Decay rate of critical fluctuations in steam and in dilute steam-NaCl mixtures

• Published in: International Journal of Thermophysics; (USA) Vol. 10; no. 2; pp. 397 - 407
• Main Authors: Tufeu, R., Desmarest, Ph, Le Neindre, B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: United States 01.03.1989
• Subjects: ALKALI METAL COMPOUNDS; BINARY MIXTURES; CHLORIDES; CHLORINE COMPOUNDS; CRITICAL PRESSURE; CRITICAL TEMPERATURE; DISPERSIONS; ENGINEERING; FLUCTUATIONS; GROUP THEORY; HALIDES; HALOGEN COMPOUNDS; LASER SPECTROSCOPY; LIGHT SCATTERING; MATHEMATICAL MODELS; MATHEMATICS; MIXTURES; MULTI-PHOTON PROCESSES; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; REFRACTIVITY; RENORMALIZATION; SCALING LAWS; SCATTERING; SODIUM CHLORIDES; SODIUM COMPOUNDS; SPECTROSCOPY; STEAM; TEMPERATURE DEPENDENCE; THERMAL CONDUCTIVITY; THERMAL DIFFUSIVITY; THERMODYNAMIC PROPERTIES; TRANSITION TEMPERATURE; VARIATIONS 420400 > Engineering > Heat Transfer & Fluid Flow
• ISSN: 0195-928X; 1572-9567
• DOI: 10.1007/BF01133536

The decay rate of critical fluctuations in steam and in a steam - NaCl mixture has been investigated experimentally with the aid of photon correlation spectroscopy. For pure steam, the measurements have been performed along seven isochores (({absolute value of {rho} {minus} {rho}{sub c}})/{rho}{sub c} < 0.09) as a function of the temperature T for (T {minus} T{sub t}) < 1 K. The results have been compared with the values predicted by the renormalization-group theory written as a modification of the classical mode coupling theory. The agreement between experiment and theory is satisfactory along the critical isochore, but larger deviations are noted for {rho} {ne} {rho}{sub c} when approaching the transition temperature T{sub t}. The decay rate of a 0.1% (molar) dilute mixture of NaCl in H{sub 2}O has been measured along some near-critical isochores as a function of temperature. Its behavior, which is very different from that observed for pure steam, is discussed.