Simulation of transient heat transfer during forced convection cooling of cocoyam (Colocasia Esculenta (L.) Schott ) tubers

John Ndisya; Ayub Gitau; Franz Roman; Duncan Mbuge; Barbara Sturm; Oliver Hensel

doi:10.1016/j.heliyon.2022.e12360

Simulation of transient heat transfer during forced convection cooling of cocoyam (Colocasia Esculenta (L.) Schott ) tubers

Heliyon. 2022 Dec 15;8(12):e12360. doi: 10.1016/j.heliyon.2022.e12360. eCollection 2022 Dec.

Authors

John Ndisya^{1

2

3}, Ayub Gitau², Franz Roman¹, Duncan Mbuge², Barbara Sturm^{1

4

5}, Oliver Hensel¹

Affiliations

¹ Department of Agricultural & Biosystems Engineering, Faculty of Organic Agricultural Sciences, University of Kassel, Nordbahnhof str. 1a, 37213 Witzenhausen, Germany.
² Department of Environmental & Biosystems Engineering, School of Engineering, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
³ Department of Agricultural & Biosystems Engineering, School of Engineering & Technology, Kenyatta University, P.O. Box 43844 - 00100, Nairobi, Kenya.
⁴ Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth Allee 100, 14469 Potsdam, Germany.
⁵ Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt Universität zu Berlin, Hinter der Reinhardtstr. 6-8, 10115 Berlin, Germany.

Abstract

In this study, a prediction model based on transient heat transfer was modified and validated using experimental data. The time required to cool tubers from field temperature of 30 ± 2 °C to the target storage temperature of 12 ± 0.2 °C was predicted directly from the model. Moreover, total cooling time ranged from 127.8 - 154.2 min for small tubers and 190.8-262.2 min for large tubers while the field heat removed ranged from 9.61 - 10.17 kJ for small tubers and 24.78-31.90 kJ for large tubers between the extremes of the air velocity. Tuber orientation to airflow neither influenced the heat transfer coefficients and Biot numbers nor the cooling time and amount of field heat removed. The results from this study could be applied in the design and optimisation of forced convection cooling systems to precool tubers immediately after harvest and for extended duration storage.

Keywords: Field heat removal; Forced convection precooling; Postharvest storage; Transient heat transfer.