Application of gamma densitometry and statistical signal analysis to gas phase velocity measurements in pipeline hydrotransport

Abstract

Abstract. The work presents selected methods of signal analysis used in the processing of data obtained from radiometric probes. The used data came from an exemplary study of a two-phase liquid-gas flow at the laboratory installation. In such rigs many possible transport types may be observed, i.e. slug, plug and bubble flow, and each of them gives different signal-to-noise ratio of recorded data. Therefore, available radiometric methods of gas phase velocity measurements give diverse accuracies. Authors consider several improvements of data acquisition and processing which increase possibility of the flow type recognition and higher accuracy of the gas phase velocity estimation.

Prospects for the application of radiometric methods in the measurement of two-phase flows

“…Measurements of the absorption of gamma radiation associated with an analysis of two-phase liquid-gas flow were conducted at the research installation built in AGH -University of Science and Technology in Kraków. A simplified model of the stand is shown in Figure 5 [23,24]. The installation consists of a transparent acrylic glass tube with an internal diameter of 30 mm and a length of 4.5 m, to which water is pumped by a rotary pump (4) and air from the compressor (5) by an injector nozzle (7).…”

“…The idea and geometry of the measurement are shown in Figure 6 [24]. Two Am-241 sealed radioactive sources (2) emit  radiation beams (6,7), shaped by the collimator (1).…”

“…In spite of this, in both cases one may apply similar procedures in order to calculate the transport time delay, and then the velocities of the particular phases [17,18]. A universal method has to do with the function of mutual correlation, which may be efficiently used even in reference to signals which feature a weak signal-to-noise ratio [17][18][19][20][21][23][24][25][26][27]:…”

“…Articles [17,25,28,29] present other methods of the establishment of the transportation time delay, including ones based on the modifications of the mutual correlation functions, among which one may classify the following:…”

Signals features extraction in liquid-gas flow measurements using gamma densitometry. Part 2: frequency domain

“…Stochastic signals obtained for three structures of air-water flow as plug, bubble, and transitional plug -bubble one were considered. Laboratory stand and gamma absorption equipment are presented in the first part of this work and and are described in detail in [16][17][18][19].…”