Department of Horticulture
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Browsing Department of Horticulture by Author "Ambaw, A."
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- ItemEvaluation of the airflow characteristics, cooling kinetics and quality keeping performances of various internal plastic liners in pomegranate fruit packaging(Elsevier, 2020-10-23) Lufu, Robert; Ambaw, A.; Berry, Tarl M.; Opara, Umezuruike LinusThere is a trade-off to be optimised carefully as plastic liners deal with postharvest cooling processes as well as the produce quality and sustainability requirements. Understanding the implementation of plastic liners in the fresh fruit cold chain is required to reconcile the opposing roles. In this paper, the performances of four types of internal packaging plastic liners were studied. The airflow characteristics, cooling rate, cooling uniformity and quality keeping performances were measured. Cases: no liner, non-perforated liner, micro-perforated liner, macro perforated liner with 2 mm diameter holes, macro perforated liner 4 mm diameter holes were investigated. Generally, the liners delayed the cooling rate significantly. Non-perforated and micro-perforated liners are similar in terms of airflow resistance and cooling rate, both delayed the optimum cooling time by 5 h compared to the plastic-free case. On the other hand, macro-perforated liners cause a delay of only 3 h.
- ItemThe use of CFD to characterize and design post-harvest storage facilities : past, present and future(Elsevier, 2012) Ambaw, A.; Delele, M. A.; Defraeye, T.; Ho, Q. T.; Opara, Umezuruike Linus; Nicolai, B. M.; Verboven, P.There has long been an interest on the use of mathematical models for optimization of post-harvest refrigeration systems operation and design. These mathematical models are applied to predict the biophysical phenomena that take place during post-harvest handling of horticultural products. CFD has now become feasible to investigate the flow, heat and mass transfer processes in such details that include complex aspects such as product stacking, gas diffusion and kinetics, and droplet or particle dispersion. This review paper summarizes the advances in the application of CFD applied to post-harvest storage of horticultural products. Due to the geometrical complexity of post-harvest products, packages and systems and limitations due semi-empirical models for turbulence and porous media, new strategies using multiscale methods are starting to be successful.