Characterizing low-frequency flame-front oscillations – An investigation into their origin and possible mitigation

This investigation focuses on the premixed conical flame, a mainstay of combustion diagnostics. While extensive studies have explored high-frequency oscillations in the canonical Bunsen flame, little attention has been given to low-frequency oscillations affecting flame fronts. This thesis aims to explain the origins of these oscillations and...

Time-domain investigation of the ro-vibrational CH₄ v₂ Raman spectrum via fs/ps CRS for combustion diagnostics

With the onset of climate change it is crucial to eliminate emissions, particularly for aviation reliant on gas turbine combustion. Computational models aid combustor improvement, but experimental data needed for validation is difficult to obtain. Fortunately, laser diagnostics can now achieve non-intrusive, high-resolution combustion...

A study on effects of geometry on internal ballistics of multiple BATES grain Solid Rocket Motors

Solid rocket motors power sounding rockets and their thrust profile are determined mostly by their internal geometry. This study investigates the effect of the changes in internal geometry by changing the aspect ratio, truncation and elongation of grains in multiple BATES grain solid rocket motors. BATES grains are propellant segments in a thick...

Enhanced single – shot flame thermometry with femtosecond / picosecond CARS using a phase – characterized picosecond probe

Hybrid fs/ps coherent anti-Stokes Raman CARS is a powerful laser diagnostic technique for thermometry and concentration measurements in chemically-reacting flows. The use of SHBC to generate the ps probe pulse is simple, robust, and relatively efficient. However, the presence of spectral sidebands in this pulse determines an additional...

Supercontinuum generation via in-situ femtosecond-laser-induced filamentation for ultrabroadband femtosecond/picosecond coherent Raman spectroscopy: MSc Thesis

For thermometry and concentration measurements in the gas-phase two-beam hybrid femtosecond/picosecond (fs/ps) coherent Raman spectroscopy (CRS) is the benchmark. To acquire additional information on major combustion species like for example carbon dioxide, oxygen and molecular hydrogen a supercontinuum is required. In this work <i>in-situ </i...

Development of pure-rotational coherent Raman spectroscopy on hydrogen for applied flame thermometry

Work is presented on a novel hybrid fs/ps two beam CARS application for spatiotemporal gas phase hydrogen thermometry, capable of sampling at a rate of 1 kHz. The aim of the research is to assess the feasibility of directly probing hydrogen for accurate temperature measurements in a combustion environment. Typically, nitrogen is used in applied...

Development of CO2-O2 CARS thermometry and concentration measurements for applied flame diagnostics

In this M.Sc. thesis project a model is developed and validated that simulates the coherent anti-Stokes Raman scattering (CARS) signal of CO₂ and O₂ in the spectral region between 1250cm^-1 and 1680cm^-1. The aim is to perform temperature and concentration measurements in a typical hydrocarbon-air...

A spectroscopic study of the OH* radical and its application in thermometry

There is a tremendous push to explore alternative fuels such as hydrogen or synthetic fuels to combat the effects of climate change. An important step in the development of alternative fuels is the characterisation of its combustion characteristics. There are various diagnostic tools which aid in the determination of flame properties. Optical...

Free Water in Helicopter Fuel Tanks: A Computational Prediction Study

Water accumulating in the fuel tanks of any aircraft presents an unacceptable safety hazard. This accumulation, which is due to a combination of physical phenomena, is difficult to assess and therefore not well known. The purpose of this project is the development of a lightweight computational prediction method for water accumulation in...

Laminar burning velocity measurements of DNG with hydrogen addition

The worldwide gas emissions regulations are getting more stringent. Together with the fluctuations of the finite fuel resources, it is expected that the use of unconventional and renewable fuels will increase. Hydrogen fuel is a zero-emission, renewable energy source. It has a great potential as one of the principal sustainable energy sources of...

On the use of C2* emission spectroscopy for thermometry of flames in propulsion systems

The developments in combustion technology has to be catered to in parallel by the development in the instrumentation employed in collection of combustion data, to get a better picture of the complex processes involved. In this regard, the flame temperature and equivalence ratio are the most important parameters that has to be studied to infer...

Development of a slitless spectrometer for multispectral flame chemiluminescence

The measurement of the laminar flame speed of Dutch natural gas: An investigation on the burning characteristics of Dutch natural gas

The characteristics of Dutch natural gas (DNG) have been quantified by measuring the laminar flame speed of a premixed Bunsen flame over a range of equivalence ratios ϕ, varied from ϕ=0.80 to ϕ=1.55. The laminar flame speed has been calculated from the OH* chemiluminescence images recorded with a high speed camera with an acquisition rate of 1...