Experimental Study of Deflagration to Detonation Transition in Hydrogen-Air Mixtures

This dataset contains high speed videos and pressure recordings from DDT experiments in hydrogen-air mixtures. The experimental setup and method is given in the reference below. The experimental setup is given in the excel-table. Details are given in the README.txt file.Abstract of thesis:Gas explosions in a square channel have been investigated with a main focus on the deflagrationto detonation transition (DDT). The gas mixtures were hydrogen and air at different concentrations.This work have been motivated by issues of process safety and hydrogen infrastructuredevelopment. There is a need to understand the deflagration to detonation transition from asafety perspective. Recent accident have shown possibilities of DDT in premixed fuel and air.At present there are no software tools capable of predicting DDT in real scenarios, and there isa need to produce accurate experimental data for validation, but also a better understanding ofthe physics related to DDT.The experiments presented in this thesis were performed in a square channel with transparentside walls and one obstacle. The obstacle was placed 1m from the closed ignition end, and thefirst results chapter presents the experimental study of flame propagation from ignition up to theobstacle. The ignition source was both a single spark and a distributed ignition, were the latterwas assumed to produce a 2 dimensional flame front. The main conclusion of this study wasthat the 2D assumption was only valid up to the point of tulip flame formation.The study of DDT was divided in two parts, one in homogeneous gas mixtures, the otherregarding inhomogeneous gas mixtures. The homogeneous gas mixture experiments showedthat transverse waves were important for the DDT, but also that these waves originated from farbehind the leading tip of the deflagration. This conclusion was also found in a numerical studyusing the in-house FLIC code developed by Dr. Vaagsaether.The study of inhomogeneous gas mixtures were done to investigate if inhomogeneities increasedthe likeliness of DDT. The conclusion was that it was not the case in this particularsetup and method. However, other interesting results were found regarding detonation propagationin layers of reactants bound by a wall and a layer of air. The propagation mechanism ofdetonations in a reactive layer was also studied using the FLIC code, where it was observed aexpansion effect and a merging of triple points at the top wall. This was qualitatively similar asthe experimental results.