Touhami Baki^a,*, Djamel Sahel^a , Ahmed Guessab^b

Frontiers in Heat and Mass Transfer, Vol.9, pp. 1-7, 2017, DOI:10.5098/hmt.9.14

Abstract Boiling is influenced by a large number of parameters; the angle of orientation constitutes one of these parameters which have a positive impact on the heat transfer. The dynamic of the bubble plays a significant role in the improvement of heat transfer during boiling. For this reason, we are located on the bubble scale and we simulated the detachment of vapor bubble in the liquid water on a heated surface, when the angle of orientation varies from 0 to 180°. We followed the evolution of the sliding of the bubble; it appears that the thermal boundary layer is disturbed and… More >

Yun Whan Na^* , J. N. Chung^†

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-14, 2018, DOI:10.5098/hmt.11.36

Abstract Flow instabilities of convective two-phase boiling in a trapezoidal microchannel were investigated. using a three-dimensional numerical model. Parameters such as wall temperature and inlet pressure that characterize the instability phenomena of flow boiling with periodic flow patterns were studied at different channel wall heat fluxes and flow mass fluxes. Results were obtained for various wall heat flux levels and mass flow rates. The numerical results showed that large amplitude and short period oscillations for wall temperature and inlet pressure fluctuations are major characteristics of flow instability. The wall temperature fluctuations are mainly initiated by the transition from bubbly to slug… More >

Clement Roy^a,* , Prasanna Venuvanalingam^b , James F. Klausner^a , Renwei Mei^c

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-12, 2018, DOI:10.5098/hmt.11.1

Abstract This article presents both an experimental and numerical study of both stationary and sliding bubbles in a horizontal duct with forced convection heat transfer. An experimental facility was fabricated using a fully transparent, electrically-heated test section in which the bubble dynamics and the thermal field on the heated wall can be acquired using high-speed cameras and Thermochromic Liquid Crystals (TLC). Experiments were conducted using the working fluid HFE 7000 for two different turbulent Reynolds numbers. The experimental temperature field in the span-wise direction is first compared to the numerically calculated temperature field of a bubble sliding near a wall and… More >

B.G. Suhas^a,* , A. Sathyabhama^b, Kavadiki Veerabhadrappa^a , R. Suresh Kumar^a, U. Kiran Kumar^a

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.16

Abstract In the present study, heat transfer coefficient of water-ethanol mixture in the subcooled boiling region is determined in a rectangular conventional channel (Channel size ≥3 mm). When the heat flux and mass flux increase it is observed that heat transfer coefficient increases. But the effect of heat flux is significant when compared with that of mass flux in the subcooled boiling region. It is found that maximum and minimum heat transfer coefficient are observed for mixture with 25% Ethanol volume fraction and 75% Ethanol volume fraction respectively. Wall heat flux partitioning analyses is carried out for mixture with different ethanol… More >

Wenlei Lian, Zijian Sun, Taoyi Han, Yimin Xuan^*

Frontiers in Heat and Mass Transfer, Vol.14, pp. 1-6, 2020, DOI:10.5098/hmt.14.10

Abstract An experimental facility is developed to investigate the characteristics of the nucleate boiling heat transfer in a rotating water film. The High speed photography technique is used to visualize the flow field of the rotating water film. Along with the bubble photographs, the centrifugal acceleration, heat flux into the film, and the heat transfer coefficient are calculated to learn the heat transfer characteristics of the water film. It is found that the boiling heat transfer coefficient decreases with the increment of heat flux. The heat transfer coefficient increases with acceleration increasing from 20g to 60g, but show no obvious increase… More >

Shuang Cao^a,*, Hui Yang^a, Luxing Zhao^a, Tao Wang^a, Jian Xie^b,†

Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-16, 2021, DOI:10.5098/hmt.17.17

Abstract Flow boiling heat transfer is an effective way to fulfill the energy transfer. The wettability of boiling surface influences the liquid spreading ability and the growth, departure, and release frequency of bubbles, which determines the heat transfer performance. According to the wettability and combination forms, boiling surface are classified into weak wetting surface, strong wetting surface, and heterogeneous wetting surface. Fabricating by physical, chemical method or coating the original surface with a layer of low surface energy, the weak wetting surface has more effective activation point and nucleation center density to improve heat transfer performance at low heat flux. The… More >

Ningbo Guo, Xianming Gao^*, Duanling Li, Jixing Zhang, Penghui Yin, Mengyi Hua

CMES-Computer Modeling in Engineering & Sciences, Vol.136, No.3, pp. 3061-3082, 2023, DOI:10.32604/cmes.2023.026657

Abstract Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted. The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80 μm and a depth of 40, 60, and 80 μm were compared during the boiling process, and the factors influencing bubble generation were studied. A visual test bench was built, and test substrates of different sizes were prepared using a micro-nano laser. During the test, the behavior characteristics of the bubbles on the boiling surface and the temperature… More >

Baris Burak Kanbur, Sheng Quan Heng, Fei Duan^*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1711-1718, 2022, DOI: 10.32604/fdmp.2022.021792

Abstract The present study considers the impingement of a train of ethanol droplets on heated aluminum and glass surfaces. The surface temperature is allowed to vary in the interval 140°C–240°C. Impingement is considered with an inclination of 63 degrees. The droplet diameter is 0.2 mm in both aluminum and glass surface experiments. Thermal gradients are observed with a thermographic camera. It is found that in comparison to glass, the aluminum surface displays very small liquid accumulations and better evaporation performance due to its higher thermal conductivity. The relatively low thermal conductivity of glass results in higher thermal gradients on the surface.… More > Graphic Abstract

Baris Burak Kanbur, Sheng Quan Heng, Fei Duan^*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1331-1338, 2022, DOI:10.32604/fdmp.2022.021793

Abstract Steady-state hydrodynamic patterns of ethanol droplet train impingement on the heated aluminum surface is investigated in the surface temperature range of 80°C–260°C using two different Weber numbers (We) of 618 and 792. Instead of a vertical train impingement, the droplet train is sent to the aluminum surface with an incline of 63 degrees. Changes in the spreading length are observed at different surface temperatures for two different We values, which are obtained by using two different pinholes with 100 and 150 μm diameters. The greatest spreading length is seen at the lowest surface temperature (80°C) and it continuously decreases until… More >

Xiaoyu Hu, Yi Wang, Siyuan Li, Qiang Sun, Shuzhan Bai, Guoxiang Li^*, Ke Sun^*

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1049-1066, 2021, DOI:10.32604/fdmp.2021.016763

Abstract The increasing demand of cooling in internal combustion engines (ICE) due to engine downsizing may require a shift in the heat removal method from the traditional single phase liquid convection to the application of new technologies based on subcooled fluid boiling. Accordingly, in the present study, experiments based on subcooled flow boiling of 50/50 by volume mixture of ethylene glycol and water coolant (EG/W) in a rectangular channel heated by a cast iron block are presented. Different degrees of subcooling, velocity and pressure conditions are examined. Comparison of three empirical reference models shows that noticeable deviations occur especially when low… More >