Experimental Investigation on Two Types of Density-Wave Oscillation in Parallel Twin Rectangular Channels

Abstract

This paper is aimed to investigate two different kinds of density wave oscillations (D.W.O) in a forced convection upflow boiling in twin parallel rectangular channels. The first kind of D.W.O has a character of low quality, small and constant oscillation amplitude and relatively higher oscillation frequency. The second kind of D.W.O occurred with high quality, and whose amplitude of oscillation continually expands with increased heat flux once the oscillation appeared. Experiments were done on the effect of pressure, mass velocity, and inlet subcooling on two kinds of density wave oscillation. Boundary heat flux and exit quality of instability, oscillation period and amplitude, and marginal stability boundary (MSB) of two D.W.O were carefully compared based on experimental data.