Temperature of hydrogen-air detonations - Measurements by 2-color planar laser induced fluorescence of the hydroxyl radical

Temperature of hydrogen-air detonations: measurements by 2-color planar laser induced fluorescence of the hydroxyl radical

Internship Description

Compared to classical constant volume or constant pressure thermodynamic cycles, the detonation regime of combustion could increase by 40% the efficiency of engines. For a long time restricted to military applications, due to the global energetic issue, the civil applications of detonations have received in increasing interest during the last decade. One of the main challenges in this research field is to obtain a self-sustained detonation for practical fuel-oxidizer mixtures (e.g. kerosene-air), in a setup with typical dimensions comparable to those of a commercial gas turbine. 
While the quantitative characterization of flames in terms of temperature and chemical species is of current practice, the experimental study of detonation properties is mainly restricted to the determination of the detonation velocity, global pressure, and density gradient structure. Information such as the temperature or density of hydroxyl radical fields in a detonation front have never been measured. However, to better understand the detonation mechanisms and to help in validating detonation models and numerical simulations, these data are crucial. 

Objectives:  In this context, the main objective of the project is to adapt a non-intrusive thermometry technique broadly used in the combustion community, the 2-color planar laser induced fluorescence on OH, to the characterization of an H2 – air detonation. There are many challenges to obtain reliable temperature measurements of a detonation front, including single shot measurements, synchronization, spectroscopic properties of OH in the condition of the detonation front, etc. 
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Deliverables/Expectations

​First, the student will learn the 2-color PLIF technique on OH in a well characterized configuration: a stable flat flame stabilized over a McKenna burner. During this preliminary step, the uncertainty of the measurements, averaged and single shot, will be characterized. Second, the system will be implemented on a 2D detonation test rig, equipped with optical access for laser diagnostics. One of the main challenges will be the synchronization of the PLIF system with the detonation front arrival in the measurement area. Indeed, the detonation front propagates at a speed of about 2000 m/s, and the jitter between two events in the arrival of the measurement area can be as large as 1 ms. Synchronization will require time of flight measurements and analysis of the detonation propagation front. Finally, post processing of the OH PLIF images will be performed in order to determine the temperature fields. Due to the complexity of the detonation setup and combined laser diagnostics, the experimental part of this study will be performed by two persons: the intern student and an experienced researcher (senior PhD student or post-doc).​

Faculty Name

Deanna Lacoste

Field of Study

​Mechanical Engineering, Combustion, Fluid Mechanics