Viscous heating in a ball-point pen, you are asked to decide whether the apparent decrease in viscosity
Question:
Viscous heating in a ball-point pen, you are asked to decide whether the apparent decrease in viscosity in ball-point pen inks during writing results from "shear thinning" (decrease in viscosity because of non-Newtonian effects) or "temperature thinning" (decrease in viscosity because of temperature rise caused by viscous heating). If the temperature rise is less than 1K, then "temperature thinning" will not be important. Estimate the temperature rise using Eq. 10.4-9 and the following estimated data:
Clearance between ball and holding cavity 5 x 10–5 in
Diameter of ball 1 mm
Viscosity of ink 104 cp
Speed of writing 100 in/min
Thermal conductivity of ink (rough guess) 5 x 10-4 cal/s ∙ cm ∙ C
Step by Step Answer:
Viscous heating in a ballpoint pen The paralelplate approximation in 104 i...View the full answer
