Research Projects

Emulsions find their application in food industries, pharmaceuticals, cosmetics, petroleum, etc. As far as pharmaceutical applications are concerned, encapsulation through emulsification is carried out for sensitive and pharmacologically active compounds or food supplements in order to maintain the chemical integrity of the drug till it reaches the target. Apart from these, emulsions can be seen in our day-to-day lives, such as sanitizers, disinfectants, cleansing agents, etc. [1]. Further, emulsified fuels are widely being used to carry out effective combustion in engines and to control emissions. Reduction in NOx emissions was observed in the case of emulsified fuels owing to the high heat of evaporation of water thereby preventing localized peak temperatures. Moreover, the emulsified diesel is useful to achieve micro-explosions as water evaporates earlier and bursts during combustion, enhancing the diesel's atomization characteristics. This leads to a reduction in the particulate matter as reported in Jhalani et al. [2]. Khan et al. [3] reported that until now, 5-40% of water by volume of emulsion has been employed for experimental investigations. Zhu et al. [4] reviewed the active and passive methods for droplet generation. For industrial-level production, emulsions are made by active methods which comprise energy-intensive methods like mechanical homogenizers, high-pressure homogenizers, ultrasonic homogenizers, etc. which break the dispersed phase into small droplets. The major drawback is the control over the droplet size is very low leading to polydispersity. Therefore, in such circumstances passive methods are used. Most of the passive methods involve the use of microchannels for droplet generation such as T-junction, co-flow, flow focussing, edge emulsification, step emulsification, etc. Microchannel based emulsification techniques have emerged to be very capable and versatile of generating monodispersed droplets having precise control over the droplet size. Among them, step emulsification is getting popularity within the research community because of its capability of achieving droplet size in the range of submicron. However, issue of low throughput is still not addressed in the literature. Further, none of the literature studied an emulsification process to achieve water-in-diesel emulsion. This work proposes to the study the step emulsification process with the aim of investigating the effects of geometrical features and flow parameter on droplet diameter and yield in view of developing a microfluidics based device to synthesize water-in-diesel emulsion. Both numerical as well as experimental methodology will be adopted to carry out the parametric study. Geometrical parameters such as aspect ratio and divergence of microchannel, width of terrace along with flow parameters will be varied to understand its effect on droplet generation process through step emulsification.