Pressure waves in saturated porous media

Nakoryakov, V. E.; Kuznetsov, V. V.; Dontsov, V. E.

doi:10.1016/0301-9322(89)90016-5

Cited by 22 publications

(7 citation statements)

References 14 publications

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“…(15) takes on the following form: On the basis of Eq. (16), the length of the two-phase condensation region can be determined with the assumptions of the model given. Taking into account the fact that external disturbances are produced by valve E (Figure 2), with specific flow characteristics, a correction was introduced in the form of a relative flow coefficient of the valve k v .…”

Section: Computational Modelmentioning

confidence: 99%

“…A system that occurs in such a state is known as a probabilistic or stochastic system. The instabilities of the flow in a two-phase medium of "liquid-gas" type can be transferred by means of two mechanisms, namely, in the form of acoustic waves (pressure instabilities) (Ardron and Duffey [13], Cao et al [14], Comkali et al [15], Nakoryakov et al [16,17], and Xu and Chen [18]) or waves of a change of the mass flux density (being the result of oscillatory changes of the void fraction; Bergles et al [19], Heinzel et al [20], Wu and Cheng [21]). These phenomena have a wavy nature with different wave propagation velocities.…”

Section: Introductionmentioning

confidence: 98%

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Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Kuczyński

Charun

2013

Heat Transfer Engineering

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The heat removal process of a compact condenser in a refrigeration compressor system, constructed on the basis of pipe minichannels, occurs in three regions: the removal region of superheat, the two-phase proper condensation region, and the liquid subcooling region. The intensity of heat removal in the two-phase region depends on the heat efficiency of the condenser. The length of this region is determined by the process parameters and the external influences. This paper analyzes the influence of periodically generated hydrodynamic disturbances on the length of the condensation region for R134a and R404A refrigerants. Experimental tests were conducted for six diameters of pipe minichannels: 0. 64, 0.90, 1.44, 1.92, 2.30, and 3.30 mm. A range of frequencies from 0.2 to 5 Hz of periodically generated disturbances showed an explicit and unfavorable influence on the decrease of the length of the proper condensation region. This influence reduced the efficiency of the process. A computational model was developed to calculate the length of the two-phase region under disturbance conditions. The model proposed was verified by the results of the experiment, and compliance was obtained in the range of ±15%.

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Section: Computational Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Kuczyński

Charun

2013

Heat Transfer Engineering

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“…Thus, even for solid particles with a relatively high density (al/P2 = 2.46), the dispersive properties of the three-phase medium are practically no different than the dispersive properties of a gas-liquid medium. Lines 1, 4 correspond to high-frequency sonic velocity at c~ = 1, lines 2 and 5 correspond to the 1 [ 1 -1 ] [4], and lines 3 and 6 correspond to the Wood velocity [8]. An increase in the amplitude of the shock wave is accompanied by a substantial decrease in the duration of the oscillations and an increase in their acuity.…”

Section: C~ao E 4 ~Armentioning

confidence: 99%

Pressure waves in a liquid suspension with solid particles and gas bubbles

Dontsov¹,

Nakoryakov²,

Покусаев³

1995

J Appl Mech Tech Phys

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532.529The propagation of pressure disturbances in a suspension of a liquid and solid particles is a subject that has been studied quite extensively. The theory of multiple scattering was used in [1, 2] to obtain expressions for the velocity and attenuation factor of an acoustic wave, and the results were compared with experimental data. Good agreement between theoretical and experimental data on the speed and attenuation of sound in suspensions was obtained in [3] on the basis of the Biot model for the propagation of sound in saturated porous media. The author of [4] presented averaged equations of the mechanics of disperse media that make it possible to examine the evolution of waves in two-phase mixtures. The results of a series of theoretical and experimental studies on wave dynamics in gas-liquid media were presented in [5], and the propagation of waves in porous media saturated with a gas-liquid mixture was examined in [6].Our goal here is to experimentally study the evolution and structure of pressure waves of moderate intensity in a suspension of a liquid with solid particles and gas bubbles. We also want to generalize the empirical data on the basis of a theoretical analysis.We will examine the propagation of unidimensional pressure disturbances in a liquid containing suspended solid spheres and gas bubbles. We assume that the length of the waves associated with the disturbances is much greater on the dimensions of the spheres, the dimensions of the bubbles, and the distances between them. We represent a liquid with gas bubbles as a homogeneous medium having the mean density Pm, pressure p, and velocity v m. For a disperse medium (solid spheres + homogeneous gas-liquid medium), the system of equations describing the propagation of unidimensional pressure perturbations has the form [4] 8t~O m O(t~OmVni~ O(l --m)p 1 0(1 --re)pit.' 1 + =0, + -0, Ot ax at ax aom aol at, F, (1) ,~mp -~--(,~ -1) mpm~ = -.l -~dvm ~1 -(a --1) mPm~t + ((1 -m)p t + (a -1) rnPm) --~-+ F, Pt = const, = --(1 m) oxwhere Pm = P2( 1 -~P) + P3~ o; m is the porosity of the medium; ~o is the volumetric gas content of the liquid (thus, the quantity ~om will correspond to the volumetric gas content in the three-phase medium at low values of ~); c~ is a coefficient expressing the apparent additional mass of the liquid. The subscripts 1, 2, and 3 pertain to the solid, liquid, and gas phases, m pertains to the gas-liquid mixture, and 0 denotes the initial state of a phase. We represent the interfacial force F~ as [4] s cpm(lm) (v m-vl)' F=-4 dHere, d is the diameter of the solid spheres; c~ is the resistance coefficient, determined experimentally. At low relative velocities, the interfacial force depends linearly on relative velocity:Novosibirsk.

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“…The effects of interphase interaction in multiphase disperse systems including phase transitions and chemical reactions were considered by Theofanous et al [14] and Hanratty et al [15]. The stability of interfaces in multiphase media and the dynamics of solid and gaseous inclusions were studied.The evolution and structure of weakly nonlinear pressure waves in porous media saturated by a liquid or by a liquid with gas bubbles were investigated in [16,17]. The existence of two types of longitudinal waves ("fast" and "slow" modes) caused by different compressibilities of the porous skeleton and saturating liquid was shown.…”

mentioning

confidence: 99%

Propagation of shock waves in a porous medium saturated by a liquid with bubbles of a soluble gas

Dontsov¹,

Nakoryakov²

2000

J Appl Mech Tech Phys

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The process of evolution and reflection of shock waves of moderate amplitude from a rigid boundary in a porous medium saturated by a liquid with bubbles of a soluble gas is studied experimentally. Experimental values of the amplitude and velocity of the reflected wave are compared with the calculated results obtained using mathematical models. The process of dis= solution of gas bubbles in the liquid behind the shock wave is studied.Based on numerical calculations of the process of collapse of a layer of cavitation bubbles near a solid wall, Kedrinskii [1] observed the appearance of a series of high-araplitude pressure pulses on the wall, which are caused by inertial effects of collective collapsing of the bubbles. A powerful secondary shock wave generated by the collapse of a single bubble in the liquid was observed in the experiments of [2,3] by optical methods. Shima and Fujiwara [4] studied the interference of the neighboring bubbles on their disintegration and generation of secondary shock waves. Amplification of shock waves in a liquid with vapor bubbles or with bubbles of a readily soluble gas was studied experimentally in [5][6][7][8][9]. The amplification was observed both in the incident wave and in the wave reflected from the rigid boundary.The evolution and structure of pressure perturbations in a suspension of a liquid with solid particles and gas bubbles and the reflection of perturbations from the rigid boundary was studied theoretically and experimentally in [10][11][12]. Shreiber [13] proposed a model of propagation of nonlinear acoustic waves in a three-phase mixture. Evolution equations were obtained, which explain some experimental data on wave dynamics in three-phase media. The effects of interphase interaction in multiphase disperse systems including phase transitions and chemical reactions were considered by Theofanous et al. [14] and Hanratty et al. [15]. The stability of interfaces in multiphase media and the dynamics of solid and gaseous inclusions were studied.The evolution and structure of weakly nonlinear pressure waves in porous media saturated by a liquid or by a liquid with gas bubbles were investigated in [16,17]. The existence of two types of longitudinal waves ("fast" and "slow" modes) caused by different compressibilities of the porous skeleton and saturating liquid was shown.In the present paper, we experimentally studied the evolution and reflection of shock waves of moderate strength from the rigid boundary in a porous medium saturated by a liquid with bubbles of a soluble gas. The experimental data axe compared with calculations performed using the models proposed by Lyakhov [18] and Nigmatulin [19]. The process of dissolution of gas bubbles in the liquid behind the shock wave is studied.The experiments were conducted in a "shock-tube" facility [9]. The test section was a vertical thickwalled steel tube with an inner diameter of 0.053 m and a length of 1 m, which was bounded by a solid wall from below. The test section was filled by a saturated porous medium. The porous med...

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Pressure waves in saturated porous media

Cited by 22 publications

References 14 publications

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Modeling of a Two-Phase Region Length of the Condensation of R134a and R404A Refrigerants in Pipe Minichannels With Periodic Hydrodynamic Instabilities

Pressure waves in a liquid suspension with solid particles and gas bubbles

Propagation of shock waves in a porous medium saturated by a liquid with bubbles of a soluble gas

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