In:
The Journal of Chemical Physics, AIP Publishing, Vol. 124, No. 22 ( 2006-06-14)
Abstract:
Homogeneous nucleation rate isotherms of n-butanol+helium were measured in a laminar flow diffusion chamber at total pressures ranging from 50to210kPa to investigate the effect of carrier gas pressure on nucleation. Nucleation temperatures ranged from 265to280K and the measured nucleation rates were between 102 and 106cm−3s−1. The measured nucleation rates decreased as a function of increasing pressure. The pressure effect was strongest at pressures below 100kPa. This negative carrier gas effect was also temperature dependent. At nucleation temperature of 280K and at the same saturation ratio, the maximum deviation between nucleation rates measured at 50 and 210kPa was about three orders of magnitude. At nucleation temperature of 265K, the effect was negligible. Qualitatively the results resemble those measured in a thermal diffusion cloud chamber. Also the slopes of the isothermal nucleation rates as a function of saturation ratio were different as a function of total pressure, 50kPa isotherms yielded the steepest slopes, and 210kPa isotherms the shallowest slopes. Several sources of inaccuracies were considered in the interpretation of the results: uncertainties in the transport properties, nonideal behavior of the vapor-carrier gas mixture, and shortcomings of the used mathematical model. Operation characteristics of the laminar flow diffusion chamber at both under-and overpressure were determined to verify a correct and stable operation of the device. We conclude that a negative carrier gas pressure effect is seen in the laminar flow diffusion chamber and it cannot be totally explained with the aforementioned reasons.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2006
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
