Two phase flow pattern recognition in straight tubes

The two phase flow pattern identification by statistical analysis of local void fraction and ''local'' differential pressure fluctuations gives excellent results for air-water systems. All the main types of upward vertical and horizontal flow patterns are statistically analyzed and characterized through ''recognition parameters'' defined on the basis of the statistical functions. The parameters are tested on wide ranges of air and water flow rates, covering all types of vertical and horizontal flow regimes to obtaining the ''reference ranges'' for each parameter and for each flow regime. Recognition procedures are pointed out: Flow pattern identification is achieved through the comparison among ''measured'' parameters and their ''reference ranges''. The whole ''recognition procedure'' can be computerized. The recognition efficiency of the method is very high for differential pressure in horizontal and vertical cases and for the local void fraction in vertical case. The maximum efficiency and resolution on flow structure features are obtained utilizing the two types of measurement