischemic stroke in Yancheng, China

BackgroundAcute ischemic stroke (AIS) is a major global public health issue. There is limited research on the relationship between ambient temperature and AIS hospital admissions, and the results are controversial. Our objective is to assess the short-term impact of ambient temperature on the risk of AIS hospital admissions in Yancheng, China.MethodsWe collected data on daily AIS hospital admissions, meteorological factors, and air quality in Yancheng from 2014 to 2019. We used Poisson regression to fit generalized linear models and distributed lag non-linear models to explore the association between ambient temperature and AIS hospital admissions. The effects of these associations were evaluated by stratified analysis by sex and age.ResultsFrom 2014 to 2019, we identified a total of 13,391 AIS hospital admissions. We observed that the influence of extreme cold and heat on admissions for AIS manifests immediately on the day of exposure and continues for a duration of 3–5 days. Compared to the optimal temperature (24.4 °C), the cumulative relative risk under extreme cold temperature (-1.3 °C) conditions with a lag of 0–5 days was 1.88 (95%CI: 1.28, 2.78), and under extreme heat temperature (30.5 °C) conditions with a lag of 0–5 days was 1.48 (95%CI: 1.26, 1.73).ConclusionsThere is a non-linear association between ambient temperature and AIS hospital admission risk in Yancheng, China. Women and older patients are more vulnerable to non-optimal temperatures. Our findings may reveal the potential impact of climate change on the risk of AIS hospital admissions.

Experimental evaluation of localized air temperature profile and performance of serpentine copper tube heat exchanger for energy-saving crop cultivation

The objective of this study is to examine the localized air temperature profile and heat transfer performance of a serpentine copper tube heat exchanger. Particularly, the air temperature nearby the plants is controlled by the heat exchanger. The novelty of this study is to provide localized climate control only near the plants targeting periodic air temperature control with the proposed heat exchanger. This study focuses on heating and cooling for cultivation in temperate and tropical regions. In contrast to fin-and-tube heat exchangers, the serpentine heat exchanger has a simple design, provides minimal shade for plants, and is easy to maintain. This study was conducted in a laboratory. The experimental system was constructed under with the assumption that a part of actual plant cultivation was being left out. The experiments were implemented by varying the experimental operating conditions such as the inlet fluid temperature and fluid flow rate in the heat exchanger. The pressure drop in the heat exchanger was also measured. The results revealed that this heat exchanger could provide localized air temperature control. The maximum air temperature difference can be obtained at approximately 12 °C during cooling and heating from their initial air temperature even though the heat exchange is simple. The effects of decreasing the inlet fluid temperature for cooling and increasing the inlet fluid temperature for heating were more dominant than the effect of the flow rate. This simple, low-maintenance, and low-cost serpentine copper tube heat exchanger can effectively provide alternate heating and cooling for plant cultivation.

Magnetic-guided nanocarriers for ionizing/non-ionizing radiation synergistic treatment against triple-negative breast cancer

BackgroundTriple-negative breast cancer (TNBC) is a subtype of breast cancer with the worst prognosis. Radiotherapy (RT) is one of the core modalities for the disease; however, the ionizing radiation of RT has severe side effects. The consistent development direction of RT is to achieve better therapeutic effect with lower radiation dose. Studies have demonstrated that synergistic effects can be achieved by combining RT with non-ionizing radiation therapies such as light and magnetic therapy, thereby achieving the goal of dose reduction and efficacy enhancement.MethodsIn this study, we applied FeCo NPs with magneto thermal function and phototherapeutic agent IR-780 to construct an ionizing and non-ionizing radiation synergistic nanoparticle (INS NPs). INS NPs are first subjected to morphology, size, colloidal stability, loading capacity, and photothermal conversion tests. Subsequently, the cell inhibitory and cellular internalization were evaluated using cell lines in vitro. Following comprehensive assessment of the NPs’ in vivo biocompatibility, tumor-bearing mouse model was established to evaluate their distribution, targeted delivery, and anti-tumor effects in vivo.ResultsINS NPs have a saturation magnetization exceeding 72 emu/g, a hydrodynamic particle size of approximately 40 nm, a negatively charged surface, and good colloidal stability and encapsulation properties. INS NPs maintain the spectral characteristics of IR-780 at 808 nm. Under laser irradiation, the maximum temperature was 92 °C, INS NPs also achieved the effective heat temperature in vivo. Both in vivo and in vitro tests have proven that INS NPs have good biocompatibility. INS NPs remained effective for more than a week after one injection in vivo, and can also be guided and accumulated in tumors through permanent magnets. Later, the results exhibited that under low-dose RT and laser irradiation, the combined intervention group showed significant synergetic effects, and the ROS production rate was much higher than that of the RT and phototherapy-treated groups. In the mice model, 60% of the tumors were completely eradicated.ConclusionsINS NPs effectively overcome many shortcomings of RT for TNBC and provide experimental basis for the development of novel clinical treatment methods for TNBC.

Heat dissipation and temperature control method for quantum cascade lasers in external cavity spectral beam combining systems

The thermal effects of quantum cascade lasers (QCLs) can cause wavelength locking instability and reduce output power in external cavity spectral beam combining (EC-SBC) systems. We propose a micro-channel structure (MCH) for heat dissipation and temperature control that rapidly stabilizes the QCL at 20.159°C, showing a linear relationship with the controlled temperature. Experimental comparisons demonstrate that MCH enhances the heat transfer rate within the structure, reducing the time required to stabilize and control QCL temperature. The output power and locked wavelength remain stable in the EC-SBC system under high currents. This study provides technical support for heat dissipation QCL arrays.

Multiple shape factor effects of nanofluids on marangoni mixed convection flow through porous medium

This study explores the effects of multiple shape factors on nanofluids within Marangoni mixed convection flows through porous media. Nanofluids, containing nanoparticles in a base fluid, show unique thermal properties, making them valuable in cooling systems, energy storage, and medical devices. Marangoni mixed convection, driven by surface tension gradients, adds complexity to fluid dynamics and heat transfer in porous media. Analytical and numerical analyses examine how various particle geometries, nanoparticle volume fractions, and porous medium configurations influence transport phenomena. Entropy analysis calculates thermodynamic irreversibilities. Findings reveal relationships between shape factors, heat transfer rates, velocity profiles, temperature distribution, and entropy generation rates, offering insights for optimizing nanofluid-based systems. The study also investigates magnetic forces, heat source/sink effects, and viscous dissipation on thermal energy transfer in Graphene oxide/water and Molybdenum disulfide/water nanofluids. Using similarity transformations, Partial Differential Equations are converted into Ordinary Differential Equations, solved with HAM and NDSolver by using the Wolfram tools. Results graphically depict velocity, temperature, entropy, and skin friction values, providing practical insights for engineering applications.

Simultaneous Two-Colour Two-Dye Thermometry PLIF And PIV To Determine The Nusselt Number In Steady And Oscillatory Poiseuille-Rayleigh-Bénard Convection

In a flow field driven by natural or mixed convection, the measurement of heat transfer and hence the Nusselt number, requires simultaneous measurement of the vertical component of velocity and the vertical temperature gradient. The spatiotemporal nature of the formation of large-scale circulating structures, their interaction with the cross flow and its impact on heat transport, temperature distribution and wall shear stress also can be identified by simultaneous velocimetry and thermometry. An optical measurement system has been developed to apply a high sensetive ((~7 %)⁄℃) two-colour two-dye planar laser-induced fluorescence (PLIF) and particle image velocimetry (PIV) to identify the flow and temperature organization and measure the heat transfer and wall shear stress. The system is to be used to investigate a Poiseuille-Rayleigh-Bénard convection system designed and fabricated to operate in both continuous and oscillatory conditions. The aim is to allow investigation of the influence and effect of large-scale flow structures and thermal plumes on heat and flow transport properties.

Thermal properties of cooling tube battery pack embedded with triangle umbrella-shaped cellular structure

To further enhance heat dissipation efficiency and temperature uniformity of battery pack, a novel cooling tube battery pack embedded with triangle umbrella-shaped cellular structure (TUCS) with negative Poisson’s ratio (NPR) is proposed. Firstly, heat generation models of battery cell are derived and temperature rise tests are conducted to verify the accuracy of heat generation theory and simulation models of lithium battery cell. Meanwhile, cooling tube battery pack with bidirectional serpentine tube is established, and the influences of different flow rates and directions of coolant, diameter of cooling tube and spoiler columns on heat dissipation efficiency of cooling tube battery pack are investigated through simulation analysis. Moreover, relative density of TUCS is calculated and thermal conductivity expressions of TUCS are derived by Maxwell-Eucken model. Subsequently, the embedded TUCS is taken as the medium to conduct heat between cooling tubes and battery modules. Then, the influences of structural parameters of TUCS on heat dissipation efficiency of cooling tube battery pack are determined. Further, the optimal TUCS with the needs of high heat dissipation efficiency, superior temperature uniformity and more lightweight space of battery pack is achieved. Similarly, density gradient of the TUCS can be defined and impacts of TUCS with density gradient distribution on thermal performances of battery pack are investigated. Eventually, the highest temperature and maximum temperature difference of the optimal cooling tube battery pack, cooling tube battery pack embedded with the optimal TUCS and cooling tube battery pack embedded with the optimal gradient distribution TUCS are obtained. Compared with the optimal cooling tube battery pack, the highest temperatures of another two cooling tube battery packs decrease 16.50 % and 16.48 %, and the corresponding maximum temperature differences decrease 93.06 % and 93.20 %, respectively. Meanwhile, the highest temperature and maximum temperature difference of another two battery modules are 303.76 K and 3.76 K at 5C discharge rate. The proposed cooling tube battery pack with the optimal gradient distribution TUCS can decrease the highest temperature and maximum temperature difference effectively.