Jet Process Research Articles

Effect of high-pressure jet processing on the structure and physicochemical properties of plant protein isolate aqueous dispersions

There is a strong interest in incorporating proteins from plant sources into protein-rich beverages. However, the use of protein isolates in food systems is restricted by their poor solubility and overall functionality. This research aimed to investigate the impact of high-pressure jet (HPJ) processing from 0 (control) to 500 MPa on the structural and physicochemical properties of three commercial soy protein isolates (SPIs) and pea protein isolates (PPIs) 5% w/v aqueous dispersions. Processing by HPJ at 100 MPa caused a strong dissociation of large protein bodies into smaller protein aggregates, following by a linear reduction in particle size when processing from 100 to 500 MPa. Native-PAGE of the supernatants showed that the molecular weight of the obtained soluble fractions was >250 kDa (no monomeric units), indicating the lack breakdown of protein covalent bonds. The reduction of the large protein bodies into small-size protein aggregates affected the overall functionality of the protein isolates. The solubility and the foaming capacity of plant proteins increased >15% as the aggregates dropped in size due to HPJ processing. The hydroxyl radical scavenging activity of PPIs increased >15% after pressurization, but HPJ did not influence the emulsion stability. The improvement in the physicochemical properties of plant-based proteins highlights the potential use of HPJ technology to create novel ingredients that feature clean label claims.

Effects of different processes on characteristics and properties of bio‐calcium from hybrid catfish (Pangasianodon gigas × Pangasianodon hypophthalmus)

SummaryThe research was aimed to study the impact of various treatments on characteristics of bio‐calcium from hybrid catfish bone. Bio‐calcium from hybrid catfish bones (raw bone) was prepared using several 4 steps including high‐pressure water jet process (washed bone), soaking in alkaline solution (protein removal), ethanol immersion process (lipid removal), bleaching and grinding to obtain bio‐calcium powder. The obtained bio‐calcium had a yield of 14.46 g 100 g−1. Bio‐calcium had low protein, fat and moisture contents but had high ash content (P ≤ 0.05). Bio‐calcium was rich in calcium and phosphorus. Bio‐calcium contained high hydroxyproline content of 27.70 mg g−1 samples. Moreover, high contents of proline, glycine, aspartic acid alanine and glutamic acid were found in bio‐calcium. The ethanol immersion, bleaching and grinding process effectively decreased Thiobarbituric acid‐reactive substances (TBARS) values and total volatile acids (P ≤ 0.05) of bio‐calcium powder compared with washed bone, protein and lipid removal processes. Therefore, this research provided an alternative source for bio‐calcium production, which can develop as fortified in food products, calcium supplements and biomedical applications.

Simulation analysis of the decontamination effect of different nozzles abrasive jet based on CFD-DEM

To study the effect of three different types of nozzles (straight conical, Venturi, and streamline) on the decontamination effect of radioactively contaminated metals abrasive jet, the gas-solid two-phase flow in the abrasive jetting process is numerically simulated by the method of CFD-DEM coupling simulation. The coverage and distribution uniformity of abrasive particles, the impact velocity, and the wear of the nozzle itself are focused on, and the rationality and reliability of the simulation experiment method and the evaluation method of the experimental results are proved by the verification experiments. The results show that the Venturi nozzle is more suitable for the decontamination of radioactively contaminated metals because it has the advantages of uniform abrasive distribution, high abrasive impact velocity, and good nozzle wear. The nozzle is mainly subjected to low-angle micro-cutting erosion wear, so when selecting nozzle materials, more emphasis should be placed on high-hardness materials to resist micro-cutting wear. The impact distance has a very obvious impact on the decontamination effect of the abrasive. In the decontamination process, the impact distance should be set reasonably, and the uniformity of the abrasive particle distribution should be fully considered to ensure the decontamination effect.

Numerical simulation of the accumulation process in modulated liquid jets of defined volume using the volume-of-fluid methodology

Axial modulation of liquid jets leads to the well-known jet ‘bunching’effect. The associated accumulation of liquid in certain parts of the jet is advantageous, as it can increase the mechanical effect of the jet when it hits a surface. This advantage is known from empirical studies on cleaning with pulsating jets as well as from biological studies on the hunting method of archerfish. So far, however, there have been no systematic studies on modulating jets to enhance their impact on a solid surface. In this paper the VOF methodology is used to simulate jets with an axial velocity modulation. The modulation aims to accumulate the ejected liquid in a single droplet at the tip of the jet. This accumulation process has a decisive influence on the jet impact, as it changes the distribution of pressure and wall shear stresses in the impact area, which are difficult to determine experimentally. The validity of the numerical model is ensured by benchmark experiments in which both the drop shape and the impact force are used as comparison criteria. For this purpose, the velocity at the nozzle outlet was measured with high temporal resolution in the experiments, as it defines the inflow boundary conditions for the simulations. The results lead to a better understanding of the basic accumulation process. Furthermore, the improvement of the impact behaviour by jet modulation can be estimated.

Research on the Numerical Effect of VTD Model in Cross Jet

To deeply study the specific characteristics of the cross-scale phenomenon of fragmentation and atomization in the cross-jet process, this paper is based on the adaptive grid technology, using the RANS model, RNG k-ε model, LES model turbulence models, and VOF models, DPM model, VTD model multiphase flow models have carried out numerical calculations on the lateral jet process, and compared and analyzed the results to better solve the cross-scale problem and obtain more suitable research methods for the phenomenon of lateral jet breaking and atomization. It is found that: compared to the RANS model and RNG k-ε model, the LES model is more suitable for jet breaking; compared with the VOF model and DPM model, the VTD model is closer to the actual physical phenomenon in the cross jet breaking shape, and the initial surface of the liquid column is broken, the columnar broken and the band-shaped liquid filament is broken by a series of broken and atomized phenomena. And a large number of banded or filamentous liquid lumps can be captured in the continuous liquid film stage and the primary crushing stage of the jet, while discrete misty droplets can also be captured in the secondary crushing area. Based on this, this paper finds that the cross-scale VTD model is combined the phase gradient adaptive grid technology can couple the advantages of the VOF model and the DPM model to better solve the transition problem between the continuous phase and the discrete phase, thereby obtaining more accurate jet atomization characteristics.

Binder jetting printing of zirconia structures via grading powder and epoxy binder

ABSTRACT The binder jetting (BJ) process shows significant superiority in manufacturing ceramic parts with a complex structure. The performance of the green part is highly reliant on the features of raw materials. A kind of grading zirconia powder M0 was designed, its intrinsic characteristics including microstructure, size and size distribution, bulk density, porosity, hall velocity and spread performance were systematically evaluated. The design principles of M0 were illustrated in detail. Meanwhile, a kind of organic epoxy binder was prepared and its properties including density, viscosity and surface tension were estimated. The jet ability of binder was evaluated quantitatively. The compatibility and bonding strength between binder and powder were assessed through contact angle, infiltration time and microstructure of M0. As a result, M0 and epoxy binder can be successfully applied in the printer, the zirconia structure with good dimensional accuracy (shrinkage rate ≤ ±2%) and flexible strength (1.74 ± 0.28 MPa) were achieved.

General integral model for a jet in wavy current environment

An integral model for the simulation and prediction of the mixing and diffusion of submerged wastewater discharge in the form of a jet flow in a coastal dynamic environment is still lacking in the literature. In this study, a general integral model was developed to simulate and predict the movement and dilution process of jets in still water, currents, waves, and wavy current environments. Specifically, starting from the fundamental Navier–Stokes equations combined with the conservation equations of mass and scalar quantities, the equations of movement and the governing equations of mass, momentum, buoyancy, and scalar quantities were derived. Furthermore, the model employs an entrainment closure approach that distinguishes the contribution of transverse and azimuthal shear mechanisms and contains a quadratic-law turbulent drag force mechanism. A comparison with the basic experimental data for jets in still water, currents, waves, and wavy current environments supports the choice and magnitude of the entrainment coefficients contained in the entrainment formulation as well as the unified calculation formula of the drag force coefficient contained in the drag force formulation. The range of applicability of the model is carefully evaluated, and several model limitations, beyond which the integral model becomes invalid, are proposed. The general integral model provides a reliable technical approach to studying the movement and dilution process of jets in a wavy current environment and may be used to study the effects of waves and tidal currents on jets for a much wider range of source and ambient conditions than have been studied experimentally thus far.

Experimental and numerical investigation on flow condensation process of oxygen jet in crossflow of liquid oxygen

The mixing and condensation process of gaseous oxygen jet in liquid oxygen flow in the outlet pipeline of oxidizer booster pump in liquid rocket engine are studied. In the present study, experiments are performed to investigate oxygen jet condensation in crossflow of liquid oxygen in a vertical pipe. The image of the test section is obtained by visualization device and processed by digital image technology. A computational fluid dynamics (CFD) model is developed to simulate the mixing and condensation process based on multiphase VOF model and Lee phase change model. The experimental results show that, under the current operating conditions, gaseous oxygen forms a crooked jet plume at the outlet of orifices, and then the gas phase gradually condenses, forming discontinuous bubbles downstream. The effects of Reynolds number of liquid oxygen, oxygen mass flux, ambient pressure and liquid oxygen temperature on the gas distribution and axial condensation length are investigated accordingly. The mass transfer coefficient r=10000s−1 which has been verified by the experiment of oxygen jet in liquid oxygen crossflow is obtained and the predicted gas distribution by CFD simulation is in good agreement with the experimental data. The experimental dimensionless axial condensation length is in the rage of 7.3 to 18.2, and a correlation of dimensionless axial condensation length has been modified. Besides, the dimensionless axial condensation length predicted by simulation is less than 13% comparing with experiment. The averaged heat transfer coefficients obtained in experiment and simulation are around 13.89–26.04 kW/(m2K) and 12-67kW/(m2K), which is much lower than the average heat transfer coefficient in the DCC of water. The results of the present investigation will be helpful in designing the pipeline between pumps in liquid rocket engine.

The jetting process and spreading characteristics of the power-law fluids for material jetting process

Materials jetting, known as one of the 3D printing technologies, is widely applied in microelectronics packaging, biology and ceramic 3D printing due to its ability to print multi-materials by drop-on-demand. However, most of the materials are power-law fluids in 3D printing applications, the generation of satellites during the jetting process and droplet spreading characteristics are unclear and they have a great effect on the quality of the printout. In this paper, a common electromechanical and fluid-solid coupling model of the jet dispenser and observation platform of the jetting process are established. This modeling method is also suitable for other needle-driven jet dispensers. A commercial UV resin is adopted to study the jetting process of power-law fluid. To reveal the mechanism of satellite generation, the effects of input signals (rising time and falling time) on the dynamic characteristics of the needle and the jetting process are analyzed. On the basis thereof, the effectiveness of the optimal control parameters is demonstrated to eliminate satellites. In addition, the simulation and experimental results show that the falling time and fluid pressure can be controlled to adjust the spreading diameter and height of the droplet. Subsequently, the minimum line width of 0.276 mm is successfully printed with a nozzle of 0.07 mm.

Full scale experimental and numerical simulation of outside transformer fire

To study the real scale transformer fire and fire control process, this paper uses FDS to simulate the transformer fire combustion process and analyzes the data of transformer fire temperature and flow field. Through data analysis, this paper establishes a fire visualization system based on the unity3d engine and uses modeling software to complete the Substation Scene Modeling, the visualization process of fire particles and fire water jet in the whole process of transformer fire occurrence and fighting is realized. The research results are of great significance for substation fire construction and emergency rescue.

Study on the relationship between the length of mixing layer and the characteristic scale of mixing layer in multi-strut ejector

The flow structure of the multi-strut ejector based on jet segmentation has an obvious relationship with the transverse characteristic scale of the jet. Therefore, this paper studies the relationship between jet transverse characteristic size and mixing layer. Through the simulation of multi-strut ejectors with different number of struts, the development of mixing layer in the mixing process of jets with different transverse characteristic sizes is compared under the same boundary conditions. It is concluded that when there is no obvious coupling effect between the mixing layer and the shock & expansion wave, there is a linear relationship between the transverse characteristic scale of the jet and the mixing length of the flow direction, and the jet mixing with different transverse characteristic scales is consistent. When the shockwaves and expansion waves are strongly coupled with the mixing layer, the linear relationship between the jet transverse characteristic scale and the mixing layer length is not strong.

Action Law and Deterioration Characteristics of Trigger Cavity of Plasma-Jet-Triggered Air-Gap Switch

The switch-type controllable metal oxide arrester (CMOA) is a flexible method to depress deeply switching overvoltage of transmission system, and the switching time of the fast bypass switch in CMOA is less than 1 ms with the meet of engineering. The plasma-jet-triggered air-gap switch (PTAS) has obvious advantages for the above switch. However, the cumulative effect of increasing the trigger discharge times is prone to trigger failure of the PTAS. In this article, a platform about trigger lifetime of PTAS is established to study the action law and degradation characteristics. The results show that the plasma jet process is divided into three stages: rapid growth stage, stable development stage, and dissipation and decline stage. The peak plasma jet velocity is up to 1.7 km/s, and the shock pressure can reach 5 MPa. With the increase of trigger discharge times, the surface discharge channel of PTAS trigger cavity gradually degrades due to the arc ablation cumulative effect, the surface roughness and nozzle diameter increase, the plasma jet characteristic parameters decrease, and plasma jet ability is weakened. The ablation degradation of trigger cavity surface is characterized by “pore size increasing, pore connection, and gully penetration.” The plasma jet characteristics are consistent with three types of the trigger cavity insulating materials, namely, Poly tetra fluoroethylen (PTFE), PTFE +0.5% Cu powder, and PTFE +0.2% MoS2. The decay rate of plasma jet parameters for +0.5% Cu powder is the fastest. Adding 0.2% MoS2, the ac ablation ability is strengthened. However, the trigger discharge lifetimes of both +0.5% Cu powder and +0.2% MoS2 are lower than that of PTFE. PTFE has obvious advantages in gas-producing performance and ablation resistance ability. The research results provide theoretical guidance for improving the trigger performance of PTAS.

Study the Effect of Cutting Parameters of Abrasive Water Jet Process on Aluminum Alloy 5083

Study the Effect of Cutting Parameters of Abrasive Water Jet Process on Aluminum Alloy 5083

Experimental and Numerical Investigations on the Mixing Process of Supercritical Jet Injected into a Supersonic Crossflow

The mixing process and distribution characteristics of a supercritical endothermic hydrocarbon fuel (EHF) jet injected into a supersonic crossflow were investigated by experimental and numerical methods, respectively. The schlieren system and acetone planar laser-induced fluorescence (PLIF) optical system were used to capture the flow-field structural characteristics and instantaneous plume. The mixture and real gas models were employed to calculate the interaction of a transverse jet and supersonic crossflow and reveal a good accuracy with the experimental results. The mixing efficiency and total pressure loss were analyzed based on the numerical results. The results indicate that the supercritical-state EHF directly changes to a gaseous state as it enters the supersonic crossflow from the injector. The EHF jet plume boundary increases with the increasing momentum flux ratio (q). As the streamwise and spanwise distance increases, the traverse heights and expand width increase, and the EHF jet plume presents a semicircle shape in the cross-sectional plane. With the increase in the traverse direction, the concentration distribution shows a fast and then slow power exponential decreasing law; the highest concentration point starts from the near-wall region and rises in the transverse direction with the flow distance increasing. For the same injection condition, the higher the inflow Mach number, the higher the mixing efficiency. For the same Ma, the mixing efficiency is better for the case with low injection pressure and high injection temperature. The total pressure loss is greater in the higher Ma, and high injection pressure conditions cause greater total pressure loss.

Study on Penetration Mechanism of Shaped-Charge Jet under Dynamic Conditions.

Aiming at the dynamic penetration process of a shaped-charge jet, we proposed a mathematical model for the penetration of a jet under dynamical conditions based on the theory of virtual origin and the Bernoulli equation taking into account the jet and target intensities. The dynamic penetration process of the jet was divided according to the penetration channel of the jet into the static target. The dynamic penetration model of the jet based on the unperturbed section and perturbed section was established. The penetration depth variation in the shaped-charge jet vertically penetrating target plates with different moving speeds (150~400 m/s) was analyzed by finite element software. The dynamic penetration model shows that with the increase in the target moving speed, the disturbed time of the jet continuously advances, and the dynamic penetration depth continuously decreases; as the velocity of the target increases, the penetration length of the unperturbed jet decreases and then becomes stable, while the penetration length of the perturbed jet decreases. The results showed that the mathematical model is consistent with the finite element simulation, and that the mathematical model can effectively characterize the penetration depth of the unperturbed and disturbed jet portions, adequately explain the dynamic response behavior of the jet penetrating a moving target, and effectively predict the dynamic penetration depth of the jet under the influence of the target movement.

Nozzle resonance mechanism and cooperative optimization of self-excited oscillating pulse cavitation jet

The peak value and pulsation amplitude of the self-excited oscillating pulse cavitation jet nozzle are essential indices to evaluate the jet performance. We established a simulation model of the jet process of the nozzle to investigate the evolution mechanism of the inner and outer flow fields. We used the chamber fillet, chamber diameter, chamber length, and outlet-tube diameter as the design variables, and the peak value of the striking force and the amplitude of the pulsation of the striking force as the target variables. The collaborative optimization design method of the nozzle was determined by combining the orthogonal test method, the back propagation neural network, and the nondominated sorting genetic algorithm. As indicated by the results, when the inlet pressure was 3 MPa, the factors ranked as follows in terms of their effects on the jet performance of the nozzle: the chamber fillet, the outlet-tube diameter, chamber diameter, and the chamber length. To verify the feasibility of the collaborative optimization method, the nozzle was fabricated via 3D printing, and the simulation model was verified by testing. This study provides support to the development of design theory for self-oscillating pulsed cavitation jet nozzles.

Multiphysics modeling and experimental verification of solidification point of melt-electrospun jet

Melt electrospinning has been recognized as an attractive solvent-free process over the past few decades to alleviate the solvent-related problems generated by traditional electrospinning techniques. In melt spinning, the drawing process of molten jets occurs in the liquid phase region before the phase transformation. Besides, the insufficient chain flow in the solid phase results in the non-stretchable properties of the jet in this state. This analysis predicted the phase transition displacement in the polymer jet during the melting process using a two-dimensional non-isothermal flow model integrated with an electric field. High-speed photography was employed to collect photographs of the phase transition point of the jet to verify the simulation results. Additionally, we evaluated the diameters of fibers manufactured with various phase transition displacements induced by different applied voltages. The findings of the experiments reveal that as the applied voltage is enhanced, the freezing point of the jet becomes gradually closer to the nozzle side, and the solidification length significantly reduces, resulting in smaller fiber diameter. Moreover, the results mentioned above are consistent with the law predicted by the simulation, proving the feasibility and accuracy of the model. This work will provide potential guidance for the study of nanoscale melt fibers from the perspective of fluid phase transformation.

Multifunctional Core–Shell Particle Electrodes for Application in Fluidized Bed Reactors

Fluidized particle electrodes are well-suited for a wide range of electrochemical reactions due to their large specific surface area and their tolerance toward suspended solid contaminants and gas bubbles. For effective electrode performance, particles require (i) high conductivity, (ii) efficient interparticle contact, and (iii) chemical inertness toward a broad range of reagents and solvents. In particular, sufficient interparticle contact remains a critical challenge. Magnetic stabilization of the fluidized bed provides a potential solution but requires the use of magnetic electrode materials. However, the synthesis of electrode particles with high magnetic susceptibility remains an ongoing challenge. Herein, electrojetting of magnetite/poly(methyl methacrylate) suspensions into a graphite powder bed is demonstrated to be a facile and effective route toward magnetically stabilizable electrode particles. Energy-dispersive X-ray spectroscopy and Raman spectroscopy confirmed the composition and core–shell structure of the particles. Characterization of their magnetic and electric properties showed an exceptionally high saturation magnetization of 11.1 A·m2/kg and a conductivity of 28 S/m. Further, scanning electron microscopy revealed an average diameter of approximately 200 μm, large surface areas, and spherical shapes, three prerequisites for homogeneous fluidization. Compared to previously reported fluidized bed electrodes, electrodes comprised of these novel core/shell particles showed 2-fold increases in current densities and conversion rates. These results underline the potential of the electrohydrodynamic jetting process for the design and synthesis of novel, tailor-made core–shell particles as key components of fluidized bed electrodes for electrochemical reactions.

Micro-machined deep silicon atomic vapor cells

Using a simple and cost-effective water jet process, silicon etch depth limitations are overcome to realize a 6 mm deep atomic vapor cell. While the minimum silicon feature size was limited to a 1.5 mm width in these first generation vapor cells, we successfully demonstrate a two-chamber geometry by including a ∼25 mm meandering channel between the alkali pill chamber and the main interrogation chamber. We evaluate the impact of the channel conductance on the introduction of the alkali vapor density during the pill activation process and mitigate glass damage and pill contamination near the main chamber. Finally, we highlight the improved signal achievable in the 6 mm silicon cell compared to standard 2 mm path length silicon vapor cells.

Mechanical characterisation of water-jet shot peened H13 tool steel surface

A wear-resistant surface is achievable via the surface treatment of various sources such as laser, water-jet, ion beam, and plasma. This paper investigates the parameters of water-jet shot-peened H13 tool steel for minimum surface roughness and maximum hardness properties. Water jet processing parameters are significant in determining the surface roughness as well as hardness properties. Water-jet shot-peened (WJSP) was used in this experiment to improve the surface properties of H13 tool steel. The parameters are pressure and feed rate of 172 MPa to 310 MPa and 2600 mm/min to 10000 mm/min. The shot-peened samples were characterised for surface topography, surface roughness, and hardness properties. A laser confocal microscope was used to determine the dimension of the modified surface from shot peening and average surface roughness. Hardness properties were measured using the Vickers scale. From topography analysis, the surface roughness reading on the shot-peened surface was measured as much as 6.88 µm to 14.06 µm. Minimum surface roughness measured was 6.88 µm on sample processed at pressure and feed rate 172 MPa and 2600 mm/min. The hardness properties of the shot-peened subsurface were between 196 HV and 227 HV. The resulted hardness properties were due to plastic deformation from abrasive particle bombardment during shot peening. The findings are important to designing enhanced surface properties for mould and die applications.