科研之友
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摘要
The work described in this article is a new analytical and experimental study of two-phase gas-liquid horizontal flow in a conduit for flow pattern identification by a digital signal processing technique. The data are acquired online using a pressure transducer and a National Instruments data acquisition card. The true signal voltage changes rather smoothly as a function of the number of samples, whereas many kinds of noise are added; as a result, rapid, random changes in amplitude from point to point within the signal are observed. To reduce the noise, a smoothing technique is employed. In the smoothing, the data points of a signal are modified so that the individual points that are higher than the immediately adjacent points are reduced and points that are lower than the adjacent points are increased. This naturally leads to a smoother signal. For this purpose, the simplest smoothing algorithm, namely, a simple moving average, is employed and is able to successfully eliminate the noise. After eliminating the noise, the slope of the Curve is continuously tracked to determine sudden or abrupt changes. It is interesting to note that, from the signal obtained, the slope is always decreasing in nature and the magnitude is oil the order of 5 x 10(-3). According to the data and the slope, different now regimes can be identified by using cross-correlation method.
- 出版日期2010-3-17
