Saturated Liquid Research Articles

Nonlinear plane waves in saturated porous media with incompressible constituents

We consider the propagation of nonlinear plane waves in porous media within the framework of the Biot–Coussy biphasic mixture theory. The tortuosity effect is included in the model, and both constituents are assumed incompressible (Yeoh-type elastic skeleton, and saturating fluid). In this case, the linear dispersive waves governed by Biot’s theory are either of compression or shear-wave type, and nonlinear waves can be classified in a similar way. In the special case of a neo-Hookean skeleton, we derive the explicit expressions for the characteristic wave speeds, leading to the hyperbolicity condition. The sound speeds for a Yeoh skeleton are estimated using a perturbation approach. Then we arrive at the evolution equation for the amplitude of acceleration waves. In general, it is governed by a Bernoulli equation. With the present constitutive assumptions, we find that longitudinal jump amplitudes follow a nonlinear evolution, while transverse jump amplitudes evolve in an almost linearly degenerate fashion.

Numerical simulation of boiling liquid outflows process

  Computational algorithm was developed based on the well-known ANSYS Fluent  software package for studying unsteady wave outflow of a saturated liquid from high-pressure pipelines during emergency depressurization. The unsteady processes of the outflow of liquid, boiling as a result of depressurization of high-pressure vessels, have been investigated. The system of equations for the conservation of mass, momentum, and energy in a two-dimensional coordinate system is used in order to create mathematical model this process. The system of equations for the conservation of mass, momentum, and energy in a two-dimensional coordinate system is used to describe the initial stage of the unsteady outflow process. The features of the formation of jets of boiling liquid at various equilibrium initial states of water in a high-pressure vessel under conditions close to the experiments carried out by the authors [10] have been studied. The spatial distributions of pressure, temperature and velocity of the forming jet are obtained. Numerical results have shown that, over time, the character of the velocity distribution acquires a conical shape. With an increase in the initial temperature and pressure, this distribution is preserved, and the opening angle increases. The results are in qualitative agreement with the experimental data. &nbsp

Using CO2 as a Cooling Fluid for Power Plants: A Novel Approach for CO2 Storage and Utilization

To our knowledge, the potential use of CO2 as a heat-transmitting fluid for cooling applications in power plants has not been explored very extensively. In this paper, we conduct a theoretical analysis to explore the use of CO2 as the heat transmission fluid. We evaluate and compare the thermophysical properties of both dry air and CO2 and perform a simple analysis on a steam-condensing device where steam flows through one of the flow paths and the cooling fluid (CO2 or air) is expanded from a high-pressure container and flows through the other. Sample calculations are carried out for a saturated-vapor steam at 0.008 MPa and 41.5 °C with the mass flow rate of 0.01 kg/s. The pressure of the storage container ranges from 1 to 5 MPa, and its temperature is kept at 35 °C. The pressure of the cooling fluid (CO2 or dry air) is set at 0.1 MPa. With air as the heat-removing fluid, the steam exits the condensing device as a vapor-liquid steam of 53% to 10% vapor for the container pressure of 1 to 5 MPa. With CO2 as the heat-removing fluid, the steam exits the device still containing 44% and 7% vapor for the container pressure of 1 MPa and 2 MPa, respectively. For the container pressure of 3 MPa and higher, the steam exits the device as a single-phase saturated liquid. Thus, due to its excellent Joule–Thomson cooling effect and heat capacity, CO2 is a better fluid for power plant cooling applications. The condensing surface area is also estimated, and the results show that when CO2 is used, the condensing surface is 50% to 60% less than that when dry air is used. This leads to significant reductions in the condenser size and the capital costs. A rough estimate of the amount of CO2 that can be stored and utilized is also carried out for a steam power plant which operates with steam with a temperature of 540 °C (813 K) and a pressure of 10 MPa at the turbine inlet and saturated-vapor steam at 0.008 MPa at the turbine outlet. The results indicate that if CO2 is used as a cooling fluid, CO2 emitted from a 1000 MW power plant during a period of 250 days could be stored and utilized.

Fick Diffusion Coefficient in Binary Mixtures of [HMIM][NTf2] and Carbon Dioxide by Dynamic Light Scattering and Molecular Dynamics Simulations.

Dynamic light scattering (DLS) experiments and equilibrium molecular dynamics (EMD) simulations were performed in the saturated liquid phase of the binary mixture of 1-hexyl-3-methylimidazolium bis(trifluormethylsulfonyl)imide ([HMIM][NTf2]) and carbon dioxide (CO2) to access the Fick diffusion coefficient (D11). The investigations were performed within or close to saturation conditions at temperatures between (298.15 and 348.15) K and CO2 mole fractions (xCO2) up to 0.81. The DLS experiments were combined with polarization-difference Raman spectroscopy (PDRS) to simultaneously access the composition of the liquid phase. For the first time in an electrolyte-based system, D11 was directly calculated from EMD simulations by accessing the Maxwell-Stefan (MS) diffusion coefficient and the thermodynamic factor. Agreement within combined uncertainties was found between D11 from DLS and EMD simulations for CO2 mole fractions up to 0.5. In general, an increasing D11 with increasing xCO2 could be observed, with a local maximum present at a CO2 mole fraction of about 0.75. The local maximum could be explained by an increasing MS diffusion coefficient with increasing xCO2 over the entire studied composition range and a decreasing thermodynamic factor at xCO2 above 0.7. Finally, PDRS and EMD simulations were combined to investigate the influence of the fluid structure on the diffusive process.

Concerning the methods of thermocouple embedding in experimental studies of cooling the high-temperature bodies in subcooled and saturated liquids

Concerning the methods of thermocouple embedding in experimental studies of cooling the high-temperature bodies in subcooled and saturated liquids

Attenuation of Seismic Waves in Partially Saturated Berea Sandstone as a Function of Frequency and Confining Pressure

Frequency-dependent attenuation (1/Q) should be used as a seismic attribute to improve the accuracy of seismic methods and imaging of the subsurface. In rocks, 1/Q is highly sensitive to the presence of saturating fluids. Thus, 1/Q could be crucial to monitor volcanic and hydrothermal domains and to explore hydrocarbon and water reservoirs. The experimental determination of seismic and teleseismic attenuation (i.e., for frequencies < 100 Hz) is challenging, and as a consequence, 1/Q is still uncertain for a broad range of lithologies and experimental conditions. Moreover, the physics of elastic energy absorption (i.e., 1/Q) is often poorly constrained and understood. Here, we provide a series of measurements of seismic wave attenuation and dynamic Young’s modulus for dry and partially saturated Berea sandstone in the 1–100 Hz bandwidth and for confining pressure ranging between 0 and 20 MPa. We present systematic relationships between the frequency-dependent 1/Q and the liquid saturation, and the confining pressure. Data in the seismic bandwidth are compared to phenomenological models, ultrasonic elastic properties and theoretical models for wave-induced-fluid-flow (i.e., squirt-flow and patchy-saturation). The analysis suggests that the observed frequency-dependent attenuation is caused by wave-induced-fluid-flow but also that the physics behind this attenuation mechanism is not yet fully determined. We also show, that as predicted by wave-induced-fluid-flow theories, attenuation is strongly dependent on confining pressure. Our results can help to interpret data for near-surface geophysics to improve the imaging of the subsurface.

Design and operation of the in-vessel cryopump for the new upper divertor in ASDEX Upgrade

To study alternative divertor configurations in the ASDEX Upgrade (AUG) tokamak a new upper divertor, Div-IIo, with two in-vessel coils and a cryopump (CP) will be installed in 2022. For efficient density control in the new divertor configuration during plasma discharges, the CP has to guarantee an effective pumping speed for deuterium (D2) of at least Seff = 15 m3/s. The CP will be installed behind the inner divertor with a toroidal pumping gap of width 30 mm between the inner and outer divertor plates. It consists of 7 modules with a major radius of R = 1.2 m and a total active length of 5.4 m.To investigate reactor relevant D2-He gas mixtures during upper single null discharges, the liquid helium cryo-panels are coated with activated charcoal as cryosorbent.For quick regeneration of the charcoal from the accumulated gases, heating wires on the cryo-panels are installed.To reduce the pumping speed during high density discharges, an in-vessel cryo valve between two modules is installed. The pumping speed can be reduced by 35%.The cryo-panels operate with saturated liquid helium (LHe) at a temperature of 4.4 K. The thermal radiation shield consisting of reflector and chevron-baffle operate with saturated liquid nitrogen (LN2) at 80 K. To supply the new upper CP with LHe and LN2 the existing LHe-LN2-supply of the lower CP will be used. Therefore, an additional distributor box and a multi-channel transfer line to the upper CP have been installed in 2019.

Does taper water boil at all temperatures?

The liquid-vapor equilibrium for water in the presence of air involves a saturated liquid solution of air in water and a vapor phase composed of air and water vapor. The boiling point is the temperature at which the vapor pressure of a liquid system equals the external pressure acting on the liquid. At any temperature between the melting and boiling points of pure water, the vapor pressure of water in equilibrium with air (vapor pressure of water plus partial pressure of air) is obviously equal to the external pressure. Therefore, in an open system, such liquid solution would be at the boiling point for all temperatures at the same atmospheric pressure. However, our everyday experience does not seem to suggest it. Throughout this paper, different aspects of that apparent paradox are discussed.

Broadband Q-Factor Imaging for Geofluid Detection in the Gulf of Trieste (Northern Adriatic Sea)

Seismic surveys allow estimating lithological parameters, as P-wave velocity and anelastic absorption, which can detect the presence of fracture and fluids in the geological formations. Recently, a new method has been proposed for high-resolution imaging of anelastic absorption, which combines a macro-model from seismic tomography with a micro-model obtained by the pre-stack depth migration of a seismic attribute, i.e., the instantaneous frequency. As a result, we can get a broadband image that provides clues about the presence of saturating fluids. When the saturation changes sharply, as for gas reservoirs with an impermeable caprock, the acoustic impedance contrast produces “bright spots” because of the resulting high reflectivity at its top. When the fluid content changes smoothly, the anelastic absorption becomes a good detector, as fluid-filled formations absorb more seismic energy than hard rocks. We apply this method for imaging the anelastic absorption in a regional seismic survey acquired by OGS in the Gulf of Trieste (northern Adriatic Sea, Italy).

Assessment of a high-performance geothermal-based multigeneration system for production of power, cooling, and hydrogen: Thermodynamic and exergoeconomic evaluation

The novel multi-generation system is developed to produce power, cooling, and hydrogen. The present work is suggested to employ the geothermal energy to start a Kalina cycle and then with regard to the high temperature of the saturated liquid leaving the Kalina cycle separator, the absorption refrigeration system is employed for providing cooling as a subsystem. Also, an electrolyzer and the power production capacity of the cycle have been utilized to produce hydrogen. The proposed system is evaluated thermodynamically and exergoeconomically, and a parametric study was performed for the following parameters: geothermal heat source temperature (THS,in), the temperature difference in vapor generator 1 (ΔTPP,vg1), the pressure of vapor generator 1 (Pvg1), condenser temperature (Tcon), evaporator temperature (Teva) and ammonia concentration (YB). The governing equations are coded in the EES software. In the base case, the results display that the proposed system is capable of producing 258.6 kW of cooling, and in this case, the thermal and exergy efficiencies and the unit cost of multigeneration are 22.28%, 21.37% and 29.29 $/GJ, respectively. Also, increasing the evaporator temperature does not have a significant effect on power production capacity. Moreover, condenser 1 has the most exergy destruction rate of 65.03 kW.

Water weakening of soft and stiff outcrop chalk induced by electrical double layer disjoining pressure

In this work we assessed the strength and stiffness of high and low porosity outcrop chalk plugs saturated with three different fluids. Plugs were triaxially tested in a Hoek cell at varying confining stress to probe different parts of the failure envelope as described in the p-q’ space (brittle, transition and yield failure modes). Stiffness of the plugs was derived from bulk density and P and S-wave ultrasonic velocities measured throughout the mechanical test. Selection of the saturating fluids was aimed at testing the hypothesis that water weakening of chalk arises due to a physico-chemical process acting on the vicinity of the chalk grain contact, the electrical double layer (EDL) disjoining pressure. This pressure depends both on the salinity and ionic species dissolved in the saturating water. Fluids used were designed to exert varying levels of disjoining pressure between the chalk grains: calcium chloride brine (highest), calcite equilibrated water (moderate) and as reference Isopar-L or Ethylene glycol (no induced disjoining pressure). We found that both strength and stiffness parameters are affected by the level of the EDL disjoining pressure: The higher the pressure between grains induced by the saturating fluid, the weaker and softer were the core plugs. Water related reduction in strength and stiffness were more prevalent in the soft chalk samples and for the samples mechanically tested at low confining stress. We attribute this selectivity to the smaller cementation area between grains (assessed by Biot's coefficient) for the softer chalk.

New correlation for the temperature dependent viscosity of saturated refrigerants liquids

In this paper, we proposed a new correlation for the temperature dependent viscosity of saturated refrigerants liquids based on the recent progresses on the relation between surface tension and viscosity of liquids [J. X. Tian et al., Industrial & Engineering Chemistry Research, 53, 9499, 2014] and the temperature dependent surface tension of liquids [S. G. Yang et al., Industrial & Engineering Chemistry Research, 59, 6336, 2020]. By comparing with the experimental data of 80 saturated refrigerants liquids in the DIPPR database, it is found that the proposed correlation can predict the DIPPPR data with average absolute relative deviation (AARD) less than 5% for all the 80 liquids, AARD less than 3% for 76 liquids. These results indicate superior accuracy of the proposed correlation compared to other well-known correlations including the Arrhenius equation and the Vogel-Fulcher-Tamman equation.

Non-linear Stability in Transitional and Rotatory Regime of the Cooking of Gari, Food Based on Cassava Tubers

The present study focuses on the non-linear stability in the transient rotary regime of the cooking process of gari. The process of cooking gari consists of a rotating rectangular cavity filled with grated cassava flour, pressed, retted and considered to be an anisotropic porous medium in a permeably saturated viscoelastic fluid. The cavity is heated from below to a constant temperature. The lower wall of the cavity is impermeable and the upper wall is permeable. Using a numerical method, we have established the transient expressions of the Nusselt number, the flow and temperature fields as a function of the anisotropy parameters of the porous medium and of the Taylor number. The results obtained showed that the anisotropy of the porous medium and the Taylor number greatly influenced the cooking of gari over time.

PρT parameterization of SAFT equation of state: developing a new parameterization method for equations of state

The lack of a transparent and universal parameterization method is one of the main problems in developing SAFT-type equations of state and it's an obstacle in their way of becoming an industrial equation of state. Usually, vapor-pressure and saturated liquid density data with a local optimization algorithm are used to parameterize SAFT-type equations of state. In addition to the ambiguity in the data selection process, using a local optimization method reduces the accuracy of the estimated parameters. Therefore, in this paper, a new method for calculating the adjustable parameters of SAFT or any equations of state with several parameters is presented. By providing a clear and explicit data selection procedure, including data categorization, comparison, and validation, integrated with the use of a combination of global and local optimization methods, the new methodology achieves the best possible parameters set for the equation of state. The proposed computational program for fitting parameters is based on the use of the Differential evolution algorithm as the main process and the Levenberg-Marquardt algorithm as the post-process along with applying one (or two) hyperparameter. Afterward, a wide range of pressure-temperature-density data has been used to estimate the parameters of 60 non-associating and associating pure compounds. Then, the SAFT equation of state with the new parameters, so-called PρT-SAFT-HR, is applied to predict pressure (P), temperature (T), density (ρ), vapor-pressure (Psat), saturated vapor density (ρvapsat), saturated liquid density (ρliqsat), critical point, isochoric heat capacity (cv), isobaric heat capacity (cP), speed of sound (u), isothermal compressibility (κT), and isobaric thermal expansivity (αP). All properties are calculated with the PρT-SAFT-HR equation of state, and the results are compared with experimental data and SAFT-HR and the average absolute percentage deviation is reported for all of them. In total, 19460 experimental and pseudo-experimental data were used to reparameterization the SAFT equation of state, and more than 74,000 data were validated to calculate thermodynamic properties. The results showed a significant improvement in predicting second-order thermodynamic derivative properties. In general, PρT-SAFT-HR performs better than SAFT-HR, and in some cases, such as pressure, speed of sound, isothermal compressibility, and isobaric thermal expansivity, the results have been significantly improved, and the average absolute deviation of PρT-SAFT-HR has been much less than SAFT-HR.

Simulation of geoelectrical responses of structures buried in freshwater and brackish water environments

Marine geoelectrical simulation offers the opportunity to predict matrix type, interstitial fluid and geometry of buried structures. In this research, simulation of geoelectrical responses over buried structures in freshwater and brackish water environments were tested. A model tank made of acrylic and housed within an iron frame was built for the experiment. The tank was filled with water and sieved sediment having grain sizes ≤1.18 mm, corresponding to very coarse sand to colloid. Four models were designed namely freshwater static model (FSM), brackish water static model (BSM), freshwater model with buried structures (FMBS), and brackish water model with buried structures (BMBS). A bamboo pipe, metal pipe and granite block were buried in the FMBS and BMBS. Physico-chemical parameters of the water which includes temperature (22.74 – 26.06 °C), salinity (0.07 – 15.72 psu), conductivity (153 – 25,420 μS/cm and resistivity (5.6 x 103 – 6.6 x 103 Ω-cm) were measured. Dipole-dipole array using inter-electrode separation (a) of 5 cm and 1≤n≤5 was adopted. Resistivity measurements obtained were processed and inverted using non-linear least-square optimization technique. We present obtained results as contoured 2D resistivity structures. FSM and FMBS were characterized by relatively high resistivity values compared with the BSM and BMBS. The buried materials were effectively resolved in the freshwater models, compared to the brackish water model due to higher contrast in resistivity between the material and saturating fluid. The bamboo pipe was not effectively delineated in the brackish water medium, as a result of the low resistivity contrast which exists between the medium and the material. Zones with high compaction are characterized by high resistivity values, while concealed channel structures were characterized by low compaction. Estimated depth were exact for the freshwater models but was over estimated by `∼12.5% in the brackish water models. Marine electrical resistivity method shows great potential in mapping structures buried in medium with high contrasting resistivity values, and sedimentary structures with varying degree ofcompaction.

Experimental characterization of air-saturated porous material via low-frequencies ultrasonic transmitted waves

An improved acoustic method is proposed for measuring the tortuosity and the viscous and thermal characteristic lengths of air-saturated porous materials via low-frequency ultrasonic transmitted waves (70 kHz–110 kHz). The equivalent fluid model is considered. The interaction between the saturated fluid and the structure is taken into account in two frequency response factors: the dynamic tortuosity of the medium and the dynamic compressibility of the air which are described by their high-frequency expansion in powers of the viscous and thermal skin depth, either limiting the expansion to the first two leading terms or the first three leading terms with the introduction of two new viscous and thermal shape factors. These two new factors play an important role in stabilizing and improving the inverted parameters of the tortuosity and the viscous and thermal characteristic lengths in the frequency band considered. The inverse problem is solved numerically in the frequency domain by minimizing the spectrum of simulated and experimental transmitted signals. Optimized parameters of tortuosity, viscous and thermal characteristic lengths, and viscous and thermal shape factors are obtained simultaneously. The tests are carried out with three samples of plastic foam. The results obtained by the two procedures are discussed and compared to those given in the literature.

The Influence of the Clearance on Performance of Compressor

Cold compressor (CC) was adopted to pump saturated liquid helium to obtain subcooled helium. In the Experimental Advanced Superconducting Tokamak (EAST) system, cold presses were studied and would replace the oil ring pump. The cold compressor processing and installation had been completed, and it had been tested by cold nitrogen gas. For cold compressors, testing at low temperature was essential, but the real working condition of low-temperature helium gas had great risks for large helium cryogenic system. Therefore, an independent cold nitrogen test system was an economical solution. In this work, numerical simulation and quantitative analysis method were used to investigate the flow field around different tip clearances and mass flow by CFD at liquid nitrogen temperature, and they were validated by experiments. When the tip clearance was increased by 0.1mm, the pressure ratio dropped 0.27% and the polytropic efficiency dropped 0.82%. To a certain extent, a larger tip clearance could improve the surge condition and had little influence on the efficiency. Therefore, in the design and operation, the tip clearance could be appropriately increased.

Dissolution Behavior of Sn in CaO–CaF2 Molten Flux and Its Distribution Ratio Between CaO–CaF2 Molten Flux and Liquid Iron

The dissolution behavior of Sn in CaO– $$\hbox {CaF}_2$$ flux was investigated. A chemical equilibration technique was employed which allows pure liquid Sn dissolves into the molten flux under various oxygen partial pressure and the flux composition. At an equilibrium, (% Sn) in the flux increased by increasing (% CaO) and $$p_{\text{O}_2}$$ . It was found that Sn dissolves into the molten flux as ( $$\hbox {SnO}_3$$ ) $$^{4-}$$ in the condition of the present study. Distribution of Sn between CaO saturated flux and C saturated liquid Fe was measured under a pure CO atmosphere. Sn distribution ratio ( $$L_{\text{Sn}} = (\%\,\text{Sn})_{\text{flux}}/[\%\,\text{Sn}]_{\text{iron}}$$ ) was as low as $$\sim 10^{-4}$$ , which was consistent with a thermodynamic prediction. Sn distribution was favored at a lower temperature. Thermodynamic modeling was carried out for the Sn dissolution in the flux. A noticeable negative deviation between CaO and SnO was identified.

Geological and statistical modeling of oil recovery of carbonate formations

For the conditions of fourteen groups of low productivity, complex features in the carbonate reservoirs of the Volga-Ural oil and gas province were constructed geological and statistical modeling that allows predicting the ultimate oil recovery factor for deposits similar to those studied when solving various development tasks. Based on the consideration of cause-and-effect relationships between geological and technological parameters, the physical interpretation of the obtained models is given. It is established that the variety of oil deposits in carbonate reservoirs according to the conditions of occurrence, geological-physical and physical-chemical properties of reservoirs and their saturating fluids requires a differentiated approach when modeling and using models of the oil recovery process.

Kinetic Simulations of Compressible Non-Ideal Fluids: From Supercritical Flows to Phase-Change and Exotic Behavior

We investigate a kinetic model for compressible non-ideal fluids. The model imposes the local thermodynamic pressure through a rescaling of the particle’s velocities, which accounts for both long- and short-range effects and hence full thermodynamic consistency. The model is fully Galilean invariant and treats mass, momentum, and energy as local conservation laws. The analysis and derivation of the hydrodynamic limit is followed by the assessment of accuracy and robustness through benchmark simulations ranging from the Joule–Thompson effect to a phase-change and high-speed flows. In particular, we show the direct simulation of the inversion line of a van der Waals gas followed by simulations of phase-change such as the one-dimensional evaporation of a saturated liquid, nucleate, and film boiling and eventually, we investigate the stability of a perturbed strong shock front in two different fluid mediums. In all of the cases, we find excellent agreement with the corresponding theoretical analysis and experimental correlations. We show that our model can operate in the entire phase diagram, including super- as well as sub-critical regimes and inherently captures phase-change phenomena.