Enhancement of nucleate pool boiling heat transfer in ammonia/water mixtures (Effect of surface-active agent)

✍ Scribed by Toshiaki Inoue; Masanori Monde; Teruki Kuwahara; Yoshio Teruya

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 505 KB
• Volume: 40
• Category: Article
• ISSN: 1099-2871
• DOI: 10.1002/htj.20328

✦ Synopsis

Abstract

Nucleate boiling heat transfer coefficients of ammonia/water mixtures have been measured when a surface‐active agent was added into the mixtures. The experiment has been carried out on a horizontal heated wire at a pressure of 0.4 MPa. The effect of concentration of the ammonia and the surface‐active agent on the coefficients was investigated experimentally for the ammonia fractions C = 0.3 and 0.7 and the surfactant concentration C~S~ = 0 to 3500 ppm. The result shows that just after onset of boiling the nucleate boiling heat transfer coefficient enhances at the lower ammonia fraction i.e., C = 0.3. It was found that the enhancement effect by the surface‐active agent disappeared when the surfactant concentration is more than 1000 ppm at an ammonia fraction C = 0.3.

It is also shown that the generated heat of mixing near the vaporBliquid interface can be removed easily and the pressure and temperature in the system can be controlled easily by placing a cooling pipe on the vaporBliquid interface, resulting in improvement of accuracy in measuring the heat transfer coefficients. We correlated the effect of the surfactant on the heat transfer coefficient using the improved measurement data in the current paper. 8 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/htj.20328