Characterization of the internal & surface friction behavior of granular material for a solid dynamic ISOL targets.

SCK•CEN Mentor

Houngbo Donald, dhoungbo@sckcen.be, +32 (0)14 33 34 16

Expert group

Proton Target Research

SCK•CEN Co-mentor

Popescu Lucia, lpopescu@sckcen.be, +32 (0)14 33 34 11

Introduction

In order to replace the ageing BR2 research reactor, SCK•CEN is developing MYRRHA (Multi-purpose hybrid research reactor for high-tech application). This fast reactor is conceived as an accelerator driven system, using a high-intensity proton beam from a linear accelerator. Part of the beam from this accelerator will be sent towards several target stations, dedicated to the production of radioactive isotopes for various purposes, such as medical applications, material research or fundamental-physics studies.

One of the foreseen target stations will be part of an isotope-separation online (ISOL) installation, for the production and study of short-lived nuclei (half-lives as low as few 100 ms).  But the high intensity of the primary beam which is beneficial in producing higher yields also entails the need for development of new high-power targets for this facility. The dynamic granular ISOL target is one concept currently studied by the Proton Target Research (PTR) group at SCK•CEN for meeting the challenge of an ISOL target capable of operation under a high power proton beam while maintaining decent release properties.

Objective

Discrete Element Methods (DEM) are generally applied in simulating the flow of granular material. Such simulation results can however strongly depend on input parameters that can only be obtained experimentally. The main objective of this work is to perform a systematic study of the friction behavior of granular material. More specifically, this work will provide information on how sensitive the repose angle of granular material is on the internal friction coefficient. Similarly, calibration studies will be conducted on the external friction parameter.

Workflow

  • Literature study on Discrete elements methods

  • Elaboration of the internal friction test case

  • Setup and run of the internal friction test case simulations with LIGGGHTS, a DEM code

  • Construction of a script to extract the angle of repose out of the simulation output

  • Run the simulation with different internal friction coefficient values, to obtain a mapping between the value of the coefficient and the angle of repose of poured granules

  • Elaboration of the surface friction test case

  • Setup and run of the surface friction test case simulations with LIGGGHTS

  • Run the simulation, sweeping over different surface friction coefficient values, to obtain a mapping between the value of the coefficient and the angle to induce flow of granules

  • Definition of the experimental setup required to identify the actual values of both friction parameters.

The minimum diploma level of the candidate needs to be

Academic bachelor

The candidate needs to have a background in

Physics , Mathematics