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Effect of Changes in the Roughness of the Inflow Surface of a Sloping Segmental Orifice with Point Pressure Reception on its Characteristics

100%

Mrowiec A. , Andruszkiewicz A. , Piechota P.

tom Vol. 17, no 4

150--161

The subject of this paper is the effect of changing the roughness of the inflow surface of an orifice on its characteristics. A sloping segmental orifice was chosen as the reducer and its surface roughness was changed by lining its inflow surface with sandpaper of different roughness parameters. In such a system, the dependence of the flow stream on the differential pressure at the orifice was measured on a test stand in the range of Reynolds numbers 4110-17000, the flow coefficient C was calculated and flow characteristics were prepared. The study was carried out for a selected segmental orifice with flow coefficient C= 0.723 installed in a pipeline with diameter Dw = 50.35 mm. The roughness of the inflow surface was changed by sticking sandpaper with a gradation of P120 ÷ P1200 to its surface. The roughness parameter Ra was in the range Ra = 5.69 μm ÷ 25.85 μm and Rz = 43.84 μm ÷ 164.83 μm. The dependence of the variation of the coefficient C on the roughness parameter Ra is then presented and the relative errors of the flow stream measurements were calculated. The paper also presents distributions of the differential pressure measured at the orifice for different flow streams depending on the roughness parameter.

Evaluation of liquid-gas flow in pipeline using gamma-ray absorption technique and advanced signal processing

75%

Hanus R. , Zych M. , Mosorov V. , Golijanek-Jędrzejczyk A. , Jaszczur M. , Andruszkiewicz A.

tom Vol. 28, nr 1

145--159

Liquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of the gamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble, and bubble one. In the research, a radiometric set consisting of two Am-241 sources and two NaI(TI) scintillation detectors have been applied. Based on the analysis of the signals from both scintillation detectors, the gas phase velocity was calculated using the cross-correlation method (CCM). The signal from one detector was used to determine the void fraction and to recognise the flow regime. In the latter case, a Multi-Layer Perceptron-type artificial neural network (ANN) was applied. To reduce the number of signal features, the principal component analysis (PCA) was used. The expanded uncertainties of gas velocity and void fraction obtained for the flow types studied in this paper did not exceed 4.3% and 7.4% respectively. All three types of analyzed flows were recognised with 100% accuracy. Results of the experiments confirm the usefulness of the gamma-ray absorption method in combination with radiometric signal analysis by CCM and ANN with PCA for comprehensive analysis of liquid-gas flow in the pipeline.