Propagation characteristics of compression and rarefaction pressure pulses in one-component vapor-liquid mixtures

The hydrodynamics of two-phase flows in the injection part of a conventional ejector

“…Tangren et al (1949) worked on a homogeneous flow model, totally neglecting the flashing of gas from the liquid phase downstream of the choke. Grolmes and Fauske (1970) and Henry and Fauske (1971) presented two homogeneous flow models considering thermal equilibrium. Within the past 30 years, the five most popular models for estimating the total mass flow rate of multiphase flows were established by (1) Sachdeva et al (1986) who developed a very simplistic model involving the use of the homogeneous density equation thus no slip, (2) Perkins (1993) who developed a model based on the gas-phase energy equation rather than the multiphase momentum equation and proved valid for the estimation of both critical and sub-critical flow-rates, (3) Selmer-Olsen and Lemonnier (1995) who developed the so called 'Hydro Model' comprising two sub models Mifsud et al / International Journal of Multiphase Flow 00 (2018) 1-58 6 referred as the long and short mechanistic models which use the momentum density equation and consider slip, (4) Alsafran and Kelkar (2009) who proposed a refined model of the Sachdeva et al (1986) approach in which a pressure recovery term was introduced and slip between phases was considered, and (5) Asheim's model as given in the work of Haug (2012) which involves the integration of the Bernoulli relationship, expressing the homogeneous mixture via the ideal gas law, but totally neglecting phase slippage and downstream pressure recovery.…”

“…As noted in the methodology section, the introduction of the Mach number for two-phase flow conditions incurs a more complex calculation than for single-phase flows. An expression for c was derived from the well-known "frozen two-phase sonic velocity" model from Grolmes and Fauske (1970). The resulting Ma numbers caused the scattered data points (for Φ 2 LO HG v.s.…”

Two-component two-phase critical flow

“…The sonic velocity c in equation 8is calculated with the so-called "frozen two-phase sonic velocity" model [12]…”

Discussion: “A Pressure Pulse Model for Two-Phase Critical Flow and Sonic Velocity” (Moody, F. J., 1969, ASME J. Heat Transfer, 91, pp. 371–381)

“…In regard lo the comments of the author on the suggestions of Davies; the data of reference [31] for steam-water bubbb flow indicate that the front of both compression and rarefaction pressure pulses propagate with a velocity characteristic of that given by the homogeneous frozen model. Care must be taken to distinguish between the propagation velocity associated with the front and that of later stages of the pressure pulse.…”