Increasing the Certainty to Estimate 1-Gravity (1-g) Separation Time Based on any-g Force (N) and g- Equivalent Concepts

Abstract:

As it is well established, Stokes law has been used to calculate the time required to precipitate a particle in a fluid under specific conditions such as sphericity, laminar flow, differences on densities (particle and fluid) and fluid viscosity for a specific gravity force (g). However, when the separation under 1-g takes days or months and it is crucial to estimate that time in just minutes, the separation time at 1-g can be estimated making a relationship with any other g (n). However, in any centrifuge the n value is not reached instantaneously but in a specific time and during this time the g-value is never constant, but it is always growing (at the first stage). Then, after reaching the n-value, the centrifuge could stay at that value for a certain time and then, (the third stage) the n value will change again, this time decreasing. Therefore, the aim of this study is to establish a mathematical model that considers the acceleration and deceleration periods and expresses them as equivalents of the n period by using a numerical approach [1-3]. It is expected the g-equivalent concept increases the certainty of the separation time estimation.

• Periodical: Defect and Diffusion Forum (Volume 420)
• Pages: 19-25
• DOI: https://doi.org/10.4028/p-txpoi1
• Online since: November 2022
• Authors: F. Ernesto Carvajal-Larenas*
• Keywords: Certainty, Gravity, Precipitation, Separation, Stokes

References

[1] J. Crank. The Mathematics of Diffusion. second ed., Oxford University Press, New York, (2011).

[2] R.E. Treybal, Mass-Transfer Operations, third ed., McGraw-Hill Company, Singapore, (1981).

[3] A. Ibartz, G.V. Barbosa-Cánovas, Operaciones Unitarias en la Ingeniería de Alimentos, Ediciones Mundi-Prensa, Madrid, (2005).

[4] R.P. Singh, D.R. Heldman, Introduction to Food Engineering, fifth ed., Academic Press, San Diego CA, (2014).