Can a heat transfer surface be too slick?
Can a heat transfer surface be too slick?
(OP)
I am debottlenecking a continuous dryer which fouls at high production rates. What impact would adding a diamond like coating or nitriding or polishing the 316 stainless steel have on the heat and hydrodynamic transport?
Adhesion (cohesion) of the sodium organic salt to a mill finished stainless steel is very high at the operating temperature 300 F. It is highly agglomerating and forms crust if not mechanically disturbed.
The dryer is built as a heated horizontal cylinder, containing a center shaft with a spiral of short blades that intermesh with stationary hooks, to clean the heated blades (~ 3 mm clearence).
If I only modify the cylinder interior, I imagine sliding but the hooks would result in surface renewal. Is there a negative to not coating the hooks, shaft and blade? Lack of convective turnover? increased stress on the hooks?
If I modify all surfaces, can I be too slick?
Adhesion (cohesion) of the sodium organic salt to a mill finished stainless steel is very high at the operating temperature 300 F. It is highly agglomerating and forms crust if not mechanically disturbed.
The dryer is built as a heated horizontal cylinder, containing a center shaft with a spiral of short blades that intermesh with stationary hooks, to clean the heated blades (~ 3 mm clearence).
If I only modify the cylinder interior, I imagine sliding but the hooks would result in surface renewal. Is there a negative to not coating the hooks, shaft and blade? Lack of convective turnover? increased stress on the hooks?
If I modify all surfaces, can I be too slick?





RE: Can a heat transfer surface be too slick?
I haven't tried them, but I came across boron nitride release agents when researching a different type of sticking problem at high temperature. A simple release agent applied during cleanouts may be an alternative.
RE: Can a heat transfer surface be too slick?
www.eypmcf.com
RE: Can a heat transfer surface be too slick?
If it is to slick, how are you ever going to predict the boundary layer effect?
Ken
Ken
KE5DFR
RE: Can a heat transfer surface be too slick?