Shock-tube study at High-pressure of Oxygenated fuels for Chemical Kinetic – SHOCK
Shock tube study at High-pressure of Oxygenated fuels for Chemical Kinetic
Development of a high pressure shock tube for auto-ignition measurements
Unique experimental setup in France for new generation fuel auto-ignition study
Auto-ignition is a fundamental process in combustion engines since it is the ignition process for Diesel engines and efficiency-restricting process for spark-ignition engines (knock onset). Therefore, auto-ignition is important for designers to predict and control for optimizing the desired performance in the gas turbines combustion. Indeed, the development and application of alternative fuels require the characterization of auto-ignition phenomena under well-controlled thermodynamic conditions (pressure, temperature, concentration).<br />The shock tube is an effective tool to study the evolution of reacting mixtures and their auto-ignition. The challenge in this project is to reach thermodynamic conditions close to real engine conditions above 20 bar up to 40 bar. The project goal is the development and characterization of a high pressure shock tube and the study of oxygenated alternative fuels from biomass.<br />
The stainless steel shock tube has a 9.10 m long, 5 cm inner diameter. It consists of two sections, a 4m driver section and a 5m driven section. These two sections are separated by an intermediate section, which is isolated between two diaphragms.
Ignition delay time t represents the required time for run-away reaction. It is a characteristic time for release of chemical energy and is detected by the increase in temperature and pressure and substantially concurrent appearance of many active species (OH radicals, O atoms, H). Two methods were used for determination:
- by spectroscopic monitoring in the case of very dilute mixtures (greater than 98% argon). It follows the detection by the photomultiplier of the emission of excited OH * radicals to the wavelength ? = 306 nm.
- by monitoring the rise pressure by piezoelectric sensors in the case of little diluted mixtures (less than 98% argon).
The results obtained show the change of the delay based on pressure, temperature and fuel concentration.
The experimental equipment, high pressure shock tube, has been developed and validated for the measurement of ignition delay times of gaseous and liquid fuels by comparison with results from the literature.
This tube was used to study an oxygenate from biomass as part of a collaboration with the CNRS ICARE lab in Orleans. This collaboration will continue in the framework of a joint thesis. Further work is also carried out in collaboration with the Combustion Chemistry Centre (Galway, Ireland) for a study of oxygenated fuels.
This project enabled to publish an article in an international journal with referees:
«A high pressure experimental and numerical study of methane ignition« El Merhubi H., A. Keromnes, G. Catalano, B. Lefort, L. Le Moyne, Fuel, 177, pp. 164-172, 2016.
and two international communications (posters) and an invited lecture to an international workshop.
Shock tube study at High-pressure of Oxygenated fuels for Chemical Kinetic.
The project will start in September 2013 and end in September 2015.
Fundamental data such as ignition delay times and species profiles at practical conditions are invaluable for the improvement and extension of chemical kinetics models to engine applications. High pressure shock tubes are ideal to perform such measurements and have been used during last decades. This device has been already used in France however never built to reach engines relevant conditions and used in this purpose. The project aim is to develop a unique high pressure shock tube for autoignition measurements. First step will be to obtain measurements and compare them with literature results to validate the tube, and then the apparatus will be operated to study and characterize oxygenated compounds which would be used as fuel.
This is a research area of very high impact in renewable energy and combustion science and technology. High pressure combustion has been recognised as central for clean and efficient advanced combustion energy technologies.
This research program will be divided into three main parts:
- The first part consists in the design and manufacture of a high-pressure shock tube;
- The second part consists in the validation of the high-pressure shock;
- The third part is based on the use of the shock tube in order to study the oxidation process of different fuels.
All results of this project will be published in peer-reviewed journals and all work content will be disseminated through international conferences.
The team is consists of five people. Dr. Lefort is the project leader, Associate Professor and is involved at 95% in the project. Dr. Kéromnés, Associate Professor, is involved at 85%. Pr. Le Moyne, Professor, is involved at 15%. M. Erard is a technician and involved at 20%. The post-doctoral researcher will be hired for this project and involved at 100%.The partners for this project are highly complementary thanks to their different backgrounds which cover all the physical and chemical aspects of the combustion process, including mixture preparation, combustion initiation, propagation and chemical kinetics. Moreover, they have a strong experimental background in both the development of experimental devices and the development of analysis tools and/or methods in order to study the combustion process. Finally, they also cover a large numerical background thanks to 3D modelling, 0D modelling and the development of chemical kinetics mechanisms.
This project is to create a new research field into the DRIVE laboratory. The grant requested is 228800 €.
There is no doubt that the results of this project will be very valuable to the project team to build collaborations leading to breakthroughs in the field.
Keys words: high pressure shock tube, autoignition, biofuel, chemical kinetic combustion.
Madame Benoîte LEFORT (Département de Recherche en Ingénierie des Véhicules pour l’Environnement) – firstname.lastname@example.org
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
DRIVE Département de Recherche en Ingénierie des Véhicules pour l’Environnement
Help of the ANR 164,320 euros
Beginning and duration of the scientific project: December 2013 - 24 Months