Injection Tube Research Articles

Orifice Flow Dynamics in a Rocket Injector as an Excitation Source of Injector-Driven Combustion Instabilities

To investigate a hypothesis of the orifice flow-induced instability in rocket engine thrust chambers, a single liquid oxygen (LOX) injector with an optically accessible orifice module was used for experiments, with water as a simulant for LOX. The unsteady pressure downstream of the orifice was measured using high-speed piezoelectric sensors under cavitating and non-cavitating intra-injector flow conditions. The cavitating orifice flows were directly visualized via backlight imaging with a high-speed camera through the optically accessible orifice module. Cavitation initiated at the cavitation number of 2.05, and the downstream bubble cloud formation started below 1.91. The unsteady pressure spectrum arising from cavitation comprises multiple peaks over a broad frequency range, which can cause low- and high-frequency instabilities. The dominant frequencies from cavitation decrease with increasing pressure drop, while the frequencies during non-cavitating flow increase. The non-cavitating orifice flow excites the second longitudinal acoustic mode of the injector tube. The acoustic mode excited by the non-cavitating flow becomes stronger when the pressure peak in the range of whistling phenomenon is close to the first longitudinal acoustic mode. In conclusion, the excitation mechanisms of the orifice-induced instability for the cavitating and non-cavitating flows were well identified, despite the limitations of water as a simulant for LOX.

Hodgkin lymphoma in the bone marrow aspirate of a young patient with human immunodeficiency virus.

Hodgkin lymphoma in the bone marrow aspirate of a young patient with human immunodeficiency virus.

Study on transient flow characteristics and measurement method for multi-point injection system of natural gas engine

This paper presents an innovative measurement method of injection characteristics for the multi-point injection (MPI) system of the natural gas engine. The gas injection rate of different nozzle structures can be obtained by measuring the change of gas pressure in the measurement chamber. Base on this, the gas injection characteristics and their variations under different nozzle structures were studied. The results show that, with the increase of injection pressure, the beginning injection moment hysteresis and the end injection moment advances. When the energizing time is less than 6 ms, the injection mass decreases with the increase of injection pressure, and the injection pressure becomes the dominant hindering factor affecting the increase of injection mass. Due to the circumferential open-hole injection tube structure can not directly use the axial momentum of the gas flow along the tube, the injection duration is longer than that of the straight-through injection tube structure.

Experimental Results for a Novel Flash Evaporation and Phase Separation System for Desalination of Sea Water

Abstract A novel system combining dynamic flash evaporation and vapor separation for desalination has been investigated in this work. The feed water passes through injection tubes which are connected to injector passages installed tangentially onto a separator tube. Flashing in the injection tubes is initiated from pressure drop due to friction and acceleration resulting in a two-phase mixture. Centrifugal force from tangential injection separates the two-phase mixture. In this compact system, vapor production and phase separation occur on the order of several milliseconds. Tap water and seawater were used as inlet feed water for the system. Thermal conversion efficiency to analyze the vapor production efficacy and phase separation efficiency to evaluate the purity of the condensate were investigated to evaluate the system. Thermal conversion and phase separation efficiencies up to 98% were obtained with the single stage system. Further improvement in purity of condensate was achieved with a two-stage system. In the two-stage system, the vapor captured along with some entrained droplets from the first stage was directed to a second set of injector passages connected in series to the first stage retrieval tube. With a two-stage system and seawater with salt concentration by mass of 2.5%, collected condensate with salt concentrations lower than 0.02% by mass was achieved, which is comparable to that of potable water. Thus, the novel dynamic flash evaporation and vapor separation system have been demonstrated to be very effective in producing potable water.

Establishment of a new horizontal casting device and evaluation system for characterizing the homogeneity of food soft matter solution

A non-destructive dynamic solution casting device with in-situ roundness calculation for evaluating the homogeneity of food soft matter solutions is designed. The Charge-Coupled Devices (CCD) camera takes pictures of solution casting while the roundness is calculated by image software. Homogeneous single-component solutions were casting on a horizontal casting disc. The optimal combination of device hardware was obtained as the overflow hole diameter of 4 mm, overflow hole depth of 2 mm, injection tube diameter of 2 mm and injection height of 8 mm. The volume of sample solution was determined as 50 mL, and the relative roundness error of casting solution could be controlled below 0.25% when casting on a 304 stainless steel disc polished by 7000 Cw sandpaper. Finally, solutions with different viscosities must be casting with casting tubes of different diameters was proved. This work provides fundamental information for future analyses of the compatibility of food soft matter solutions.

Improvement of a Closed Mixed Injection Tube to Prevent Accidental Opening to the Atmosphere of a Central Venous Catheter

【背景】中心静脈ルートに接続した三連型混注管（セーフタッチ®）が大気に開放された経験に基づき予防策を策定したので報告する．

Experimental investigation of non-equilibrium plasma-assisted ammonia flames using NH2* chemiluminescence and OH planar laser-induced fluorescence

This study investigates the effect of nano-second pulsed non-equilibrium plasma on ammonia combustion in a model gas turbine combustor using NH2* chemiluminescence and OH planar laser-induced fluorescence (PLIF). Nano-second pulsed plasma discharge is generated at the exit of the premixed ammonia/air mixture injection tube. Broadband chemiluminescence observation shows that plasma can improve the stabilization of ammonia/air flame and extend the attached flame regime to a lower equivalence ratio. To understand the coupling effect between plasma kinetics and flame dynamics, NH2* chemiluminescence and OH PLIF of ammonia/air flames are measured at different conditions. With the increase of discharge voltage or discharge power, both NH2* chemiluminescence intensity and OH PLIF signal intensity increase, and this observation may explain the improved stabilization of ammonia flames. At very lean condition (equivalence ratio between 0.48 and 0.57, no visible flame existed), both NH2* chemiluminescence and OH PLIF signal are observed in the proximity of electrode region with plasma activation. If air is replaced by pure nitrogen (N2), NH2* chemiluminescence is measurable but extremely weak. As the oxygen (O2) concentration in the oxidizer stream gradually increases, NH2* chemiluminescence intensity increases linearly with O2 concentration under plasma activation. This finding indicates that the NH2* production in plasma-assisted ammonia oxidation process is possibly related to the production of OH or oxygen-related species. The direct electron impact on NH2* production might be secondary.

Hydrodynamic characteristics of a pilot-scale gas-driven inverse liquid-solid fluidized bed with a central draft tube

A new pilot-scale gas-driven inverse liquid-solid fluidized bed with a central draft tube (GDFB-II) was studied. With gas bubbles rising through the draft tube and enabling an upflow liquid, the associated liquid downflow fluidizes light particles downwards in the main column, forming a GDFB. Hydrodynamic characteristics of the GDFB-II were carefully studied using particles of different diameters and densities. Three flow regimes including packed bed, fluidized bed, and circulating bed regimes were identified and these regimes were demarcated by the initial fluidization gas velocity (Ug,if) and the minimum circulating gas velocity (Ug,mc). Ug,if and Ug,mc increase with the increase of particle diameter or the decrease of particle density. The effects of the draft tube diameter and the gas injection tube diameter on Ug,if and Ug,mc were also investigated. As the superficial gas velocity increases, the particle bed height increases first and then plateaus, while the average solids holdup decreases rapidly first and then remains constant.

A Facile Single-Phase-Fluid-Driven Bubble Microfluidic Generator for Potential Detection of Viruses Suspended in Air.

Microfluidics devices have widely been employed to prepare monodispersed microbubbles/droplets, which have promising applications in biomedical engineering, biosensor detection, drug delivery, etc. However, the current reported microfluidic devices need to control at least two-phase fluids to make microbubbles/droplets. Additionally, it seems to be difficult to make monodispersed microbubbles from the ambient air using currently reported microfluidic structures. Here, we present a facile approach to making monodispersed microbubbles directly from the ambient air by driving single-phase fluid. The reported single-phase-fluid microfluidic (SPFM) device has a typical co-flow structure, while the adjacent space between the injection tube and the collection tube is open to the air. The flow condition inside the SPFM device was systematically studied. By adjusting the flow rate of the single-phase fluid, bubbles were generated, the sizes of which could be tuned precisely. This facile bubble generator may have significant potential as a detection sensor in detecting viruses in spread droplets or haze particles in ambient air.

Investigation of corrosion sequence in the overhead pipeline of H2S stripper column through CFD models

The corrosion mechanism of the overhead pipeline of the H2S stripper tower was studied by macro examination, metallography, SEM and EDS analysis. The primary reason for the corrosion is the unsuitable material selected for the inhibitor injection pipe. In a H2S + HCl + NH3 + H2O environment, first dew point corrosion occurs. Then oil and gas erosion corrosion causes the injection tube to perforate and break, which directly alters the flow pattern and temperature in the overhead pipeline. Eventually, the tube is broken by erosion and acid corrosion. A computational fluid dynamic tool has been used for the simulation of the multiple phases inside the corroded pipe. The numerical simulation proves our conclusion of the development of corrosion in multiple locations.

Effect of Residual Volume in a Three-way Stopper and a Syringe on Actual Dose of Radiopharmaceuticals: Effect of Different Three-way Stoppers and Washing

The purpose of this study were to evaluate the residual volume of radiopharmaceuticals in the three-way stopper and syringe used during radiopharmaceutical administration and the effect of washing. The three-way stoppers were a top injector tube, a top three-way stopper, and a Nipro three-way stopper with a needle. Sodium pertechnetate [99mTc] injection (99mTcO4-) was used to compare the residual volume of radiopharmaceuticals in the three-way stopper and syringe without and with washing. Clinically, 137 patients who underwent cerebral blood flow scintigraphy, dopamine transporter scintigraphy, and bone scintigraphy were included. N-isopropyl-p-[123I]iodoamphetamine (123I-IMP), 123I-N-ω-fluoropropyl-2β-carboxymethoxy-3β-(4-iodophenyl)nortropane (123I-FP-CIT), and 99mTc-methylene diphosphonate (99mTc-MDP) were used to compare the residual volume of radiopharmaceuticals in the three-way stopper and syringe without and with washing. The residual volume depended on the type of three-way stopper and radiopharmaceutical used. The residual volume could be reduced by washing, but the effect depended on the type of three-way stopper and radiopharmaceutical used. The residual volume of radiopharmaceuticals in three-way stoppers and syringes can be determined and subtracted to achieve more accurate dose control.

Research and application of water flooding injection and production technology after polymer flooding

For reservoir water flooding after polymer flooding injection points existing in the mining process of high temperature resistant performance is poor and multistage unlock difficulty, examination, and the sealing problems such as in-depth study and analysis, innovation to a new set of return to spit points injection points production technology, to produce more suitable sealing high voltage can be found on a variety of well conditions return to spit points a column technology, is helpful for better improvement points injection tube service life, At the same time, it can effectively solve the problem of clogging downhole concentric test and adjustment unit. Oilfield exploration into the follow-up after water flooding stage, the well will show the water fast, fast production decline, the characteristics of a return so often need to take back to spit on mining technology, but the technology has high pressure resistance and multistage unlock difficulty problem, makes the life of the mining process is shorter, so according to the technical problems existing in the in-depth study and analysis, The effective outcome measures are put forward to provide necessary technical support for reservoir benefit after polymer flooding.

Fast visible camera diagnostic for dual shattered pellet injections at KSTAR

Direct imaging from fast visible cameras can provide intuitive information for the detailed dynamics of a fusion plasma. Images with different toroidal positions help our understanding of the 3D structure of the plasma phenomena. Fast-Visible camera (FVC) system was installed in KSTAR to investigate the assimilation process during plasma disruptions induced by Shattered Pellet Injections (SPIs). Since these events are highly non-axisymmetric and good toroidal coverage and high spatial and temporal resolution is required, the field of view of each camera is oriented towards the injection tube of each of the two SPIs, which are located toroidally opposite to each other. To investigate fragment penetration and ablation using images from a FVC, all components of the system should be able to support a fast frame rate due to the speed of shattered fragments of several hundreds of meter per second. The KSTAR FVC system typically uses a complementary metal-oxide-semiconductor (CMOS) with 10,000 frame per second at a resolution of 832 × 600 pixel typically for SPI experiments and its maximum frame rate is up to 600,000 frames per second with 64 × 8 pixels resolution. A hybrid optical system that consists of 2.04 m long relay optics mounted in the viewport cassette and a 4.5 m long imaging fiber bundle secures sufficient distance to reduce the harmful effects on the sensitive fast camera from radiation, neutron impact, and strong magnetic field. This paper reports the installation of the FVC system on KSTAR is introduced and semi three-dimensional observations of disruption mitigation processes during SPIs.

Impact of non-symmetric confinement on the flame dynamics of a lean-premixed swirl flame

The impact of confinement on a turbulent lean premixed swirl flame is investigated using a finite-volume large-eddy simulation method to solve the compressible Navier-Stokes equations and a combined G-equation progress variable approach to model the flame. The geometry is an experimentally investigated burner by Moeck et al. [Combust. Flame, 159, 2650-2668 (2012)] in which a precessing vortex core (PVC) and a self-excited thermoacoustic instability occur. To analyze the effect of confinement on the M-shaped flame, three configurations are investigated, i.e., an unconfined configuration, a symmetric confined configuration, and a non-symmetric confined configuration. The symmetric confined configuration corresponds to the experimental burner and the numerical results are in good agreement with the measurements. The flow fields of the confined and unconfined configurations differ significantly due to a more pronounced PVC downstream of the injection tube in the confined configurations. The numerical results confirm experimental findings from the literature, i.e., the confinement defines the recirculation zones and the turbulence intensity of the swirling jets. Furthermore, the present results show that the limit-cycle amplitude of the thermoacoustic instability, which occurs in the confined configurations due to a resonant coupling of the flame with the acoustic quarter-wave mode of the combustion chamber, is significantly reduced in the non-symmetric confined configuration. The mode determined by a dynamic mode analysis (DMD) that describes the impact of the acoustic quarter-wave mode on the velocity field only occurs in the symmetric confined configuration. Consequently, a lower coupling of the acoustic oscillations due to the thermoacoustic instability with the flame is evident. The results emphasize the sensitivity of the thermoacoustic instabilities on the confinement configuration and indicate the dependence of their oscillation amplitudes on the location of the swirl flame in the combustion chamber.

Numerical investigation of inertial sphere impaction on a cylinder in subcritical flow

This study examined the accuracy of a Lagrangian scheme for simulating both the motion and wall impaction of neutrally buoyant inertial spheres (8.85 St 18.04) moving in the subcritical regime (Re = 10,972 and 22,366) of flows past a circular cylinder. The accuracy of the eddy-resolving simulations of the flow field was verified based on available data at nearly comparable flow conditions. The accuracy of the particle tracking scheme was verified with respect to corresponding experimental data in a laboratory flume. Particle dispersion en route to the circular cylinder is mostly driven by the flow disturbance from the particle injector tube. The trends in collision rates are largely explained by the rate of particle entertainment into the boundary layer around the cylinder and the inertial condition of the spheres in this proximity region—both of which can be better assessed by post-processing of the numerical outcomes. The primary incentive to undertake this work was the need for validating a particle-based method for quantifying the hydraulic stressors leading to bodily damage of fish passing flows influenced by hydraulic infrastructure.

Cross Platform Analysis of Volatile Organic Compounds Using Selected Ion Flow Tube and Proton-Transfer-Reaction Mass Spectrometry.

Volatile breath metabolites serve as potential disease biomarkers. Online mass spectrometry (MS) presents real-time quantification of breath volatile organic compounds (VOCs). The study aims to assess the relationship between two online analytical mass spectrometry techniques in the quantification of target breath metabolites: selected ion flow tube mass spectrometry (SIFT-MS) and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). The two following techniques were employed: (i) direct injection with bag sampling using SIFT-MS and PTR-ToF-MS and (ii) direct injection and thermal desorption (TD) tube comparison using PTR-ToF-MS. The concentration of abundant breath metabolites, acetone and isoprene, demonstrated a strong positive linear correlation between both mass spectrometry techniques (r = 0.97, r = 0.89, respectively; p < 0.001) and between direct injection and TD tube (r = 0.97, r = 0.92, respectively; p < 0.001) breath sampling techniques. This was reflected for the majority of short chain fatty acids and alcohols tested (r > 0.80, p < 0.001). Analyte concentrations were notably higher with the direct injection of a sampling bag compared to the TD method. All metabolites produced a high degree of agreement in the detection range of VOCs between SIFT-MS and PTR-ToF-MS, with the majority of compounds falling within 95% of the limits of agreement with Bland-Altman analysis. The cross platform analysis of exhaled breath demonstrates strong positive correlation coefficients, linear regression, and agreement in target metabolite detection rates between both breath sampling techniques. The study demonstrates the transferability of using data outputs between SIFT-MS and PTR-ToF-MS. It supports the implementation of a TD platform in multi-site studies for breath biomarker research in order to facilitate sample transport between clinics and the laboratory.

Developments in the field of removable anchors

The design of inner-city building pits is a challenging task in geotechnical engineering. Due to rising property prices and the limited vacant plots in urban areas, the installation of building pit support measures is often constrained. Besides rigid systems, struts or anchors are often used to support such building pits. On the one hand, this support is required to come up with an economical design and on the other hand, it is necessary to keep the deformations of adjacent structures within certain limits. In this paper a new approach for the design and the (de-)installation process of removeable anchors is presented. By using a non-explosive cracking agent, a fully removeable anchor has been developed. Laboratory test results have shown, that by filling a pre-installed injection tube with the non-explosive cracking agent, a partial destruction of the grout body and consequently a reduction of the bond along the cement body and the steel tendon can be achieved. As a result, an extraction of the steel tendon is possible.

Modal properties diagnostics of the high-pressure fuel injection pipes in off-road diesel engine

Injection systems of modern commercial vehicle power units are still a frequent topic for development engineers in terms of durability and reliability. Therefore, the content of this study is just an investigation of the dynamic behaviour of high-pressure injection pipes of a four-cylinder combustion engine. The modal properties of the injection tubes are evaluated by experimental modal analysis (EMA). Another phase of the measurements is the sensing and analysing of the acceleration on each injection pipe during the engine speed ramp in the entire range of the speed spectrum. There was investigated the modal behaviour of the structure to the operational character of the excitation. The work includes a numerical model established by finite element method (FEM), where the boundary conditions correspond to the real installation of injection pipes from the measurement. The modal properties of injection pipes were primarily investigated through the numerical approach, several variants of pipe attachments were considered in simulations. Comparing the FEM results of different pipe attachments, the suitability of the clamp position with respect to the specific installation in the power unit from the measurement is discussed. From the evaluated results, it is possible to assume the dynamic behaviour of the high-pressure injection pipe in the power unit. Based on the performed analyses, the critical mode shapes of the injection pipes are described considering the engine operating condition. When the engine speed frequency and some pipe eigen frequency interfere together, it is undesirable state. In many cases, this leads to a crack initiation and subsequent damage of the injection pipes during the cyclic load. The presented results and conclusions in this study should improve the overall knowledge on high-pressure fuel pipes in terms of modal properties and its vibration behaviour during operating condition.

Fresh Produce Container Operated with a Routine of Hypobaric Application, CO2 Injection and Diffusion Tube Opening for Keeping Beneficial Modified Atmosphere

A concept of household container to create and keep the modified atmosphere (MA) beneficial for fresh produce mix was devised and tested under typical chilled storage conditions of 3°C. The container system containing mixed products is initialized by applying weak hypobaric condition (0.9 atm) and subsequently injecting CO2 gas at an appropriate low level (0.03 atm). The passive atmosphere modification by produce respiration is then induced to reach a target until gas diffusion tube of proper dimension starts to open. The design was made to attain quasi-steady state mass balance of O2, CO2 and N2 to maintain the desired MA through the storage. Interrupted opening for taking out or placing some products was to reinitialize the loop of control logic. The developed concept was tested by the container which held commodities of spinach, pak choi, oyster mushroom, peeled onion, strawberry and cut carrot. The target optimum MA of 11% O2 and 10% CO2 (0.11 and 0.10 atm, respectively) was set to avoid injurious range of O2 and CO2 concentrations for any commodities. The developed container system could work to reach and maintain beneficial MA of 0.10-0.12 atm O2 and 0.07-0.10 atm CO2 close to the target during the storage contributing to quality retention of products measured in weight loss, chlorophyll content of spinach, ascorbic acid content of pak choi, color of onion, texture of oyster mushroom, bacterial count of strawberry and carotenoids of carrot. The container system shows potential to improve current preservation practice of fresh produce mix on consumers’ level.

Study on the uniformity of water film in a transpiring wall reactor for supercritical water oxidation

AbstractA three‐dimensional computational fluid dynamic model of a transpiring wall reactor for supercritical water oxidation has been built to optimize the uniformity of water film. Results show that the temperature and species distributions at the nozzle outlet deviate from the reactor centre. The inner wall of the porous tube near the transpiring water injection tube displays low temperatures, while high temperatures are recorded far from the injection tube. The circumferential temperature distribution on the inner wall of the porous tube is uneven. This phenomenon is due to the uneven injection of the transpiring water, leading to the uneven protection of the water film and local overheating of the porous wall. The injection velocity of the transpiring water significantly decreases when the number of injection tubes is increased, and the circumferential velocity and temperature distributions on the porous wall gradually become even. Moreover, high pressure drops across the porous wall at low porosities are useful for the uniform injection of the transpiring water. This characteristic is also conducive to obtaining a more uniform water film protection.