TY - JOUR
T1 - Change of evaporation rate of single monocomponent droplet with temperature using time-resolved phase rainbow refractometry
AU - Wu, Yingchun
AU - Li, Haipeng
AU - Wu, Xuecheng
AU - Gréhan, Gérard
AU - Mädler, Lutz
AU - Crua, Cyril
PY - 2018/10/3
Y1 - 2018/10/3
N2 - Droplet evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as evaporation rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and evaporation rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet evaporation rate increases with temperature, from -1.28×10−8 m2/s at atmospheric 293 K to a range of (−1.5, −8)×10−8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and evaporation rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local evaporation rate in this work, PRR is a promising tool to investigate single droplet evaporation in real engine conditions.
AB - Droplet evaporation characterization, although of great significance, is still challenging. The recently developed phase rainbow refractometry (PRR) is proposed as an approach to measuring the droplet temperature, size as well as evaporation rate simultaneously, and is applied to a single flowing n-heptane droplet produced by a droplet-on-demand generator. The changes of droplet temperature and evaporation rate after a transient spark heating are reflected in the time-resolved PRR image. Results show that droplet evaporation rate increases with temperature, from -1.28×10−8 m2/s at atmospheric 293 K to a range of (−1.5, −8)×10−8 m2/s when heated to (294, 315) K, agreeing well with the Maxwell and Stefan–Fuchs model predictions. Uncertainty analysis suggests that the main source is the indeterminate gradient inside droplet, resulting in an underestimation of droplet temperature and evaporation rate. With the demonstration on simultaneous measurements of droplet refractive index as well as droplet transient and local evaporation rate in this work, PRR is a promising tool to investigate single droplet evaporation in real engine conditions.
KW - Phase rainbow refractometry
KW - Droplet
KW - Size change
KW - Temperature
KW - Evaporation rate
U2 - 10.1016/j.proci.2018.09.026
DO - 10.1016/j.proci.2018.09.026
M3 - Article
SN - 1540-7489
VL - 37
SP - 3211
EP - 3218
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
IS - 3
ER -