scholarly journals Modeling of the Drying Kinetics of Slurry Droplet in Spray Drying

2012 ◽  
Vol 11 (2) ◽  
pp. 1 ◽  
Author(s):  
Boris Golman
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Spray Drying ◽  
Parametric Study ◽  
Suspended Solids ◽  
Droplet Diameter ◽  
Gas Temperature ◽  
Drying Time ◽  
Droplet Drying ◽  
Kinetics Of

The detail analysis of the heat and mass transfer between the droplet containing suspended solids and the drying gas was carried out numerically. The temperature and moisture distributions within the slurry droplet were calculated during the first and second drying phases. The parametric study revealed that the droplet drying time decreases with increasing the drying gas temperature and decreasing the droplet diameter.

scholarly journals Research of High-Temperature Heat and Mass Transfer and Kinetics of Phase Transformations during combustion higher alkanes in the air

2015 ◽  
Vol 16 (2) ◽  
pp. 347-350
Author(s):  
S.G. Orlovska ◽  
A.O. Odnostalko ◽  
F.F. Karimova ◽  
M.S. Shkoropado
Keyword(s):  
Mass Transfer ◽  
High Temperature ◽  
Phase Transformations ◽  
Burning Rate ◽  
Heat And Mass Transfer ◽  
Rate Constants ◽  
Room Temperature ◽  
Combustion Kinetics ◽  
Temperature Heat ◽  
Kinetics Of

 The paper presents a study of high-temperature heat and mass transfer and combustion kinetics of octadecane particle in room temperature air taking in consideration fuel heating, melting and evaporation. The consecutive stages of droplet combustion are described. Burning rate constants and flame heights are determined for droplets with different initial diameters

scholarly journals МАТЕМАТИЧЕСКАЯ МОДЕЛЬ И МЕТОД РАСЧЕТА ДИНАМИКИ СУШКИ И ТЕРМОДЕСТРУКЦИИ БИОМАССЫ

2018 ◽  
Vol 82 (1) ◽  
Author(s):  
Наталья Николаевна Сороковая ◽  
Дмитрий Николаевич Коринчук
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Thermal Decomposition ◽  
Numerical Method ◽  
Heat And Mass Transfer ◽  
The Body ◽  
Physical Factors ◽  
Deformation Equation ◽  
The Mathematical Model ◽  
Kinetics Of

Разработана математическая модель и численный метод расчета динамики тепломассопереноса, фазовых превращений и усадки при сушке коллоидных капиллярно-пористых тел цилиндрической формы в условиях равномерного обдува теплоносителем. Математическая модель строилась на базе дифференциального уравнения переноса субстанции (энергии, массы, импульса) в деформируемых системах. Проведены экспериментальные исследования кинетики обезвоживания частиц энергетической вербы в потоке воздуха с целью верификации математической модели. Обоснована возможность ее использования для расчета совместных процессов сушки и начального этапа термического разложения биомассы. С использованием ранее полученных данных по значениям энергии активации Аэф(Т) для различных видов биомассы проведено математическое моделирование динамики и кинетики высокотемпературной сушки в потоке дымовых газов энергетической вербы, которая сопровождается термодеструкцией гемиоцеллюлозы. Результаты численных экспериментов свидетельствуют об адекватности предложенного подхода, эффективности математической модели и метода ее реализации. На их основе возможно проводить исследование динамики тепломассопереноса при сушке частиц различных видов измельченной биомассы; определение температуры начала и окончания первой стадии термического разложения; момента достижения равновесного влагосодержания в зависимости от свойств материала и сушильного агента. Эти данные позволяют выбирать оптимальные с точки зрения сохранения энергии и качества высушиваемого продукта  режимные параметры процесса.         A mathematical model and a numerical method for calculating the dynamics of heat and mass transfer, phase transformations and shrinkage during the drying of colloidal capillary-porous cylindrical bodies under conditions of equitable winding by a coolant are developed. The mathematical model was based on the differential equation of substance (energy, mass, impulse) transfer in deformable systems. It includes the equations diffusion-filtration transfer of energy for the system as a whole, and the mass transfer of the liquid, vapor and air phases in the pores of the body. Expressions for the intensity of evaporation of a liquid, capillary pressure, and the diffusion coefficients are presented. The relative volume strain was found by means of an analytical solution of the thermoconcentration deformation equation. Based on the explicit three-layer counting difference scheme and the procedure splitting of algorithm  by physical factors, a numerical method for realizing this mathematical model is developed.Experimental studies of the kinetics of dehydration of energy willow particles in the airflow were carried out to verify the mathematical model. Its applicability for calculating combined processes of drying and of the initial stage of thermal decomposition of biomass is substantiated. Using the previously obtained data on the activation energy values for various types of biomass, a mathematical simulation of the dynamics and kinetics of high-temperature drying in the flue gas flow of energy willow was carried out, which is accompanied by thermal destruction of hemiocellulose. The results of numerical experiments indicate the adequacy of the proposed approach, the effectiveness of the mathematical model and the method of its implementation. On their basis, it is possible to study the dynamics of heat and mass transfer when drying particles of different types of ground biomass; determination of the temperature of the beginning and ending of the first stage of thermal decomposition; the moment when the equilibrium moisture content is reached, depending on the properties of the material and the drying agent. These data allow choosing the process parameters that are optimal in terms of energy saving and quality of the dried product.

A Short Review on Fluidized Bed Dryer

2021 ◽  
pp. 104-105
Author(s):  
Akash H. Mali ◽  
Aditya R. Nikam ◽  
Azam Z. Shaikh.
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Short Review ◽  
High Heat ◽  
Drying Process ◽  
Drying Time ◽  
Fluidized Bed Dryer ◽  
Advantages And Disadvantages ◽  
Fluidized Bed Drying

This artical also discusses about demostration of fluidized bed dryer with principle and application and other processing. This has lead to development of thechnology, process and equipments which not only reduce time but also increasing the output. A Fluidized bed dryer significantely reduce drying time, compared with vaccum dryer or tray dryer. In the pharmacutical industry, fluidized bed dryer are typically used for pellets drying, coating and granulation. Fluidized bed drying are very well known to yield high heat and mass transfer and hence adopted to many industrial drying process particularly pharmacy product. In this paper we show construction, working of the fluidized bed dryer. It work on the drying principle. It has several advantages and disadvantages.

Evaluation of Convective Heat and Mass Transfer in Open Sun and Green House Drying

2008 ◽  
Author(s):  
S. K. Shukla
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Ambient Air ◽  
Natural Mode ◽  
Transfer Coefficients ◽  
Drying Time ◽  
Sun Drying ◽  
Green House ◽  
Hourly Data

In this communication, a study on open sun and green house drying has been performed to evaluate the convective heat and mass transfer coefficients as a function of climatic parameters. The hourly data for the rate of moisture removal, crop temperature, relative humidity inside greenhouse and outside greenhouse and ambient air temperature for complete drying have been recorded. The experiments were done in the premises of Allahabad Agricultural Institute-Deemed University, after the crop-harvesting season from February 2006 to April 2006. Using these data, the value of convective heat and mass transfer in open sun drying (OSD) and green house sun drying (GHD) under natural and forced convection mode, have been calculated. Also the empirical relations of convective heat and mass transfer with drying time under natural and forced modes have been developed. On the basis of the present study, it is inferred that the value of convective heat and mass transfer is more in open sun drying than in the green house drying under natural convection mode. However its value increases in forced mode of greenhouse drying as compared to natural mode in the initial stage of drying.

scholarly journals Heat and Mass Transfer of Droplet Vacuum Freezing Process Based on Dynamic Mesh

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Lili Zhao ◽  
Yuekai Zhang ◽  
Zhijun Zhang ◽  
Xun Li ◽  
Wenhui Zhang
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Droplet Diameter ◽  
Dynamic Mesh ◽  
Freezing Process ◽  
Freezing Time ◽  
Droplet Temperature ◽  
Obvious Effect ◽  
Initial Droplet ◽  
Vacuum Freezing

A numerical simulation using dynamic mesh method by COMSOL has been developed to model heat and mass transfer during vacuum freezing by evaporation of a single droplet. The initial droplet diameter, initial droplet temperature, and vacuum chamber pressure effect are studied. The surface and center temperature curve was predicted to show the effect. The mass transfer rate and radius displacement were also calculated. The results show the dynamic mesh shows well the freezing process with the radius reduction of droplet. The initial droplet diameter, initial droplet temperature, and vacuum pressure have obvious effect on freezing process. The total freezing time is about 200 s, 300 s, and 400 s for droplet diameter 7.5 mm, 10.5 mm, and 12.5 mm, respectively. The vacuum pressure less than 200 Pa is enough for the less time to freezing the droplet, that is, the key point in freezing time. The initial droplet temperature has obvious effect on freezing but little effect on freezing temperature.

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