Wyniki wyszukiwania - BazTech

1

Impact of friction coefficient on particles circulation velocity calculated by euler-lagrange model in spouted bed apparatus for dry coating

Ludwig W.

Technical Sciences / University of Warmia and Mazury in Olsztyn

|

2018

|

nr 21(4)

303--321

EN

This paper is a continuation of research concerning gas-solid flow modelling using the Euler-Lagrange approach in a spout-fluid bed apparatus. The major challenge in this case was to determine the friction coefficient for particles hitting against the walls of the apparatus. On the basis of the properties of similar materials the value of this quantity was estimated at 0.2. Therefore, it proved useful to check the model’s sensitivity to the value of this parameter. The study investigated the effect of friction coefficient on calculated values of particles velocity in the draft tube and the annular zone of the device for various volumes of the circulating bed. In the course of calculations, a relatively small influence of friction coefficient on particles velocity was observed in the tested zones of the apparatus. The changes were most visible for large volumes of the bed, which was connected with an increase in the number of collisions of particles with the walls.

2

Comparison of eddy dissipation concept and finite-rate/eddy dissipation models in case of coal gasification in a two-stage entrained flow gasifier and their relation to the experimental results

Mularski J., Modliński N., Pawlak-Kruczek H.

Rynek Energii

|

2018

|

Nr 4

97--106

EN

In this paper, a CFD tool – Ansys Fluent 17.2 was applied to obtain a 3-D operational model of a 200 td-1 pilot-scale gasifier that was tested in Japan. The gasifier is an up-flow co-current reactor comprising combustor and reductor separated by a throat. For the modelling procedure, the Eulerian-Lagrangian method has been used. Euler approach describes the gas phase processes, whereas Lagrange describes the solid phase. The aim of this paper is at first to compare simulation results of two turbulence-chemistry interaction procedures available in Ansys Fluent and their impact on coal gasification and secondly to compare obtained results with the experiment.

PL

W tej pracy zastosowano program CFD – Ansys Fluent 17.2, aby otrzymać model 3D pilotażowej zgazowarki MHI 200 t/d, która była testowana w Japonii. Jest to reaktor współprądowy typu up-flow zawierający komorę spalania oraz reduktor oddzielone od siebie przez gardziel. Do otrzymania modelu zastosowano podejście Lagrange’a-Eulera. Faza dyspersyjna opisywana jest metodą Lagrange’a, natomiast faza ciągła – gazowa metodą Eulera. Celem tego badania było porównanie dwóch modeli opisujących wzajemne interakcje między kinetyką reakcji a turbulencją pod kątem całego procesu zgazowania oraz zestawienie uzyskanych wyników z wynikami eksperymentalnymi.

3

Comparison of a discrete coal gasification global model in an entrained flow gasifier with the GRI-Mech 1.2 mechanism

Mularski J., Modliński N., Pawlak-Kruczek H.

Archivum Combustionis

|

2017

|

Vol. 37 nr 2

139--154

EN

In this study a two-dimensional model of the coal gasification process in an entrained flow gasifier is investigated with a CFD software. Euler approach is used to simulated gas phase while the Lagrangian one is used to describe the solid phase. The current paper is focused on the importance of the gas phase simulation on the gasification model performance. Eddy dissipation concept is applied to simulate homogenous phase reactions a turbulence-chemistry interaction. Other available models have also been mentioned. Global reaction mechanism have been used initially. Consecutively the detailed GRI-Mech 1.2 Mechanism was implemented. GRI-Mech 1.2 Mechanism used in this study includes 176 homogenous embedded reactions and additional 3 heterogeneous reactions. The results of calculations obtained with both mechanisms exhibit good compatibility.