Short-Time-Transient Surfactant Dynamics and Marangoni Convection Around Boiling Nuclei  

Oleh:

Manglik, Raj M. ; Wasekar, Vivek M.

Jenis: Article from Bulletin/Magazine
Dalam koleksi: Journal of Heat Transfer vol. 125 no. 5 (Oct. 2003), page 858-866.
Topik: boiling; short - time - transient; surfactant dynamics; marangoni convection; boiling nuclei

Ketersediaan

Perpustakaan Pusat (Semanggi) Nomor Panggil: JJ90.7 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

Lihat Detail Induk

Isi artikel

The effects of surfactant concentration on the initial short - time - scale Marangoni convection around boiling nuclei in aqueous solutions have been computationally investigated. The model consists of a hemispherical bubble (1 – 100 µm radius) on a downward - facing constant - temperature heated wall in a fluid pool with an initial uniform temperature gradient. Time - dependent transport of liquid mass, momentum, energy, and surfactant bulk and surface convection along with the adsorption kinetics are considered. Conditions for bubble sizes, surfactant bulk concentrations, and wall heat flux levels are represented by a range of thermocapillary and diffusocapillary Marangoni numbers (6 <= Ma(T) <= 10(3), 0 <= Ma(S) <= 8.6×10(5)) over a micro - scale time period (1 µs – 1 ms). With a surfactant in solution, a surface concentration gradient develops at the bubble interface that tends to oppose the temperature gradient and reduce the overall Marangoni convection. The maximum circulation strength, which is dependent on the bubble size, corresponds to a characteristic surfactant adsorption time. This, when scaled by a ratio of bubble radius, is found to depend solely on the surfactant bulk concentration. Moreover, the interfacial surfactant adsorption does not display a stagnant cap behavior for the range of parameters and time scales covered in this study.

Opini Anda

Klik untuk menuliskan opini Anda tentang koleksi ini!

Kembali