Fluid Separation Research Articles

Formation and evolution of the calcic-magnesian Saheb Fe (Cu) skarn deposit from the Sanandaj-Sirjan Belt, NW Iran: Evidence for multistage boiling in episodes of magnetite saturation

The Saheb Fe (Cu) skarn deposit is located along the northwestern end of the Sanandaj-Sirjan Zone. This deposit occurs over an approximately 2 km distance along the contact zone between the Upper Cretaceous causative granite and the Upper Permian calcareous host rock, with several iron orebodies occurring as high-grade lenticular massive magnetite bodies (with a length of up to 90 m and a width of 25 m).Following the formation of pyroxene hornfels facies, four main stages of skarn formation have been recognized: (I) early prograde stage (type I garnet + clinopyroxene + olivine): fluid inclusions in the type I garnet yielded a high temperature and salinity (average of 506 °C and 57 wt% NaCl equiv.), which may represent the composition of initial magmatic fluids. Higher salinities at this early stage can be associated with orthomagmatic differential fluid exsolution. (II) late prograde stage (type II and III garnets ± clinopyroxene ± disseminated magnetite): the coexistence of vapour-rich and halite-bearing fluid inclusions in type II garnet and their similar homogenization temperatures (420°–480 °C) presumably signify that fluid immiscibility from a supercritical fluid occurred at lithostatic pressures of 300 to 500 bar, corresponding to a depth of 1.5–2.0 km. (III) early retrograde stage (massive magnetite + pyrite + chalcopyrite + epidote + quartz + type I calcite + amphibole + serpentine + talc): hypersaline liquid and low-salinity vapour phases trapped within the epidote, quartz, and type I calcite are coexisting, indicating phase separation of hydrothermal fluids at temperatures of 300°–400 °C and pressures ranging from 310 to >100 bar under hydrostatic conditions, equivalent to a depth of 1.5 to 2.0 km. Hypersaline inclusions in the quartz and type I calcite show Td(NaCl) > Th(L-V), deduced to have been trapped by the over-saturated fluids or under over-pressured conditions before the hydrofracturing (up to 2200 bars). (IV) Late retrograde stage (type II calcite ± quartz ± chlorite), which is characterized by moderate temperature and salinity and non-boiling fluid inclusion assemblage (with average of 172 °C and 17 wt% NaCl equiv.).The first boiling event is documented in the type II garnet of the late prograde stage and provoked the ore-bearing fluids to precipitate the disseminated iron ore. The main deposition of magnetite has plausibly been triggered by the second episode of fluid boiling, recorded in epidote, quartz, and type I calcite during the early retrograde stage. Two boiling events mean producing more fractured and brecciated zones, which can act as conduits for the iron-bearing hydrothermal fluids. This seems to be why there are dozens of isolated magnetite orebodies in the Saheb skarn deposit, which extend over an area of greater than two kilometers (in an E-W direction). Comparably higher salinities even in the type II calcite of the late retrograde stage (25 wt% NaCl equiv.) may reveal that significant mixing of saline magmatic fluids with external, dilute, and cold fluids is almost implausible, despite the presence of brecciated zones. Boiling, therefore, can be pondered as the most salient factor in controlling the ore precipitation at the Saheb Fe (Cu) skarn deposit. However, mixing with meteoric fluids and shifting in pH values could also facilitate the alteration and mineralization.

Chlorine from seawater is key to the generation of calc-alkaline lavas

• A lot of Cl from seawater is in fluids released from subducting slab. • Cl-rich slab-derived fluids oxidize the mantle wedge and primary arc magma . • Cl-rich slab-derived fluids enhance the mobility of fluid mobile elements. • Cl-rich slab-derived fluids sequester some FeO* from arc mantle and magma. • Some calc-alkaline lava FeO* are in the Fe-sulphides in porphyry ore deposits . Most primary magmas evolve compositionally as either tholeiitic or calc-alkaline lava series. The most voluminous magmas are generated through decompression melting of the upper mantle beneath diverging tectonic plates and differentiate as tholeiitic lavas. Calc-alkaline lavas, on the other hand, consist mainly of the bulk of differentiating arc magmas generated through H 2 O-fluxed melting of the upper mantle beneath converging plates. The exact origin of the calc-alkaline lava series is one of the earliest but still unresolved controversies in petrology. Here I propose that the calc-alkaline lava series acquires its distinct compositional features mainly because of the Cl content of subducted seawater. The long-held view that the low FeO* differentiation trend of calc-alkaline lava series is primarily due to the early fractionation of its Fe-Ti oxides may be inaccurate. Instead, the calc-alkaline lava series is characteristically depleted in FeO* and oxidized because some of its Fe are sequestered early from its mantle source and parental arc magma by Cl-rich slab-derived fluids as Fe-chlorides, transit upward as part of a separate fluid phase in the upwelling magma and, then, precipitate eventually in the crust as Fe, ore metal-sulphides.

Using Specified Risk Materials-Based Peptides for Oil Sands Fluid Fine Tailings Management.

Fluid fine tailings are produced in huge quantities by Canada’s mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids. Settling results using synthetic kaolinite slurries demonstrated that, though not as effective as hydrolyzed polyacrylamide, a commercial flocculant, the use of SRM-derived peptides enabled a 2-3-fold faster initial settling rate than the blank control. The pH of synthetic kaolinite tailings was observed to be slightly reduced with increasing peptides dosage in the test range (10–50 kg/ton). The experiments on diluted fluid fine tailings (as a representation of real oil sands tailings) demonstrated an optimum peptides dosage of 14 kg/ton, which resulted in a 4-fold faster initial settling rate compared to the untreated tailings. Overall, this study demonstrates the novelty and feasibility of using SRM-peptides to address intractable oil sands fluid tailings.

Experiments and Simulation of Counter-Current Extraction (Subcritical Fluid Separation) by Supercritical CO<sub>2</sub> with Hops-Extract Ethanol Solution

Experiments and Simulation of Counter-Current Extraction (Subcritical Fluid Separation) by Supercritical CO<sub>2</sub> with Hops-Extract Ethanol Solution

High Concentration Fine Particle Separation Performance in Hydrocyclones

The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and the classification mechanism are still unclear. In order to gain insights into the interaction between fine particles in the high concentration hydrocyclone field and to improve the hydrocyclone separation performance of these particles, a Dense Discrete Phase Model (DDPM) of the Euler-Eulerian method under the Ansys Fluent 14.5 software was employed. Numerical simulations were carried out to study the characteristics of the hydrocyclone field of dense particles and the influence of parameters, such as the diameter of the overflow outlet, diameter of the underflow outlet, and material concentration, on separation performance. The trajectories and separation efficiencies of two kinds of fine particles with different densities and six different particle sizes at high concentration were obtained. The results show that for the hydrocyclone classification of high-concentration fine particles, particles with large density and small particle size are more likely to enter the internal cyclone and discharge from the overflow. Particles with small density and large particle size are more likely to enter the external cyclone and discharge from the underflow. The research results of this topic could provide a feasible reference and theoretical basis for the centrifugal separation of high-concentration fine particle fluid.

Method of determining the cohesion and adhesion parameters in the Shan-Chen multicomponent multiphase lattice Boltzmann models

The cohesion and adhesion parameters are the two essential parameters in the Shan-Chen multicomponent and multiphase lattice Boltzmann models for determining the separation of fluids and the wettability of surfaces, and thus should be carefully chosen. In this study, we propose a systematic method of determining these parameters from a physical point of view. The cohesion parameters of different water/alkane systems are determined by matching the interfacial tensions, and the adhesion parameters between the water/alkane and the silicon dioxide are obtained by matching the contact angles as such that their physical meanings are preserved. Based on the linear relationship between the interfacial tension and the cohesion/adhesion forces, an improved equation for predicting the adhesion parameter is proposed and validated by comparing the simulated contact angles using the predicted adhesion parameters with experimental results. Further, the effect of cohesion and adhesion parameters on the advancing and receding angles of the oil slug in a capillary tube in the movement initialization process was also investigated.

A Piecewise Model for In Situ Raman Measurement of the Chlorinity of Deep-Sea High-Temperature Hydrothermal Fluids

The chlorinity of deep-sea hydrothermal fluids, representing one of the crucial deep-sea hydrothermal indicators, indicates the degree of deep phase separation of hydrothermal fluids and water/rock reactions. However, accurately measuring the chlorinity of high-temperature hydrothermal fluids is still a significant challenge. In this paper, a piecewise chlorinity model to measure the chlorinity of high-temperature hydrothermal fluids was developed based on the OH stretching band of water, exhibiting an accuracy of 96.20%. The peak position, peak area ratio, and F value were selected to establish the chlorinity piecewise calibration model within the temperature ranges of 0-50 ℃, 50-200 ℃, and 200-300 ℃. Compared with that of the chlorinity calibration model built based on a single parameter, the accuracy of this piecewise model increased by approximately 4.83-12.33%. This chlorinity calibration model was applied to determine the concentrations of Cl for high-temperature hydrothermal fluids in the Okinawa Trough hydrothermal field.

Aerodynamic study for the flow through cascade blades of gas turbine with vibration effect: a review

A research survey on aerodynamic with/without vibration effect and investigations for turbine components of gas turbine engines is presented. Experimental and numerically predicted results are presented from investigations undertaken over the past 70 years. The aerodynamics between the turbine blades is very important as it determines the overall system performance. The importance of aerodynamics is being in the pressure distribution above and below each airfoil, the locations of the vortices occurring, their number, distribution, direction, and shedding, and the determination of the regions of fluid separation from the wall that is directly related to the fluid velocity. Many ranges of vibration that affect different bodies were taken, and some of these ranges were small (10-200 Hz), and others had large ranges from 1.5 to 10 KHz. therefore the result evolution and shedding of vortices corresponding to the deformation in fluid structure depends on the Reynolds number and value of amplitude and frequency for vibration. The Mach number is a clear indicator to represent these characteristics. It also includes studying the theoretical methods used and simulations of the researchers’ aerodynamics, the accuracy of the results reached, the representation of the body contour and the diagrams for each of the pressure and Mach number, the pressure (Cp ) and lift (CL ) coefficients, and their amount of change occurring at each location of the airfoil. The importance of the above topics has motivated us to prepare a comprehensive review mostly of the aerodynamics of turbine blades and the effect of the vibration on the flow. The main concepts of aerodynamics, such as Cp and CL as well as vibration frequency are presented. It also highlights the performance of the turbine blades as a result of vibration

Fluid separation and network deformation in wetting of soft and swollen surfaces

When a water drop is placed onto a soft polymer network, a wetting ridge develops at the drop periphery. The height of this wetting ridge is typically governed by the drop surface tension balanced by elastic restoring forces of the polymer network. However, the situation is more complex when the network is swollen with fluid, because the fluid may separate from the network at the contact line. Here we study the fluid separation and network deformation at the contact line of a soft polydimethylsiloxane (PDMS) network, swollen with silicone oil. By controlling both the degrees of crosslinking and swelling, we find that more fluid separates from the network with increasing swelling. Above a certain swelling, network deformation decreases while fluid separation increases, demonstrating synergy between network deformation and fluid separation. When the PDMS network is swollen with a fluid having a negative spreading parameter, such as hexadecane, no fluid separation is observed. A simple balance of interfacial, elastic, and mixing energies can describe this fluid separation behavior. Our results reveal that a swelling fluid, commonly found in soft networks, plays a critical role in a wetting ridge.

A review on the mechanics of inertial microfluidics

In a number of microfluidics-based systems where the Reynolds number is in an intermediate range, both viscosity and inertia are significant, and thus, plenty of interesting effects appear including inertial motion and secondary flow. In recent years, this rapidly expanding area of science has opened a new window of possibilities for micro-particle inertial focusing in high-throughput cellular separation and physiological fluids processing. Moreover, this science is applicable in bio-particle focusing in clinical diagnostics along with widespread applications in environmental cleanup. In this review, fundamental concepts governing the mechanics and physics of inertial microfluidics are discussed. Furthermore, recent mathematical frameworks and theoretical developments that have made this science what we know today are presented in detail. Finally, a number of possible futuristic promising directions in this novel field are proposed since, despite tremendous recent progress, this mainstream technology is still a nascent area of research.

Validation of the Molar Flow Rates of Oil and Gas in Three-Phase Separators Using Aspen Hysys

A three-phase separator is the first vessel encountered by well fluids. The application of separators has been of great value to the oil and gas industry. In order to generate the gas phase envelope that is applicable to the study of reservoir fluid and the selection of optimum operating conditions of separators, this research utilizes a specified reservoir fluid stream to simulate a three-phase separator executed in Aspen HYSYS. Subsequently, a comparative study of the effects of specified inlet operating conditions on the output of gas and oil streams was carried out. The results show that changing the inlet pressure of the separator from 1000 to 8000 kPa reduces the gas outlet flow from 1213 to 908.6 kg mol/h, while it increases the liquid flow rate from 374 to 838.0 kg mole/h. By changing the temperature of the separator feed stream from 13 to 83 °C, the gas outlet stream was raised from 707.4 to 1111 kg mol/h, while the liquid flow rate dropped from 1037.0 to 646.1 kg mol/h. It was observed that the concentration of the outlet methane product is not affected by changing the flow rate of the feed stream at a specific pressure and temperature. Therefore, the thermodynamic property method is appropriate to simulate the separation of reservoir fluids which was achieved by selecting the Peng–Robinson (PR) model. The operating conditions of the separator were at 8000 kPa and 43 °C, which lies right on the dew point line. This is comparable to similar work on CHEMCAD which was in turn validated by plant data. Thus, the gas flow rate and the oil flow rate were dependent on pressure and temperature conditions of the plant.

Power-law coarsening in network-forming phase separation governed by mechanical relaxation

A space-spanning network structure is a basic morphology in phase separation of soft and biomatter, alongside a droplet one. Despite its fundamental and industrial importance, the physical principle underlying such network-forming phase separation remains elusive. Here, we study the network coarsening during gas-liquid-type phase separation of colloidal suspensions and pure fluids, by hydrodynamic and molecular dynamics simulations, respectively. For both, the detailed analyses of the pore sizes and strain field reveal the self-similar network coarsening and the unconventional power-law growth more than a decade according to ℓ ∝ t1/2, where ℓ is the characteristic pore size and t is the elapsed time. We find that phase-separation dynamics is controlled by mechanical relaxation of the network-forming dense phase, whose limiting process is permeation flow of the solvent for colloidal suspensions and heat transport for pure fluids. This universal coarsening law would contribute to the fundamental physical understanding of network-forming phase separation.

Role of CO2 in the evolution of Kimberlite Magma: Experimental constraints at 5.5 GPa and 1200–1450 °C

According to the existing models of kimberlite origin, free exsolution CO2 may be an important agent in the evolution of primary kimberlite magma and initiation of crack propagation. We study the reaction of garnet lherzolite with carbonatitic melt rich in molecular CO2 and H2O in experiments at 5.5 GPa and 1200–1450 °C. The experimental results show that carbonation of olivine with formation of orthopyroxene and magnesite can buffer the contents of molecular CO2 in the melt, which impedes immediate separation of CO2 fluid from melt equilibrated with the peridotite source. The solubility of molecular CO2 in the melt decreases from 20 -25 wt% at 4.5–6.8 wt% SiO2 typical of carbonatite to below 7–12 wt% in more silicic melts with 26–32 wt% SiO2. Interaction of garnet lherzolite with carbonatitic melt (at a weight proportion of 2:1) in the presence of 2–3 wt% H2O and 17–24 wt% of total CO2 at 1200–1450 °C yields low-SiO2 (<10 wt%) alkali‑carbonated melts, which shows multiphase saturation with magnesite-bearing garnet harzburgite. Thus, carbonatitic melts rich in volatiles can originate in a harzburgite source at moderate temperatures common to continental lithospheric mantle (CLM). Excessive volatiles may be present in carbonatitic melts not equilibrated with the peridotitic source due to the formation of metasomatic reaction zones.Having separated from the source, carbonatitic magma enriched in molecular CO2 and H2O can rapidly become more silicic (>25 wt% SiO2) by dissolution and carbonation of entrapped peridotite. Furthermore, interaction of garnet lherzolite with carbonatitic melt rich in K, CO2, and H2O at 1350 °C produces immiscible carbonate-silicate and K-rich silicate melts. Quenched silicate melt develops globules of foam-like vesicular glass. Differentiation of immiscible melts early during their ascent may equalize the compositions of kimberlite magmas generated in different CLM sources. The fluid phase can release explosively from ascending magma at lower pressures as a result of SiO2 increase which reduces the solubility of CO2 and due to the decarbonation reaction of magnesite and orthopyroxene.

Numerical Investigation on Hydrodynamic Characteristics of Immersed Buoyant Platform

The Next Generation Subsea Production System (NextGen SPS) is considered as a competitive alternative system used for offshore petroleum production in ultra-deep sea based on the artificial seabed technology. The Immersed Buoyant Platform (IBP), which is located at a constant depth below the free surface of the water to minimize wave loading, provides a buoyant stable platform for supporting the well completion equipment. Therefore, the hydrodynamic characteristics of IBP in the currents play an essential role in determining the global responses of NextGen SPS. In this paper, aiming at acquiring an optimum structural form of IBP, the hydrodynamic characteristics of the flow past the cylindrical IBP with different height-to-diameter ratios are systematically investigated by use of the large eddy simulation (LES) approach. The simulations with fifteen different height-to-diameter ratios (H/D) are investigated. The Reynolds numbers are ranged from 0.94×106 to 3.45×106. It can be verified that the separated fluid reattaches on the surface of the cylinder when the aspect ratio is between 0.1 and 0.4. Due to the specific shape ratio and obvious 3D effect of the cylindrical IBP, no significant vortex shedding has been clearly observed when the aspect ratio is between 0.1 and 0.4. In the case of 0.4≤H/D≤5.0, a series of regular and alternating vortex street shedding appear behind the circular cylinder. The simulation results also show that the recirculation region length behind the cylindrical IBP can be significantly reduced with the decreasing aspect ratio. It can be concluded that the cylindrical IBP performs the best hydrodynamic characteristics when the aspect ratio is between 0.3 and 0.4. The research findings will be of great significance to providing valuable reference and foundation to determine the optimum form of underwater structures, such as the buoyancy cans of the hybrid riser system.

Ethanol Distillation Heating Mantle with Timer and Temperature Display

Heating mantle or isomantle is a laboratory equipment used to spread heat to containers designed to distill or separate chemical fluids using heat. In the laboratory, distillation is generally used to perform fluid separation with low boiling points such as Ethanol. Ethanol has health benefits such as antiseptics, solvents of various chemicals, and more. However, the distillation process using an open fire will be perilous because the fire can break out towards organic solvent vapor. So the author innovating the heating mantle tool for distillation by using a dry heater as a heater that will heat the tube as well as monitoring the liquid temperature using the LM35 sensor with a digital timer and LCD. The study results obtained the temperature measurement results of 79 °C with an average of 79,6 °C and an error value of 0,7%. This value is still at the permissible threshold of +/−1 °C. For 2 hours 30 minutes, the timer obtained an average of 2 hours 28 minutes, and errors of 1,3 %. For ethanol amount with an average of 144 mL, after general testing, it can be concluded that heating mantle for Ethanol distillation equipped with a timer and temperature display can be appropriately used and keep on within the tolerable threshold value.

Deciphering Multiphasic Structure of Protein-RNA Condensates

Intracellular biomolecular condensates, such as the nucleolus and stress granules, are phase separated fluids which commonly display complex internal sub-structures. These sub-structures are understood as a consequence of internal de-mixing of condensate components into distinct co-existing phases. Although some in vitro model systems have been successful in recapitulating such multi-phasic structures in phase-separated condensates, it remains unknown how spatial arrangement of multiple co-existing liquid phases is regulated. We answer this question by employing a three-component system, comprising of a prion-like polypeptide (PLP), an arginine-rich polypeptide (RLP), and RNA, exhibiting overlapping inter-molecular interactions. Using experiments and simulations, we show that PLP-RLP-RNA ternary system forms stable coexisting PLP and RLP-RNA condensates. We find that the topology of these bi-phasic condensates sensitively depends on the hierarchy of inter-molecular interactions at the liquid-liquid interface, which can be tuned via mixture composition and polypeptide sequence perturbations. This finding enabled us to predictively control multi-phasic morphologies, allowing us to design totally-engulfed, partially-engulfed, completely-detached, and Janus-like condensates in the PLP-RLP-RNA ternary mixture. The direct correspondence between the microscopic intermolecular interactions and the mesoscopic multiphase structuring is a manifestation of tunable interfacial tensions in the system. Our finding allows us to reliably control the multiphasic structuring, highlighting hitherto unknown physical principles that regulate the spatial organization of multiphasic biomolecular condensates.

A practical and economically feasible surfactant EOR strategy: Impact of injection water ions on surfactant utilization

One grand challenge of surfactant technologies in high salinity sandstone reservoirs is the surfactant retention and its utilization for commercial projects. A proven mitigation strategy to reduce surfactant retention is to soften the seawater or produced brine and add alkali with the surfactant and polymer. However, softening produced brine can be costly and the addition of alkali can impose other issues such as scale and produced fluid separation. A comprehensive chemical enhanced oil recovery (CEOR) laboratory program was carried out to compare different surfactant formulations for both alkali-surfactant-polymer (ASP) and surfactant-polymer (SP) implementation in a giant Middle East sandstone oil reservoir with high salinity on the order of 160,000 ppm. The efficacies of ASP and SP floods were investigated in laboratory corefloods and simulations with emphasis on surfactant retention to improve techno-economic feasibility.Both ASP and SP floods were designed with low operational cost in mind and were tested in laboratory corefloods under reservoir conditions. Different injection water salinities were considered for practical field application. The handling and availability of injection water with a suitable composition has significant implications in CEOR projects. The SP design using produced brine with minimum water treatment is an attractive option for field commercial deployment. We considered different injection water salinities, surfactant molecules, and brine treatment requirements for several ASP and SP formulations and injection design strategies.ASP and SP corefloods recovered nearly all the remaining oil after waterflooding. The surfactant retention was lower for SP floods when brine with reduced concentration of Ca2+ and Mg2+ (hardness) was used. Both ASP and SP formulations were also tested for crude oil samples from different zones. A minimal adjustment in injection salinity was required for different oils with our surfactant formulations. Field implementation strategies were evaluated via numerical simulation. The effect of strong aquifer drive on SP performance was shown to be minimized with optimized injection/production strategies. SP was shown to be technically and economically an attractive candidate tertiary process.

A combined interfacial polymerization and in-situ sol-gel strategy to construct composite nanofiltration membrane with improved pore size distribution and anti-protein-fouling property

Pore size distribution is crucial for the application of nanofiltration membrane in size-selective separation of industrial fluids. In this work, a novel combined interfacial polymerization (IP) and in-situ sol-gel strategy was proposed to fabricate composite nanofiltration membrane with narrow pore size distribution. Aqueous solution of piperazine and polyvinyl alcohol (PVA) was employed to perform interfacial polymerization with organic solution of trimesoyl chloride and tetraethyl orthosilicate (TEOS) on porous support. The non-reactive additive TEOS within the interfacially synthesized selective separation layer was then employed to perform sol-gel. The space-limited hydrolysis and condensation of TEOS molecules and their chemical bonding with PVA molecules were confirmed by analyzing membrane physico-chemical property and were found to be effective in tuning mean pore diameter, narrowing the pore size distribution and thus enhancing membrane perm-selectivity. Compared to those of membrane PA1 with similar mean pore size fabricated by only IP technique, the water permeability and rejection ratio of PEG1000 to raffinose (RPEG1000/Rraffinose) of membrane PA-TEOS0.5 fabricated by combined IP and sol-gel technique were higher by 25.0 and 20.1%, respectively. Moreover, static adsorption and dynamic deposition tests using aqueous bovine serum albumin solution proved that in-situ sol-gel process could endow the membrane with better protein fouling resistance.

Onset Criteria for Bulk-Mode Thermoacoustic Instabilities in Supercritical Hydrocarbon Fuels

Abstract We have investigated supercritical-p (p &amp;gt; 1192 psi (8.22 MPa)) methanol at pressures up to 1645 psi (11.3 MPa) flowing through a heated tube at flow rates of 4–7 lb/h (1.8–3.2 kg/h). Tube heated lengths have been varied from 4 to 6 in (10 to 15 cm), internal diameters from 0.027 to 0.069 in (0.069 to 0.175 cm), and heat inputs between zero and 800 W. Fluid temperature at the tube inlet remained subcritical (T &amp;lt; 464 °F (513 K)); outlet temperatures were transcritical or supercritical. Two phenomena were observed: system-wide bulk-mode oscillations and localized acoustic modes. In this study, predictive efforts are undertaken to characterize system-wide bulk-mode oscillations. The parameter space has been nondimensionalized, yielding four dimensionless variables. Stability criteria based on these dimensionless groups have been established for two separate test articles and fluids; both criteria suggest that the heat required for the onset of oscillations is proportional to the mass flow rate times the mean pressure and inversely proportional to the fuel density.

Internally cooled membrane-based absorber for dehumidification and water heating: Validated model and simulation study

This paper presents a comprehensive model for advanced membrane-based absorber components accounting for three separate fluid streams, one of them providing internal cooling, with complex flow patterns. The model was implemented with various liquid desiccants and their properties (including LiCl, CaCl2, and [emim][OMS] ionic liquid [IL]). The model has been validated using data from two laboratory prototype absorbers, one with CaCl2 as the working fluid and one with an IL as the working fluid. Entropy analysis was further carried out to verify the model and understand effect of internal cooling on the entropy variation of three fluid streams. The developed model and codes are expected to enable detailed configuration optimization and provide in-depth understanding of three-fluid heat and mass exchanger (HMX) performance. The paper also describes parametric studies of the HMX components in utilizing the latent heat removed in space cooling to heat water and numerically explores the unique benefit of its application in a semi-open absorption heat pump water heater. The results show that a single three-fluid HMX has the potential to achieve simultaneous dehumidification and water heating efficiently at cost effectiveness, particularly in hot and humid climates.