Measurement Techniques

The applied measurement techniques are grouped into conventional and optical techniques.

Conventional Techniques

Time-of-arrival photodiodes

Hamamatsu S1336-18BQ photodiodes along the channel axis are employed for the determination of flame arrival. Linear interpolation between diodes yields flame velocity v as a function of distance x from the point of ignition. This data is provided in the datasets.

Pressure transducers

We employ up to 8 Kistler 601A piezoelectric pressure transducers installed in the channel top plate and in the end plate (last transducer). The top plate transducers measure side-on pressure, the end plate transducer reflected (head-on) pressure. The transducers have a measurement range of 0-250 bar overpressure and an eigenfrequency of 150 kHz. The signals are acquired simultaneously on 8 channels at a 250 kS/s sampling rate.

Optical Techniques

Optical measurements are taken at different positions along the channel. Therefore, the optical segment (OS) can be installed between any standard segments. The position is denominated OS1 (OS between x = 0 m and 0.6 m), OS2 etc. Please note that the channel length is typically reduced if the OS is used, compared to a configuration without the OS because the OS is shorter (0.6 m) than the standard segments (0.9) and replaces a standard segment. The overall length of the channel is given in every dataset in the database.

All optical measurement techniques employ Photron high-speed cameras as detectors. The models used are SA5, SA-X and APXI2.


A classical shadowgraph/ schlieren setup in a z-configuration with two concave (f=2500mm) and two additional planar turning mirrors with an LOT Oriel 350 W Xe light source is used, cp. Fig. M.1. Either the Photron SA5 or SA-X camera is installed, combined with either a 85/1.4 Nikon camera lens or a single achromatic lens as a focusing element. The camera frame rate is 80 kfps in most DDT experiments.


As far as we can confirm this is the first application of high-speed OH-PLIF to a DDT experiment here. The laser system, Fig. M.2., comprises an Edgewave IS8II pumplaser with 2 mJ pulse energy and 10 ns pulse width at 532 nm and a repetition rate of up to 40 kHz. Usually only one of the two laser cavities is operated at 20 kHz. This laser is combined with a Sirah Credo dye laser with Rhodamine 6G as a dye. The system yields 283 nm UV emission for OH-PLIF at the Q1(6) line at typically 20 kHz repetition rate and pulse energies of about 100μJ.

For detection, either the Photron SA5 or the SA-X camera is combined with a Hamamatsu C10880-03 image intensifier, coupled by lens optics. A UV-CERCO-SODERN 45mm1:1.8 camera lens is employed with a Semrock BrightLine HC 320±20 nm bandpass filter.

The system is synchronised by means of Stanford Research delay generators (DG535 and DG645).

If you are interested in further details and applications of the OH-PLIF system, please refer to the following publications:

[1] Boeck, L.R., Deflagration-to-Detonation Transition and Detonation Propagation in H2-Air Mixtures with Transverse Concentration Gradients; Ph.D. Thesis, Lehrstuhl für Thermodynamik, Technische Universität München, 2015

[2] Boeck, L.R., Fiala, T., Hasslberger, J. Sattelmayer, T., Application of High-Speed OH-PLIF to DDT Experiments; 25th International Colloquium on the Dynamics of Explosions and Reactive Systems, Leeds, UK, 2015

[3] Baumgartner, G., Boeck, L.R., Sattelmayer, T., Investigation of the Flame-Flow Interaction during Flame Flashback in a Generic Premixed Combustion System by Means of High-Speed Micro-PIV and Micro-PLIF; ISFV16-1135, 16th International Symposium on Flow Visualization, Okinawa, Japan, 2014.

[4] Hoferichter, V., Boeck, L.R., Baumgartner, G., Sattelmayer, T., Flame Flashback in Hydrogen Combustion with Acoustic Excitation: Simultaneous PIV and OH PLIF Measurements at High Repetition Rate; Fachtagung "Lasermethoden in der Strömungsmesstechnik", Karlsruhe, 2014.

[5] Boeck, L.R., Primbs, A., Hasslberger, J., Sattelmayer, T., Investigation of Flame Acceleration in a Duct Using the OH PLIF Technique at High Repetition Rate; Lasermethoden in der Strömungsmesstechnik, München, Germany, 2013.