Effect of Sublimation on the Behavior of Cryodeposits PDF Download

Author: J. Perry Campbell
Publisher:
ISBN:
Category : Cryoelectronics
Languages : en
Pages : 28

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Book Description
The rates of energy loss due to sublimation have been calculated for water, carbon dioxide, argon, krypton, xenon, and oxygen over the temperature range in which these materials are solids and have vapor pressures of less than 1 torr. These energy losses are compared with the possible thermal radiation losses of such deposits in the same temperature range. The energy loss rate from these cryodeposits due to sublimationis quite sensitive to the surface temperature of the deposit. There is only a narrow temperature range over which the sublimation and radiation energy losses are of the same magnitude and in which both phenomena must be considered in a heat balance. At temperatures above this range, sublimation is the dominant energy-loss mechanism; at lower temperatures the radiation energy loss is the more important. The surface temperature, mass loss, and deposit lifetime of a subliming cryodeposit, both with and without an incident energy heat load, are evaluated. Numerical results are given for a typical ice cryodeposit, both with and without an incident energy heat load from a 300 K blackbody, for substrate temperatures ranging from 190 to 270 K, and for deposit thicknesses ranging from 10 Irn to 1 cm.