抄録
To have some phenomenological and fundamental information on the desublimation processes in an annular-tube cold trap to be operated with a closed system at such low pressures that the Navier-Stokes equations may not be valid, we made experimental studies on the desublimation processes of naphthalene vapor in stationary nitrogen gas.
It was found that the desublimation process consisted of an initial transient period and a subsequent quasi-steady period. Because the latter should be important for the design of the cold trap, under the quasi-steady period, we estimated three characteristic quantities such as the local desublimation rate, the apparent density and the reference length of desublimated solid layer. The effects of operating conditions on these quantities were studied by means of new dimensionless parameters, Ma and Pe which were induced from our theoretical development based on Maxwell''s moment method. It was found that the desublimation process in the transition region depended strongly upon Ma but scarcely upon Pe.
