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Indexed by:期刊论文

Date of Publication:2018-08-01

Journal:INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

Included Journals:SCIE、EI

Volume:123

Page Number:821-825

ISSN No.:0017-9310

Key Words:Regenerative cooling; Hydrocarbon fuel; Transient response; Thermoacoustic wave; Pressure oscillation

Abstract:A numerical study has been conducted to analyze boundary effects, including different inlet boundary conditions and different inlet section lengths (distances from the inlet boundary to the heated section), on flow dynamics in transient supercritical-pressure heat transfer of n-decane in a circular tube. As the inlet boundary condition changes from a constant flow velocity to a constant stagnation pressure, the pressure oscillation frequency is nearly doubled, and the thermoacoustic wave is in the first longitudinal mode. The frequency of mass flow rate oscillation is essentially the same as that of the pressure wave. Different inlet boundary conditions exert no effect on the pressure wave amplitude but make strong influence on the amplitude of mass flow rate oscillation at the outlet of the heated section. As the inlet insulation section length increases under a constant inlet stagnation pressure, frequencies of both pressure and mass flow rate oscillations proportionally decrease, and the thermoacoustic waves remain in the first longitudinal mode. Different inlet section lengths appear to make only minor effect on the amplitudes of both pressure and mass flow rate oscillations at the outlet of the heated section, and the maximum amplitude in each wave is around 10% of its steady-state value. (C) 2018 Elsevier Ltd. All rights reserved.