Computational modelling of the vacuum drying of Australian hardwoods

Australian hardwoods are an important commodity to the national building industry but before the wood can be used for commercial purposes it must be treated. One of these treatments is drying which is an expensive and time-consuming operation. Often referred to as the ‘bottleneck’ of the production process, drying consumes up to 90% of processing time and approximately 70% of the energy required to transform green material into high value dried material. Vacuum drying, an emerging technology in Australia, compared with current conventional drying methods, has the ability to reduce drying times by up to 60%, reduce energy costs up to 50%, and reduce airborne Volatile Organic Compound (VOC) greenhouse gas emissions to zero (compared to 0.07 kg/m3 for conventional drying).

The skills and knowledge acquired during the proposed project would enhance current and future research being undertaken at QUT, Queensland Primary Industries and Fisheries (QPIF) and elsewhere, to support Queensland’s transition from native forest to plantation hardwood resources. The Forest and Wood Products Australia (FWPA), a forest industry body, has funded the overarching project for which this project is a core component.

The specific objectives of the project are to:

• Refine an existing softwood-drying model developed previously by Turner and Perré for simulating the drying of a single hardwood board in the QPIF vacuum drier
• Identify efficient and accurate computational techniques to implement this vacuum drying model on the QUT HPC system
• Apply these new computational strategies to study the vacuum drying of wood coupling stress/strain and transfer models to optimise vacuum drying schedules
• Produce advanced visualisation software to study the moisture, temperature and pressure evolution fields in the board during drying, when subjected to various drying schedules
• Validate and calibrate the modelling approaches using experimental work carried out in the laboratories of QPIF on the hardwood species spotted gum and messmate

A significant outcome of the work will be the identification of vacuum drying schedules that not only optimise drying quality of the hardwoods, but also minimise overall energy consumption.

Participants

Professor Ian Turner
Discipline of Mathematical Sciences, Queensland University of Technology

Professor Patrick Perré
AgroParisTech-ENGREF

Industry Participants

Queensland Primary Industries and Fisheries