Water-coalescence in an oil-in-water emulsion droplet burning under microgravity

Modeling Temperature Distribution Inside an Emulsion Fuel Droplet Under Convective Heating: A Key to Predicting Microexplosion and Puffing

“…At high temperature, the ability is weakened, and coalescence of water sub-droplets occurs. Therefore, water sub-droplet coalescence occurs after they have been heated for a certain time in a combustor (Segawa et al, 2000;Suzuki et al, 2011).…”

“…Recently, emission regulations for NOx, CO2 and soot from combustion engines have become more and more stringent due to growing concerns over environmental issues. Using emulsion (emulsified) fuel in combustion engines is considered as one promising solution (Dryer, 1977;Law et al, 1980;Lasheras et al, 1984;Sheng et al, 1994;Segawa et al, 2000;Kadota and Yamasaki, 2002;Fuchihata et al, 2003;Zeng and Lee, 2007;Tarlet et al, 2009;Watanabe et al, 2010;Suzuki et al, 2011;Watanabe and Okazaki, 2013;Shinjo et al, 2014). Emulsion fuel is a blend of immiscible liquids such as oil and water, formed with the help of surfactant agents.…”

“…In single-droplet experiments, a large droplet of O(1mm) was used to enable detailed observation and measurement (Law et al, 1980;Lasheras et al, 1984;Segawa et al, 2000;Kadota and Yamasaki, 2002;Suzuki et al, 2011). But its relevance to fuel spray droplets of O(10m) has not been well addressed.…”

“…It has been reported that aggregation and coalescence of dispersed water sub-droplets may occur when the inner droplet temperature is high and stratified (Segawa et al, 2000;Kadota and Yamasaki, 2002;Suzuki et al, 2011). Aggregation of sub-droplets is due to thermocapillary (Marangoni) migration and coalescence of sub-droplets is due to reduced effectiveness of the surfactants at high temperature (Segawa et al, 2000;Suzuki et al, 2011).…”

“…Aggregation of sub-droplets is due to thermocapillary (Marangoni) migration and coalescence of sub-droplets is due to reduced effectiveness of the surfactants at high temperature (Segawa et al, 2000;Suzuki et al, 2011). In enlarged-scale single-droplet experiments, these phenomena may play a role, but for real-scale small spray droplets of O(10m), it is considered that there is no sufficient time for these phenomena to develop.…”