arXiv subjects

Martin Sommerfeld

Publications and source records attributed to Martin Sommerfeld.

2 recordsLinked to original sources

arXiv2024

Study of parameters affecting the cooling capacity of liquid jets by using OpenFoam as tool to solve the inverse heat transfer problem

In this work, some of the parameters influencing the cooling capacity of a liquid jet impinging onto Inconel 718 and C45 plates were experimentally investigated. The experiment included a high-speed camera to record the dynamic of the jet during the cooling process while an infrared camera was used to record the temperature field at the opposite surface. Jets made of water and oil-in-water emulsion were analysed as well as the influence of the oil concentration. Other parameters studied here include initial temperature of the plate, nozzle-to-plate distance, nozzle diameter, jet velocity, and impinging angle. The cooling performance was analysed by solving a full 3D inverse heat transfer problem (IHTP) with the Conjugate Gradient Method (CGM) implemented in a new solver in OpenFoam. The basic organization and implementation of the solver is shown, followed by its validation with a made-up case. Finally, the growth of the wetting front was analysed for different oil concentrations and a combination of nozzle diameters and jet velocities for the same flow rate. For the latest, unexpected results emerged when comparing the wetting growth for the two plate materials.

physics.flu-dyn↗

arXiv2023

Rigid3D: a hybrid multi-sphere DEM framework for simulation of non-spherical particles in multi-phase flow

This article presents the development and validation of a hybrid multi-sphere discrete element framework - Rigid3D, for the simulation of granular systems with arbitrarily shaped particles in 3D space. In this DEM framework, a non-spherical particle is approximated by three different geometric models: (1) multi-sphere model with overlapping spheres (MS model), (2) particle surface with triangle mesh (surface model), and (3) discretized particle body with polyhedral cells (cell model). The multi-sphere approach will be the "engine" for efficient DEM simulations, while the particle's mesh and cell models will be updated simultaneously according to the position and orientation of their associated MS model, for use in particle-related inter-phase couplings in a multi-phase flow. In this sense, Rigid3D tries to combine the best of both worlds in multi-sphere and polyhedral DEMs: multi-sphere method for the efficiency and acceptable accuracy in the DEM simulation of granular flows, while the surface and cell models for the couplings between particles and other phases (continuous or dispersed phases) without affecting the performance of DEM simulations.

cs.CE↗