Wyniki wyszukiwania - BazTech

1

Calibration of Selected Bulk Biomaterials Parameters for DEM Simulation of Comminution Process. Case Study: Corn and Rice Grains

Kruszelnicka Weronika, Diviš Jan, Hlosta Jakub, Gierz Łukasz, Žurovec David

Advances in Science and Technology. Research Journal

|

2022

|

Vol. 16, no 5

64--77

EN

Computer simulation of bulk materials behavior, including comminution and fragmentation, using DEM has been growing fast, recently. One of the important tasks to get the reliable simulation results is to provide proper materials and contact parameters, which need to be determined in a series of laboratory experiments. For comminution simulation the additional parameters describing the breakage probability and breakage functions are necessary. While some simulation parameters are available in the literature for brittle materials, valid data are lacking for biomaterials such as cereal, rice or corn grains, especially for comminution parameters. The aim of this study was to present the calibration approach and determination of materials, contact, interaction and breakage parameters for grainy biomaterials. The calibration process was done for rice and corn grains. The calibration approach consists of grains size distribution and shape characterization, friction and restitution coefficient determination, and breakage probability description. Based on the results of the experiments, the models were created in the DEM software. The result was the set of calibrated parameters for rice and corn grains.

2

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.

3

Coefficient of restitution and plastic strain for impact of elements welded with micro-jet cooling

Hadryś D., Piwnik J., Węgrzyn T., Łazarz B.

Transport Problems

|

2014

|

T. 9, z. 2

61--68

EN

The main purpose of investigations is the qualification how post-accident repair of model car body parts influence on the value of coefficient of restitution. Evaluation of impact energy absorption by model car body parts repaired with MIG welding (with and without micro-jet cooling) was carried out. The results of investigations present that the value of coefficient of restitution changes with speed of impact. Coefficient of restitution is bigger for elements welded with micro-jet cooling than for element welded with ordinary method. This could have influence on passive safety of vehicle.

PL

Głównym celem badań jest określenie wpływu metody spawania (MIG chłodzeniem mikrojetowym i bez chłodzenia) naprawianych części nadwozia pojazdu na wartości współczynnika restytucji i ich odkształcenie plastyczne. Wyniki z badań przedstawiają wartość współczynnika restytucji w funkcji energii uderzenia. Współczynnik restytucji jest większy dla elementów spawanych z chłodzeniem mikrojetowym niż dla elementów spawanych zwykłą metodą. To może mieć wpływ na bezpieczeństwo bierne pojazdu.

4

Research on elastic-damping properties of unit loads

Piątkowski T.

Journal of Polish CIMAC

|

2013

|

Vol. 8, no 3

75--81

EN

In the paper, the results of tests of free-fall of unit load (cubicoidal package) from a height on the stiff ground are presented. The aim of this study is to determine the elastic-damping properties of packaging for all surfaces, edges and corners. These tests allow us to evaluate the protective ability of packages in case of impact in any direction typical for real transport systems. The maximum accelerations registered during experimental tests are subjected to approximation by means of B-spline surface. It enables the visual interpretation of data in three-dimensional space, allowing detection critical packaging places for the safety of transported goods. In addition, the registered acceleration waveforms were used to determine the coefficients of: restitution, damping and rigidity. These parameters are required to the analytical descriptions of loads contact with obstacles - such as in the models of sorting or positioning processes of packagings.

5

Erosion Problems In Pneumatic Transport Installations

Krupicz B.

Journal of Polish CIMAC

|

2009

|

Vol. 4, no 2

145-154

EN

In the paper, the analysis of erosion of a fan blade was conducted. Erosion is recorded into two zones on the blade. In the first zone, erosion occurs at the front of the blade and it is caused by particle’s impacts during first contact. This is “impact erosion” zone. Second “friction erosion” zone is formed in the place of the next contact, determined by the angle rotation of the rotor Δϕ and the path of rebound s. The impact takes place at the angle α with participation of friction forces. Dependences of particle’s velocities on stress, which cause plastic strains on surface layer, were presented. Coefficient of velocity restitution in the stream ks=βk was calculated. Restitution coefficient of particle’s velocity in a stream always amounts to β ≥ 1. Its value can be determined by f.e.: shape of particle’s, their diameter, stream velocity. Time τ between successive impacts is the function of rotor angular velocity and restitution coefficient k. Angle of rotation Δφ is only depends on coefficient k. The equation describing dependence of angle rotation Δφ on coefficient ks is as follows: Δφ(1+k) = tg(Δφ). The solution of the equation was presented in a graphical way.