scholarly journals Mathematical Model of a Flash Drying Process

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Erik W. Aslaksen
Keyword(s):  
Mathematical Model ◽  
Inert Atmosphere ◽  
Industrial Applications ◽  
Economic Importance ◽  
Drying Process ◽  
Basic Model ◽  
Coal Particles ◽  
Heat And Moisture ◽  
Flash Drying

The paper presents a basic model of the flash drying process, as it is applied in a number of industrial applications, and illustrates this by means of a particular application: the drying of subbituminous coal. Besides its economic importance, that application is representative of those where the product is combustible, so that the drying needs to be conducted in an inert atmosphere, which is achieved by recycling some of the drying gas. A novel feature of the model is that it takes explicit account of the transport of heat and moisture within the coal particles. The model provides the basis for the development of a tool to support the design of a flash drying plant.

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

Control and Optimized Management of Grain Drying in Forced-Aerated Bins

2019 ◽  
pp. 199-229
Author(s):  
Alexey Nicolaevich Vasiliev ◽  
Alexey Alexeevich Vasiliev ◽  
Dmitry Budnikov ◽  
Dmitry Tikhomirov ◽  
Asan Bekeshovich Ospanov
Keyword(s):  
Mathematical Model ◽  
Ambient Air ◽  
Central Cylinder ◽  
Informational Entropy ◽  
Drying Process ◽  
Moisture Exchange ◽  
Physical Description ◽  
Grain Drying ◽  
Analytic Expression ◽  
Heat And Moisture

In the chapter, both informational and system-based approaches have been applied to the analysis of grain drying process as an interaction of two systems, namely, “drying agent” and “grain layer.” It made it possible to evaluate the information content of the process. Analytic expression has been obtained for grain layer informational entropy variations which enabled to make the conclusion that an adequate physical description of grain drying process has to include ambient air parameters control, as well as that of drying agent's parameters in its exit out of a grain layer, as well as parameters of both drying agent and grain in one point of grain layer. A mathematical model of heat-and-moisture exchange in dense grain layer has to be applied. As a result of modeling, it has been proved that the sensors of both drying agent and grain parameters have to be located at a distance of 10 to 11 cm from the central cylinder of the forced-aerated drying bin.

scholarly journals Heat and Moisture Transport in Multi-Layer Walls: Interaction and Heat Loss at Varying Outdoor Temperatures / Siltuma Un Mitruma Pārnese Caur Daudzslāņainām Būvkonstrukcijām: Āra Temperatūras Izmaiņu Ietekme Uz Siltuma Zudumiem Iekštelpā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 32-43 ◽  
Author(s):  
A. Ozolinsh ◽  
A. Jakovich
Keyword(s):  
Mathematical Model ◽  
Energy Efficiency ◽  
Moisture Transport ◽  
Heat Losses ◽  
Condensate Formation ◽  
Heat And Moisture Transport ◽  
U Value ◽  
Technical Solutions ◽  
Heat And Moisture ◽  
Humidity Profiles

Abstract The heat and moisture transport in multi-layer walls is analysed for five building units. Using the developed program, a typical of Latvian conditions temperature and relative humidity profiles in multi-layered constructions has been obtained and the indoor heat losses estimated. Consideration is also given to the risk of condensate formation and to the influence of moisture on the U-value. The created mathematical model allows forecasting the energy efficiency and sustainability of different technical solutions as refer to the heat and moisture transport in buildings.

A Novel Approach of Fabricating Monodispersed Spherical MoSiBTiC Particles for Additive Manufacturing

2021 ◽  
Author(s):  
Zhenxing Zhou ◽  
Suxia Guo ◽  
Weiwei Zhou ◽  
Naoyoki Nomura
Keyword(s):  
Additive Manufacturing ◽  
Melting Process ◽  
Industrial Applications ◽  
Elemental Distribution ◽  
Drying Process ◽  
High Concentration ◽  
Novel Approach ◽  
Composition Ratios ◽  
Mesh Structures ◽  
Ejection Method

Abstract It is very challenging to fabricate spherical refractory material powders for additive manufacturing (AM) because of their high melting points and complex compositions. In this study, a novel technique, freeze-dry pulsated orifice ejection method (FD-POEM), was developed to fabricate spherical MoSiBTiC particles without a melting process. Elemental nanopowders were dispersed in water to prepare a high-concentration slurry, which was subsequently extruded from an orifice by diaphragm vibration and frozen instantly in liquid nitrogen. After a freeze-drying process, spherical composite particles with arbitrary composition ratios were obtained. The FD-POEM particles had a narrow size range and uniform elemental distribution. Mesh structures were formed within the FD-POEM particles, which was attributed to the sublimation of ice crystals. Furthermore, owing to their spherical morphology, the FD-POEM particles had a low avalanche angle of 42.6°, exhibiting good flowability. Consequently, the combination of FD-POEM and additive manufacturing has great potential for developing complex refractory components used in industrial applications.

scholarly journals The control system of the yeast drying process

2018 ◽  
Vol 241 ◽  
pp. 01022 ◽  
Author(s):  
Piotr Wolszczak ◽  
Waldemar Samociuk
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Temperature Control ◽  
Object Identification ◽  
Control Methods ◽  
Drying Process ◽  
Process Flow ◽  
Non Linear ◽  
Linear Object

The article presents the results of choosing how to control a real non-linear object. Yeast drying requires a precise temperature control due to the possibility of overheating. The object changes properties during of the process flow. Object identification is used and a mathematical model is developed. The model is used to select roboust control methods. The results are compared to the system of two PID regulators used in practice.

scholarly journals Modeling Drying of Degenerated Calluna vulgaris for Wildfire and Prescribed Burning Risk Assessment

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 759 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Mass Loss ◽  
Diffusion Coefficients ◽  
Prescribed Burning ◽  
Fire Hazard ◽  
Fire Risk ◽  
Calluna Vulgaris ◽  
Fire Danger ◽  
Drying Process

Research highlights: Moisture diffusion coefficients for stems and branches of degenerated Calluna vulgaris L. have been obtained and a mathematical model for the drying process has been developed and validated as an input to future fire danger modeling. Background and objectives: In Norway, several recent wildland–urban interface (WUI) fires have been attributed to climate changes and accumulation of elevated live and dead biomass in degenerated Calluna stands due to changes in agricultural activities, i.e., in particular abandonment of prescribed burning for sheep grazing. Prescribed burning is now being reintroduced in these currently fire prone landscapes. While available wildfire danger rating models fail to predict the rapidly changing fire hazard in such heathlands, there is an increasing need for an adapted fire danger model. The present study aims at determining water diffusion coefficients and develops a numerical model for the drying process, paving the road for future fire danger forecasts and prediction of safe and efficient conditions for prescribed burning. Materials and methods: Test specimens (3–6 mm diameter) of dead Calluna stems and branches were rain wetted 48 h and subsequently placed in a climate chamber at 20 °C and 50% relative humidity for mass loss recordings during natural convection drying. Based on the diameter and recorded mass versus time, diffusion coefficients were obtained. A numerical model was developed and verified against recoded mass loss. Results: Diffusion coefficients were obtained in the range 1.66–10.4 × 10−11 m2/s. This is quite low and may be explained by the very hard Calluna “wood”. The large span may be explained by different growth conditions, insect attacks and a varying number of years of exposure to the elements after dying. The mathematical model described the drying process well for the specimens with known diffusion coefficient. Conclusions: The established range of diffusion coefficients and the developed model may likely be extended for forecasting moisture content of degenerated Calluna as a proxy for fire danger and/or conditions for efficient and safe prescribed burning. This may help mitigate the emerging fire risk associated with degenerated Calluna stands in a changing climate.

Numerical Simulation of Boiling Flows Using an Eulerian Multi-Fluid Model

2005 ◽  
Author(s):  
J. Han ◽  
D.-M. Wang ◽  
D. Filipi
Keyword(s):  
Mathematical Model ◽  
Fluid Model ◽  
Bubble Diameter ◽  
Interfacial Area ◽  
Nucleate Boiling ◽  
Industrial Applications ◽  
Turbulent Dispersion ◽  
Steady State Mode ◽  
Simple Method ◽  
Bubble Number

A mathematical model to simulate boiling flows in industrial applications is presented. Following the Eulerian multifluid framework, separate sets of mass, momentum, and energy conservation equations are solved for liquid and vapor phases, respectively. The interactions between the phases are accounted for by including relevant mass, momentum, heat exchanges and turbulent dispersion effects. Velocity-pressure coupling is achieved through a multiphase version of the SIMPLE method and the standard k-ε turbulence model is employed. In order to validate and assess the accuracy of the boiling model, subcooled nucleate boiling flows in a vertical annular pipe are simulated in the steady-state mode. The computed axial velocities, volume fractions, temperature profiles are compared with available experimental data (Roy et al., ASME J. of Heat Transfer, Vol. 119, 1997). The result obtained by assuming a constant value for the bubble diameter shows a reasonable agreement, but several limitations are observed in the details. A more advanced mathematical model incorporating separate transport equations for the bubble number density and the interfacial area is suggested.

Case Studies of Coupled Heat and Moisture Diffusion in Wool Beds

1969 ◽  
Vol 39 (2) ◽  
pp. 166-172 ◽  
Author(s):  
H. G. David ◽  
P. Nordon
Keyword(s):  
Mathematical Model ◽  
Relative Humidity ◽  
Heat Flow ◽  
Case Studies ◽  
Satisfactory Agreement ◽  
Moisture Diffusion ◽  
Wool Fabrics ◽  
Flow Through ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

The predictions from a previously developed mathematical model for coupled heat and moisture diffusion in beds of hygroscopic fibers have been tested against experimental observations on wool bales and wool fabrics. The experiments on wool bales were concerned with the changes in regain and temperature consequent upon changes in the relative humidity and temperature of the surrounding air. The experiments on fabrics included measurements of temperature and regain during Hoffman pressing and measurements of heat flow through the fabric during changes in regain. Satisfactory agreement was found between the predictions from the model and the experimental observations.

A Novel Method of Obtaining Honing Tool Profile for Machining Gears With Profile Modifications

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Michał Batsch
Keyword(s):  
Mathematical Model ◽  
Design Process ◽  
High Precision ◽  
Prediction Error ◽  
Industrial Applications ◽  
Helical Gears ◽  
Profile Deviation ◽  
Tool Profile ◽  
Novel Method ◽  
Two Parameter

Abstract In this study, a mathematical model of the honing process for helical gears with external teeth was developed. The proposed novel method of obtaining the two-parameter envelope of a family of surfaces proved useful in simulated machining by means of a tool with a profile deviation. Based on performed simulations and industrial applications, it was found that this method can be useful in predicting the accuracy of machined gear and therefore can be used in the design process of honing tool for high precision aerospace gears. For the example provided, the average absolute prediction error of machined tooth profile was 0.28 µm.

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