Optical engine research

Research in an optical engine [top]

All images and movies shown here have been recorded with a high speed monochrome camera in the optically accessible diesel engine at the Radboud University Nijmegen. In some cases, the intensities have been coded to approximately true colour to better reveal the lower intensities. Injector and sprays are illuminated by an Ar⁺ laser to visualize them before the soot incandescence starts.

[img: JME combustion]

Combustion of Jatropha-methylester, a second generation biodiesel. These images are frames from a single movie (see below). The time between the images 0.35 milliseconds, but the camera filmed at 10x this speed. From left (fuel injection, no soot yet) to right (begin of end phase) the growth and behaviour of glowing soot is visible [cf. our paper Proc. Combust. Inst., 32, 2817 - 2825, (2009) (see here)].

High speed movies of regular and biodiesel combustion

The high speed movies below have all been recorded at 28600 frames per second in the optical diesel engine. They play here at 10 frames per second and show the behaviour of regular diesel and two biodiesel fuels. Each movie has been recorded during a single fuel injection. A more elaborate description of the processes revealed by the movies is given in the literature referenced below.

Combustion of regular diesel [cf. our paper Combust. & Flame, 151, 333 - 346, (2007) (see here)]:

Combustion of regular diesel, double injection [cf. our paper Combust. & Flame, 151, 333 - 346, (2007) (see here)]:

Combustion of Jatropha-methylester (a second generation biodiesel) [cf. our paper Proc. Combust. Inst., 32, 2817 - 2825, (2009) (see here)]:

Combustion of Rapeseed-methylester (a first generation biodiesel) [cf. our paper Proc. Combust. Inst., 32, 2817 - 2825, (2009) (see here)]:

Results on various (bio-)fuels

Combustion behaviour of regular diesel, including the study of double injection, is described in our paper Combust. & Flame, 151, 333 - 346, (2007) (see here).

Combustion behaviour like soot incandescence, chemiluminescence, ignition delay and heat release of various biofuels and regular, oxygenated and synthetic fuels is described in our paper Proc. Combust. Inst., 32, 2817 - 2825, (2009), which includes 4 movies

(see here).

The behaviour of cyclohexanone, a possible biofuel, as determined from exhaust measurements of NO_x and soot and in cylinder soot imaging, is also described in our publication SAE Technical Paper 2007-01-2018 (see here). Note that cyclohexanone is marked ‘X1’ and cyclohexane is marked ‘X2’ in this SAE paper.

Combustion behaviour like ignition delay, exhaust NO_x and smoke (with and without exhaust gas recirculation) of cyclohexanone and other cyclic oxygenated (bio-)fuels and possible production routes of these fuels are discussed in our paper Energy & Fuels, 23, 1808 - 1817, (2009) (see here).

Results on laser diagnostics

Laser diagnostics are used as well in our optical engine for detection of various species during the combustion cycle.

Laser-induced fluorescence detection of pollutant NO is for instance described in our paper Proc. Combust. Inst., 31, 765 - 773, (2007) (see here and references therein).

Results on laser-induced fluorescence of formaldehyde (CH₂O) are given in our paper in Comb. & Flame (2010) (see here).

Laser-induced incandescence of soot is described in the paper Proc. Combust. Inst., 31, 685 - 691, (2007) (see here and references therein).

Sound of diesel

The dutch radio science programme Hoe?Zo! broadcast a feature about our research, entitled De schoonste biodiesel (see here).

Fuel injection in a high pressure cell [top]

The left photograph shows the Eindhoven High Pressure Cell (EHPC), used for fuel injection studies. The right photograph is a shadowgraph of a diesel fuel spray (2 µs exposure time), injected into a high pressure N₂ environment (about 3 MPa) in the EHPC [cf. our paper Fuel, 86, 1994 - 2007, (2007) (see here)].

Diesel fuel injection into the high pressure cell, recorded at 47600 frames per second. Note the formation of pressure waves in the N₂ gas next to the injector opening, due to the entry of liquid fuel [cf. our paper Fuel, 86, 1994 - 2007, (2007) (see here)].

Spray propagation of diesel fuel has been studied as a function of common rail injection pressure and ambient gas density in the EHPC. Results are described in our papers Fuel, 86, 1994 - 2007, (2007) (see here) and Energy & Fuels, 23, 1832 - 1842, (2009) (see here).