NUCLEATION OF SUPERSATURATED VAPORS IN NOZZLES .2. C6H6, CHCL3, CCL3F, AND C2H5OH

Measurements have been made of the results of homogeneous condensation in benzene, chloroform, Freon 11, and ethanol vapors expanding in steady flow in a supersonic air nozzle. Experimental results have been compared with the predictions of the classical nucleation rate equation and with the quantum-statistical treatment of Lothe and Pound. Whereas the results on C 2H6OH were inconclusive, nucleation rates in the other three vapors are in good agreement with the Lothe-Pound treatment over substantial temperature ranges. It is noted that generally fluids of polar or rod-shaped molecules follow classical theory, and that fluids of compact molecules without a large permanent dipole follow the Lothe-Pound treatment. Mass accommodation coefficients were also inferred. For CHCl3, ξ≃1; for CCl3F and C6H6, ξ≃0.1.