Uwe Koch

Experimental Verification of Heat-Flux Mitigation by Electromagnetic Fields in Partially-Ionized-Argon Flows

This paper describes an experimental study on heat-flux mitigation within high-enthalpy ionized-argon flows by application of an external magnetic-induction field. Two different axially symmetric test models containing water-cooled magnet coils have been investigated. The models have been made of a material with low thermal conductivity to visualize surface-temperature distribution.The latter has been measured by infrared thermography. Heat-flux rates have been derived from measured front- and rear-surface temperatures, taking into account temperature-dependent material characteristics and considering radiative-cooling exchange to the environment. Flowfield properties have been quantitatively characterized by laser-induced fluorescence, microwave interferometry, emission spectroscopy, electrostatic probes, and pitot probes. In addition, high-quality video recordings and photographs have been taken for shock-layer visualization. Remarkable measured surface-temperature reductions (16 and 44%) and derived heat-flux mitigations (46 and 85%) have been observed in the presence of an externally applied magnetic-induction field.

Numerical and Experimental Study of High Enthalpy Flows in a Hypersonic Plasma Wind Tunnel: L3K

In the present study, we describe the end-to-end model of a plasma wind tunnel. A plasma wind tunnel is an useful facility for the ground-based experiment of high enthalpy flows including hypersonic flows, because it can provides a similar flow environment which is experienced by a vehicle during hypersonic flights. For the experimental research of high enthalpy flows, the German Aerospace Center (DLR) Cologne research facility has an arc heated plasma wind tunnel, L3K. The accurate prediction of flow characteristics is very important to calibrate measurement devices and choose measurement methods in a plasma wind tunnel experiment. However, it is difficult to understand the detailed flow conditions of a plasma wind tunnel, because the flow inside a plasma wind tunnel is usually in strong chemical and thermal non-equilibrium state. we numerically simulate a high enthalpy flow inside a plasma wind tunnel using a multi-temperature model and compare with the measured data using CARS method. The numerical model of a plasma wind tunnel will be useful to design a new wind tunnel and determine flow conditions at the test section of a plasma wind tunnel.

Two-Photon Laser-Induced Fluorescence Measurements of Atomic Oxygen Density in Hypersonic Plasma Flow

An experimental investigation of high-enthalpy air flow generated by L2K arc-jet facility of DLR is carried out by means of two-photon absorption laser-induced fluorescence (TALIF) measurements of ...

Characterization of High-Enthalpy-Flow Environment for Ablation Material Tests Using Advanced Diagnostics

For reliable material qualification in high-enthalpy flows, detailed characterization of material and flow parameters is essential. Therefore, the flowfield of arc-heated facility L3K, which has be...