Computational calculation of temperature and electrical resistance to control Joule heating of green Pinus radiata logs

• Published in: Applied thermal engineering 2019-08, Vol.159, p.113855, Article 113855
• Main Authors: Nursultanov, N., Heffernan, W.J.B., van Herel, M.J.W.M.R., Nijdam, J.J.
• Format: Article
• Language: English
• Subjects: Computational modelling; Electrical resistance; Finite volume method; Fluid dynamics; Heat transfer; Heating; Non-chemical treatment; Ohmic dissipation; Ohmic heating; Resistance heating; Resistive heating; Temperature; Temperature dependence; Wood treatment
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2019.113855

•The computational model accurately predicts logs’ temperature and resistance.•The heat transfer model was validated experimentally.•Calculated log resistance provides a proxy for the log temperature.•Consideration of moisture loss is unnecessary for a short Joule heat treatment. This study describes a computational model employed to control Joule heating of green Pinus radiata logs in experiments on twenty export size logs from trees grown in the Canterbury region of New Zealand. The heating process was modelled using custom-built one-dimensional computational software based on the finite volume method (FVM). The proposed control method utilized the logs’ experimental bulk electrical resistance as a feedback variable during the Joule heating operation. As wood resistance is temperature dependent, comparing the experimental and predicted resistance values allowed an indirect determination of the actual wood temperature. The model accurately predicted the log resistance and the final log temperature, with an error of 6% and 5%, respectively. The limitations and further improvements to the model are discussed.