High-Speed PLIF Imaging for Investigation of Turbulence Effects on Heat Release Rates in HCCI Combustion

• High-speed laser diagnostics was utilized for single-cycle resolved studies of the fuel distribution in the combustion chamber of a truck-size HCCI engine. A multi-YAG laser system consisting of four individual Nd:YAG lasers was used for planar laser-induced fluorescence (PLIF) imaging of the fuel distribution. The fundamental beam from the lasers at 1064 nm was frequency quadrupled in order to obtain laser pulses at 266 nm suitable for excitation of acetone that was used as fuel tracer. Bursts of up to eight pulses with very short time separation were produced, allowing PLIF images with high temporal resolution to be captured within one single cycle event. The system was used together with a high-speed framing camera employing eight ICCD modules, with a frame-rate matching the laser pulse repetition rate. The combustion evolution was studied in terms of spatial distribution and rate of fuel consumption for different engine hardware configurations as well as operating conditions e.g. different stoichiometries and combustion phasing. Two different piston crown geometry were used for altering the degree of turbulence in the combustion chamber. In addition to the optical investigations, the impact of turbulence effects was also studied by calculating the rate of heat-release and combustion phasing from the pressure trace.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Annan maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Other Mechanical Engineering (hsv//eng)

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

1064 nm

Combustion phasing

Frame-rate

Framing Camera

Fuel distribution

Hardware configurations

HCCI combustion

HCCI engine

Heat release

Heat Release Rate (HRR)

High temporal resolution

High-speed

Laser systems

ND : YAG lasers

Operating condition

Optical investigation

Planar laser induced fluorescence

PLIF images

Single cycle

Time separation

Turbulence effect

Laser diagnostics Combustion engines laser system

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