Publications de Alexandros Terzis

Celebration of Professor Bernhard Weigand on his 60th birthday

PERGAMON-ELSEVIER SCIENCE LTD2022

Transient Liquid Crystal Thermography Using a Time Varying Surface Heat Flux

Peter Ott, Alexandros Terzis, Michele Gaffuri

Heat transfer measurements are required in a wide range of fields, for example to validate new cooling concepts in turbomachinery, to assess the performances of heat exchangers, and to provide data for numerical simulations. Thereby transient methods are o ...

2021

Narrow Impingement Channels: Recent Advancements and Future Directions

Peter Ott, Alexandros Terzis, Michele Gaffuri

This paper summarizes the state-of-the-art related to the heat transfer characteristics of narrow impingement cooling channels, which can nowadays be integrated within the external wall of turbine airfoils. Particular emphasis is given to the experimental ...

European Turbomachinery Society2019

Evaluation of Heat Transfer Coefficients for an Impingement Cooling Cascade: Experimental Challenges and Preliminary Results

Peter Ott, Alexandros Terzis, Michele Gaffuri

In this paper, a modification of the widely used transient liquid crystal heat transfer measurement technique for impingement cooling is presented, in which a constant heat flux at the surface is used to drive the experiment, instead of a step change in th ...

2018

On the Effects of Coating Thickness in Transient Heat Transfer Experiments Using Thermochromic Liquid Crystals

Peter Ott, Alexandros Terzis, Sebastian Schulz

Transient heat transfer experiments typically employ thermochromic liquid crystals to temporally map surface temperatures. The desired heat transfer coefficient is then calculated from the solution of Fourier’s 1D transient heat conduction equation which i ...

Elsevier2016

Effect of Varying Jet Diameter on the Heat Transfer Distributions of Narrow Impingement Channels

Peter Ott, Alexandros Terzis, Bernhard Weigand

The development of integrally cast turbine airfoils allows the production of narrow impingement channels in a double-wall configuration, where the coolant is practically injected within the wall of the airfoil providing increased heat transfer capabilities ...

Asme2015

Impact of ns-DBD Plasma Actuation on the Boundary Layer Transition Using Convective Heat Transfer Measurements

Peter Ott, Alexandros Terzis, Bernhard Weigand, Philip Peschke, Dirk Ullmer

This paper demonstrates that the impact of nanosecond pulsed dielectric barrier discharge (ns-DBD) actuators on the structure of the boundary layer can be investigated using quantitative convective heat transfer measurements. For the experiments, the flow ...

Iop Publishing Ltd2015

A method to visualise near wall fluid flow patterns using locally resolved convective heat transfer experiments

Peter Ott, Alexandros Terzis, Bernhard Weigand

The present study demonstrates an alternative approach for describing ﬂuid ﬂow characteristics very close to the wall, using locally resolved convective heat transfer experiments. Heat transfer coefﬁcients on the base surface and around a surface mounted v ...

Elsevier2015

High-Resolution Heat Transfer Measurements and Crossflow Regulation in Narrow Impingement Cooling Channels with Divergent Geometries

Peter Ott, Alexandros Terzis, Stavros Bontitsopoulos

The present study describes an experimental investigation into narrow impingement cooling channels with divergent geometries. The following analysis aims to clarify the influence that this particular form factor exerts on the heat transfer distribution, as ...

2015

Heat Transfer Characteristics of High Crossflow Impingement Channels: Effect of Number of Holes

Peter Ott, Alexandros Terzis, Santiago Llucià

In modern turbine airfoils, narrow impingement cooling channels can be formed in a double-wall configuration. In these wall-integrated cooling cavities, the generated crossflow is one of the most important design factors, and hence, the number of impingeme ...

2015