Modelling of water droplets heat and mass transfer in the course of phase transitions. I: Phase transitions cycle peculiarities and iterative scheme of numerical research control and optimization

2016 ◽  
pp. 135-151 ◽  
Author(s):  
Gintautas Miliauskas, ◽  
◽  
Arvydas Adomavičius ◽  
Monika Maziukienė ◽  
◽  
...  
Keyword(s):  
Mass Transfer ◽  
Phase Transitions ◽  
Heat And Mass Transfer ◽  
Iterative Scheme ◽  
Water Droplets ◽  
Numerical Research

scholarly journals Investigation of Regularities of Heat and Mass Transfer and Phase Transitions during Water Droplets Motion through High-Temperature Gases

2014 ◽  
Vol 6 ◽  
pp. 865856 ◽  
Author(s):  
Roman S. Volkov ◽  
Olga V. Vysokomornaya ◽  
Genii V. Kuznetsov ◽  
Pavel A. Strizhak
Keyword(s):  
Mass Transfer ◽  
Phase Transitions ◽  
High Temperature ◽  
Heat And Mass Transfer ◽  
Water Droplet ◽  
Small Neighborhood ◽  
Droplet Evaporation ◽  
Optical Methods ◽  
Water Droplets ◽  
Two Phase

The macroscopic regularities of heat and mass transfer and phase transitions during water droplets motion through high-temperature (more than 1000 K) gases have been investigated numerically and experimentally. Water droplet evaporation rates have been established. Gas and water vapors concentrations and also temperature values of gas-vapor mixture in small neighborhood and water droplet trace have been singled out. Possible mechanisms of droplet coagulation in high-temperature gas area have been determined. Experiments have been carried out with the optical methods of two-phase gas-vapor-droplet mixtures diagnostics (“Particle Image Velocimetry” and “Interferometric Particle Imaging”) usage to assess the adequateness of developed heat and mass transfer models and the results of numerical investigations. The good agreement of numerical and experimental investigation results due to integral characteristics of water droplet evaporation has been received.

Numerical Research of Heat and Mass Transfer Processes in Water Vapors and Gaseous Thermal Decomposition Products Mixture above the Combustible Wood on the Conditions of Chemical Reaction Termination in it

2014 ◽  
Vol 1040 ◽  
pp. 535-540
Author(s):  
Alena O. Zhdanova ◽  
Genii V. Kuznetsov ◽  
Pavel A. Strizhak
Keyword(s):  
Mass Transfer ◽  
Thermal Decomposition ◽  
Heat And Mass Transfer ◽  
Decomposition Reaction ◽  
Decomposition Products ◽  
Transfer Processes ◽  
Water Vapors ◽  
Mass Transfer Processes ◽  
Thermal Decomposition Products ◽  
Numerical Research

The numerical analysis has been made of complex interrelated heat and mass transfer processes, chemical reactions and phase transformations under the thermal decomposition reaction suppression of typical combustible wood (needles of a pine, fir, fir-tree and larch, branches of a pine, fir, birch and larch, cones of a pine, leaves of aspen) by the “water slug” trace. Characteristic times have been calculated of the thermal decomposition reaction suppression of typical combustible wood at typical temperatures in “water slug” trace and the thickness of warmed material layers.

scholarly journals Modelling of Heat and Mass Transfer for Wire-Based Additive Manufacturing Using Electric Arc and Concentrated Sources of Energy

2018 ◽  
Vol 7 (4.38) ◽  
pp. 741
Author(s):  
Dmitriy Trushnikov ◽  
Anatoly Perminov ◽  
Shengyong Pang ◽  
K. P. Karunakaran ◽  
Vladimir Belenkiy ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Phase Transitions ◽  
Additive Manufacturing ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Initial Temperature ◽  
Fluid Motion ◽  
Density Variation ◽  
Phase Region ◽  
Two Phase

The paper presents a model developed by the authors and aimed to describe heat and mass transfer during wire-based additive manufacturing, when electron beam, plasma or arc are used as energy sources in case of non-consumable electrode welding. The model describes non-stationary and non-equilibrium conjugated processes of heat and mass transfer in free-surface liquid metal. The solution of differential equations of viscous fluid motion (Navier-Stokes), with convective terms and at laminar flow, has become the model base. Melting and crystallization of the metal is recognized by heat release in a two-phase region. The material density variation during phase transitions of the first and the second order can be described by introducing a certain dependence on temperature. The model is able to consider the use of preliminary and additional induction heating by changing the initial temperature and establishing an additional distributed bulk heat source. Variables for the simulation of heat and mass transfer during additive formation are the intensity and type of the heat source, the plate initial temperature, the power density distribution, the intensity of the additional bulk heating, the dependence of material thermal and physical characteristics on temperature, the characteristics of the phase transitions, the motion velocity of the heat source, the rate of wire feeding. 

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