POWDER TECHNOLOGY
·
2022
·
IF 5.64
Jinxin Zhang,Xiaoping Luo,Liangfeng Wang,Zhenfei Feng,Tengfei Li
In this work, electric field and nanofluid are coupled to enhance flow boiling heat transfer in minichannel. Pin electrodes are adopted to create non-uniform electric field. The effects of nanoparticle mass concentration, surfactant type and mass concentration under electric field on nanofluid flow boiling heat transfer are studied. Image analysis technique is used to quantify boiling bubble behaviors. The results demonstrate that without electric field, bubbles for nanofluid flow boiling are smaller and more discrete than R141b. Under electric field, bubble size reduces and the number of bubbles increases, which reveals synergy effect of electric field and nanofluid on bubble behaviors is effective. Besides, electric forces mitigate bubble coalescence and delay transition from bubbly to slug flow. Maximum heat transfer coefficient of nanofluid is 80% higher than R141b. Under electric field, boiling heat transfer of nanofluid modified by anionic surfactant (SDBS) is better than cationic (CTAB) and nonionic (Span80) surfactant.
研究领域:
热力学
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2024
·
IF 8.1
Yuan Zhou,Shaojie Zheng,Xiao Cheng,Liu Liu,Hao Lei,Nianbing Zhong,Zhichao Deng,Wenqian Zhang,Xuefeng He
Direct liquid fuel cells (DLFCs) offer a promising alternative energy solution by directly utilizing "liquid sunshine fuels", thereby avoiding the complexities of hydrogen storage systems. Despite their potential, DLFC performance is often compromised by gas bubble accumulation at the anode, which reduces the active electrochemical surface area and disrupts fuel transport. In this study, we introduce an inspired Janus electrode with combined hydrophobic and hydrophilic properties designed to shorten the gas diffusion pathway, promoting efficient in-situ bubble release and improving mass transfer. Using visualization techniques, finite element analysis, and mechanical modeling, we investigated the dynamic behavior and transport mechanisms of gas bubbles. The results demonstrate that DLFCs equipped with Janus electrodes achieve superior performance at high current densities, reducing voltage fluctuations and optimizing gas-liquid two-phase flow. This work suggests that Janus electrodes can effectively overcome the bubble-induced limitations in conventional DLFCs.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 6
·1451-1460
·
IF 7.2
Su Zhun,Lu Wenquan,Ding Zongye,Zhao Liang,Yang Fan,Li Jianguo,Hu Qiaodan
Laser powder bed fusion (LPBF) is used to fabricate complex-shaped, dense, and high-performance oxide ceramics. During LPBF, bubbles form and evolve in the melt pool and ultimately remain in the printed ceramics as pores, which significantly degrade the mechanical properties. Therefore, it is essential to understand the bubble behaviors during LPBF. Herein, we conducted an in-situ investigation of the bubble dynamics in the melt pool of homogeneously mixed Al 2 O 3 –Y 2 O 3 powders using synchrotron high-speed X-ray imaging. The formation, growth, motion, and evolution of bubbles, as well as the relationship between the instability of melt flow and bubble rupture during LPBF, were elucidated. The findings reveal that bubbles from the interstices within the powder bed grow following three distinct modes, i.e., uplift growth, gas channel attachment, and bubble coalescence. Furthermore, melt flow oscillations caused by the bursting of large bubbles can lead to local instability of the melt pool. Results from this study enhance the understanding of bubble dynamics during LPBF and may provide valuable insights for pore elimination in LPBF-processed oxide ceramics.
研究领域:
材料科学
·
制造工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Longyun Zheng,Zhangyu Guo,Hui Liu,Kai Guo,Chunjiang Liu
CO 2 absorption into amine solutions is an important method for reducing carbon emissions. The influence mechanism of chemical reactions on the bubble behavior and mass transfer needs to be comprehensively investigated. In this study, firstly, we measure the bubble behavior and mass transfer of single CO 2 bubbles freely rising in monoethanolamine (MEA)/ N , N -diethylethanolamine (DEEA) blended solutions and DEEA solutions by high-speed photography. Moreover, we investigate the effect of amine concentration on the bubble shape, aspect ratio, rising trajectory, rising velocity, and mass transfer coefficient. The results show that CO 2 bubbles in MEA/DEEA blended solutions experience significant shape deformation, oscillation damping, surface contamination, and mass transfer deterioration. In contrast, CO 2 bubbles in DEEA solutions behave similarly to those in ultrapure water, i.e. negligible surface contamination and mass transfer enhancement. Furthermore, we consider the differences in the bubble behavior and mass transfer from the viewpoint of the chemical reaction kinetics and bubble surface contamination degree. The location where a chemical reaction occurs is close to the bubble surface with a fast reaction, and as a result, the bubble surface is likely to be contaminated. Finally, this study provides insights into the intensification of amine-based CO 2 chemical absorption processes.
研究领域:
化学工程
·
环境科学
✓ 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）