Aerodynamics


Aerodynamic characteristics - a very important parameter, on which the speed and quality of drying lumber and operation costs (the cost of electricity consumed by the fans).

Greatly simplified the solution of aerodynamic problems is as follows:
The task of fans:
- stir the air in the drying kiln so that the temperature difference at different points in the kiln was minimal
- create movement of air as evenly throughout the stacking at a minimum speed of air flow.
Why at a minimum speed of air flow? Because the aerodynamic resistance stacking lumber in the drying kiln increases sharply with increasing air velocity.
Let's consider two variants with identical volume of stacking for the drying kiln:
- width 2.0 m, height - 3.0 m
- width 3.0 m, height - 2.0 m
At the first variant of stacking the task of fans is solved much easier, than the second.
Try not to make stacking too wide. Optimal width-2.2 m. This width allows an even distribution of air flow in the give pleasing cost of electricity for the fans. The height of stacking at the same time is usually chosen around (2.5 - 3.0) m.
Do not forget to round off the corners of the drying kiln, where the speed of air flow high, do not create air stoppers.
The higher flow speed, the more precisely to keep the technique of drying wood. At high flow speeds and insufficient humidity of air may occur a phenomenon that is often called tanning surface of the wood. Surface becomes dry and hard and drying process is stopped. To resolve this have to raise humidity to soften the surface layer of wood.