Showing papers by "Anthony G. Straatman published in 2019"
TL;DR: In this article, the authors characterize the resistance of mesh filters, in terms of pressure drop as a function of flow velocity, in order to model any filtration process, and apply it to mesh filters.
Abstract: Characterizing the resistance of mesh filters, in terms of pressure drop as a function of flow velocity, is an important part of modeling any filtration process. Most commonly, filters are characte...
8 citations
TL;DR: In this article, a numerical model for solids separation using continuously moving, inclined fine mesh filters is presented, based on the drainage curve, an analytical formulation is developed for the cake resistance, as a function of the filtered volume per unit area, V and removal efficiency is also correlated with V through a sieve test.
5 citations
TL;DR: In this paper, a produce gas respiration model and fruit-stack geometric digital generation approach is used with commercial CFD software (ANSYS CFXTM) to conduct shape-level simulations of the fluid flow, heat and respiration processes that occur during the storage of produce, with the ultimate purpose of providing detailed information that can be used to develop closure coefficients for volume-averaged simulations.
Abstract: A produce gas respiration model and fruit-stack geometric digital generation approach is used with commercial CFD software (ANSYS CFXTM) to conduct shape-level simulations of the fluid flow, heat and respiration processes that occur during the storage of produce, with the ultimate purpose of providing detailed information that can be used to develop closure coefficients for volume-averaged simulations. A digital generation procedure is used to develop an accurate representation of the shapes of the different produce. The produce shapes are then implemented into a discrete element modelling tool to generate a randomly-distributed stack of produce in a generic container, which is then utilized as a representative elementary volume (REV) for simulations of airflow and respiration. Simulations are first conducted on single pieces of produce and compared to a recently published experimental data for tomatoes and avocadoes to generate coefficients for the respiration model required for the shape-level simulations on the REV. The results of the shape-level simulation are then processed to produce coefficients that can be used for volume-averaged (porous-continuum-level) calculations, which are much more practical for simulations of large areas of storage comprised of hundreds or thousands of boxes of different commodities. The results show that the multi-level approach is a viable means for developing the simulation parameters required to study refrigeration, ripening and storage/transport of produce.
3 citations
TL;DR: In this article, the authors revisited the rotating duct problem examined by Polihronov and Straatman and derived closed form expressions for velocity, temperature, density and pressure along the duct.
Abstract: The present study revisits the rotating duct problem examined by Polihronov and Straatman (J. Polihronov and A. G. Straatman, Phys. Rev. Lett. v. 109, p. 054504 (2012)). Starting from the general compressible Euler equations in a non-stationary reference frame closed form expressions for velocity, temperature, density and pressure along the duct are determined. The present results are more general than those obtained by Polihronov and Straatman, as the change of in-frame kinetic energy has been retained. The improvement of the present results over Polihronov and Straatman’s is demonstrated by comparison with the results of a computational fluid dynamics study. The new results have been further generalized to the case of a rotating duct with varying cross-sectional area, and again for a general curved passage in three-dimensional space. The work required or derived from the rotating duct has also been computed. The choked flow condition within the passage of varying cross-sectional area has been identified, along with the constraints which must be placed on the Mach, Rossby, and tip Mach numbers to avoid choked flow. Finally, a straightforward technique to identify any locations where an ideal rotating flow in a constrained passage will become sonic has been presented.
2 citations