High-pressure Liquid Injection Research Articles

Numerical simulation of control rod ejection velocity in a projectile rod accident based on STAR-CCM+

Abstract To simulate and analyze the control rod ejection time in the process of reactor bomb rod accidents, the design input of bomb rod accident safety analysis is made. In this study, STAR-CCM+ simulation software was used to simulate the pressure field and velocity field in the process of high temperature and high-pressure liquid injection after the CRDM pressure casing was broken, and the ejection time of the control rod under different lifting forces was obtained comprehensively. At the same time, the simulation results are compared with the theoretical calculation results. The pop-out time of the control rod is about 0.1 s. Therefore, the results calculated by the simulation model established in this study can be used as the design input for the safety analysis of the projectile rod accident.

High-pressure liquid refrigerant injection for reciprocating compressors

Isentropic (adiabatic) compression of superheated vapor in vapor compression refrigeration cycles usually results in some discharge superheat, i.e. the discharge temperature exceeding the condensing temperature. Large discharge superheat reduces both operating range and compression efficiency. Sub-isentropic compression with heat rejection to the heat sink is therefore superior to adiabatic compression, as it results in lower discharge superheat and improved efficiency. However, significant temperature reduction by heat transfer through the working chamber walls is difficult to facilitate in common refrigeration compressors, particularly reciprocating compressors. Refrigerant and oil injection is a well-established method for reducing temperatures and increasing efficiency in screw and scroll compressors, as well as multi-stage systems. In comparison, effective methods for temperature reduction in single-stage reciprocating compressors are fairly limited. Therefore, a concept for high-pressure liquid injection is proposed. By means of a pump and injection valve, high-pressure liquid refrigerant is injected into the working chamber and atomized. The compressed gas is cooled through the evaporation of the injected liquid. The injection valve allows for control over the injection timing and quantity, enabling adjustment of the temperature profile, which is a major distinction from existing refrigerant injection methods. The coupled compression-injection process is evaluated for various refrigerants using an energetic chamber model. The injection is found to be particularly suitable for refrigerants with a large evaporation heat and a shallow dew line slope. For the example of ammonia, a theoretical reduction in compression work of 8.9% at an evaporation temperature of −10 °C and a condensing temperature of 45 °C is found.

COMPUTATIONAL STUDY OF HIGH-PRESSURE LIQUID INJECTION PROCESS BY MEANS OF LES AND PANS APPROACHES

For internal combustion engine, the determination of combustion characteristics and subsequent emissions formation relies heavily on the fuel injection process. With the increasing demand for enhanced fuel efficiency and reduced emissions, it becomes vital to develop fundamental understanding of physical process involved in the fuel injection process. In this study, an optimal numerical approach to predict high pressure liquid injection process in the context of industrial computations has been investigated. In particular, this study focuses on the respective performance of the Partially-Averaged Navier-Stokes and Large Eddy Simulation models to predict turbulent igniting sprays. Both approaches are coupled with widely used Lagrangian Discrete Droplet Method for spray modelling. The results are validated against well established ECN Spray A case in reactive and non reactive conditions. For reacting conditions, Flamelet Genrated Manifold (FGM) combustion model is employed in the present work. Comparative study and validation against experimental data showed that PANS turbulence model allows for coarser grids while still maintaining accurate results.

Modeling and LES of high-pressure liquid injection under evaporating and non-evaporating conditions by a real fluid model and surface density approach

Numerical modeling of high-pressure liquid fuel injection remains a challenge in various applications. Indeed, experimental observations have shown that injected liquid fuel jet undergoes a continuous change of state from classical two-phase atomization and spray droplets evaporation to a dense-fluid mixing phenomenon depending on the ambient pressure, temperature, and fuel properties. Accordingly, a predictive and efficient computational fluid dynamics (CFD) model that can represent the possible coexistence of subcritical and supercritical regimes during the fuel injection event is required. The widely used Lagrangian Discrete Droplet Method (DDM) requires parameter tuning of model constants and cannot model the dense near-nozzle region. Meanwhile, the high computational cost of Interface Capturing Methods (ICM) has prohibited their application to industrial cases. Thus, another alternative is an Eulerian Diffuse Interface Model (DIM), where the unresolved interface features are modeled instead of being tracked. Accordingly, the current work proposes a fully compressible multi-component two-phase real-fluid model (RFM) with a diffused interface and closed by a thermodynamic equilibrium tabulation method based on a real-fluid equation of state. The RFM model is complemented with a postulated surface density equation for fuel atomization modeling within the Large Eddy Simulation (LES) framework. The Engine Combustion Network (ECN) Spray A injector non-evaporating and nominal evaporating conditions are used as a reference for the proposed model validation. Simulations are performed using the proposed RFM model that has been implemented in the CONVERGE CFD solver. Under the non-evaporating condition, the RFM model can capture well the fuel mass distribution in the near-nozzle field, but also the interfacial surface area. Besides, the predicted drop size from simulations falls within the experimental data range. On the other hand, under the evaporating condition, spray liquid and vapor penetrations and fuel mixture fraction distribution are also accurately predicted. The vaporization effect on the surface area density is revealed to enhance surface generation in the dense spray region while reducing the surface density in the dilute spray region. The mean droplet size is also relatively reduced under the evaporating condition in the diluted spray region. Overall, the accuracy and computationally efficiency of the proposed RFM model coupled with the surface density equation for high-pressure fuel injection modeling are confirmed, allowing its use for high pressure industrial configurations in future studies.

Clinical Evaluation of Sequential Transdermal Delivery of Vitamin B6, Compound Glycyrrhizin, Metronidazole, and Hyaluronic Acid Using Needle-Free Liquid Jet in Facial Seborrheic Dermatitis.

Facial seborrheic dermatitis (FSD) is a common facial inflammatory dermatitis. Needle-free transdermal jet injection (NTJI) is a non-invasive injection of drug solution by using a high-pressure liquid injection instrument. To explore a safer, more tolerable, and convenient medical way using NTJI in the treatment of FSD, the patients were treated with vitamin B6, glycyrrhizin compound, metronidazole, and hyaluronic acid sequentially using NTJI every 2 weeks, and only those treated for more than three times were included. A VISIA facial imaging system for the evaluation of erythema, superficial lipid level, and roughness of skin surface and a CK analyzer for biophysical parameters, including the stratum corneum hydration, facial surface lipid, and trans-epidermal water loss, were applied. Erythema was significantly reduced after every treatment (weeks 2, 4, and 6; P < 0.05), whereas superficial lipid level was not improved significantly until week 6 (P < 0.05), and roughness of the skin surface was not improved significantly during the whole treatment. The stratum corneum hydration of lesional skin was significantly increased after three times of treatment (P < 0.05). No observable adverse effect, such as marked erythema, blistering, or atrophy, was observed. Sequential transdermal delivery of small molecular weight drugs (vitamin B6, glycyrrhizin compound, metronidazole, and hyaluronic acid) using NTJI is a safe, low-toxicity, and take-home drug-free therapy for the treatment of FSD.

Electric Triggering for Enhanced Control of Droplet Generation.

Serial femtosecond crystallography (SFX) is a powerful technique that uses X-ray free-electron lasers (XFEL) to determine structures of biomolecular complexes. Specifically, it benefits the study of atomic resolution structures of large membrane protein complexes and time-resolved reactions with crystallography. One major drawback of SFX studies with XFELs is the consumption of large amounts of a protein crystal sample to collect a complete X-ray diffraction data set for high-resolution crystal structures. This increases the time and resources required for sample preparation and experimentation. The intrinsic pulsed nature of all current X-ray sources is a major reason why such large amounts of sample are required. Any crystal sample that is delivered in the path of the X-ray beam during its "off-time" is wasted. To address this large sample consumption issue, we developed a 3D printed microfluidic system with integrated metal electrodes for water-in-oil droplet generation to dynamically create and manipulate aqueous droplets. We demonstrate on-demand droplet generation using DC potentials and the ability to tune the frequency of droplet generation through the application of AC potentials. More importantly, to assist with the synchronization of droplets and XFEL pulses, we show that the device can induce a phase shift in the base droplet generation frequency. This novel approach to droplet generation has the potential to reduce sample waste by more than 95% for SFX experiments with XFELs performed with liquid jets and can operate under low- and high-pressure liquid injection systems.

Specifics of hydro-loosening of coal seams with account of rocks displacement parameters

The analysis of efficiency decline of methods for hydraulic influence on outburst-prone coal seams in the conditions of large depths is represented. The models are considered for parameters calculation of high-pressure liquid injection, based on the hypotheses of the stress-strain state formation of the coal seam; the patterns of rock pressure manifestation as well as calculation discrepancy between the liquid injection pressure and the terms of large depths, are established. It is shown that in the parameters calculation of the high-pressure liquid injection, it is necessary to take the height of the column of rocks which lost their integrity and form the stratification zone in the underworked massif instead of depth Н of the seam mining. It has been established that the efficiency of hydro-loosening depends not only on the injection pressure, but also on the location of borehole filtration part relative to the maximum of abutment zone.

Vorticity dynamics for transient high-pressure liquid injection

The liquid jet from a round orifice during the transient start-up and steady mass flux periods of a high pressure injector is studied via Navier-Stokes and level-set computations. Via post-processing, the role of vorticity dynamics is examined and shown to reveal crucial new insights. A brief review of relevant literature is made. An unsteady, axisymmetric full-jet case is solved. Then, a less computationally intensive case is studied with a segment of the jet core undergoing temporal instability; agreement with the full-jet calculation is satisfactory justifying the segment analysis for three-dimensional computation. The results for surface-shape development are in agreement with experimental observations and other three-dimensional computations; the initial, axisymmetric waves at the jet surface created by Kelvin-Helmholtz (KH) instability distort to cone shapes; next, three-dimensional character develops through an azimuthal instability that leads to the creation of streamwise vorticity, lobe shapes on the cones, and formation of liquid ligaments which extend from lobes on the cones. The cause of this azimuthal instability has been widely described as a Rayleigh-Taylor instability. However, additional and sometimes more important causes are identified here. Counter-rotating, streamwise vortices within and around the ligaments show a relationship in the instability behavior for jets flowing into like-density fluid; thus, density difference cannot explain fully the three-dimensional instability as previously suggested. Furthermore, the formation of ligaments that eventually break into droplets and the formation of streamwise vorticity are caused by the same vortical dynamics. Waviness is identified on the ligaments which should result in droplet formation. The nonlinear development of the shorter azimuthal waves and ligament waves explains the experimental results that droplet sizes are usually smaller than KH wavelengths. The higher the relative velocity and/or the lower the surface tension the shorter are the values of the most unstable wavelengths.

Non-equilibrium gas–liquid interface dynamics in high-pressure liquid injection systems

The transition of classical spray atomization processes to single-phase continuous dense-fluid mixing dynamics with diminished surface tension forces is poorly understood. Recently, a theory has been presented that established, based on a Knudsen-number criterion, that the development of such mixing layers is initiated because the multicomponent two-phase interface becomes much wider than the mean free molecular path. This shows that the transition to mixing layers occurs due to interfacial dynamics and not, as conventional wisdom had suggested, because the liquid phase has heated up to supercritical temperatures where surface tension forces diminish. In this paper we focus on the dynamics of this transition process, which still poses many fundamental questions. We show that such dynamics are dictated by substantial statistical fluctuations about the average interface molecule number and the presence of significant interfacial free energy forces. The comprehensive analysis is performed based on a combination of non-equilibrium mean-field thermodynamics and a detailed modified 32-term Benedict–Webb–Rubin mixture state equation. Statistical fluctuations are quantified using the generally accepted model of Poisson-distributions for variances in systems with a small number of molecules. Such fluctuations quantify the range of pressure and temperature conditions under which the gradual transition to dense-fluid mixing dynamics occurs. The interface begins to deteriorate as it broadens substantially. The related interfacial free energy forces do not instantly diminish only because vapor–liquid equilibrium conditions do not apply anymore. Instead, such forces along with the present interfacial statistical fluctuations are shown to gradually decrease as the interface transitions through the molecular chaos regime and to diminish once the interface enters the continuum regime. Then, the interfacial region becomes a continuous gas–liquid mixing layer with diminished free energy forces that is significantly affected by single-phase real-fluid thermodynamics and transport properties.

Innovations in high-pressure liquid injection technique for gas chromatography: pressurized liquid injection system.

In gas chromatography (GC), highly volatile liquefied hydrocarbons are commonly injected using devices such as high-pressure syringes, piston valves, liquid rotary sampling valves, or vaporizing regulators. Although these techniques are adequate in some cases, there are known deficiencies. A new generation of sampling valve has been recently innovated and commercialized. Some of the highlights of the pressurized liquid injection system (PLIS) include compact size, the capability to directly couple to an injection port without the need for preinjection vaporization and transfer lines, and sample sizes ranging from 0.2 to 2.0 micro L. Although the valve has a specification of helium leak-free rating of 82.7 bar (1200 psig), the valve passes a hydrostatic pressure test of up to 414 bar (6000 psig). In the unheated version of PLIS, vaporization of solutes occur mainly because of the sheering effect of carrier gas in combination with thermal energy drawn from an injection port or a heated adaptor. This was found to be adequate for solutes with high to medium volatility of up to nC14 hydrocarbon. A higher molecular weight range of up to nC44 hydrocarbon can be achieved with the implementation of a heated version of PLIS, in which the channel of the shaft can be resistively heated at a rate of up to 400 degrees C/s. With its first introduction in May 2002, PLIS has gained acceptance amongst practitioners in GC because it addresses a key unarticulated need in sample introduction/enrichment and by specifically targeting many deficiencies encountered in contemporary high-pressure injection devices. In this paper, the design and performance of the various valve systems of PLIS, as well as industrial chromatographic applications, is presented.

A multiphase model for compressible flows with interfaces, shocks, detonation waves and cavitation

A compressible multiphase unconditionally hyperbolic model is proposed. It is able to deal with a wide range of applications: interfaces between compressible materials, shock waves in condensed multiphase mixtures, homogeneous two-phase flows (bubbly and droplet flows) and cavitation in liquids. Here we focus on the generalization of the formulation to an arbitrary number of fluids, and to mass and energy transfers, and extend the associated Godunov method.We first detail the specific problems involved in the computation of thermodynamic interface variables when dealing with compressible materials separated by well-defined interfaces. We then address one of the major problems in the modelling of detonation waves in condensed energetic materials and propose a way to suppress the mixture equation of state. We then consider another problem of practical importance related to high-pressure liquid injection and associated cavitating flow. This problem involves the dynamic creation of interfaces. We show that the multiphase model is able to solve these very different problems using a unique formulation.We then develop the Godunov method for this model. We show how the non-conservative terms must be discretized in order to fulfil the interface conditions. Numerical resolution of interface conditions and partial equilibrium multiphase mixtures also requires the introduction of infinite relaxation terms. We propose a way to solve them in the context of an arbitrary number of fluids. This is of particular importance for the development of multimaterial reactive hydrocodes. We finally extend the discretization method in the multidimensional case, and show some results and validations of the model and method.

High Pressure Liquid Injection of Imidacloprid for the Control of Mole Cricket Nymphs, 1997

Abstract A field efficacy trial was performed to evaluate the timing and placement of imidacloprid (Merit 75 WP) applications for the control of mole cricket nymphs. Plots 16 ft X 70 ft were established on a heavily infested bermudagrass fairway at the Fox Squirrel Country Club in Brunswick Co, NC. Treatments were replicated four times and randomly assigned to the plots. The first insecticide treatments (egglay/hatch) were applied on 4 Jul. The 4-inch soil temperature on this date was 88°F. Air temperature was 93°F. Broadcast applications were made using a CO2-powered backpack sprayer delivering 30 gpa. Subsurface treatments were applied using a self-propelled SGI&amp;#x99; Subsurface Injection System to inject the liquid insecticide mixture to a depth of 1 inch using high-pressure (2800 psi) pulses. At this depth the equipment applies approximately 1.0 gal/100 ft2. Insecticides were injected every 4 inches in 4-inch strips to produce a 4-inch X 4-inch treatment pattern. According to the equipment’s designer, the insecticide spreads out below the soil surface into a circular treatment area approximately 1 inch in diam. The fairway irrigation system was used to apply 0.25 inch of water to the entire test site immediately after application. The same equipment was used again on 31 Jul to apply the subsurface treatment directed against early and midsize nymphs. Soil was moist at the time of application and the 4-inch soil temperature was 75°F. Soil at the test site was classified as a Kureb fine sand with a pH of 5.8 and 0.56% humic matter. Soapy water flush sampling of areas adjacent to the test indicate that the fairway population was approximately 85% SB and 15% SV. Plots were evaluated for fresh damage on 14, 20 Aug, and 10 Sep using the damage grid evaluation method of Mack and Cobb (1989). A m2 grid divided into nine subsections was placed randomly in each plot and a damage rating (0-9) given depending on the number of subsections in which fresh damage was observed. Five damage ratings were taken in each plot on each sampling date. Actual damage means are presented in the Table. All data were transformed x + 0.5 prior to ANOVA and Tukey’s Studentized Range Test.

Enhanced Efficacy of Isazophos Against Japanese Beetle (Coleoptera: Scarabaeidae) Grubs Using Subsurface Placement Technology

Two methods of subsurface placement technology, high-pressure liquid injection (HPLI) and an adapted overseeder (OS), were used to apply isazophos (Triumph) to golf course roughs that were infested with Japanese beetle ( Popillia japonica Newman) grubs. In every instance (five trials with an emulsifiable concentrate formulation, one trial with a granular formulation), isazophos applied subsurface at 1.1 or 0.6 kg (AI)/ha performed as well or better than isazophos applied conventionally on the surface at 2.2 k (AI)/ha. This apparent enhancement of efficacy of isazophos should provide turf managers with an alternative that can reduce the amount of insecticide on turf, at least under certain field conditions. In addition, irrigation after application on plots treated with HPLI appeared to be less critical to efficacy of isazophos than on plots treated conventionally.

Sub-Surface Vs. Conventional Application of Turcam for Control of Japanese Beetle Grubs on Golf Course Rough, 1991

Abstract An experiment using two methods of sub-surface application of pesticides was conducted on a golf course rough in Bolton, MA. The rough consisted primarily of Kentucky bluegrass (50%), perennial ryegrass (30%), and annual bluegrass (20%), and was maintained at a mowing height of 5.0 cm until 3 d before application. At that time the turf was mowed to 1.9 cm and clippings removed. Thatch remaining averaged 1.9 cm with a moderate density. Insecticides were applied on 5 Sep to 1.7 × 4 m plots arranged in a complete randomized block design. Each plot was separated from the next by 0.3 m, and there was a 3 m border between replications. Conditions at the time of application were as follows: air temperature 25°C; general overcast with high humidity; soil type, silty loam; soil moisture moderate; soil pH, 6.5; water pH, 6.4. Liquid treatments were applied using a High Pressure Liquid Injection (HPLI) research unit (built by Cross Equipment Co., Albany, GA), delivering 1,650 PSI through nozzles at 7.5 cm spacing, 1000 liters/ha, 5.6 kmph or with a watering can, using 3 liters water per plot. Granules were applied using a Cushman overseeder prototype, delivering granules through slices cut 1.9 cm (soil/thatch interface) with 5 cm spacing between slices or with hand-held shakers with perforated lids. All plots were watered in with 0.6 cm irrigation immediately after application and an additional 0.6 cm 12 h after application. Product efficacy was evaluated 28 DAT (4 Oct) by cutting two 0.1 m2 samples out of each plot, dislodging soil with a hand trowel, and counting all grubs to a depth of 10 cm.

Improvements in sample introduction for mass spectrometry using pulsed high-pressure fluid injection with resonant two-photon ionization detection

Pulsed supercritical fluid and pulsed high-pressure liquid injection are used as means of introducing thermally labile biological species into a time-of-flight mass spectrometer (TOFMS) system. The analyte species are then ionized by resonant two-photon ionization, which can produce either soft ionization or extensive fragmentation on the basis of laser power and wavelength. Since the solvent is transparent to the laser radiation, hard ionization can be produced without physical separation of the analyte from the effluent jet expansion. In addition, the pulsed liquid injection method allows introduction of the sample from high-pressure fluids at relatively low temperatures without the extensive clustering that normally occurs in liquid expansions unless a much higher temperature is utilized. Using this method, we have been able to study the laser-induced ionization mass spectrometry of several classes of small polar biological molecules in a TOFMS.

Pulsed High-Pressure Liquid Injection of Biological Molecules into Supersonic Beam/Mass Spectrometry with Resonant Two-Photon Ionization Detection

Pulsed high-pressure liquid injection is used as a means of introducing thermally labile biological species into a time-of-flight mass spectrometer (TOFMS) system. The analyte species are then ionized by resonant two-photon ionization (R2PI) in the near ultraviolet. This method serves as a means of producing soft ionization or extensive fragmentation on the basis of the laser power and wavelength, without physical separation of the analyte from the effluent jet expansion. In addition, the pulsed liquid injection method allows introduction of the sample in methanol at 80°C without the extensive clustering that normally occurs in continuous expansions unless much higher temperature is utilized. With the use of this method the R2PI of catecholamines and indoleamines, as well as their metabolites, is studied in a TOFMS. The ability to obtain some spectral selectivity from jet expansions of liquid methanol is also demonstrated.