Troels Dyhr Pedersen.indd - Solid Mechanics
Troels Dyhr Pedersen.indd - Solid Mechanics
Troels Dyhr Pedersen.indd - Solid Mechanics
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12.5 Observations of detonation in HCCI combustion<br />
The previous section dealt with determination of steady state properties of a detonation.<br />
The studied establish a reference for the velocities and pressure differences that may be<br />
expected to arise in detonations. By inspecting the pressure fluctuation under knocking<br />
conditions, it may be possible to see if a detonation is the cause. Even a partly developed<br />
detonation wave, which has not reached its full speed and amplitude, will be clearly<br />
discernible from an unevenly progressing explosion by its large amplitude and<br />
discontinuous pressure increase.<br />
12.5.1 Experimental setup<br />
An experiment was made to study detonation waves in HCCI combustion. Since it was<br />
desired to obtain planar detonation waves, the combustion chamber was made rectangular<br />
by designing a piston crown with a rectangular channel. The idea was that a planar onedimensional<br />
detonation wave would be more likely to occur than a radial detonation<br />
wave, as well as easier to detect since it would travel in one direction only. The piston<br />
crown is illustrated in figure 32.<br />
Figure 32: Piston crown with rectangular cut-out
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