Bidirectional Pumping Research Articles

Numerical simulation and experimental study of energy dissipation in a bidirectional axial extended tubular pump with different blade angles

Numerical simulation and experimental study of energy dissipation in a bidirectional axial extended tubular pump with different blade angles

A biparametric analysis on the steady performance of bidirectional pumping hydrodynamic-static hybrid dry gas seal

Purpose The purpose of this paper is to obtain the matching relationship between spiral groove, equalizing groove and operation parameters through the biparametric analysis for the bidirectional pumping hydrodynamic-static hybrid dry gas seal (BP-HHDGS). Design/methodology/approach The large eddy simulation (LES) model in Fluent is used to simulate the flow field of BP-HHDGS, and the biparameter variables method is chosen to analyze the effects of different parameters on the performance of BP-HHDGS. Findings BP-HHDGS has a greater opening force than hydrostatic dry gas seal (HDGS); the vortex is formed after lubricating gas is exhausted from the throttle. Increasing the depth of the equalizing groove and spiral groove has a synergistic enhancement effect on the opening force and leakage of BP-HHDGS. There is a matching relationship between spiral angle and rotational speed. The preferred parameter ranges in current conditions are found as follows: spiral angle αa = 15°–24°; groove-dam ratio λ = 0.4–0.7; equalizing groove depth hj > 35 µm; spiral groove depth hg = 5-10 µm. Originality/value The high starting capacity of HDGS is given to the hydrodynamic type seal, and thus the application promotion of HDGS in high-speed working condition is realized at the same time. This work also provides precise and quick theoretical guidance for the selection and design of hydrodynamic-static dry gas seal and further promotion.

Substrate-Controlled Bidirectional Pumping by a Bienzymatic Micropump.

The development of autonomous, miniaturized pumps remains a problem of much interest, particularly with a view on microfluidics-based devices with increased portability and simplicity of use by nonspecialists. Spatially localized patches of enzyme imprinted on walls have been shown to induce a hydrodynamic flow when supplied with the corresponding enzyme substrate. Thus, such enzymatic micropumps are seen as a possible way of providing the means for nonmechanical, structurally simple, autonomous pumping. Hereby, we extend the current knowledge of enzymatic micropumps in two ways. First, we introduce β-glucosidase as an enzyme that facilitates building micropumps with robust inward flows in the presence of cellobiose (e.g., 2.51 ± 0.56 μm s-1 in the presence of 80 mM cellobiose). Second, we embed β-glucosidase and urease within the same patch and thus obtain a bienzymatic micropump. The latter exhibits the so far missing capability of bidirectional pumping as it produces inward flows in the presence of cellobiose (e.g., 0.95 ± 0.37 μm s-1 in the presence of 20 mM cellobiose) and outward flows in the presence of urea (e.g., 1.46 ± 0.47 μm s-1 in the presence of 20 mM urea). This bienzymatic micropump is a significant step for the development of biocompatible micropumps with versatile, controlled, and on-demand hydrodynamic pumping capabilities.

Collaboration to Remove Barriers to Pump Integration With the Electronic Health Record.

The Institute for Safe Medication Practices and The Joint Commission recommend the implementation of bidirectional smart infusion pump interoperability with the electronic health record (EHR) to improve medication safety. However, there are barriers associated with implementation of this process. The purpose of this process improvement project was to identify, evaluate, and implement improvements in pump integration with the EHR to decrease manual programming and increase the use of the smart pump functions (the dose error reduction system or infusion guardrails). A medication safety task force was formed, and end users were surveyed for barriers. The task force found and implemented solutions to improve the process. Infusion pump integration rates for seven hospitals improved from 79.4% to 91.8% (p < .001), and the use of smart pump programming increased from 84.7% to 93.6%. Including all stakeholders in the project allowed barriers to be identified and solutions to be implemented. As more healthcare systems implement technology-related processes to improve patient safety, this work can guide medication safety teams on how to optimize technology use by removing barriers to the use of pump integration with the EHR.

C + L-band tunable sub-kHz linewidth single frequency fiber laser by combining a fiber sub-ring with a saturable absorber

A sub-kHz linewidth single-frequency fiber laser that can be tuned in the full range of C + L band is proposed and experimentally demonstrated. A broad band gain fiber by bidirectional pumping combining with a wide tunable filter is used to realize 75.87 nm tuning range from 1529.98 to 1605.85 nm, which can be further improved if a wider tunable filter is available. To achieve single-frequency ultra-narrow linewidth laser operation, a ring-cavity laser configuration with a fiber sub-ring and a saturable absorber is utilized. The measured optical signal-to-noise ratio (OSNR) of the fiber laser is over 80 dB, the side mode suppression ratio (SMSR) can be improved to ∼60 dB, and the linewidth can be narrowed to ∼453 Hz. The output power of the laser exceeds 28 mW, and the slope efficiency is 2.05 %. This proposed fiber laser has the advantages of narrow linewidth, excellent wavelength tunability, and high output power, which is promising for the applications in optical sensing and optical communication systems.

Analysis of the influence of different support types on the operation performance of bidirectional shaft tubular pump

Abstract Because of the particularity of the pump’s bidirectional operation, and the difference of the flow channels on both sides of the pump. The device has a mature impeller and guide vane combination when it is running forward. And when the device runs in reverse, the support on the shaft side acts as the rear guide vane of the impeller, which has great influence on the performance of the device. However, due to the few operating conditions in reverse operation, the importance of support is often ignored. In this paper, the influence of different support types on the bidirectional flow pattern and performance of the device is analyzed by numerical simulation. The results indicate that by optimizing the variation trend of the edge arc radius of the supporting baffle section, it is possible to effectively control the section with poor flow distribution, thereby reducing hydraulic losses. The support adopts three partitions arranged at an interval of 120°, which has little difference in performance during forward operation compared with other schemes. But during reverse operation, it reduces the impact and friction losses of water flow. And it fully utilizes the direct guide vane function of recovering vorticity, resulting in a significant increase in efficiency. At the same time, the accuracy of numerical simulation results is verified by model tests. The stability of positive and negative operating pressure pulsation supporting the inlet and outlet under the optimal scheme is analyzed.

Electronically actuated artificial hinged cilia for efficient bidirectional pumping.

Cilial pumping is a potent mechanism used to control and manipulate fluids on microscales. Recently, we introduced an electronically driven μ-cilial platform that can create arbitrary flow patterns in liquids near a surface with the potential for various engineering applications. This μ-cilial platform, however, utilized the coupling between elasticity and viscous drag to obtain pumping and had several limitations. For example, each cilium could only pump in one direction. Thus, to create bidirectional flows, it was necessary to fabricate and separately actuate two oppositely facing cilia. As another example, the generation of non-reciprocal cilial motions, a necessary condition for pumping at these scales, could only be achieved by matching the elastic stresses inherent in actuating the cilia with the viscous drag forces generated by the flows. This criterion severely restricted the frequency range over which the cilia could be operated and resulted in a small swept area, both of which restricted the volume of fluid being pumped in each cycle. These limitations contrast with the capabilities of natural cilia, which can achieve omnidirectional transport and operation over a broad range of frequencies. In natural cilia, these capabilities arise from their complex internal structure. Inspired by this strategy we designed hinged cilia and show they can achieve bidirectional pumping of larger fluid volumes over a broad range of frequencies. Finally, we demonstrate that even regular arrays of individually controlled hinged cilia can generate a variety of flow patterns using fewer cilia than in previous cilia metasurface designs.

Mxene-supported NbVH nanoparticles as efficient catalysts for reversible hydrogen storage in magnesium borohydride

Bimetallic niobium vanadium hydride nanoparticles (NbVH NPs) anchored on Ti3C2 were synthesized using a facile ball milling method as an effective catalyst for the dehydrogenation kinetics and reversibility of Mg(BH4)2. It was found that the onset dehydrogenation temperature of the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite was 105.7 °C and released 9.07 wt% of hydrogen at 330 °C, while undoped Mg(BH4)2 only released 4.2 wt% of H2 from 248 °C to 330 °C. Additionally, the Mg(BH4)2 + 30NbVH NPs@Ti3C2 composite achieved remarkable hydrogen release of over 9.44 wt% at a temperature as low as 230 °C, indicating unexpected dehydrogenation kinetics. In the reversible hydrogen desorption tests, Mg(BH4)2 + 30NbVH NPs@Ti3C2 released 5.98 wt% of H2 in the 2nd cycle at 250 °C and maintained a reversible capacity of 4.35 wt% after 10 cycles, demonstrating a remarkable enhancement in reversibility. The enhancement in the dehydrogenation kinetics of Mg(BH4)2 could be attributed to the greatly reduced activation energies from 343 kJ·mol−1 and 138.3 kJ·mol−1 to 103.7 kJ·mol−1 and 124 kJ·mol−1. Investigations on the evaluation of catalyst and Mg(BH4)2 during reversible hydrogen storage have revealed that NbVH NPs actually acted as a “bidirectional hydrogen pump”, facilitating both the hydrogen release and uptake from Mg(BH4)2. This strategy of multi-component hydrides may show a new way to design effective catalysts for solid-state hydrogen storage materials.

Acoustics-driven multifunctional microreactor bioinspired by Phylum Porifera for bidirectional pumping and mixing production of silica nanofluids

The Phylum Porifera is one of the most primitive multicellular animals without a mouth, digestive cavity, or central nervous system. Its pores are strewn with flagella inside. Phylum Porifera wiggles its flagella to inhale the seawater, which brings in oxygen, bacteria, microscopic algae, and other organic debris to feed on. Inspired by this natural system, a microreactor based on sharp-edge has been developed and applied in microfluidics to achieve bidirectional pumping and mixing. Here we demonstrate a multifunctional microreactor for bidirectional pumping and mixing that mimics the internal flagella of the Phylum Porifera. The microreactor is designed based on microscale nonlinear acoustics to achieve functionalities via the acoustic streaming generated by the vibration of sharp-edge under the acoustic field. Numerical simulation is conducted to investigate the effect of sharp-edge numbers, dip angles, spreading angles, spacing of sharp-edges, and channel width on the pumping performance. And the bidirectional pumping is verified by experiments. Similarly, numerical simulation and experimental validation are conducted to investigate the effect of flow rate, amplitude, and sharp-edge density on mixing performance. Finally, to verify the application potential and good mixing performance of the developed microreactor, silica nanofluids were synthesized with excellent stability and uniform particle size distribution. These results not only provide important guidelines for the rational design of functional nanomaterials, but also shed new light on the development of efficient microreactors.

Research of the Meshing Performance of New Concave-convex Ball Teeth

Aiming at the limitations of the existing hydraulic pumps, a new type of bidirectional water-hydraulic internal ball gear pump using concave-convex ball teeth meshing to transfer power is proposed. In this paper, the principle of internal gear pump is utilized to establish the model of internal ball gear pump, and its mechanical properties and dynamic meshing characteristics are numerically investigated by using the finite element method. The results show that (a) the concave-convex ball gears run smoothly without any interference, and (b) increasing the number of gear rows can effectively reduce the maximum stress and meshing impact under a given load and speed. This study provides a basis for the development of high-performance ball gear pumps.

High gain and low noise O+E bands fiber amplification based on hybrid bismuth-doped fiber

In this paper, we propose and demonstrate a hybrid bismuth-doped fiber approach for broadband amplification in the O + E bands. The bismuth-doped fibers were fabricated by the MCVD process combined with solution doping technique. The amplification performance was investigated by the two pump wavelengths of 1240 nm and 1270 nm combined with different pump configurations. The results show that the maximum gain of 38.2 dB with the NF of 3.7 dB was achieved at 1350 nm by the bi-directional pumping configuration. Furthermore, the hybrid bismuth-doped fiber was demonstrated to improve the gain in E-band and maintain the gain flatness between O-band and E-band. A wide bandwidth of ∼150 nm (1310 nm–1460 nm) was achieved by the hybrid fiber, with a gain >15 dB, gain flatness of 8 dB, and NF of 4.1 dB–5.7 dB.

High on-chip gain spiral Al2O3:Er3+ waveguide amplifiers

We demonstrate reactively sputtered Al2O3:Er3+ waveguide amplifiers with an erbium concentration of 3.9 × 1020 ions/cm3, capable of achieving over 30 dB small signal net gain at 1532 nm using bidirectional pumping at 1480 nm. We observe on chip output powers of 10.2-13.6 dBm of amplified signal power at 1532 nm for a 12.9 cm waveguide amplifier considering -25.4 dB of lumped coupling losses per facet. Annealing was used to improve the performance of the devices, which were patterned using electron beam lithography and reactive ion etching. This result, to our knowledge, represents record breaking on-chip internal net gain for Al2O3:Er3+ waveguide amplifiers, which show promise over other technologies due to wafer scalability and promise of easy monolithic integration with other material platforms to support a wide variety of applications.

Pair induced quenching in high concentration Holmium-doped fiber amplifiers

The spectrum required for future optical communication systems is being extended towards the C-, L- and U-bands, resulting in a significant interest in the spectral region around 2 μm wavelength. Since Holmium doped fiber amplifiers (HDFAs) provide amplification in this spectral region, they have become a focus of researchers working on doped fiber amplifiers. A major factor resulting in the performance degradation of HDFAs is the inhomogeneous energy transfer within Ho3+ ion-pairs in high-concentration Holmium-doped fibers (HDFs), an effect generally known as pair-induced quenching (PIQ). In this paper, we study the luminal and temporal dynamics of pulses of different repetition rates at 2.05 μm in high-concentration HDFs considering the effects of ion-pairs. Input pulses having repetition rates of 25 GHz and 500 kHz are generated using wavelength tunable actively mode-locked Holmium-doped fiber laser (AML-HDFL) based on a single ring cavity and bidirectional pumping. The characteristics of the pulses propagating through high-concentration HDF are analyzed based on different metrics such as average power, peak power, pulse energy, full-width at half maximum (FWHM), and time delay without and with ion-pairs for values of fraction of ion-pairs k = 0 and k = 10%, respectively. The results obtained at optimized length of HDF show that ion-pairs significantly degrade the average power, peak power, and energy of the output pulses for both of the repetition rates. For both k = 0 and k = 10%, the FWHM and shape of the output pulses remain same in the presence of the ion-pairs while, time delay of 4 ps and 19 ns is observed in the output pulses at repetition rates of 25 GHz and 500 kHz, respectively. The effects of increasing the pump and signal power on the average power and energy of the output pulses for k = 0 and k = 10% are also discussed for both repetition rates. This analysis provides important guidelines for designers of 2 μm fiber lasers and amplifiers based on high-concentration HDFs.

Dense wavelength division multiplexing scheme based on effective distributed inline light fiber Raman amplifier configuration

Abstract This paper demonstrated the dense wavelength division multiplexing scheme based on effective distributed inline light fiber Raman amplifier configuration. Various forward/backward and bidirectional pumping power configurations are studied versus fiber reach. Output light signal power is demonstrated against fiber reach without Raman amplification technique. Output light signal power in the forward Raman amplification scheme is clarified with pumping power of both 500 mW and 700 mW in various fiber channel configurations. As well as output light signal power in the backward Raman amplification scheme with pumping power of both 500 mW and 700 mW in various fiber channel configurations. Amplification Raman gain parameter coefficient is demonstrated with various values of pumping power pump based on various fiber channel configurations. Backward amplification net parameter gain is studied for different single mode/true wave/freelight fibers channel configuration at different both pumping power values and fiber reach. As well as the forward amplification net parameter gain is clarified for different single mode/true wave/freelight fibers channel configuration at different both pumping power values and fiber reach.

OSNR enhancement of Rayleigh-assisted Brillouin-Raman fiber laser via double pass configuration.

We propose and demonstrate a 10 GHz spacing multi-wavelength Brillouin-Raman fiber laser (MBRFL) with wide bandwidth and an outstanding optical signal-to-noise ratio (OSNR). This is achieved by utilizing loop mirror at one end of the laser cavity through a symmetrical bi-directional Raman pumping scheme. The setup is arranged in a double pass configuration by employing different lengths of dispersion compensating fibers (DCF). The attainment of MBRFL with outstanding performance necessitates the optimization of Raman pump power, Brillouin pump wavelength, and DCF length. By employing an 11 km DCF, when setting the Brillouin pump wavelength at 1531.4 nm, 504 Stoke lines are produced with a channel spacing of 0.08 nm. All the counted laser lines have less than a 1-dB peak amplitude variation and are spread across a 40.4 nm bandwidth that covers from 1531.4 to 1571.8 nm wavelength. In this case, the Raman pump power is fixed at 900 mW which results in average OSNR and Stokes peak amplitude level of 28 dB and -7 dBm respectively. To date, this is the simplest cavity design with the widest bandwidth and flattest spectrum together with outstanding OSNR attained in 10 GHz spacing multi-wavelength fiber lasers that incorporate a single low-power Raman pump unit.

Simultaneous realization of high gain and low DMG of four-mode EDFA under bidirectional hybrid-mode pump.

We theoretically and experimentally verify that, the bidirectional hybrid-mode pumping scheme can address the optimization problem of trade-off between high gain and low differential modal gain (DMG) of four-mode erbium-doped fiber amplifier (4M-EDFA), in comparison with traditional both forward and backward hybrid-mode pumping scheme. It is noticed that, when the total pump power is fixed, the bidirectional hybrid-mode pumping scheme can not only achieve higher gain, but also suppress DMG due to different overlap integrals for the forward and backward pumping schemes. The bidirectional hybrid-mode pumped 4M-EDFA is developed with the forward pumping at LP02 mode and the backward pumping at LP21 mode, under a pump power ratio of 30%:70%. Thus, we can achieve an average gain of up to 21.16 dB and a low DMG of 0.43 dB at 1550 nm, and an average gain of up to 20.64 dB with a DMG of less than 1.6 dB over the C-band. In particular, the bidirectional hybrid-mode pumping scheme allows us to tailor the gain characteristics of the few-mode erbium-doped fiber amplifiers (FM-EDFAs), by adjusting the power ratio between forward and backward pumps.

Hydraulic performance improvement of a two-way pumping station through bell mouth shape design

A two-way pumping station is a specialized device that facilitates bidirectional water pumping and drainage. The pressure pulsation characteristics of two-way pumping stations have emerged as a prominent research focus in the field of hydraulic engineering. In this work, with the aim of systematically proposing optimization measures to ensure operational stability, a transient numerical simulation is conducted to elucidate the influence mechanism of the suspension height of the bell mouth (SHb) on the internal flow field and pressure pulsation of a two-way pumping station. High-precision experiments are performed to compare time-frequency domain characteristics under different SHb using a continuous wavelet transform (CWT). The findings indicate that an appropriate reduction in SHb effectively reduces unstable flow and pressure pulsation within the inlet conduit, consequently reducing the pressure pulsation of the impeller. With a reduction in SHb, the influx of low-velocity backflow into the bell mouth is prevented and the generation and propagation of suction vortices are suppressed. However, the reduction amplifies the flow impact between the mainstream flow and the bell mouth wall. The spatial distribution of the pressure pulsation is also examined, and it is found that a reduction in SHb increases the pressure pulsation intensity on the side facing the incoming flow and on the rear side, while the mainstream area tends to exhibit stability. In terms of time-frequency domain characteristics, a reasonable reduction in SHb leads to improved circumferential uniformity of the impeller inflow and the effective suppression of low-frequency disturbances.

Bandwidth extension to 1627 nm of over 20 dB gain in an erbium-doped silica fiber via two-photon absorption.

In this study, PbS/Er co-doped fibers (PEDFs) were fabricated by atomic layer deposition (ALD) combined with modified chemical vapor deposition (MCVD). A pumping scheme based on two-photon absorption at 1310 nm of PEDF is proposed for L + band amplification. Through the theoretical analysis, the local environment of Er3+ is changed due to the co-doping of PbS, which improves the two-photon absorption efficiency near 1300 nm. Compared with the 980 nm pump, the PEDFs excited by the 1310 nm pump show better amplification performance in the L + band. And in a bi-directional pumping system, PEDF achieves over 22 dB of gain in the whole L band. In particular, the bandwidth of over 20 dB gain was extended to 1627 nm with a noise figure as low as 4.9 dB. To the best of our knowledge, this is the first time that a high-gain bandwidth of L band amplification has been extended to 1627 nm. The results of unsaturated loss also show that PbS co-doping improves the two-photon absorption efficiency of PEDF to broaden the amplification bandwidth of L + band. These results demonstrate that an effective L + band amplification method is practically provided for future ultra-wideband optical communications.

Occupation-Dependent Particle Separation in One-Dimensional Non-Hermitian Lattices.

We unveil an exotic phenomenon arising from the intricate interplay between non-Hermiticity and many-body physics, namely, an occupation-dependent particle separation for hardcore bosons in a one-dimensional lattice driven by unidirectional non-Hermitian pumping. Taking hardcore bosons as an example, we find that a pair of particles occupying the same unit cell exhibit an opposite non-Hermitian pumping direction to that of unpaired ones occupying different unit cells. By turning on an intracell interaction, many-body eigenstates split in their real energies, forming separable clusters in the complex energy plane with either left-, right-, or bipolar-types of non-Hermitian skin effect (NHSE). The dependency of skin accumulating directions on particle occupation is further justified with local sublattice correlation and entanglement entropy of many-body eigenstates. Dynamically, this occupation-dependent NHSE manifests as uni- or bidirectional pumping for many-body initial states, allowing for spatially separating paired and unpaired particles. Our results unveil the possibility of designing and exploring novel non-Hermitian phases originated from particle nonconservation in subsystems (e.g., orbitals, sublattices, or spin species) and their spatial configurations.

Real-time imaging of standing-wave patterns in microresonators

Real-time characterization of microresonator dynamics is important for many applications. In particular, it is critical for near-field sensing and understanding light-matter interactions. Here, we report camera-facilitated imaging and analysis of standing wave patterns in optical ring resonators. The standing wave pattern is generated through bidirectional pumping of a microresonator, and the scattered light from the microresonator is collected by a short-wave infrared (SWIR) camera. The recorded scattering patterns are wavelength dependent, and the scattered intensity exhibits a linear relation with the circulating power within the microresonator. By modulating the relative phase between the two pump waves, we can control the generated standing waves' movements and characterize the resonator with the SWIR camera. The visualized standing wave enables subwavelength distance measurements of scattering targets with nanometer-level accuracy. This work opens broad avenues for applications in on-chip near-field (bio)sensing, real-time characterization of photonic integrated circuits, and backscattering control in telecom systems.