Standardized Air Permeability Test Parameters for Raw Flax Bundles
Air permeability fineness tests for raw flax require strict 65 percent RH conditioning, precise chamber packing density, and pre-cleaning of shive debris.
Non-Laminar Flow
Fluid Turbulence
Irregular movement of liquids within a dyeing machine or washing range ensures that chemicals are distributed evenly across the fabric surface. Non-laminar flow occurs when the velocity of the liquor is high enough to create eddies and random currents. In linen processing, this turbulence is necessary to force dye molecules into the dense, crystalline structure of the flax fibre.
Without this chaotic movement, the dye might only settle on the surface of the cloth.
Liquor Distribution
Chaotic fluid dynamics prevent the formation of stagnant zones where the chemical concentration would be lower than the rest of the bath. When non-laminar flow is maintained in the jet dyer, the fabric is hit by the liquor from multiple angles. This action is particularly important for heavy linen fabrics that are difficult for fluids to penetrate.
Engineers design the pumps and nozzles to maximize this effect without causing mechanical damage to the delicate flax fibres.
Processing Efficiency
Rapid mixing of the dye and auxiliary chemicals reduces the total time required for the cycle. Achieving non-laminar flow allows for a more consistent shade from the beginning of the roll to the end. It also aids in the removal of unfixed dye and impurities during the final rinsing stages.
Controlling the Reynolds number within the machine is the technical method used to guarantee this type of flow.