scholarly journals A many-body dissipative particle dynamics with energy conservation study of droplets icing on microstructure surfaces

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Chenyang Wang ◽  
Xiao Wu ◽  
Pengfei Hao ◽  
Feng He ◽  
Xiwen Zhang
Keyword(s):  
Contact Angle ◽  
Dissipative Particle Dynamics ◽  
Real Life ◽  
Transfer Model ◽  
Change Model ◽  
Droplet Volume ◽  
Many Body ◽  
Cold Surface ◽  
One Dimensional ◽  
Large Factor

AbstractDroplets icing has important applications in real life. The icing process of droplets on microstructure is explored based on the MDPDE method in this study. Firstly, the correctness of the heat transfer model was verified by one-dimensional heat conduction simulation, and then the feasibility of the phase change model was verified by investigating the icing process of droplets. The influence of cold surface temperature, droplet volume and contact angle on freezing time of droplets was discussed, and it was found that the temperature of cold surfaces had a greater effect on freezing. We finally explored the influence of different microstructure surfaces on the icing of droplets, and results showed that the presence of microstructures greatly enhanced the anti-icing effect of the surface. In our research, the contact angle is a relatively large factor affecting the icing of droplets. In addition, it was discovered that the droplet had the strongest ability to delay freezing on the surface of triangle microstructures with a contact angle of 157.1°.

Spontaneous motion of droplet in tubes: The effects of surface wettability and segment length

2021 ◽  
pp. 2150358
Author(s):  
Dingni Zhang ◽  
Qianqian Shangguan
Keyword(s):  
Contact Angle ◽  
Dissipative Particle Dynamics ◽  
Stable State ◽  
Tube Length ◽  
Segment Length ◽  
Angle Distribution ◽  
Many Body ◽  
Droplet Flow ◽  
Number Of Segments ◽  
Spontaneous Motion

This work studies the spontaneous droplet flow in tubes with different wettability gradient and number of segments by using a particle-based numerical method, many-body dissipative particle dynamics (MDPD). The study aims to understand how the different contact angle sets (gradient contact angle distribution along with different segments of a tube) and the number of segments could affect the droplet flow velocity and time to reaching a stable state. Simulation results show that even with the same wettability gap, a contact angle set with higher values of contact angle along the tube segments can drive the droplet to flow faster in the tubes; moreover, with the same contact angle set and tube length, the tubes with fewer segments can allow a faster flow of droplet, thus a shorter time to reaching the stable state. The numerical findings in this work can provide a new idea and direction for the design of droplet-based microfluidic systems.

ELECTROWETTING-INDUCED DROPLET JUMPING SIMULATION USING MANY-BODY DISSIPATIVE PARTICLE DYNAMICS

2019 ◽  
Author(s):  
Ting Liu ◽  
Anupam Mishra ◽  
Mohsen Torabi ◽  
Ahmed A. Hemeda ◽  
James Palko ◽  
...  
Keyword(s):  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Many Body

Many-body dissipative particle dynamics study of the local slippage over superhydrophobic surfaces

2021 ◽  
Vol 33 (7) ◽  
pp. 072001
Author(s):  
Liuzhen Ren ◽  
Haibao Hu ◽  
Luyao Bao ◽  
Mengzhuo Zhang ◽  
Jun Wen ◽  
...  
Keyword(s):  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Superhydrophobic Surfaces ◽  
Many Body ◽  
Local Slippage

scholarly journals Undecidability in quantum thermalization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Naoto Shiraishi ◽  
Keiji Matsumoto
Keyword(s):  
Turing Machine ◽  
Thermal Equilibrium ◽  
General Theorem ◽  
Nearest Neighbour ◽  
Many Body ◽  
Initial State ◽  
One Dimensional ◽  
Universal Turing Machine ◽  
Many Body Systems ◽  
Neighbour Interaction

AbstractThe investigation of thermalization in isolated quantum many-body systems has a long history, dating back to the time of developing statistical mechanics. Most quantum many-body systems in nature are considered to thermalize, while some never achieve thermal equilibrium. The central problem is to clarify whether a given system thermalizes, which has been addressed previously, but not resolved. Here, we show that this problem is undecidable. The resulting undecidability even applies when the system is restricted to one-dimensional shift-invariant systems with nearest-neighbour interaction, and the initial state is a fixed product state. We construct a family of Hamiltonians encoding dynamics of a reversible universal Turing machine, where the fate of a relaxation process changes considerably depending on whether the Turing machine halts. Our result indicates that there is no general theorem, algorithm, or systematic procedure determining the presence or absence of thermalization in any given Hamiltonian.

A Many-Body Dissipative Particle Dynamics Study of Forced Water–Oil Displacement in Capillary

Langmuir ◽  
2011 ◽  
Vol 28 (2) ◽  
pp. 1330-1336 ◽  
Author(s):  
Chen Chen ◽  
Lin Zhuang ◽  
Xuefeng Li ◽  
Jinfeng Dong ◽  
Juntao Lu
Keyword(s):  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Many Body ◽  
Oil Displacement

A Model for Predicting Temperature of Electrofusion Joints for Polyethylene Pipes

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Jianfeng Shi ◽  
Jinyang Zheng ◽  
Weican Guo ◽  
Ping Xu ◽  
Yongquan Qin ◽  
...  
Keyword(s):  
Thermal Contact ◽  
Power Input ◽  
Ultrasonic Test ◽  
Thermal Contact Conductance ◽  
Transfer Model ◽  
Contact Conductance ◽  
One Dimensional ◽  
Polyethylene Pipes ◽  
Heating Wire ◽  
Good Agreement

With the increasing application of electrofusion (EF) welding in connecting polyethylene (PE) pipes for gas distribution, more effort has been invested to ensure the safety of the pipeline systems. The objective of this paper is to investigate and understand the temperature distribution during EF welding. A one-dimensional transient heat-transfer model was proposed, taking the variation in the rate of power input, the phase transition of PE, and the thermal contact conductance between heating wire and PE into consideration. Then, experiments were designed to verify the power input and the temperature. The measured values of the power input were shown to be in good agreement with the analytical results. Based on ultrasonic test (UT), a new “Eigen-line” method was presented, which overcomes the difficulties found in the thermocouples’ temperature measurements. The results demonstrate good agreements between prediction and experiment. Finally, based on the presented model, a detailed parametric study was carried out to investigate the influences of the variation in the power input, the physical properties of PE, and the thermal contact conductance between heating wire and surrounding PE.

A Heat Transfer Model of Dropwise Condensation Underneath a Horizontal Substrate

2011 ◽  
Vol 199-200 ◽  
pp. 1604-1608
Author(s):  
Yun Fu Chen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Contact Angle ◽  
Fractal Model ◽  
Condensation Heat Transfer ◽  
Droplet Growth ◽  
Transfer Model ◽  
Dropwise Condensation ◽  
Small Contact Angle ◽  
Horizontal Substrate

For finding influence of the condensing surface to dropwise condensation heat transfer, a fractal model for dropwise condensation heat transfer has been established based on the self-similarity characteristics of droplet growth at various magnifications on condensing surfaces with considering influence of contact angle to heat transfer. It has been shown based on the proposed fractal model that the area fraction of drops decreases with contact angle increase under the same sub-cooled temperature; Varying the contact angle changes the drop distribution; higher the contact angle, lower the departing droplet size and large number density of small droplets; dropwise condensation translates easily to the filmwise condensation at the small contact angle ;the heat flux increases with the sub-cooled temperature increases, and the greater of contact angle, the more heat flux increases slowly.

scholarly journals Multiphase modeling of nitrate photochemistry in the quasi-liquid layer (QLL): implications for NO<sub>x</sub> release from the Arctic and coastal Antarctic snowpack

2008 ◽  
Vol 8 (16) ◽  
pp. 4855-4864 ◽  
Author(s):  
C. S. Boxe ◽  
A. Saiz-Lopez
Keyword(s):  
Gas Phase ◽  
Liquid Layer ◽  
Solar Spectrum ◽  
The Arctic ◽  
Transfer Model ◽  
Multiphase Model ◽  
Gas Phase Reactions ◽  
One Dimensional ◽  
Quasi Liquid Layer ◽  
Summer Range

Abstract. We utilize a multiphase model, CON-AIR (Condensed Phase to Air Transfer Model), to show that the photochemistry of nitrate (NO3−) in and on ice and snow surfaces, specifically the quasi-liquid layer (QLL), can account for NOx volume fluxes, concentrations, and [NO]/[NO2] (γ=[NO]/[NO2]) measured just above the Arctic and coastal Antarctic snowpack. Maximum gas phase NOx volume fluxes, concentrations and γ simulated for spring and summer range from 5.0×104 to 6.4×105 molecules cm−3 s−1, 5.7×108 to 4.8×109 molecules cm−3, and ~0.8 to 2.2, respectively, which are comparable to gas phase NOx volume fluxes, concentrations and γ measured in the field. The model incorporates the appropriate actinic solar spectrum, thereby properly weighting the different rates of photolysis of NO3− and NO2−. This is important since the immediate precursor for NO, for example, NO2−, absorbs at wavelengths longer than nitrate itself. Finally, one-dimensional model simulations indicate that both gas phase boundary layer NO and NO2 exhibit a negative concentration gradient as a function of height although [NO]/[NO2] are approximately constant. This gradient is primarily attributed to gas phase reactions of NOx with halogens oxides (i.e. as BrO and IO), HOx, and hydrocarbons, such as CH3O2.

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