Self-excited pressure pulsations in ethanol under heater subcooling

Abstract

This paper presents experimental results of investigation of high-intensity cooling of high-temperature metal heater by subcooled ethanol flow. The experiments have proved the presence of self-excited pressure pulsations with amplitude of 1.15 MPa, arising in ethanol. Expanding real signals of the sensors by the Hilbert−Huang transform has resulted in the intrinsic mode functions. Analysis of these functions and the high-speed video shooting results allows identifying the basic frequencies and mechanisms of pressure oscillations. Comparison of the results with the data of film cooling and bubble boiling on the cooled heater has shown that maximum values of non-stationary heat-transfer coefficients for the self-excited oscillations and for the bubble boiling are the same.