Modeling of weak shock waves propagation in aqueous foam layer

Dynamics of low-intensity air shock waves in the shock tube containing an aqueous foam layer is theoretically investigated. Modeling of studied process is carried out using two-phase model of aqueous foam developed by the authors in single-pressure, single-speed and two-temperature approximations. The model takes into account the Ranz-Marshall interphase contact heat transfer, effective Herschel-Bulkley viscosity, which describes foam behavior as a non-Newtonian fluid, and elastic properties of aqueous foam under a weak shock impaction without destruction of foam structure. Properties of air and water as the foam components are described by realistic equations of state. Computer implementation of the aqueous foam model is carried out in the solver, developed by the authors in OpenFOAM software. The influence of aqueous foam viscoelastic properties on the intensity and structure of a shock wave has been investigated. When analyzing the obtained solutions, reliability of the proposed model and method of numerical modeling is estimated by comparative analysis of the found solutions and literature experimental data.

Experimental research of mass transfer in a stabilized foam layer

The object of research: mass transfer processes on a combined contact element in a column apparatus. Investigated problem: determination of the regularities of process parameters in the processing of gas-liquid systems in a foam layer, as well as to interpret the obtained experimental data. The problem of processing industrial gas flows is solved by conducting the process in an intensive mode. The main scientific results: as a result of the study, the regularities of ammonia absorption were revealed depending on the main parameters of the experiment: gas velocity in the column cross-section, ammonia concentration, free cross-section of the combined contact element, and liquid loads. The process of mass transfer in the gas phase is significantly influenced by hydrodynamic parameters – the gas velocity in the apparatus and the specific load on the liquid, which indirectly affect the height of the liquid layer on the plate and the gas content of the layer. The area of practical use of the research results: sorption processes for processing gases and liquids in technological processes, absorption of harmful substances in the treatment of gas emissions. Innovative technological product: new block poppet-nozzle contact device that operates in a stabilized hydrodynamic mode; new ball-shaped weighted nozzle for three-phase foam layer. Scope of application the innovative technological product: technological processes in the treatment of gas emissions or technological gases.

Three-Phase Separator Online Measurement and Data Analytics for Fluid Interface and Emulsion Thickness Utilizing a Single Emulsion Watch Profiler

Separators can over the length of field life be exposed to operating conditions outside the set design conditions, which can cause operating issues in terms of separator efficiency, operating expenditures and potential need for frequent maintenance and/or retrofitting new internals. In mature operations with heavy oils, there can be severe issues with Water-in-Oil and Oil-in-Water emulsion layers. In late life operations, enhanced oil recovery (EOR) efforts with polymer injection can also take place to produce more, but at the same time making the separator function in terms of phase separation even more complex. Emulsion thickness and residence time optimization in separators and tanks are key issues in the oil and gas operations. Real-time data of the full level profiling is complicated and has been based on instruments with varying reliability and performance. Operations have been relying on other process parameters and bottle tests. However, in this work, separator profiler utilizing electrical tomography was used for monitoring separator content online, especially fluid interface levels as well as emulsion and foam layer thicknesses. In addition, effect of polymer injection to the wells is investigated. From the single profiler, data for the separator fluid levels, emulsion and foam thicknesses can be derived. The profiler used is a safe-to-use non-radioactive probe-type measurement sensor which is installed through an existing separator nozzle. The actual separator profiler with dimensions 5 cm diameter and 3 m length was installed downstream of the inlet cyclones and the flow distribution baffles in the three-phase separator located at one of the production fields in the Middle East. Water-oil interface, turbulent water-in-oil dispersion band, oil-gas interface and foam layer thickness were monitored continuously for several months with varying flowrates and operation conditions. Later, effect of polymer injection was also investigated. Interface level and layer monitoring results will be given and discussed. The results show that the profiler is highly useful for monitoring the separator fluid distribution online, building a rigid data analytics model over time that can be utilized by the operations to improve and optimize the performance. This paper shares novel information on operational experience of data analytics used for three-phase separators operating in a heavy oil field with polymer injection. The sensor type used is novel to the industry with high robustness and reliability generating multiple data points per second, enabling a highly detailed analytics model generating new possibilities for operational optimization through digitalization. In addition, commissioning and monitoring of the sensor was done remotely during covid-19 shutdown without the need of external personnel entering the field demonstrating remote commissioning and digital oil field concepts.

Polyurethane Electrospun Fiber Biomimetics Membrane for Constructing the Structure of Grain Layer with Good Breathability for Cattle Split Leather

The traditional thick coating on split leather does not have the ability to breathe like full grain leather. The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production

Physicochemical properties of the new drug Penox-1

The physicochemical properties of the substances included in the composition of the new disinfectant Penox-1 have been studied. Assessment of its disinfecting properties of veterinary in-spection objects, with the study of solubility in water and sodium chloride, surface tension of solutions, stability and adhesion of foam on vertical and ceiling test surfaces in laboratory conditions. At the initial stage, the temperature dependence of the solubility of slaked lime in water was es-tablished. It was determined by the change in the activity of OH- ions as the temperature of the over-saturated solution of slaked lime increased. Distilled water was used as a solvent. The solubility of slaked lime was also studied by adding 1.0; 3.0; 5.0 and 10.0 % sodium chloride solution. The experi-ments were carried out according to the method "On the procedure for testing new disinfectants for veterinary practice (1987)". Assessment with the study of the surface tension of solutions, resistance and adhesion of foam was carried out at the Institute of Physics, DSCRAN, also according to the indi-cated method. As a result of the experiments, it was found that with an increase in water temperature, the sol-ubility of slaked lime in it decreases. Adding 1 and 3% sodium chloride solution to a 90 % solution of slaked lime, the solubility increases by 2.15 and 2.2 times, respectively. With an increase in sodium chloride content to 5%, the solubility of hydrated lime begins to decrease. The presence in the solution of 20 % slaked lime and 3 % sodium chloride solution, 5 % foaming agent (PO-6k) reduces surface ten-sion and increases foam stability. It was also found that the thickness of the foam layer depends on the type of surface. The critical thickness of the foam layer on vertical surfaces was from 1 to 4 cm, on the ceiling – from 2 to 7 cm. The stability of the foam depends on its concentration in the solution. The foam content up to 5–6 % in the solution increased the resistance on vertical surfaces up to 16 minutes, and on ceiling surfaces up to 18 minutes.

Effect of multi-layer prosthetic foam liner on the stresses at the stump–prosthetic interface

The prosthetic liner plays a significant role in the redistribution of the pressure between the stump and the socket, as it adding a cushioning layer between the stump and the socket which relieves pain and makes the prosthesis more comfortable. This study employed nonlinear finite element analyses to investigate the peak pressure and shear stress at stump–prosthetic interface in the case of multi-layer prosthetic foam liner, this liner having an inner polymeric foam layer Surrounded by another type of polymeric foam layer, we used three different types of foams in different order to define this liner (flexible polyurethane foam, polyurethane-shape memory polymer foam, and natural rubber latex foam). That’s allows comparing 6 deferent configuration of multi-layer prosthetic foam liner.

Thermal Energy Storage and Heat Transfer of Nano-Enhanced Phase Change Material (NePCM) in a Shell and Tube Thermal Energy Storage (TES) Unit with a Partial Layer of Eccentric Copper Foam

Thermal energy storage units conventionally have the drawback of slow charging response. Thus, heat transfer enhancement techniques are required to reduce charging time. Using nanoadditives is a promising approach to enhance the heat transfer and energy storage response time of materials that store heat by undergoing a reversible phase change, so-called phase change materials. In the present study, a combination of such materials enhanced with the addition of nanometer-scale graphene oxide particles (called nano-enhanced phase change materials) and a layer of a copper foam is proposed to improve the thermal performance of a shell-and-tube latent heat thermal energy storage (LHTES) unit filled with capric acid. Both graphene oxide and copper nanoparticles were tested as the nanometer-scale additives. A geometrically nonuniform layer of copper foam was placed over the hot tube inside the unit. The metal foam layer can improve heat transfer with an increase of the composite thermal conductivity. However, it suppressed the natural convection flows and could reduce heat transfer in the molten regions. Thus, a metal foam layer with a nonuniform shape can maximize thermal conductivity in conduction-dominant regions and minimize its adverse impacts on natural convection flows. The heat transfer was modeled using partial differential equations for conservations of momentum and heat. The finite element method was used to solve the partial differential equations. A backward differential formula was used to control the accuracy and convergence of the solution automatically. Mesh adaptation was applied to increase the mesh resolution at the interface between phases and improve the quality and stability of the solution. The impact of the eccentricity and porosity of the metal foam layer and the volume fraction of nanoparticles on the energy storage and the thermal performance of the LHTES unit was addressed. The layer of the metal foam notably improves the response time of the LHTES unit, and a 10% eccentricity of the porous layer toward the bottom improved the response time of the LHTES unit by 50%. The presence of nanoadditives could reduce the response time (melting time) of the LHTES unit by 12%, and copper nanoparticles were slightly better than graphene oxide particles in terms of heat transfer enhancement. The design parameters of the eccentricity, porosity, and volume fraction of nanoparticles had minimal impact on the thermal energy storage capacity of the LHTES unit, while their impact on the melting time (response time) was significant. Thus, a combination of the enhancement method could practically reduce the thermal charging time of an LHTES unit without a significant increase in its size.

A model for gravity changes induced by lava fountaining at Mt Etna

<div> <p><span>Lava fountains represent a common eruptive phenomenon at basaltic volcanoes, which consist of jets of fluid lava ejected into the atmosphere from active vents or fissures. They are driven by rapid formation and expansion of gas bubbles during magma ascent. The dynamics of lava fountains is thought to be controlled by the gas accumulation in the foam layer at the top of a shallow magmatic reservoir, which eventually collapses triggering the lava fountaining. Gravity measurements taken from a location close to summit of Mt. Etna during the 2011 lava fountain episodes showed a pre-fountaining decrease of the gravity signal. The interplay between gas accumulation in the foam layer and its subsequent exsolution in the conduit has been interpreted as the mechanism producing the gravity decrease and eventually leading to the foam collapse and onset of the lava fountaining activity. Gravity measurements have proved helpful in recording the earliest phases anticipating the lava fountain episodes and inferring the amount of gas involved. However, more accurate estimates of the accumulating and ascending gas volume and total magma mass require considering the possible effect of non-spherical magma chamber geometries and magma compressibility. </span></p> </div><div> <p><span>Under task 4.4 of the H2020 NEWTON-g project, we are accomplishing a detailed study aimed to simulate the gravity signal produced in the stage prior to a lava fountain episode, through a magma chamber - conduit model. We use a prolate ellipsoidal chamber matching the inferred shape of the shallow chamber active at Mt. Etna during the lava fountain episodes, and calculate the surface gravity changes induced by inflow of new magma into the chamber-conduit system. We use a two-phase magma with fixed amount of gas mass fraction and account for magma compressibility. We find that a realistic chamber shape and magma compressibility play a key role and must be considered to produce realistic gravity changes simulations. We combine our physical model with empirical distributions of recurrence time and eruption size of the past lava fountains at Mt. Etna to stochastically simulate realistic time series of gravity changes. The final goal of this study is to develop a prediction model for the amount of magma and duration of lava fountains at Mt. Etna.</span></p> </div>