2. Shock tube and laser system
The stainless steel, high purity, low pressure shock tube facility
(LPST) at KAUST is used to perform these experiments. The shock
tube is made of a 9 m driver section and a 9 m driven section, with
an inner diameter of 14 cm. The driver section is composed of four
sections and thus the total length can be varied depending on the
required test times. All experiments are performed behind the re-
flected shock waves. The incident shock speed is measured using a
series of five piezoelectric PCB pressure transducers over the last
1.5 m of the shock tube and linearly extrapolated to the endwall.
Reflected shock temperatures and pressures are determined from
the measured incident shock speed at the endwall using standard
normal shock relations. Uncertainties in the calculated pressure
and temperature are approximately ±0.7% and ±1%, respectively,
mainly due to the uncertainty in the measured shock velocity
(±0.2%). The OH laser diagnostic, along with a Kistler 603B piezoelectric
pressure transducer for pressure history measurements,
is located at a test section 2 cm from the driven section endwall.
The facility is also equipped with a magnetically-stirred 95 l mixing
vessel and a well-furnished mixing manifold for the accurate
preparation of mixtures. The shock tube and mixing tank can also
be heated to temperatures up to 100 C using a heating jacket. This
can facilitate the usage of chemicals with low-vapor pressures such
as heavy ketones (for example, hexanone has a vapor pressure of
9 Torr at ambient temperature).