Bicomponent Drop’s Evaporation: Effect of Acoustics and Hot Surrounding

Abstract

The effect of acoustic streaming on the circulation inside methanol–water drops evaporating in a heated environment is examined. The circulation and the evaporation of drops for various acoustic frequencies with added white noise are recorded at varied surrounding temperatures (T_S). Visualization reveals intense streaming at the drop’s immediate vicinity at a lower frequency and elevated T_S. The streaming velocity rises with (i) the reduction in acoustic frequency at a given T_S and (ii) the escalation in T_S at a given frequency. The drop’s internal circulation is detected to be oscillatory, and the oscillation frequency reduces drastically with the temperature rise at the lowest acoustic frequency. Taken together, the higher streaming at a low acoustic frequency and elevated T_S lead to higher air entrainment into the drop interior and quicken circulation by suppressing its oscillation. Thus, a greater mass is swept around the drop, causing an enhancement of the evaporation rate with T_S.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (Project number: SPR/2020/000086, CRG/2021/000225, CRG/2021/000508).

Notes on contributors

Suraj Prasad

Suraj Prasad has been a Ph.D. scholar at the Indian Institute of Technology Dhanbad, India, since 2016. He received his master’s in mechanical engineering (specialization: thermal engineering) in 2016. He works on the evaporation of various drops under the influence of acoustics in the Fluid Surface Interaction Lab under the supervision of Drs. Narayanan and Mandal.

Subhramanian Narayanan

Subhramanian Narayanan received his Ph.D. in Mechanical Engineering in 2011 with a thesis on the broad area of noise reduction of an airfoil from the Indian Institute of Technology Madras. Following his Ph.D., he joined as a post-doctoral researcher at the University of Southampton, UK, where he worked in a similar field. Following this, he joined the Indian Institute of Technology Dhanbad in 2015, where he is currently working as an Associate Professor in Department of Mechanical Engineering.

Deepak Kumar Mandal

Deepak Kumar Mandal obtained his Ph.D. in Mechanical Engineering in 2013 with a thesis on circulation inside evaporating drops from the Indian Institute of Technology Madras. Following his Ph.D., he joined as a post-doctoral researcher at York University, Canada, where he worked on shedding drops under ambient and icing conditions. After two years (June 2013 to June 2015), he joined as an Assistant Professor at the Indian Institute of Technology Dhanbad, where he is currently working as an Associate Professor. For his research, he has developed various setups to study a drop’s impact, evaporation, and shedding. Therefore, his expertise is in drop dynamics, evaporation, and shedding.