Multifractal detrended fluctuation analysis of pressure fluctuation signals in an impinging entrained-flow gasifier

摘要

On a laboratory-scale testing platform of impinging entrained-flow gasifier with two-burner,the pressure signals are measured at two axial positions with stainless steel water-cooled probes.The probes are traversed radially from the wall to the reactor centerline (spaced 15 cm apart) for six radial positions (0,3,6,9,12,and 15 cm) to acquire pressure signals.Multifractal detrended fluctuation analysis (MF-DFA) is a method which is accurate and easy to implement,therefore it is used on the pressure fluctuation to examine the multifractal characteristics.It is found that the pressure fluctuation exhibits multifractal characteristics,the analysis of the pressure fluctuation signals under "unstable operating state","stable operating state" and also "cold state" suggests that the combustion system is characterized by a dynamical change from heterogeneity toward homogeneity,revealed by a loss of multifractality.Moreover,the analysis confirms the existence of multifractal characteristics in the investigated pressure fluctuation series.Origin of multifractal phenomena of the pressure signal measured in the entrained-flow gasifier is interpreted in terms of the multiplicative cascade process.