Mathematical Correlation
Mathematical formulations that relate convective heat and mass transfer coefficients provide the basis for predicting drying rates in fabric stenters. The chilton colburn analogy establishes a relationship between these transfer modes by using dimensionless groups to account for fluid properties. This relation enables engineers to calculate mass transfer rates using only measured heat transfer data.
The correlation holds across a wide range of turbulent flow regimes in textile finishing.
Transport Analogy
Turbulent boundary layers on the surface of moving textile webs determine the rate of moisture removal during thermal fixation. Applying the chilton colburn analogy allows the estimation of mass transfer from measured thermal resistance without running separate evaporation trials. Calculations rely on the similarity of the temperature and concentration profiles in the boundary layer.
Velocity fluctuations drive both transport mechanisms in an identical fashion.
Drying Influence
Drying calculations for fabric running through a multi-zone stenter frame require continuous assessment of local evaporation rates. High velocity air jets impinge on the fabric surface to accelerate moisture removal, creating complex flow profiles that are difficult to model directly. By utilizing the chilton colburn analogy, the system calculates the mass transfer from the heat transfer coefficient derived from air temperature measurements.
This simplifies the control system by reducing the number of required physical sensors in the hot drying chamber. The method provides stable drying curves across different fabric weights.
Process Prediction
Limitation of this transport relation occurs when radiation dominates heat transfer. Chemical reactions on the fabric surface also disrupt the mathematical correlation.
