Publications by Peter Ott | EPFL Graph Search

Celebration of Professor Bernhard Weigand on his 60th birthday

PERGAMON-ELSEVIER SCIENCE LTD2022

Experimental investigation of sequential narrow impingement channels for turbine cooling

Sequentially stacked impingement channels allow for a more effective use of the cooling fluid and can limit the heat transfer reduction due to the crossflow when the number of jets increases. In this paper, sequential impingement channels are experimentall ...

2021

Transient Liquid Crystal Thermography Using a Time Varying Surface Heat Flux

Peter Ott, Michele Gaffuri, Alexandros Terzis

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

Heat Transfer Enhancement in a Double Sequential Impingement Channel

Peter Ott, Michele Gaffuri

Sequential impingement channels can reduce the adverse effect of crossflow in narrow impingement channels, as well as increase the cooling efficiency. In this work, sequential impingement channels are experimentally investigated using the transient liquid ...

2021

Narrow Impingement Channels: Recent Advancements and Future Directions

Peter Ott, Michele Gaffuri, Alexandros Terzis

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

Mechanisms of Control Authority by Nanosecond Pulsed Dielectric Barrier Discharge Actuators on Flow Separation

Pénélope Leyland, Peter Ott, Hugo Bosse, Christoforos Skourides, Dimitrios Nyfantis

The mechanisms that should be considered for separation flow control applications of nanosecond pulsed dielectric barrier discharge (DBD) actuators were investigated on a NACA 0015 profile for velocities of 10 m/s (Re = 100, 000) and 20 m/s (Re = 200, 000) ...

2019

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

Peter Ott, Michele Gaffuri, Alexandros Terzis

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

Ammonia toxicity: from head to toe?

Peter Ott, Veronika Rackayová

Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurologica ...

Springer Verlag2017

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

OES Characterization of Steamers in a Nanosecond Pulsed SBDB Using N2 and Ar Transitions

Christoph Hollenstein, Pénélope Leyland, Peter Ott, Sami Goekce, Philip Peschke

The characterization of non-thermal homogeneous plasmas is possible using optical emission spectroscopy (OES), notably by estimating the reduced electric field. This method was applied to characterize streamers generated by a nanosecond pulsed surface diel ...

Iop Publishing Ltd2016

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

Peter Ott, Bernhard Weigand, Alexandros Terzis

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, Bernhard Weigand, Philip Peschke, Alexandros Terzis, 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

Aeroeleasic Investigation of an Annular Transonic Compressor Cascade: Experimental Results

Peter Ott, Virginie Anne Chenaux, Achim Zanker

A reliable determination of the unsteady aerodynamic loads acting on the blades is essential to predict the aeroelastic stability of vibrating compressor cascades with accuracy. At transonic flow conditions, the vibration of the shock may change the blade ...

2015

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

Peter Ott, Bernhard Weigand, Alexandros Terzis

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

Turbulent scale resolving modelling of rotating stall in low-pressure steam turbines operated under low volume flow conditions

Peter Ott, Benjamin Megerle, Ivan William McBean

Non-synchronous excitation under low volume operation is a major risk to the mechanical integrity of last stage moving blades (LSMBs) in low-pressure (LP) steam turbines. These vibrations are often induced by a rotating aerodynamic instability similar to r ...

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

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 ...

Sage Publications Ltd2015

Detailed Heat Transfer Distributions of Narrow Impingement Channels with Varying Jet Diameter

Peter Ott, Bernhard Weigand, Alexandros Terzis

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 ...

ASME2014

Experimental and Numerical Assessment of the Aeroelastic Stability of Blade Pair Packages

Peter Ott, Achim Zanker

The stabilizing effect of grouping rotor blades in pairs has been assessed both, numerically and experimentally. The bending and torsion modes of a low aspect ratio high speed turbine cascade tested in the non-rotating test facility at EPFL (Ecole Polytech ...

ASME2014