This review describes the history and development of plasma-assisted catalysis focussing mainly on the use of atmospheric pressure, non-thermal plasma. It identifies the various interactions between the plasma and the catalyst that can modify and activate the catalytic surface and also describes how the catalyst affects the properties of the discharge. Techniques for in situ diagnostics of species adsorbed onto the surface and present in the gas-phase over a range of timescales are described. The effect of temperature on plasma–catalysis can assist in determining differences between thermal catalysis and plasma-activated catalysis and focuses on the meaning of temperature in a system involving non-equilibrium plasma. It can also help to develop an understanding of the gas-phase and surface mechanism of the plasma–catalysis at a molecular level. Our current state of knowledge and ignorance is highlighted and future directions suggested.

http://iopscience.iop.org/article/10.1088/0022-3727/49/24/243001/pdf

Plasma–catalysis: the known knowns, the known unknowns and the unknown unknowns

This paper deals with the evolution of infrared (IR) thermography into a powerful optical tool that can be used in complex fluid flows to either evaluate wall convective heat fluxes or investigate the surface flow field behavior. Measurement of convective heat fluxes must be performed by means of a thermal sensor, where temperatures have to be measured with proper transducers. By correctly choosing the thermal sensor, IR thermography can be successfully exploited to resolve convective heat flux distributions with both steady and transient techniques. When comparing it to standard transducers, the IR camera appears very valuable because it is non-intrusive, it has a high sensitivity (down to 20 mK), it has a low response time (down to 20 μs), it is fully two dimensional (from 80 k up to 1 M pixels, at 50 Hz) and, therefore, it allows for better evaluation of errors due to tangential conduction within the sensor. This paper analyses the capability of IR thermography to perform convective heat transfer measurements and surface visualizations in complex fluid flows. In particular, it includes the following: the necessary radiation theory background, a review of the main IR camera features, a description of the pertinent heat flux sensors, an analysis of the IR image processing methods and a report on some applications to complex fluid flows, ranging from natural convection to hypersonic regime.

/pdf/infrared-thermography-for-convective-heat-transfer-56a0bwe7om.pdf

Infrared thermography for convective heat transfer measurements

A multidisciplinary approach to understand the interactions of nonthermal plasma and catalyst: A review

Thermo-fluid-dynamics of submerged jets impinging at short nozzle-to-plate distance: A review

Experimental study of oil cooling systems for electric motors

A review of heat transfer between concentric rotating cylinders with or without axial flow

An experimental study on hot round jets impinging a concave surface

Local heat transfer due to several configurations of circular air jets impinging on a flat plate with and without semi-confinement

Dielectric barrier discharge (DBD) based surface plasma actuators have been well studied as flow manipulation devices. However, there is a dearth of research on their application for convective heat transfer enhancement. The adoption of DBD actuators to such areas requires a detailed study on the thermal characteristics of the plasma discharge. The present study conducts infrared thermography measurements on the surface of a thick dielectric (2?4?mm) based DBD actuator and characterizes it against various electrical and geometrical parameters. The temperature distribution is also studied in relation to the regimes of the discharge cycle through comparison with intensified charge-coupled device (iCCD) imaging. Measurements are also conducted with thin cylindrical electrode (wire) based configurations to study the influence of streamer inhibition. Based on the observed experimental results, a hypothesis is proposed on the mechanism of dielectric heating and the relationship between dielectric surface temperature and gas temperature.

https://iopscience.iop.org/article/10.1088/0022-3727/47/25/255203/pdf

Matthieu Fénot

Papers

A review of heat transfer between concentric rotating cylinders with or without axial flow

An experimental study on hot round jets impinging a concave surface

Local heat transfer due to several configurations of circular air jets impinging on a flat plate with and without semi-confinement

Temperature characterization of dielectric barrier discharge actuators: influence of electrical and geometric parameters

Experimental investigation of the flow and heat transfer of an impinging jet under acoustic excitation