Boiling Investigation on a Surface With Artificial and Natural Nucleons Sites

The water and Na₂SO₄ water solution boiling investigation had been carried in pool on the surfaces with artificial and natural nucleons sites under different pressures using high speed digital camera. The boiling of water was investigated at atmosphere pressure on a surface with a artificial nucleons site, which had a micro scale (cavity’s diameters – 100 and 200 μm and depth – 80 μm), in the Fridrich-Alexander University Erlangen-Nu¨rnberg, Germany in the Institute of Fluid Mechanics. The boiling of water and Na₂SO₄ water solution with concentration 20 g/l was investigated on a surface with natural nucleons sites in the pressure range 0.1 – 1 MPa in the Moscow Power-Engineering Institute (Technical University) on department of Thermal Physics. The “hand” video processing was used for the study’s results in case of the pool boiling on a surface with a artificial nucleon site. The data processing was realized for the study’s results using with a program “Bubble Detector”, which was specially developed for case of the pool boiling on a surface with the natural nucleon sites, and the “hand” processing was carried for video, which showed the reliability of the program “Bubble Detector”. First the distributions and dependences of basic boiling characteristics (frequency, departure diameter) were obtained at water pool boiling on a surface with a artificial cavity in the range of heat flux from 20 to 128 kW/m² and the time dependence of vapor bubble’s grow. It was obtained, that departure diameters of vapor bubbles do not depend in case of boiling on a surface with a single cavity practically on heat flux. First the distributions and dependences of swimming velocities and equivalent diameters were obtained at water and Na₂SO₄ water solution with concentration 20 g/l pool boiling on a surface with natural nucleon sites in range of pressures from 0.1 to 1 MPa. The comparison of diameters’ and swimming velocities’ distributions of vapor bubbles was carried for under consideration conditions.