Precise Numerical Calculation of the Bond Number of a Fluid Drop and of the Surface Tension Coefficient at the Fluid-Gas Interface

Abstract

Precise calculation of the Bond number of a fluid drop and the surface tension coefficient at the fluid-gas interface plays an important role in modeling of the behavior of fluids in aircraft fuel tanks during overloads resulting from flight and the behavior of fluids in power supply and life support systems of spacecraft and space stations. The existing methods of calculation of the Bond number of a fluid drop and of the surface tension coefficient at the fluid-gas interface are based on the method, proposed by F. Bashforth and J. Adams, using tables of calculation of the profiles of dimensionless drops, compiled in accordance with photos of real fluid drops of a wide range of Bond numbers and of contact angles manually. In the existing interpretations of this method, these tables are replaced by computer calculations of the profiles of dimensionless drops. However, due to the fact that these methods simply duplicate these tables, and the choice of the calculated Bond numbers of a fluid drops is performed manually, the precise calculation of the fluid drop profile that corresponds to the actual fluid drop image, and, accordingly, the precise calculation of the surface tension of coefficient at the fluid-gas interface is impossible. The article presents the developed computer program of precise numerical calculation of the Bond numbers of wide range of fluid drops in accordance to photos of real fluid drops, in which adjustment of the Bond number corresponding to a real drops of fluid are carried out automatically by a computer with high accuracy and of precise numerical calculation of surface tension coefficient at the fluid-gas interface, which permits to calculate the precise value of the Bond number of a fluid drop, at which the calculated profiles of a fluid drops coincide with high accuracy with the photographic images of the real profile of a fluid drops and to calculate the precise value of the surface tension coefficient at the fluid-gas interface within a few seconds.

Keywords: Bond numbers, Computer numerical calculations, Drop image, Surface tension coefficient at the fluid-gas interface,