This paper describes an integrated experimental procedure for obtaining accurate measurements with both single normal (SN) and X hot-film probes in water flows. The first pari of the paper describes techniques developed to overcome the common problems of temperature variations and contamination in a recirculating test facility, leading to long-term calibration stability. The second part of the paper describes the development of fast, reliable and accurate computer-based calibration methods for both SN and X probes. The final section of the paper describes comparative measurements between an SN and an X probe in vertical upward water pipe flow, demonstrating the validity of the methods developed.
This paper describes the development of a novel computer-based hot-fiim anemometer measurement technique for the investigation of the local structure of two-phase flows. The technique enables the total signal to be separated into the parts corresponding to bubbles and continuous phase, from which the local volume fraction can be evaluated. Evaluation procedures are also presented for analysing the remainder of the signal corresponding to the turbulent continuous phase after eliminating the bubble signals. Methods are described and discussed for the evaluation of the longitudinal mean velocity, normal stress, autocorrelation and energy spectrum. Finally typical results for a vertical up-flow of a bubbly kerosene/water mixture are presented.
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