Article
Thermodynamics
Utsav Bhardwaj, Rabindra Kumar, Shyama Prasad Das
Summary: This study presents an experimental investigation on flooding phenomenon in a pulsating heat pipe (PHP) unit cell, and analyzes the impact of flooding on the performance of PHP. The study recognizes three different flooding mechanisms and finds that currently accepted correlations for predicting flooding velocity are inaccurate. The study emphasizes the need for further research on flooding in PHPs.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: Liquid jet impact cooling is widely used in various industries. This study focuses on the transient cooling characteristics of laminar jet impacting on cylindrical cooling targets. The results reveal that the transient process of jet impact can be divided into non-wetted, developing wetted, and fully wetted stages, and the durations of these stages vary with the jet outlet velocity and impact height. Distinctions are observed in the durations of each transient stage and a secondary inflection point in surface temperature variation due to secondary mixing of the liquid film.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
G. Marseglia, M. G. De Giorgi, P. Pontes, R. Solipa, R. R. Souza, A. L. N. Moreira, A. S. Moita
Summary: This paper investigates the advantages and challenges of two-phase flows, specifically flow boiling of pure liquids and nanofluids, for cooling microchannel heat sinks. The study finds that even at low concentrations, the water-Au nanofluid exhibits superior cooling performance compared to other fluids, indicating that even small concentrations of nanoparticles can significantly impact heat transfer mechanisms.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yujun Gou, Yi Qin, Jiachun Li, Xiaohui Zhong, Jia Han, Wenbo Zhang
Summary: This study investigated the effect of magnetic field on droplet freezing using a visualization system. The results showed that the supercooling degree and freezing time of droplets were influenced by magnetic field intensity, cold surface temperature, and droplet volume.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yunpeng Xue, Yongling Zhao, Shuo-Jun Mei, Yuan Chao, Jan Carmeliet
Summary: This study investigates the impact of building morphology on local climate, air quality, and urban microclimate. The researchers conducted an experimental investigation in a large-scale water tunnel, analyzing heat and flow fields using Laser-induced Fluorescence (LIF) and Particle Image Velocimetry (PIV). The findings show that factors such as canyon configuration, buoyant force, and approaching flow magnitude significantly influence fluid flow in street canyons, and the morphology of the street canyon dominates ventilation rate and heat flux. For example, changing the aspect ratio of a street canyon can lead to a significant change in air ventilation rate, ranging from 0.02 to 1.5 under the same flow conditions.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Sangwook Jin, Hojin Choi, Jong-Ryul Byun, Gisu Park
Summary: The combustion characteristics of a liquid-hydrocarbon-fueled dual-mode ramjet combustor with a new injector, including a cavity-type flame holder, were investigated. The results showed that the combustor operated in the ramjet mode, with subsonic flow near the flame holder and supersonic flow at the exit. The new injector exhibited higher pressure levels, steep increase, and more uniform pressure distribution at the combustor exit compared to the baseline injector.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Jiangyou Long, Junwei Wu, Yujun Zhou, Xiaozhu Xie
Summary: This study investigates the capillary-fed evaporation/boiling process and finds that the critical heat flux decreases by 51.8% after five boiling cycles using a grooved wick fabricated by ultrafast laser micromachining. Analysis reveals that the decrease in critical heat flux is caused by the degradation of hydrophilicity in the evaporator. The study also demonstrates that nanoporous surfaces can effectively mitigate the undesired hydrophilicity degradation.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Weilin Zheng, Qijiao Wang, Xiaoxiao Chen, Fan Xie, Hongyu Ma, Wen Zeng
Summary: Experiments were conducted on the expanding flame of turbulent premixed natural gas/air mixtures in a fan-stirred turbulent combustor for the first time. The results showed that methane cannot be used as a representative for studying turbulent burning velocities of natural gas. A new correlation based on the ratio of Karlovitz number and Damköhler number was proposed to describe the characteristics of turbulent flames.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Faiz Azhar Masoodi, Rahul Goyal
Summary: The presence of vortex breakdown in hydraulic turbines hampers their operational flexibility and affects pressure fluctuations and efficiency.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Syed Ehtisham Gillani, Yasir M. Al-Abdeli
Summary: This study investigates the asymmetry in bluff-body stabilised annular jets and finds that swirl can significantly mitigate the asymmetry and restore the symmetry of the jets. Moreover, increasing the Reynolds number and the swirl intensity can both decrease the asymmetry of the jets.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Longjuan Ji, Jinhua Wang, Weijie Zhang, Deli Li, Guangya Hu, Zuohua Huang
Summary: The nonlinear behavior of thermoacoustic oscillation for premixed swirl flames fueled with CH4/air mixtures is experimentally studied. The study reveals the effects of changing equivalence ratio phi, combustor inlet bulk velocity Uin, and swirl number S on the flame modes and oscillations. The study also shows the relationship between the appearance of flame in the outer circulation zone and the occurrence of quasi-periodic and limit cycle oscillations. Furthermore, the study finds that the lean/rich blow-off limits and oscillation range are extended with a larger S, while the stable combustion regime is wider with a smaller S.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Hailing Yu, Xin Zhou, Hong Wang, Qian Zhang, Xun Zhu, Yu Dong Ding, Rong Chen, Qiang Liao
Summary: Investigating the dynamic behavior of water droplets impacting on superhydrophobic surfaces in a supercooled environment is crucial for preventing icing. This study visualized the dynamic behavior of the impacting droplets using a high-speed camera and emphasized the effect of temperature difference on the droplets' behavior. The results showed that viscosity plays a significant role in the behavior of the droplets, and there are interesting phenomena observed when the surface or droplet temperature changes. The study provides valuable insights for the development of anti-icing technology.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Aoyue Hong, Qiang Xu, Shuaizhi Jiang, Xiangyu Li, Qimeng Liu, Liejin Guo
Summary: This paper investigates the interface behavior and sound pressure oscillation of a steam jet in flowing water through experiments and analysis. Two typical condensation regimes are observed under low steam mass flux, and the intensities of interface oscillation and sound pressure oscillation decrease with increasing steam mass flux. It is quantitatively confirmed that the sound pressure oscillation is primarily caused by the interface oscillation.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Xuanqi Liu, Yufeng Lai, Callum Fisk, Jon Willmott, Huaichun Zhou, Yang Zhang
Summary: A comprehensive study was conducted on the effect of incorporating a woven mesh with varying mesh numbers and positions into the downstream region of a Rijke tube, revealing its ability to change oscillation frequency, suppress amplitude, and influence system dynamics.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Andrey G. Zditovets, Nickolay Kiselev, Yurii A. Vinogradov, Sergey Popovich
Summary: Moist air expansion in supersonic nozzles leads to spontaneous condensation due to a sudden decrease in temperature and pressure. However, in the near-wall boundary layer, the moist air temperature decreases slightly, resulting in the vapor remaining overheated and condensation not spreading fully. This process causes cooling of the near-wall gas layers and a decrease in the adiabatic wall temperature.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Anthony Graziani, Virginie Tihay-Felicelli, Paul-Antoine Santoni, Yolanda Perez-Ramirez, Frederic Morandini, Antoine Pieri, William Mell
Summary: With climate change, complex fire scenarios at Wildland Urban Interfaces (WUI) have become a growing concern. This study investigates the relationship between the properties of flames generated by a reconstructed rockrose hedge and atmospheric wind turbulence using field-scale experiments. The results show similarities in phase durations and dynamics of the fires, but also reveal dependencies on Reynolds number and turbulent kinetic energy. Additionally, a slight flapping motion of the flames and its association with the turbulent cascade in the kinetic energy power spectra are observed.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
J. Braun, I. Rahbari, G. Paniagua, P. Aye-Addo, J. Garicano-Mena, E. Valero, S. Le Clainche
Summary: Investigation of a canonical wavy surface exposed to a Mach 2 flow reveals its unsteady characteristics and different flow features through various measurement methods.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Liuyang Yang, Dalei Zhang, Haiming Fan, Xikun Fu, Runze Yan, Zhiyi Wei, Huiliang Wu
Summary: The effects of flow accelerated corrosion (FAC) on pipeline defects, specifically localized corrosion mechanisms in depressions and welded joints with weld reinforcements, were investigated using wire beam electrode (WBE) techniques and fluid dynamics simulations. Findings showed that swirling vortex and fluid separation in the weld reinforcement can accelerate localized corrosion. Pressure fluctuations in the upper and trailing edge regions of depressions and the weld toes, as well as enhanced interfacial mass transfer processes, result in severe localized corrosion failure.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Hu Hao, Biao Hao, Weihang Kong, Jiliang Chen, Xiaodan Zhang
Summary: This study presents the design and development of an integrated optical-electrical coaxial cross-modal probe sensor (IOECCMPS) for measuring phase volume fraction in oil-water-gas flow. The results demonstrate that the IOECCMPS is capable of accurately measuring the phase volume fraction in multi-phase flows, providing valuable insights for oil production monitoring technology.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yingnan Shen, Liang Hu, Xin Fu
Summary: This study provides an initial understanding of the transition from bubbling to jetting of submerged jets generated by gas-liquid mixing flows through a minichannel into water. It is found that different flow patterns lead to different jet behaviors, and the presence of liquid phase in mixing flows promotes the transition from bubbling to jetting.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
