Micromachines
·
2022
·Vol. 13
·期 11
·1949
·
IF 3.523
Chao Chang,Yaoguang Yang,Lilin Pei,Zhaoyang Han,Xiu Xiao,Yulong Ji
With the rapid development of electronic technologies towards high integration, high power and miniaturization, thermal management has become an increasingly important issue to guarantee the reliability and service life of electronic devices. The oscillating heat pipe (OHP), which was governed by thermally excited oscillating motion, was considered as a promising technology to dissipate high-density heat and had excellent application prospects in many important industrial processes. A flat-plate OHP, however, was fabricated by traditional welding methods, which were difficult and inefficient, resulting in increasing the cost and wasting the production time. In this work, we adopted a new metal 3D printing technology to develop an aluminum flat-plate OHP, which made it facile to build complex inner channels with high-precision molding at one time. AlSi10Mg powders, as raw materials, were selectively melted and solidified to form the container of the flat-plate OHP. The sintered inner surface presented excellent wettability to the working fluid, which facilitated the evaporation of the working fluid. Acetone was chosen as the working fluid, and the filling ratios with a range of 40–70% were loaded into the flat-plate oscillating heat pipe to analyze its effect on heat transfer performance. It was found that the 3D-printed flat-plate OHP with a 60% filling ratio had a better heat transfer performance and a lower thermal resistance, and it was able to work properly in both vertical and horizontal operation modes. The 3D-printed flat-plate OHP had been successfully applied for the thermal management of high-power LEDs, and the results showed that the temperature of LEDs was maintained within 60 °C, and its service life was prolonged.Keywords:3D printing;oscillating heat pipe;thermal resistance;heat transfer performance
研究领域:
电子工程
·
热管理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Zhaohao Li,Run Qi,Zheng Zhang,Heng Zhang,Haiping Chen,Dan Gao
Condensation is the common mechanism of water intake from gases. Transport membrane condenser is a newly proposed technology to recover water from flue gas based on the mechanism of condensation. Most of the existing heat transfer research on transport membrane condenser focuses on water vapor phase change or fluid convection heat transfer, and there is a lack of research on the thermal conductivity of ceramic membranes. The significance of studying thermal conductivity is to optimize the overall heat transfer performance. The thermal conductivity of alumina ceramic solid materials is not good enough, which can affect the industrial application performance to a certain extent. There is currently a lack of experimental measurements or theoretical calculations to quantitatively characterize the thermal conductivity of ceramic membranes. This affects the optimization of overall heat transfer performance of transport membrane condenser. In this paper, coal fly ash is used as the raw materials to prepare macroporous ceramic membranes. Coal fly ash is a very cheap material. It can greatly reduce the manufacturing cost of transport membrane condenser using coal fly ash to prepare ceramic membranes. The classical theoretical model of thermal conductivity of porous materials is introduced, the calculation and experimental results are compared, and the validity and limitation of the classical models in analyzing the heat transfer problem of transport membrane condenser are discussed. Finally, based on the composite effective medium theory, combining with the experimental results, a modified model is proposed. The modified model reduces the average theoretical error to 7.20%, and enriches the research on the heat transfer theory of transport membrane condenser.
研究领域:
材料科学
·
热力学
·
环境工程
✓ 已验证
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2024
·
IF 6.1
Yaode Li,Yanyu Wu,Mingshuai Qiao,Cong Qi,Zhiguo Zhang
Nanofluid boiling heat transfer in microchannels has the advantages of small size and high heat transfer efficiency, and can meet the requirements of large heat load and high structural integration. In this paper, the enhanced heat transfer characteristics experiment of nanofluids under electro-magnetic co-excitation were studied on a microchannel boiling flow experimental platform. The generation, deformation and motion mechanism of bubbles in nanofluids under electro-magnetic co-excitation were studied by high-speed photography and numerical simulation, achieving microscopic visualization of nanofluids. The experiment shows that the small bubbles are affected by the electric field force and pass through the electrode wire, and perform regular lateral reciprocating motion between the two sides of the wall. This motion of the bubbles can not only strengthen the orderly disturbance inside the fluid, but also will not disrupt the heat transfer mechanism between various media, making the heat transfer enhancement and not chaotic. Magnetic excitation causes the nanoparticles to form a magnetic coupling structure along the direction of the magnetic field, the average strengthening effect increased to 29%. When the current is applied and the electromagnetic coupling field is formed, the heat transfer effect is improved by 36%.
研究领域:
热力学
·
纳米科技
·
传热学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2023
·
IF 5.2
Zhihao Sun,Kang Luo,Hongliang Yi,Jian Wu
The low thermal conductivity of organic phase change materials (PCMs) has seriously obstructed the performance of thermal latent-heat thermal storage (LHTS) system. For the first attempt, we experimentally studied the phase-change heat transfer characteristics of octadecane inside a horizontal cavity with the passive addition of nano graphene and the active application of an electric field. The effects of nano graphene weight ratio, direct current (DC) voltage magnitude and polarity on melting heat transfer and their corresponding mechanism are then examined. Results are reported for the real-time melting process, the liquid fraction, and the evolution of absorbed energy. The velocity fields obtained by particle image velocimetry (PIV), the temperature fields measured by fiber Bragg grating (FBG) sensors, and the current-voltage curves are reported to reveal the heat transfer enhancement mechanism. The absorbed thermal energy is increased by 33.6% when nano graphene is added alone. A single electric field promotes the energy absorption by 153.5% where electric field driven flow develops. The net charge is generated by the conduction mechanism. For composite PCMs’ melting, the absorbed energy is enhanced by 124.8% at most when the cavity's bottom wall is exposed to -10.0 kV. However, when +10.0 kV is applied to the bottom wall the electrophoretic deposition takes place, and the combined augmentation effect on absorbed thermal energy is 111.2%. The present results provide a reference for improving the LHTS system's performance through sole or synergistic heat transfer enhancement method.
研究领域:
材料科学
·
热能工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Hongqiang Chen,Yonghai Zhang,Lei Huang,Xiong Zhao,Xiang Ma,Zihuan Ma,Junsheng Hou,Jinjia Wei,Paolo Di Marco,Omid Mahian,Nanjing Hao
Flow boiling heat transfer in microchannels is fundamentally important for the thermal management of high-power electronics. The combination of silica nanofluids and micro pin-fins structure is expected to solve the limitations of the internal trade-off between the heat transfer coefficient (HTC) and critical heat flux (CHF). However, the high cost, preparation complexity, poor stability, and particle agglomeration limit the further development of silica nanofluids. Herein, we present a simple and straightforward microfluidic strategy for continuous, ultrafast, and high-throughput synthesis of functional silica nanofluids with excellent stability. Numerical simulation and experimental validation are conducted to investigate the excellent mixing performance of spiral microreactor. The morphology and size of SiO 2 can be precisely controlled by simple flow rate. The excellent stability of time (∼30 d) and temperature (∼80 ℃) significantly improved the problem of easy aggregation of nanofluid particles previously used for heat transfer. The flow boiling heat transfer in microchannels on micro pin-fins silicon chip demonstrates the simultaneous enhancement of CHF (124%) and HTC (153%) at extremely low power consumption (pressure drop less than 1.5 kPa) compared to the base fluid. These findings provide important guidelines for the embedded cooling and shed new light on significant energy savings on electronics.
研究领域:
热管理
·
纳米流体
·
微流控
·
传热
·
微通道冷却
·
高功率电子设备
·
能效
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Feifan Huang,Chao Liu,Siqin Cheng,Tao Li
Microwave thermal regeneration is an emerging technique for activated carbon regeneration, which has been extensively investigated experimentally. However, relevant simulation receives limited attention, with the mechanism of microwave thermal regeneration not very well understood. In this study, a multiphase, porous media model coupling electromagnetic , heat and mass transfer is established to study microwave thermal regeneration characteristics of spent activated carbon. The results show that inhomogeneous electromagnetic distribution in the cavity is the main factor contributing to the inhomogeneity of the sample temperature. The desorption of adsorbate in the hot spot region (dry basis) mainly relies on microwave radiation heating. The desorption of adsorbate in the cold spot region (wet basis) depends on heat conduction and convection in the hot spot region, as well as capillary diffusion caused by the concentration gradient . In addition, the uniformity of sample temperature distribution is optimized by rotating microwave thermal regeneration, and energy consumption is reduced by about 58 %. Therefore, this model can provide technical guidance for optimizing the microwave thermal regeneration process of spent activated carbon while explaining the mechanism of microwave regeneration.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED THERMAL ENGINEERING
·
2022
·
IF 6.465
Feifan Huang,Weijun Liu,Shaoai Chen,Zhongxun Tian,Jingtao Wei
Thermal desorption of adsorbate in activated carbon is the main part in the thermal regeneration process of spent activated carbon, and previous studies have carried out a series of numerical simulations on it. However, since activated carbon is a porous medium, the heat and mass transfer in activated carbon is different from that in solid. In this paper, a multiphase model of heat and mass transfer in porous media was constructed to study the thermal desorption characteristics of adsorbate in spent activated carbon. In addition, a simplified evaporation rate formula is proposed in this paper, and the agreement between the simulation and the experimental results is verified. When the surroundingtemperature is less than 673.15 K, increasing the surrounding temperature has a significant effect on reducing the thermal desorption time of the adsorbate. Using activated carbon with a thermal conductivity of 5 W / m ∙ K can save about 40% of energy consumption. The model established in this paper can accurately simulate the thermal desorption of adsorbate in activated carbon, which is helpful to deeply understand the mechanism of activated carbon thermal regeneration. In engineering practice, the model can provide technical support for optimizing the thermal regeneration process of spent activated carbon and reducing energy consumption in a targeted manner.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2025
·
IF 1.9
Qianqian Lv,Chuanshuo Wang,Xiaoxuan Xu,Xiaofang Lv,Wen Xia,Jinru Shang,Aokai Qin,Qianli Ma,Yang Liu,Shidong Zhou,Jimiao Duan
Drag reducers have become a common method for reducing resistance and increasing transportation efficiency in pipeline transportation of waxy crude oil. The prominent heat transfer weakening effect of drag reducers may impact the deposition of waxy oil. This study uses cold finger experiments to clarify wax deposition characteristics and mechanisms in drag-reduced waxy oil. The wax deposition mass and components are examined under different temperatures, stirring rates, drag reducer dosages, and types. The results show that a low dosage of drag reducer at high stirring rates can simultaneously reduce the total wax deposition and the overall wax content in high waxy oil. 5 mg/kg drag reducer can reduce total wax deposition by up to 15.66% and overall wax content by 7.26%. A systematic investigation reveals that adding drag reducers changes the carbon number distribution in the wax deposition layer. This change is similar to the effect of increasing wall temperature. The heat insulation and transfer weakening effects of drag-reducing fluids are likely the main mechanisms inhibiting the increase in wax deposition mass and wax content. The heat insulation effect reduces the temperature gradient near the pipe wall, while the transfer weakening effect decreases radial heat transfer. However, under low stirring rates and high dosages, the deposition mass of the drag-reduced waxy oil system increases, with the adhesive effect of polymer-type drag reducers becoming more pronounced. These findings provide a foundation for optimizing drag reducer usage in waxy crude oil pipelines, potentially leading to significant energy savings and improved operational efficiency.
研究领域:
石油工程
·
化学工程
·
流体力学
·
传热学
✓ 已验证
产品关联
DOI
高影响因子
AICHE JOURNAL
·
2015
·Vol. 61
·期 10
·3441-3450
·
IF 2.748
Xiaofei Song,Feng Xin,Hongchao Yan,Xingang Li,Hongri Jia
A method of direct heat removal resulting from the phase change of n-tetradecane was used to intensify the heat transfer during hydrate formation. The growth rates of methane hydrate in aqueous slurries containing 25–45 wt % of solid n-tetradecane were investigated at pressures between 4.70 and 6.46 MPa (gauge) and near the fusion point of solid n-tetradecane. Methane hydrate growth started at a practically constant rate, which became variable after a sudden increase. Two rate laws were established to correlate with the experimental data for the constant and variable rate stages. The methane hydrate growth rates achieved with solid n-tetradecane were significantly enhanced compared with those obtained under indirect heat removal. © 2015 American Institute of Chemical Engineers AIChE J , 61: 3441–3450, 2015
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
·
2022
·
IF 5.431
Zhen Yang,Yuanpeng Yao,Huiying Wu
Surfactants are often used as additives to stabilize the dispersed phase of the water-based multicomponent fluids (such as non-azeotropic emulsion) for enhancing the boiling process, but their effects on the boiling heat transfer of water are still not clear. In this paper, a pool boiling experiment is designed to investigate the specific effects of surfactants (Tween20 (Polysorbate 20), Span20 (Arlasel 20), and Tween20-Span20 mixture) on the subcooled boiling heat transfer characteristics of pure water. The experimental results are analyzed by considering the influences of addition type and concentration of surfactant as well as the applied heat loads. It is found that: (1) Tween20 can achieve excellent boiling enhancing performance (decreasing the wall superheat by up to 10.4 °C and raising the boiling heat transfer coefficient by up to 13.4%) by increasing the number of nucleation sites. And the enhancement is improved with the increase of concentration when the heat flux is below a certain level, while it is weakened at high heat flux for Tween20 with a high concentration (1 mL L -1 ). The reason is that high concentration Tween20 results in an excessive increase of nucleation sites which prevents the return of working fluid and weakens the enhancement of heat transfer. (2) Span20 shows a boiling enhancement only when its concentration is 0.05 mL L -1 (lower than the CMC) among the test ones. Further increment in Span20 concentration (exceeding the CMC) leads to a large increase of wall superheat because it increases the viscosity of working fluid and deteriorates the heat transfer performance. (3) Tween20-Span20 mixture significantly aggravates the aforementioned boiling deterioration effect of Span20 (due to the reduced CMC for the mixture of Tween20 and Span20, weakening the heat transfer), and thus is not suitable for preparing boiling-heat-transfer-enhancing fluids. These results can provide a better understanding of surfactants and guide the practical preparation of multicomponent fluids for boiling heat transfer enhancement.
研究领域:
热力学
·
传热学
✓ 已验证
产品关联
DOI
高影响因子
Case Studies in Thermal Engineering
·
2023
·
IF 6.8
Jing Fan,Dazhi Gao,Fenhong Song
Deep eutectic solvents are now widely used in metal electrochemical deposition, biomass catalysis and material synthesis because of their advantages of greenness, low cost, good biocompatibility and biodegradability, and it is proved that DESs have great potential for its utilization as heat transfer fluids. In this work, eight DESs were prepared by thermal method using choline chloride as the hydrogen bond acceptor and glycerol, polyethylene glycol 600, lactic acid and o-cresol as the hydrogen bond donor. Based on the flow calorimetry method, the specific heat capacity system was established and its reliability and precision were verified by measuring the specific heat capacity of deionized water. The maximum deviation of the experimental value and the standard value under the pressure 101 kPa was 2.03%, and the average absolute deviation was 1.01%, and the repeatability was less than 1.5%. Then, the densities and the constant pressure specific heat capacities of eight DESs in the temperature range of 293 K–353 K and 293 K–373 K were measured respectively. The experimental results could support for the scale utilization of DESs.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Case Studies in Thermal Engineering
·
2025
·
IF 6.4
Junjie Wu,Junsheng Hou,Li Ma,Lei Huang,Zihan Ding,Hao Zhang,Baiqi Tian,Wenjing Zhou,Zhenzhen Chen,Nanjing Hao
With the development of the coal chemical industry, the production of coal gasification slag (CGS) is increasing, and the utilization is becoming challenging. Products of CGS utilization mainly include activated carbon, zeolites, silicon-carbon composites. However, the consumption of these products above is limited, which is insufficient to utilize the output thoroughly. As a result, it is urgent to expand the application area for large-scale and high-value utilization of CGS. CGS is rich in elements including aluminum and calcium, presenting a promising material for synthesizing nanofluids, which is promising for the thermal management of microelectronic devices. This study synthesizes hydrocalumite nanofluids from CGS and applies the nanofluids for flow boiling heat transfer experiment. Nanofluids with an average particle size of 50 nm are synthesized and applied to flow boiling heat transfer experiments. The critical heat flux (CHF) and the heat transfer coefficient (HTC) are improved by a maximum of 43 % and 52 %. Moreover, the fundamental principle of enhancement is discussed. Improved wettability, delayed bubble coalescence, additional nucleation sites are attributed to the improvement. This study not only presents a novel method for high-value utilization of CGS but also introduces a potential approach for thermal management enhancement of microelectronic devices.
研究领域:
材料科学
·
能源工程
·
电子器件热管理
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）