Wave propagation in wet steam

Abstract

Linear wave equations for equilibrium and subcooled wet steam are introduced in the paper, accounting for thermal and inertial relaxation processes between the vapour and droplets. Relations for sonic velocity and absorption were found to be frequency dependent. Analysis of propagation of a step pressure disturbance suggests that the frozen speed of sound should be used to define, for example, the direction of characteristics and conditions for choking of a wet steam flow. It is concluded further that in a near-equilibrium approximation the non-linear wave phenomena in a wet steam can be analysed by the Korteweg-deVries-Burger equation, accounting for non-linear, dispersive and dissipative effects.

On the Speed of Sound in Steam

“…For lower values of the dryness of wet steam given in Table 1, continuum models lose validity, and it is necessary to investigate the propagation of waves in a heterogeneous (two-phase) environment. Examples can be found in [5,6]. The metastable-vapor region is defined by IAPWS [4,7] from the saturation line to the 95 % equilibrium dryness line for pressures from the triple-point pressure up to 10 MPa.…”

“…The data on the speed of sound in wet steam have not yet been integrated. Papers [5,6] provide much stimulation for further studies of the speed of sound in wet steam, because they deal with the propagation of waves in wet steam. However, no measured data have in fact been published.…”

Experimental validation of sonic speed theory for wet steam

“…According to Petr’s wet steam sonic theory, 25 if the harmonic acoustic wave of angular frequency ω propagates through the equilibrium wet steam, three limiting cases can be defined as follows:(1)ωnormalτnormalT ≪ 1 low frequency acoustic wave. The relaxation processes, momentum, and heat exchange may vary with small disturbances.…”

“…However, in addition to aerodynamic parameters, the equation considers that wetness is the only parameter that affects the sonic speed of wet steam, while the effects of droplet size and sound frequency are not discussed. In 2004, Petr 25 pointed out that the sonic speed of wet steam is a function of pressure, wetness, droplet size, and acoustic frequency. So far, this theory is one of the most advanced wet steam sonic speed theories.…”

BWR Steam Dryer Alternating Stress Assessment Procedures

“…Acoustic damping within the steam must also be modeled. The damping within steam may be estimated using guidance from various sources [Karplus, 1961;Petr, 2004]. The 3D RPV models are coupled to the MSL 1D models at the MSL inlets, thus enforcing continuity of particle velocity.…”