Lars Krenkel

Magnetic Resonance Imaging and Computational Fluid Dynamics of High Frequency Oscillatory Ventilation (HFOV)

In order to better understand the mechanisms of gas transport during High Frequency Oscillatory Ventilation (HFOV) Magnetic Resonance Imaging (MRI) with contrast gases and numerical flow simulations based on Computational Fluid Dynamics(CFD) methods are performed.

Vortex Generator Pairs for Vortex Induced Heat Transfer Enhancement in Heat Exchanger Channels

The objective of the presented work is to investigate possibilities for increasing the heattransfer in heat-exchanger channels for aircraft applications by using flow-manipulating devices. Focal point of the investigation are different arrangements of vortex-generator pairs within a generic heat-exchanger channel. The DLR URANS CFD solver THETA has been used to carry out numerical simulations of the laminar flow within a rectangular channel with integrated vortex generators. In particular, the analysis of the interaction of generated vortices with the stratified thermal boundary layer, the impact of vortical flow structures on heated walls and the enforced mixed-convection flow is of special interest. The final goal is the evaluation of the applicability of oppositely arranged vortex-generator pairs for the enhancement of vortex-induced heat-transfer.