| 1. |
- Grunditz, Simon, 1990, et al.
(författare)
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Fit-for-Purpose VSI Modelling Framework for Process Simulation
- 2021
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Ingår i: Minerals. - : MDPI AG. - 2075-163X. ; 11:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The worldwide shortage of natural sand has created a need for improved methods to create a replacement product. The use of vertical shaft impact (VSI) crushers is one possible solution, since VSI crushers can create particles with a good aspect ratio and smooth surfaces for use in different applications such as in construction. To evaluate the impact a VSI crusher has on the process performance, a more fit-for-purpose model is needed for process simulations. This paper aims to present a modelling framework to improve particle breakage prediction in VSI crushers. The model is based on the theory of energy-based breakage behavior. Particle collision energy data are extracted from discrete element method (DEM) simulations with particle velocities, i.e., rotor speed, as the input. A selection–breakage approach is then used to create the particle size distribution (PSD). For each site, the model is trained with two datasets for the PSDs at different VSI rotor tip speeds. This allows the model to predict the product output for different rotor tip speeds beyond the experimental configurations. A dataset from 24 different sites in Sweden is used for training and validating the model to showcase the robustness of the model. The model presented in this paper has a low barrier for implementation suitable for trying different speeds at existing sites and can be used as a replacement to a manual testing approach.
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| 2. |
- Grunditz, Simon, 1990
(författare)
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Modeling of Vertical Shaft Impact Crushers
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the largest products in most civilized societies is concrete used to build various types of constructions. To create this product, a mixture of cement, chemical binders, and rock aggregates are combined and then poured into molds where it hardens. The sand part of the rock aggregates is either from natural sources or manufactured. Vertical shaft impact crushers can be used to create this machine sand but existing models make it hard to plan new sites and achieve a viable replacement to the natural sand. In this thesis, the use of vertical shaft impact crushers to crush aggregate rock to rounder particles is investigated. The main aim of this is to develop and further the understanding of the relationship between the machine and material properties with respect to the resulting crushed product in an effort to achieve an improved product. In order to gain a better understanding of the underlying mechanics of particle breakage, Discrete Element Method has been used to obtain particle collision energies. Several different product size distribution models have also been used to better predict the behavior of different crushers and feed sizes. To facilitate this, a framework to improve sites has been developed. The resulting framework simulates existing VSI machines and optimizes the machine parameters with respect to the specified feed material and PSD to create sought products. The framework can also be used to optimize existing sites which increases the effectiveness in terms of minimizing energy usage and waste products.
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| 3. |
- Grunditz, Simon, 1990, et al.
(författare)
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Prediction of Collision Energy in the VSI Crusher
- 2015
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Ingår i: Proceedings; European Symposium on Comminution and Classification 2015 September 7-10.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- VSI crushers are established comminution machines often used for size reduction and to improve the sphericity of rock particles. Data collection and experimental observation inside VSI crushers remains difficult, leading to lack of understanding of the full extent of the particle dynamics inside a VSI crusher. The aim of this paper is to attempt to characterize the probability of collision of particles in relation to their distance from the rotor. By comparing the number of collisions at a given location with the overall amount of collisions, the probability of a collision event related to the distance a particle has travelled from the rotor can be estimated. The result is an increased understanding of VSI crushers and the particle collision behaviour inside of a VSI crushing chamber.
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| 4. |
- Grunditz, Simon, 1990, et al.
(författare)
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The Effect of Rotor Tip Speed of a Vertical Shaft Impactor on the Collision Energy Spectrum
- 2015
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Ingår i: Proceedings;Minerals Engineering Conference Computational Modelling 2015 June 10-11.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The increasing restrictions on natural aggregates have led to a demand for effective production of artificial sand and gravel. VSI crushers are established comminution machines often used in order to improve the sphericity of particles. Due to the difficulty in data collection, the full extent of the particle dynamics inside a VSI crusher has remained unexplored.The aim of this paper is to use DEM simulations to model a full-scale crusher, generate a realistic material flow and make a number of crusher tests with different rotor tip speeds. Each particle’s collision energy compared to its size will provide a spectrum which can be related to the probability of breakage. This will show how increasing rotational speed affects collisions and the impact energy of particles inside the crusher. The result is an increased understanding that can allow optimization and modeling of VSI crushers with higher accuracy.
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