High Pressure Region Research Articles

Lubrication mechanism and characteristics of aerostatic bearing with close-spaced micro holes

Insufficient load capacity and stiffness of aerostatic bearings with traditional inherent orifices is limiting their applications. Recently, the aerostatic bearing with close-spaced micro holes (ABMH) shows the potential of performance improvement. However, its lubrication mechanism is still not clear and the static characteristics have not been comprehensively investigated. This paper applies numerical method and extends the pneumatic resistance theory from single orifice bearing to ABMH to reveal its lubrication mechanism. The results indicate that ABMH reduces the gas flow towards the high-pressure region of bearing center and impedes the pressure decrement in this area, thus resulting in the higher load capacity and stiffness. Additionally, bearing load capacity has positive relationships with total mass flow rate and exhibits similar varying trends.

Study on waterproof and drainage technology of mountain tunnel in high-pressure and water-rich region

High-pressure groundwater brings great challenges to the construction of mountain tunnels. Hence, controlling and discharging groundwater are two key problems that must be addressed before constructing tunnels in high-pressure and water-rich region. Fluid–solid coupling seepage analysis method is used to analyze the variation of displacement, stress and pore water pressure of the tunnel. A waterproof and drainage method suitable for tunnels in high-pressure and water-rich region is proposed. Curtain grouting plays a dual role in waterproof and reinforcing surrounding rock. Decompression drainage holes are designed in order to further reduce the pore water pressure acting on the initial lining. The thickness of grouting circle, the permeability coefficient ratio and the decompression drainage holes distribution rate of the initial lining are the main factors that affect the waterproof and drainage effect of tunnels in high-pressure and water-rich region. Suggested parameters on waterproof and drainage measures for tunnels in high-pressure and water-rich region are given after comprehensive analysis, which can provide basis for the technology on high-pressure groundwater treatments and constructions of underground engineering under complex geological conditions.

Dynamic modeling of cavitation bubble clusters: Effects of evaporation, condensation, and bubble–bubble interaction

We present a dynamic model of cavitation bubbles in a cluster, in which the effects of evaporation, condensation, and bubble–bubble interactions are taken into consideration. Under different ultrasound conditions, we examine how the dynamics of cavitation bubbles are affected by several factors, such as the locations of the bubbles, the ambient radius, and the number of bubbles. Herein the variations of bubble radius, energy, temperature, pressure, and the quantity of vapor molecules are analyzed. Our findings reveal that bubble–bubble interactions can restrict the expansion of bubbles, reduce the exchange of energy among vapor molecules, and diminish the maximum internal temperature and pressure when bursting. The ambient radius of bubbles can influence the intensities of their oscillations, with clusters comprised of smaller bubbles creating optimal conditions for generating high-temperature and high-pressure regions. Moreover, an increase in the number of bubbles can further inhibit cavitation activities. The frequency, pressure and waveform of the driving wave can also exert a significant influence on cavitation activities, with rectangular waves enhancing and triangular waves weakening the cavitation of bubbles in the cluster. These results provide a theoretical basis for understanding the dynamics of cavitation bubbles in a bubble cluster, and the factors that affect their behaviors.

Effect of Audible Sounds on the Forces Acting between Charged Surfaces in Water.

We aimed to determine if audible sounds could change the forces acting between charged surfaces in water and their electric double layers (EDLs). This was achieved by using an atomic force microscope to measure force-distance curves between a microsized silica particle attached to a cantilever (probe) and a silicon wafer in water in the absence and presence of sound. Sound decreased the repulsive forces acting between the probe and silicon wafer, where the range and magnitude of the forces decreased with an increase in the sound frequency from 300 to 15000 Hz. The decrease in the force range was explained by a decrease in the EDL thickness. This result was explained by (1) the shrinkage of the EDL by a high-pressure region of the sound wave, where an increased sound frequency caused the number of high-pressure regions that passed between the probe and the substrate to increase and (2) the inability of the EDL to fully re-expand to its original thickness during the time that a low-pressure region of the sound wave was applied. The decrease in the force magnitude with a sound frequency increase was explained by the increased screening of charged surfaces that accompanies a decrease in the EDL thickness. An increase in the force measurement speed caused the sound waves to reduce the repulsive forces less. A faster speed decreased the time to measure a force curve, which reduced the number of high-pressure regions of the sound wave to pass through the water between the probe and the substrate. This reduced the number of times that the EDL was compressed by the sound wave.

Influence of bionics shark gills tunnel portal on the micro-pressure wave at the tunnel exit

In this study, the bionic principle is used to relieve the micro-pressure waves (MPWs) at the tunnel exit. A bionic shark gill tunnel portal with holes was studied, and the effects of the opening ratios and oblique cutting angles of the bionic shark gill opening tunnel portal on the initial compression wave (ICW) and MPW induced by a high-speed train (HST) passing through the tunnel are examined. The results show that when the opening ratio of the bionic shark gill tunnel portal is 24%, the highest mitigation effect on the ICW pressure gradient and MPW is observed. In addition, the high-pressure region of the ICW in the tunnel decreased with increasing opening ratio. The greatest mitigation effect on the ICW pressure gradient and MPW is obtained for the oblique cutting angle of the bionic hole on the tunnel portal (with an opening ratio of 24%) of 16°, because the oblique cutting angle facilitates the expulsion of the jet-stream from the bionic hole at the tunnel portal.

Low-frequency large-scale unsteadiness analysis of lateral jet interactions on a slender cylinder in hypersonic flows using fast-responding pressure-sensitive paint

Lateral jet interactions, commonly encountered in high-speed vehicles, are typical complex three-dimensional (3D) shock wave/boundary layer interactions. The spatiotemporal features of surface pressure are crucial for understanding such complex interactions. In this study, fast-responding pressure-sensitive paint measurements are implemented at a sampling rate of 3000 Hz and a spatial resolution of 0.35 mm/pixel to investigate global pressure fields in lateral jet interactions on a slender cylinder under hypersonic flow conditions. Tests are conducted at three angles of attack (0°, 5°, and 10°) and two sideslip angles (0° and 2.5°) at Mach 6 and a Reynolds number of 1.35 × 107/m. The mean pressure results indicate the presence of a 3D high-pressure region beneath the bow shock feet, the area and pressure level of which depend on the cylinder attitude. Moreover, significant low-frequency broadband unsteadiness associated with the large-scale motion of bow shock is found in the high-pressure region. Statistical, coherence, and modal analyses are performed to clarify the characteristics of the large-scale unsteadiness. The results indicate that the dominant pressure mode is induced by streamwise oscillation of the bow shock, which exhibits two subregions with opposite pressure-fluctuation variations. Furthermore, the effects of the cylinder attitude on the unsteadiness extent and intensity are discussed.

PROPELLER INFLUENCE ON SURFACE PRESSURE FLUCTUATION UNDER BOUNDARY LAYER INGESTION CONDITION

Research on propeller noise under boundary layer ingestion condition is essential for designing new aircraft concepts. Measurements of pressure spectra on a flat plate below a propeller give important information about the noise coming from the blades. These also are important for designing surface noise mitigation structures, such as acoustic black holes, meta-materials, and liners. This paper investigates the effects of a propeller on the flat plate surface pressure under boundary layer ingestion, using bottom of the wind tunnel channel as flat plate. Tripping devices on the wind tunnel bottom wall control the boundary layer thicknesses. The surface pressure is measured using an instrumented plate positioned underneath the propeller. The plate has 87 pressure taps to measure the unsteady and steady pressure using the remote microphone probe (RMP) technique. The results show the influence of the propeller inflow, the advance ratio, and the number of blades on the different regions underneath the propeller, and on coherent turbulent structures of the incoming flow. The boundary layer thicknesses affects the static pressure upstream of the propeller - creating high pressure regions. The propeller affects the turbulent structures downstream of the blades, increasing its correlation length.

Enhanced CO2 capture potential of UiO-66-NH2 synthesized by sonochemical method: experimental findings and performance evaluation

The excessive release of greenhouse gases, especially carbon dioxide (CO2) pollution, has resulted in significant environmental problems all over the world. CO2 capture technologies offer a very effective means of combating global warming, climate change, and promoting sustainable economic growth. In this work, UiO-66-NH2 was synthesized by the novel sonochemical method in only one hour. This material was characterized through PXRD, FT-IR, FE-SEM, EDX, BET, and TGA methods. The CO2 capture potential of the presented material was investigated through the analysis of gas isotherms under varying pressure conditions, encompassing both low and high-pressure regions. Remarkably, this adsorbent manifested a notable augmentation in CO2 adsorption capacity (3.2 mmol/g), achieving an approximate enhancement of 0.9 mmol/g, when compared to conventional solvothermal techniques (2.3 mmol/g) at 25 °C and 1 bar. To accurately represent the experimental findings, three isotherm, and kinetic models were used to fit the experimental data in which the Langmuir model and the Elovich model exhibited the best fit with R2 values of 0.999 and 0.981, respectively. Isosteric heat evaluation showed values higher than 80 kJ/mol which indicates chemisorption between the adsorbent surface and the adsorbate. Furthermore, the selectivity of the adsorbent was examined using the Ideal Adsorbed Solution Theory (IAST), which showed a high value of 202 towards CO2 adsorption under simulated flue gas conditions. To evaluate the durability and performance of the material over consecutive adsorption–desorption processes, cyclic tests were conducted. Interestingly, these tests demonstrated only 0.6 mmol/g capacity decrease for sonochemical UiO-66-NH2 throughout 8 consecutive cycles.

Utilizing an Ultrasonic Inspection System Operating Inside an Autoclave and Machine Learning to Quantify Porosity within Composites During Cure

ABSTRACT Composite materials are increasingly being utilized in aerospace applications for their high stiffness and strength to weight ratios and fatigue resistance. However, defects in the composite may arise during cure (e.g. porosity, delamination, fiber waviness), and current technology only allows for post-cure evaluation (e.g. microscopy, ultrasonic inspection). A high-temperature ultrasonic scanning system was developed for deployment in an autoclave, which can detect porosity in composites during the cure process. This study focused on the implementation of machine learning techniques to help generate a model that can quantify porosity, in addition to detection and localization that has previously been demonstrated. Two, six-hour-long experiments were conducted on curing of 762 mm × 305 mm (30 in. ×12 in.) composite panels with a [0/45/90/-45]4s layup and varying regions of high and low pressure due to its tapered geometry in contact with a flat caul plate. The first experiment utilized a thick (12.7 mm) caul plate and the second utilized a thin (3.2 mm) caul plate. During experimentation, within the scan area (406 mm × 13 mm), data was recorded and stored for ultrasonic amplitude. Additional variables were measured or predicted including temperature, autoclave pressure, number of plies, slope of the composite panel surface with respect to the transducer, viscosity, and glass transition temperature. The pre-processed data was entered into the Regression Learner Application in MATLABⓇ,1 and a rational quadratic Gaussian process regression (GPR) was chosen for the machine learning algorithm. The model was then trained on a larger data set to make it more robust and capable of predictions using a function callout. The result was a machine learning algorithm that can reliably quantify porosity in a composite panel during cure based on measured amplitude response and generate images for intuitive visualization. This tool can be further trained with more experimentation and potentially employed for real-time porosity detection and quantification of composite components during cure in an autoclave. Practical use of this technology is the potential to dynamically control processing parameters (e.g. autoclave pressure) in real-time to reduce the level of porosity within the laminate to acceptable limits (e.g. 2% by volume).

CO2 competes with radioactive chemicals for freshwater recovery: Hydrate-based desalination

Here, we introduce CO2 hydrate-based desalination (CHBD) technology for freshwater recovery from radioactive wastewater, for water particularly containing Cs and Sr. The hydrate equilibrium curves of CO2 hydrates shift towards lower temperature and higher pressure regions as the concentrations of CsCl and SrCl2 increase. X-ray diffraction and Raman spectroscopy measurements found that neither CsCl nor SrCl2 can affect the structure of CO2 hydrates. The high-pressure micro-differential scanning calorimetric results demonstrate that CO2 hydrates in the presence of CsCl and SrCl2 started to dissociate at lower temperatures due to the enrichment of CsCl and SrCl2 in the remaining solutions. The formation kinetics results indicate that increases in the concentrations of the radioactive chemicals lead to a decrease in the initial reaction rate and sub-cooling temperature. Solid-state nuclear magnetic resonance spectroscopy was utilized to confirm the exclusion of radioactive isotopes from solid gas hydrates. Importantly, the CHBD technology proposed in this study is applicable to radioactive wastewater containing Cs+ and Sr2+ across broad concentration ranges, spanning from a percent to hundreds of parts per million (ppm), and even sub-ppm levels, with comparable recovery efficiency. This study presents new insights into the potential of environmentally sustainable technologies to overcome the challenges posed by radioactive wastewater.

A new modelling approach for reliable prediction of solid-fluid behaviour: Application to the methane + benzene system including low-temperature and high-pressure regions

Because of their high melting temperature, aromatic compounds are amongst the heaviest components to deal with in the evaluation of the crystallization risk of methane-rich mixtures feeding main cryogenic heat exchangers widely employed in LNG production plants.In this paper, the GERG-2008 equation of state as implemented in the Reference Fluid Thermodynamic and Transport Properties Database (REFPROP) has been coupled to the Gibbs free energy equation for phase I of solid methane and phase I of solid benzene to predict the solubility of benzene in vapour, liquid, and supercritical methane, and the global phase diagram of the binary methane + benzene mixture down to 60 K and up to 60 MPa.Predicted values are in a rather good qualitative and quantitative agreement with solid-fluid and solid-fluid-fluid data when compared to results obtained from other solid-phase and predictive models for the fluid phases. The obtained results point out the importance of an accurate representation of the density of the fluid phase for the reliable prediction of solubility of solids in fluids.

Preparation of Elastic Macroporous Graphene Aerogel Based on Pickering Emulsion Method and Combination with ETPU for High Performance Piezoresistive Sensors.

High-performance pressure sensors provide the necessary conditions for smart shoe applications. In this paper, the elastic Macroporous Graphene Aerogel (MGA) was synthesized via the modified Hummers' method, and it was further combined with Expanded-Thermoplastic polyurethane (ETPU) particles to assemble MGA-ETPU flexible sensors. The MGA-ETPU has a low apparent density (3.02 mg/cm3), high conductivity (0.024 S/cm) and fast response time (50 ms). The MGA-ETPU has a large linear sensing range (0-10 kPa) and consists of two linear regions: the low-pressure region (0 to 8 kPa) and the high-pressure region (8 to 10 kPa), with sensitivities of 0.08 kPa-1, and 0.246 kPa-1, respectively. Mechanical test results show that the MGA-ETPU sensor showed 19% reduction in maximum stress after 400 loading-unloading compression cycles at 40% strain. Electrical performance tests showed that the resistance of MGA-ETPU sensor decreased by 12.5% when subjected to sudden compression at 82% strain and returned to its original state within 0.05 s. Compared to existing flexible sensors, the MGA-ETPU sensors offer excellent performance and several distinct advantages, including ease of fabrication, high sensitivity, fast response time, and good flexibility. These remarkable features make them ideally suited as flexible pressure sensors for smart shoes.

A multifunctional hydrogel-based strain sensor and triboelectric nanogenerator for running monitoring and energy harvesting

Recently, flexible wearable electronics for human running posture monitoring and human energy harvesting have attracted widespread attention. Hence, we design a mixed type conductive hydrogel based on polyvinyl alcohol, cotton paper, graphite oxide, and MXene, named PCGM hydrogel. Furthermore, the PCGM hydrogel can act as the PCGM-based strain sensor and triboelectric nanogenerator (P-TENG) for running posture monitoring and mechanical energy harvesting. The PCGM-based strain sensor has two sensing linear regions: The pressure sensitivity is 0.0164 kPa−1 in the low pressure region (0–16 kPa), whereas it is 0.002 86 kPa−1 in the high pressure region (16–120 kPa). To achieve comprehensive health monitoring of runners, the PCGM-based strain sensors can be installed on human joints and facial skin to monitor human posture and facial expressions. The PCGM hydrogel can be combined with a polytetrafluoroethylene film to form a P-TENG device for mechanical energy harvesting. The P-TENG maximum output power can reach 135 µW with a 30 MΩ load. The short-circuit current (Isc), open-circuit voltage (Voc), and transfer charge (Qsc) of P-TENG can reach 10.36 µA, 229.85 V, and 49.24 nC, respectively. This research provides an effective approach for human-running motion monitoring by using multifunctional flexible devices.

On the explosion characteristics of natural gas with hydrogen and inert gas additions

In this work, the explosion limits of three different natural gas mixtures (with various proportions of methane (CH4), ethane (C2H6), and propane (C3H8)) have been investigated numerically based on detailed chemical kinetics. Furthermore, a comprehensive investigation of the effects of hydrogen (H2) and inert gas (N2, CO2) addition on the explosive properties of natural gas has been carried out. The results indicate that the C3H8 components have a dominant effect on the explosion limits of natural gas. The addition of high-hydrocarbons in natural gas can significantly reduce the auto-ignition temperature, shorten the ignition delay time, and enhance the explosion risk of the mixture. Furthermore, the negative temperature coefficient (NTC) response of natural gas in the second explosion limit gradually disappears, and changes to the Z-curve response with the addition of H2. However, the explosion tendency of the mixture is reduced with the addition of H2 under normal to high-pressure conditions. In addition, with the increase of inert gas (N2, CO2), the explosion limits of the mixtures shift upwards to a higher-pressure region, which significantly reduces the explosion tendency. Nevertheless, the explosion propensity of the mixture increases significantly under low-pressure conditions when the mixture contains hydrogen. To elucidate the critical control reactions and determine their synergistic effects, sensitivity analyses under different conditions are performed. Finally, the interaction of different fuels in natural gas mixtures is further summarized by analyzing the explosion limits of single-component, binary-component, and multi-component mixtures of hydrogen to propane. This paper provides an important guidance for the development of natural gas with high safety, low risk, and low pollution.

Experimental research on self-initiation process of rotating detonation wave by high-temperature ethylene-rich gas

This study investigates an experimental process of high-temperature ethylene-rich gas and air for rotating detonation. After abandoning the pre-detonator method, the high-temperature ethylene-rich gas was injected and collided with the outer wall to create a localized high temperature and pressure region that ignited the gas mixture to form the deflagration state. Whether it is a single deflagration flame or double deflagration flame, it is eventually transformed through the deflagration-to-detonation transition (DDT) process into a double detonation wave. With propagation and collision of the double waves, the injection pressure increases, which results in shortening the self-initiation delay time. The equivalence ratio, gas temperature, and mass flow rate affect the success ratio of self-initiation. Rotating detonation engine (RDE) can be successfully initiated in the equivalence ratio range of 0.82 to 1.69. Equivalence ratio and gas temperature increase the propagation velocity of rotating detonation wave (RDW), for maximum RDW velocity of 1324.61 m/s, the gas temperature is 1021.3 °C. At the double wave collision point, a new weak RDW appears that decreases the RDE operating stability and a periodic quenching and re-initiation of RDW phenomenon occurs at that point.

Large-eddy simulation of unsteady flows past a spiked body

Unsteady flows past a spiked body are investigated numerically with wall-resolved large-eddy simulation (LES). The inflow features a Mach number of Ma=2.21 and a Reynolds number of Re=1.2×105. The ratio of the spike length to the blunt body diameter is L/D=1.0. A comparative study of three meshes of different grid resolutions has been conducted by assessing their predictive accuracies and associated subgrid-scale effects. The LES results obtained based on three meshes are compared with the experimental and numerical data found in the literature. A proper orthogonal decomposition (POD) analysis has been conducted based on the pressure and axial velocity fluctuations to investigate turbulence structures. It is observed that the turbulence structures corresponding to the first four POD modes are the most energetic. Furthermore, it is seen that the dominant recirculation zone along the spike in a pulsation cycle can be reconstructed based on the first two POD modes of axial velocity fluctuations. The physical mechanisms of the collapse and inflation processes of the pulsation cycle are investigated based on a detailed transient analysis of fine-resolution LES data. The temporal evolution of vortices and shock waves are investigated. An interesting characteristic Z-shaped trajectory of the instantaneous flow pattern is observed. It is discovered that the pulsation cycle is dominated by the pressure differences between the recirculation zone and two high-pressure regions immediately in front of the cylinder face and near the spike tip.

Flow Topology of a Slanted Cylinder with Rounded-Edges Under Compressible Conditions

In this study, the slanted afterbody was modified to more closely represent cargo aircraft afterbodies through the addition of a basal edge fillet. Two slant angles ( and ) were explored over two Mach numbers ( and ) and two Reynolds numbers ( and ) using oil flow visualization and pressure-sensitive paint to identify surface flow phenomena, while the spanwise shadowgraph enabled the observation of mean wake phenomena. The rounded-edge afterbody surface measurements displayed a centerline-separated vortex state with flow features and regions of suction qualitatively similar to those of the baseline sharp-edge case, with some notable differences. For example, a separation bubble at the slant leading edge is nearly twice the size of the baseline sharp-edge model. This is accompanied by the presence of a “source point,” indicated by a region of high pressure where the flow reattaches, and a tighter counter-rotating vortex pair in comparison to the baseline. The rounded-edge prevented the previously seen compressible transition to a fully separated wake state within the Mach number range studied while showing an increase in separation bubble size with increasing Mach number. Also noteworthy was the existence of a new vortex state for the model, where the flow remains attached at the model centerline. This is in contrast to the previously observed flow topology of the centerline-separated vortex state in the sharp-edge model, which formed a separation bubble at the model centerline. The transition between the new centerline-attached vortex state and the traditional centerline-separated vortex state was shown to be dependent on both Mach number and Reynolds number, revealing the importance of boundary-layer development on the rounded afterbody flowfield. Overall, these observations indicate that the rounded afterbody produces flowfields with distinct features that vary from the previously described sharp-edge afterbody wake field under certain conditions.

Numerical study on the design of multi-staged, opposing pulsed-jet cleaning (M-OPJC) for pleated filter cartridges

Opposing pulsed-jet cleaning (OPJC) has recently been proposed as a method to improve the filtration media regeneration of pleated filter cartridges, specifically addressing the patchy cleaning issue typically encountered in conventional pulsed jet cleaning. In this study, we first investigate the effect of pressure ratio (PR, the ratio of pressures at the opposing nozzles) on the OPJC performance in terms of cleaning intensity, uniformity, comprehensive pressure, and cleaning efficiency for pleated filter cartridges. A new OPJC strategy, named multi-staged, opposing pulsed-jet cleaning (M-OPJC), is proposed to enable the movement of a high-pressure region (formed by the collision of the pulsed-jet airflows introduced from opposing nozzles) within the core of a filter cartridge during the cleaning. The M-OPJC divides one cleaning jet cycle into four jetting stages with different PR values. Among all the evaluated cases, the M-OPJC with PR = [1.00, 1.00, 1.33, 2.00] offers the best cleaning performance for a pleated filter cartridge. Compared to conventional pulsed-jet cleaning (i.e., M-OPJC with PR = [0, 0, 0, 0]), the M-OPJC method increased the peak pressure at the cartridge’s upper part by 325.93%, comprehensive pressure by 171.10%, and cleaning efficiency by 48.85%.

Controllable C2H2/CO2 inverse adsorption and separation in pillar-layered Zn-1,2,4-triazolate-dicarboxylate frameworks induced by the ligand aromaticity

Acetylene (C2H2) and carbon dioxide (CO2) both are linear molecules and the similarity in size and physical properties makes their separation very challenging. Compared to the C2H2-selective C2H2/CO2 separation, the inscrutable CO2-selective capture (also called inverse C2H2/CO2 separation) process is ideal as it enables one-step production of high-purity C2H2. Herein, we demonstrate the controllable C2H2/CO2 inverse adsorption and separation in a series of isomorphic Zn-1,2,4-triazolate-dicarboxylate pillar-layered frameworks (Zn-FA-TRZ, Zn-MUC-TRZ, and Zn-BDC-TRZ) based on the aromaticity modulation strategy. Compared with Zn-MUC-TRZ, the utilization of shorter FA linker only with one double bond leads to an intersection point between the isothermal adsorption curves. After the intersection points, Zn-FA-TRZ showed higher CO2 uptakes than C2H2 (thermodynamic inversion) and the intersection point moving towards the high-pressure region with the increasing temperature. When BDC involved, the enhanced ligand aromaticity enables a complete thermodynamic inversion for C2H2 and CO2 adsorption due to the much stronger interactions between the aromatic ring and CO2 molecules. The isosteric heats of adsorption for CO2 and C2H2 clearly support such inverse adsorption induced by the ligand aromaticity. Furthermore, the fixed-bed dynamic breakthrough experiments indicate that Zn-FA-TRZ and Zn-MUC-TRZ both have common C2H2-selective separation process, but Zn-BDC-TRZ adsorbent shows a prominent CO2-selective inverse C2H2/CO2 separation. Specially, with temperature increased, the inverse separation performance enhanced, and high purity C2H2 (>99.99 %) can be obtained via one-step separation from C2H2/CO2 (50/50) mixture at room temperature. Overall, inverse C2H2/CO2 separation was successfully achieved in pillar-layered metal–organic frameworks, which is helpful for the exploration of practical acetylene adsorbents.

Radiative heat transfer on the peristaltic flow of an electrically conducting nanofluid through wavy walls of a tapered channel

Present analysis deals with the characteristics of radiative heat on the peristaltic flow of nanofluid through wavy walls of a tapered channel. Peristaltic flows within the pumping process arise in the region having lower to higher pressure region. Assumption of velocity slip along with the convective boundary condition energizes the thermal system as well as the flow phenomena. However, the combined effect of Brownian motion and thermophorsis due to the cross-diffusion effect affects the flow properties. One of the significant applications of the flow is that the blood pumping in the human body. It acts as a vehicle through the liquid that past through the wavy channels walls contacting liquids expands in its length due to the dynamical rush. However, solution of the transformed governing flow phenomena is obtained by employing approximate analytical technique known as Variation Parameter Method (VPM). The characteristics of the parameters involved in the system are presented via graphs. Present outcome warrants that, the significance of magnetic strength and flow through the permeable medium may favours to enhance the pumping procedure as the pressure gradient lower down in the non-Darcy medium found to be one of the important observations. Further, significant enhancement in the fluid temperature and concentration profile is exhibited due to the consideration of the convective conditions i.e. the augmentation in the thermal and solutalBiot numbers respectively.