r] = radiation heat-transfer coefficient
from the top surface to the bottom surface of the air channel, W x [K.
Then there is a heat-transfer coefficient
for the "gap" between the polymer and the roll surface.
Users plug in the profile shape and material, and the computer simulates the cooling time needed by calculating the convection heat-transfer coefficient
from the profile into the coolant, while taking into account how profile mechanical properties are impacted by specific cooling times.
But the more tool steel you add, the lower the heat-transfer coefficient
," says POM's Janson.
h can be estimated from standard heat-transfer coefficient
correlations appropriate to the type of bean-air contacting involved.
The rate of crystallization increases with 1) increase in air speed or 2) decrease in ambient temperature; the former raises the average convective heat-transfer coefficient
more than the latter.
The specific surface area of the bulk material is inversely proportional to the particle diameter, while the heat-transfer coefficient
generally becomes smaller with increasing particle diameter.
Analysis had shown that with increased line speed, the heat-transfer coefficient
between the sheet and the rolls decreased.
Purdue University researchers have shown that the technology increased the heat-transfer coefficient
, which describes the cooling rate, by as much as 250 percent.
2] D = diameter, m Gz = Graetz number, DRePr/L, dimensionless h = heat-transfer coefficient
, W [m.
With the Fourier number, the effect of the internal heat-transfer coefficient
can be calculated and separated from the external heat-transfer coefficient
in Hydrocooling of Spherical and Cylindrical Food Products.