EXPERIMENTAL INVESTIGATION OF BINARY NUCLEATION RATES OF WATER-N-PROPANOL AND WATER-N-BUTANOL VAPORS BY MEANS OF A PEX-TUBE

Measurements of homogeneous nucleation rates of two binary vapor mixtu res of water and alcohol carried in nitrogen have been performed with a new instrument for nucleation and droplet growth studies, the piston expansion tube (pex-tube). The pex-tube subjects the vapors to short supersaturation pulses generating a limited number of nuclei which gro w into monodisperse droplets. The droplets are detected in number and size by Mie lightscattering. The results provide nucleation rates betw een 10(5) and 10(9) cm(-3) s(-1) at constant temperature as a function of the vapor phase activities a(1) and a(2) of water and alcohol, res pectively. Comparison with published experimental data exhibits good a greement. (C) 1996 American Institute of Physics.