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Abstract

One of the important parameters describing pneumatic liquid atomisation is the air to liquid mass ratio (ALR). Along with the atomiser design and properties of the liquid it has extremely important influence on parameters of atomised liquid such as: mean droplet diameter, jet range and angle. Knowledge about real characteristics of an atomiser in this respect is necessary to correctly choose its operating parameters in industrial applications.

The paper presents results of experimental research of two-fluid atomisers with internal mixing built according to custom design. Investigated atomizers were designed for spraying a urea aqueous solution inside the power boiler combustion chamber. They are an important element of SNCR (selective non-catalytic reduction) installation which is used to reduce nitrogen oxides in a flue gas boiler. Obtained results were used by authors in further research, among others to determine the boundary conditions in the SNCR installation modeling.

The research included determining mean droplet diameter as a function of ALR. It has been based on the immersion liquid method and on the use of specialised instrumentation for determining distribution of droplet diameters in a spray – Spraytec by Malvern. Results obtained with both methods were later compared. The measurements were performed at a laboratory stand located at the Institute of Heat Engineering, Warsaw University of Technology. The stand enables extensive investigation of the water atomisation process.

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Authors and Affiliations

Piotr Krawczyk
Krzysztof Badyda
Szczepan Młynarz
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Abstract

The homogeneity of an immiscible liquid–liquid system was investigated in a baffled vessel agitated by a Rushton turbine. The dispersion homogeneity was analyzed by comparing Sauter mean diameters and drop size distribution (DSD) determined in different measured regions for various impeller speeds. The sizes of droplets were obtained by the in-situ measurement technique and by the Image Analysis (IA) method. Dispersion kinetics was successfully fitted with Hong and Lee (1983) model. The effect of intermittency turbulence on drop size reported by Bałdyga and Podgórska (1998) was analyzed and the multifractal exponent ������ was evaluated.
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Bibliography

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Formánek R., Kysela B., Šulc R., 2019a. Drop size evolution kinetics in a liquid–liquid dispersions system in a vessel agitated by a Rushton turbine. Chem. Eng. Trans., 74, 1039–1044. DOI: 10.3303/CET1974174.

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Authors and Affiliations

Roman Formánek
1
Radek Šulc
1

  1. Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Process Engineering, Technická 4, 160 00 Prague, Czech Republic

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