Development and Application of High-Speed Laser Visualization Techniques in Combustion Research

Abstract

In order to fulfil the requirements of available energy resources, there is a great need to obtain a sustainable and environmentally friendly energy utilization using combustion processes. In order to do this, it is of utmost importance to utilize non-intrusive diagnostic techniques with high spatial and temporal resolution which can characterize the combustion process and also validate combustion models. During the last decades different laser techniques have proven to fulfil these requirements. A special requirement in practical applications when highly turbulent flames are to be investigated, is to be able to follow the phenomena in time, i.e. it is important to develop and apply high speed laser diagnostics. In the present chapter we are describing the use of high speed lasers together with high speed detectors which make it possible to probe in two dimensions even the fastest combustion phenomena in real time. The chapter is describing the use of a so called Multi YAG laser which together with a framing camera is able to record up to eight images. Also the use of a high repetition rate laser and a high power burst laser together with CMOS cameras and their application for studies of turbulent combustion phenomena are described. The examples are mainly taken from the author’s laboratory and include more academic studies of turbulent flames but also practical applications in engines.