Jet Injection Research Articles

Vaccination in hemophilic children: Challenges, innovations, and future directions

Introduction: Hemophilia, an inherited disorder primarily affecting blood clotting due to deficiencies in clotting factors VIII or IX, presents complex challenges for vaccination. Children with hemophilia require vaccinations to prevent infections that may exacerbate their bleeding disorder. However, traditional intramuscular vaccination poses bleeding risks, necessitating specialized administration methods and careful post-vaccination care. Purpose: This study examines the efficacy and safety of vaccination in pediatric hemophilia patients, emphasizing the importance of individualized protocols to manage bleeding risks effectively. It explores recent advancements, including needle-free technologies, the potential of gene therapy, and mRNA vaccines. Materials and Methods: The study synthesizes current guidelines from global health organizations, hemophilia management protocols, and clinical studies on vaccine safety in hemophilia. It highlights techniques such as subcutaneous administration, clotting factor prophylaxis, and the use of fine-gauge needles to minimize bleeding complications. Results: Findings indicate that with appropriate management, hemophilic children achieve adequate immune responses to vaccines, with reduced bleeding risks. Emerging technologies, such as microneedle patches, jet injectors, and gene therapy, offer promising safer vaccination alternatives. Additionally, mRNA vaccines demonstrate strong immunogenicity without the need for live-virus vectors, reducing complication risks. Conclusions: Vaccination, when adapted to hemophilia-specific needs, remains essential for infection prevention in this vulnerable population. Newer vaccine technologies and individualized care protocols enhance safety and efficacy, contributing to improved quality of life and long-term health outcomes for hemophilic children.

Enhancing Bulb Turbine Performance Assessing Air Injection for Vibration Mitigation and Hydrofoil Cavitation

Small hydro technology is playing a crucial role in advancing sustainable, clean energy policies as part of the global hydro development strategy. Its contribution to social and economic development is becoming more prominent, particularly in ensuring electricity access for rural communities and supporting industrial expansion. The main causes of bulb turbine failures under high operating conditions are frequently attributed to variations in pressure in the draft tubes, which are aggravated when a spinning vortex rope is formed under load operation. Different fluid injection techniques, namely compressed air and water jet injection, address these issues and reduce the negative results of cavitation. The investigation covers the flow visualization on the suction side of a single hydrofoil utilizing a cavitation tunnel and a bulb turbine. This study assesses the effectiveness of compressed air injection in reducing vibration generated by cavitation in bulb turbines. Positive results of the experimental studies suggest a decrease in noise and vibration by air injection that prevents oscillations of the vortex rope. This research also considers how the hydrofoil design of bulb runner blades influences flow characteristics. Hence, it provides knowledge on cavitation structures in diverse cavitation numbers. Different studies that compare the original and modified hydrofoil designs reveal remarkable improvements that may be due to changes in the key parameters of the hydrofoil, such as later cavitation initiation and reduced intensity. To obtain the optimal output of a bulb turbine by considering air injection for vibration reduction and hydrofoil design changes to limit the negative effect of cavitation, the Reynolds number and cavitation number are to be defined. This multidisciplinary approach possesses enormous potential to increase the reliability and efficiency of bulb turbines in challenging operating conditions.

Magnetic dissipation in short gamma-ray-burst jets

Aims. Short gamma-ray bursts originate when relativistic jets emerge from the remnants of binary neutron star (BNS) mergers, as observed in the first multi-messenger event GW170817–GRB 170817A, which coincided with a gravitational wave signal. Both the jet and the remnant are believed to be magnetized, and the presence of magnetic fields is known to influence the jet propagation across the surrounding post-merger environment. In the magnetic interplay between the jet and the environment itself, effects due to a finite plasma conductivity may be important, especially in the first phases of jet propagation. We aim to investigate these effects, from jet launching to its final breakout from the post-merger environment. Methods. We used the PLUTO numerical code to perform 2D axisymmetric and full 3D resistive relativistic magnetohydrodynamic (MHD) simulations, employing spherical coordinates with spatial radial stretching. We considered and compared different models for physical resistivity, which must be small but still dominating over the intrinsic numerical dissipation (which yields unwanted smearing of structures in any ideal MHD code). Stiff terms in the current density are treated with IMplicit-EXplicit Runge Kutta algorithms for time-stepping. A Synge-like gas (Taub equation of state) is also considered. All simulations were performed using an axisymmetric analytical model for both the jet propagation environment and the jet injection; we leave the case of jet propagation in a realistic environment (i.e., imported from an actual BNS merger simulation) to a future study. Results. As expected, no qualitative differences are detected due to the effect of a finite conductivity, but significant quantitative differences in the jet structure and induced turbulence are clearly seen in 2D axisymmetric simulations, and we also compare different resistivity models. We see the formation of regions with a resistive electric field parallel to the magnetic field, and nonthermal particle acceleration may be enhanced there. The level of dissipated Ohmic power is also dependent on the various recipes for resistivity. Most of the differences arise before the breakout from the inner environment, whereas once the jet enters the external weakly magnetized environment region, these differences are preserved during further propagation despite the lower grid refinement. Finally, we show and discuss the 3D evolution of the jet within the same environment in order to highlight the emergence of nonaxisymmetric features.

Upstream velocity fields induced by frontal jet injection in a square cylinder

The flow characteristics around the frontal face of a square cylinder with a frontal jet injection were experimentally studied in a closed-loop wind tunnel using the PIV technique. Four characteristic flow modes were identified based on the injection ratio: swinging jet, deflected oscillating jet, deflection jet, and penetrating jet. At low injection ratio, the flow mode denoted as the swinging jet is characterised by two recirculation regions and a four-way saddle point. At moderate injection ratio, the flow mode termed deflected oscillating jet is characterised by a recirculation region and a counterclockwise rotating vortex within the recirculation region. At moderately high injection ratio, the flow mode is denoted as deflection jet, where a clockwise rotating vortex appears in the flow field. At high injection ratio, the flow mode is termed as penetrating jet, with no vortex formation in the flow field. The strength of the turbulence intensities increases considerably with high injection ratios. The time histories of instantaneous velocity for non-injection case, swinging jet, and deflected oscillating jet modes show periodic oscillations, whereas those of deflection jet and penetrating jet modes do not show periodic oscillations. The study presents and discusses the time-averaged velocity vectors, and streamlines, vorticity contours, velocity properties, velocity time histories, and power spectral density function under different flow modes.

Needle-Free Targeted Injections Using Bubble Laser Technology in Therapeutics.

This work explores bubble laser technology as an alternative to needles in injection systems for vaccination, cancer treatment, insulin delivery, and catheter hygiene. The technology leverages laser-induced microfiltration and bubble dynamics to create high-speed pneumatic jets that penetrate the skin without needles, addressing discomfort, infection risk, and needle-related concerns. The system's performance is analyzed based on laser wavelength, pulse duration, and Gaussian beam droplet size. The findings indicate a significant increase in spot size at 1064 nm compared with 400 nm, consistent with the diffraction theory. Induced bubble dynamics reveal bubble generation, jetting, and fluid interactions as the Weber number increases, as well as jet velocity and fluid inertia. For femtosecond pulses, increasing the pulse duration from 100 to 1500 fs reduces the bubble lifespan from 0.8 to 0.3 arbitrary units, and the collapse pressure decreases from 2.1 to 0.4 bar. For picosecond pulses, the bubble lifetime decreases from 0.9 to 0.5 arbitrary units, and the pressure drop decreases from 2.0 to 0.4 bar as the pulse length extends from 2000 to 8000 ps. Jet formation in laser jet injection systems is enhanced by short pulses in water that produce longer-lasting bubbles. Drug delivery based on the Rayleigh-Plesset equation is characterized by a low-pressure collapse and short bubble lifetime. Thus, this relationship suggests that bubble laser technology can provide a more controlled and safer method of needle-free procedures, increasing compliance and reducing tissue trauma.

Therapeutic Performance of Needle Injection Versus Needle-Free Jet Injector System for Polynucleotide Filler in Skin Rejuvenation.

Polynucleotide (PN) filler often causes pain and can lead to delivery inaccuracies when applied via intradermal injection using a traditional needle. To evaluate the efficacy of treatment and the pain during the procedure using conventional needle injection versus a needle-free jet system for intradermal PN filler application. In this split-face clinical trial, 10 Korean subjects were enrolled. Each subject received an intradermal injection of PN filler on one side of the face and a needle-free jet injection using CureJet on the other side. Assessments included global and 3D skin imaging at each visit. Pain intensity was evaluated using visual analogue scale (VAS) scores during the injection. Additionally, patient satisfaction and adverse events were documented. Findings revealed that Global Aesthetic Improvement Scale scores and patient satisfaction were significantly higher with the CureJet compared to the needle injection method. VAS scores were notably lower on the CureJet side. Improvements in both pore and wrinkle indices were observed from baseline, with a more pronounced improvement rate on the CureJet side compared to the needle injection side. Needle-free injection of PN for aging skin was found to be effective in enhancing pore and wrinkle improvement, while reducing associated discomfort.

The coupling effect of turbulent jet ignition and injection strategy on the combustion performance of a pure methanol rotary engine

Methanol, as an alternative fuel, has significant potential in energy conservation and emission reduction. However, the higher ignition temperature and latent heat of vaporization of methanol fuels also expose engines to the risk of cold-starting difficulties. The turbulent jet ignition (TJI) technology, aimed at enhancing ignition energy, proves effective in improving the ignition and combustion performance of pure methanol. Therefore, this study designed a jet ignition plug to optimize the combustion characteristics of methanol rotary engines. Meanwhile, the influence of injection strategy on the performance of the patterned turbulent jet ignition rotary engine(TJI-RE) was studied for the first time. On this basis, the CFD model of pure methanol TJI-RE was established and validated using relevant experimental data. Results found that the injection angle and position could change in-cylinder fuel distribution during ignition, as well as the quality of fuel entering the pre-chamber, affected by fuel impact position and in-cylinder vortex strength. These factors collectively influenced the combustion characteristics of TJI-RE. Furthermore, the optimal fuel distribution characteristics for TJI-RE included higher fuel concentration in the pre-chamber and increased fuel accumulation in the front of the cylinder Under all calculation conditions, the configuration with the fuel injector positioned 25 mm above the cylinder’s long axis and an injection angle of +50° achieved the highest peak pressure and indicated thermal efficiency for TJI-RE.

Jet injection through microneedles for large volume subcutaneous delivery

Subcutaneous (SC) drug delivery offers several advantages over intravenous (IV) delivery including: self-administration, improved patient experience, and reduced treatment costs. Unfortunately, each SC delivery is currently limited to ∼ 2.25 mL with IV administration required when the delivery volume exceeds this value. In this work, we explore a new technique for large volume subcutaneous drug delivery that uses microneedles to break through the epidermis then forms the liquid drug into many small jets that penetrate past the ends of the microneedles and into the subcutaneous (or muscle) tissue. By performing multiple simultaneous injections, this delivery approach avoids the volume limitations of SC delivery, and thus may be able to greatly increase the volume we can deliver to this space. Here, we present a novel multi-jet prototype that forms seven simultaneous jets through 30G needles that have been shortened to have an exposed length of just ∼ 1mm. The jet speed, shape, and volume of jets formed through these microneedles are measured to assess the consistency of jet production through the microneedles. We then perform jet injections of volumes up to 3.9 mL into ex vivo porcine tissue. The results demonstrate the successful delivery (>95 %) of 3.9 mL in just 0.3 s using jet injection performed through microneedles. This volume is almost double the maximum volume of current autoinjectors and the perceived limit for subcutaneous injection (2.25 mL). We also find that jet speeds of 70 m/s and below do not achieve complete delivery of 3.9 mL with our prototype system, and that the addition of microneedles leads to more consistent large volume delivery than equivalent needle-free injections. These results demonstrate the promise of multi-jet injection through microneedles to accommodate volumes much greater than current autoinjectors, and thus potentially allow patient self-administration in many more delivery applications.

Thermocavitation in gold-coated microchannels for needle-free jet injection

Continuous-wave lasers generated bubbles in microfluidic channels are proposed for applications such as needle-free jet injection due to their small size and affordable price of these lasers. However, water is transparent in the visible and near-IR regime, where the affordable diode lasers operate. Therefore, a dye is required for absorption, which is often unwanted in thermocavitation applications, such as vaccines or cosmetics. In this work, we explore a different mechanism of the absorption of optical energy. The microfluidic channel wall is partially covered with a thin gold layer, which absorbs light from a blue laser diode. This surface absorption is compared with the conventional volumetric absorption by a red dye. The results show that this surface absorption can be used to generate bubbles without the requirement of a dye. However, the generated bubbles are smaller and grow slower when compared to the dye-generated bubbles. Furthermore, heat dissipation in the glass channel walls affects the overall efficiency. Finally, degradation of the gold layer over time reduces the reproducibility and limits its lifetime. Further experiments and simulations are proposed to potentially solve these problems and optimize the bubble formation. Our findings can inform the design and operation of microfluidic devices used in phase transition experiments and other cavitation phenomena, such as jet injectors or liquid dispensing for bio-engineering.

Large eddy simulation of highly underexpanded sonic jets from elliptical nozzles

The injection of high-pressure jets into quiescent air poses significant challenges in fluid dynamics, pertinent to various industrial engineering applications. This study used large eddy simulations on a massively parallel computational framework, employing a grid of over 600 million nodes, to investigate the behavior of highly underexpanded sonic jets from elliptical nozzles at a nozzle pressure ratio of 15. Three elliptical nozzles, with aspect ratios of 1.5, 2.2, and 3.0, each having a sectional area equivalent to that of a circular jet with a diameter of D=1 mm, were analyzed. The aim was to clarify the gasdynamic and mixing characteristics of these jets to guide the design of next-generation injectors. A detailed analysis of the flow provided insights into the mechanisms of turbulence generation and Reynolds stress anisotropy. This was achieved using the componentality contour approach and a modified barycentric color mapping scheme, offering valuable reference data for developing lower-order models. The results indicate a non-axisymmetric radial expansion of the jet boundary in all elliptical injectors, leading to an axis switch phenomenon. The use of elliptical orifices was found to reduce jet penetration, mitigating issues such as fuel impingement in small engine combustion chambers and promoting improved air–fuel mixing quality.

Deflagration-to-detonation transition and detonation propagation in supersonic flows with hydrogen injection and downstream ignition

This study investigates the mechanisms of flame acceleration and deflagration-to-detonation transition (DDT) in supersonic flows using transverse hydrogen injection and downstream ignition. Utilizing the graphics processing unit accelerated adaptive mesh refinement approach, we examine the influence of downstream ignition jet pressure on DDT through high-resolution computational simulations. Our results indicate that the transverse injection of hydrogen into the supersonic mainstream generates strong turbulence and numerous vortices due to Kelvin–Helmholtz instability, enhancing fuel mixing efficiency along the flow but deviating from the ideal premixed state. Following the injection of the downstream ignition jet into the supersonic main flow, initial flame acceleration is less effective than in the premixed state due to the non-uniformity of the incoming flow. However, within the boundary layer, the flame remains stable, and the intense turbulence fosters shock–flame interactions. The convergence of multiple compression waves into a shock wave facilitates energy deposition, coupling with the flame to trigger local detonation via the reactive gradient mechanism. The detonation wave exhibits complex wavefront structures, including vertical and oblique fronts induced by boundary layer interactions. Ignition jet pressure significantly impacts the DDT process and detonation wave characteristics, reducing ignition time and affecting the detonation temperature, pressure, and propagation speed. This study provides valuable insights into the dynamics of flame acceleration and DDT in supersonic flows with non-uniform fuel distribution and downstream jet ignition. The findings highlight the critical role of ignition jet pressure in optimizing ignition and detonation processes, offering new perspectives for achieving low-energy, rapid detonation initiation within the tube.

Status and Prospect of Needle-Free Jet Injector

Needle-free jet injectors refer to a kind of medical device that uses a specific device to form a small, high-speed jet of medication to pierce the human skin, thereby achieving the delivery of medication into the human body without the use of needles. In the past few decades, needle-free jet injectors have undergone many changes with the development of healthcare systems and advancements in related technologies. In this article, the history, research status, and clinical application of needle-free jet injectors are introduced. The principles of different driving modes for needle-free jet injectors are briefly summarized, and their respective advantages and the existing problems are summarized. Combining the current research status and market application, the technical problems faced by the development of needle-free jet injectors are analyzed. Under the background of intelligent and automatic development of medical equipment, the future development and opportunities for needle-free jet injectors are prospected.

A new track for high-efficiency marine diesel engines: Initiative air jet and post-split injection combined

In pursuit of adequate mixing with a high volume of fuel injection, a re-intake scheme is proposed to promote the diffusion of combustibles and flames by using the disturbance of high-pressure air jets after the pressure peak. The results indicate that during the power stroke, an additional air jet enhances combustion by penetrating the spray and disturbing the flame front. The high-pressure air jet's obstruction of the atomization of local sprays achieves a longer combustion duration, while intensifying the vortex and temperature at the cylinder center, which enhances the evaporation of fuel near the nozzle. However, excessively high fuel injection pressure brings in more cold air, causing a temperature drop. It is necessary to have sufficient flame expansion before re-intake to eliminate the impact on pressure. By adjusting the re-intake pressure and timing, the air jet, when it reaches half the cylinder diameter, can exert its maximum advantage. By introducing post-injection and increasing the pressure of the first fuel injection, the air-spray impingement duration is extended, thereby improving thermal efficiency. This work, at 190 MPa injection pressure without changing the duration, and combined with a 5°CA re-intake, achieved a 1.82 % increase in thermal efficiency.

Jet injection and spout formation in a fluidized bed

A single jet was studied in a rectangular fluidized bed by analyzing the pressure fluctuations data to characterize the jet hydrodynamics. The bed contained with glass beads of different mean sizes (450, 650, and 920 µm) as well as pharmaceutical pellets (920 µm). The analysis of the pressure fluctuation data was performed using the power spectral density function (PSDF) and discrete wavelet transforms technique. This study investigated how the flow regime changed from a jet in a fluidized bed to a spouted regime as the gas injection velocity was increased. Increasing the mean particle size led to an increase in the minimum spouting velocity. The minimum spouting velocity for 450, 650, and 920 μm glass bead particles and for 920 μm pharmaceutical pellets were determined to be 32.47 m s-1, 38.66 m s-1, 44.78 m s-1, and 44.47 m s-1, respectively. The study also examined how the dominant frequency of the various particles and the energy percentage of scales changed with increasing injection velocities. The ratio of energy percentages of meso-scale changes as the injection velocity increases and these changes were used to estimate the minimum spouting velocity. Wavelet sub-signals analysis revealed that the Daubechies 2 (DB2) wavelet was the most effective at capturing the characteristics of the jet. Based on the Shannon entropy of the approximate coefficients, the wavelet analysis showed that 11 levels of decomposition were required. By combining the wavelet analysis and PSDF, a more detailed analysis of the meso-scale was achieved. This study provided valuable insights into the behavior of jets and spouts in fluidized beds, which can greatly contribute to the optimization of a jet in fluidized beds and spout-fluidized beds by enhancing our understanding of jet behavior in such environments.

Fuel mixing and diffusion behind the unswept ramp injector with lobed nozzle at combustor of scramjet engine

-The use of 2-lobe nozzle for efficient fuel mixing behind the ramp injector nozzle is comprehensively investigated in this article. Computational fluid dynamic is applied for the evaluation of the three-dimensional flow behind the strut with annular 2-lobe nozzle at supersonic combustion chamber. In this work, the Mach number of free steam air flow and fuel jet are 2 and 1, respectively. The usage of internal air jet for the fuel mixing improvement is also analyzed to disclose the critical features which improve the fuel diffusion in the combustor. The Mach contour on the horizontal and vertical planes in both injection model is compared to show how induced vortex pair is created and extended behind the strut. The result of computational study shows that the injection of the air jet increases the number of vortex pairs behind the strut and the interaction of the fuel with air jet is increased. However, the circulation strength is decreased by inner air jet. Use of inner jet enhances the fuel mixing more than two times behind the nozzle. Our findings show that the fuel mixing is heightened downstream of strut by coupling inner air jet with annular fuel jet.

Effect of orientation angle for needle-free jet injection

In this paper, we report on the delivery efficiency of needle-free jet injections using injectors with typical jet speed vj≈140m/s, orifice diameter do=157μm, and volume V=0.1 mL. The target substrates were either hydrogel tissue phantoms or porcine tissues combined with excised human skin. The novelty of this study is two-fold: First, we investigate the influence of injection angle relative to the skin surface, and second, we also study the influence of the jet path relative to the orientation of muscle fibers. While most commercial jet injectors employ a fitting that would render the device normal to the skin surface, recent studies have proposed oblique injections, which may be beneficial for intradermal or subcutaneous tissue injection. Furthermore, for deeper intramuscular injections, we propose that an angled jet path taking the muscle fiber orientation into account may result in a bolus or dispersion zone that is conducive to increased cellular uptake of the drug.

Enhancing High-Alloy Steel Cutting with Abrasive Water Injection Jet (AWIJ) Technology: An Approach Using the Response Surface Methodology (RSM).

The common machining technologies for difficult-to-machine materials do not remarkably ensure acceptable efficiency and precision in bulk materials cutting. High-energy abrasive water injection jet (AWIJ) treatment can cut diverse materials, even multi-layer composites characterized by divergent properties, accurately cutting complex profiles and carrying them out in special circumstances, such as underwater locations or explosion hazard areas. This work reports research on the AWIJ machining quality performance of X22CrMoV12-1 high-alloy steel. The response surface method (RSM) was utilized in modeling. The most influencing process control parameters on cut kerf surface roughness-abrasive flow rate, pressure, and traverse speed-were tested. The result is a mathematical model of the process in the form of a three-variable polynomial. The key control parameter affecting the cut slot roughness turned out to be the traverse speed. In contrast, pressure has a less significant effect, and the abrasive mass flow rate has the slightest impact on the cut slot roughness. Under the optimal conditions determined as a result of the tests, the roughness of the intersection surface Sq does not exceed 2.3 μm. Based on the ANOVA, we confirmed that the model fits over 96% appropriately with the research outcomes. This method reduces the computations and sharply determines the optimum set of control parameters.

A regularized-interface method as a unified formulation for simulations of high-pressure multiphase flows

The injection of multi-species fluids into high-pressure and high-temperature environments beyond the species' critical points is commonly found in engineering applications. At these conditions, for immiscible species, both subcritical interfacial dynamics and supercritical mixing can coexist due to variations in temperature around the mixture critical point. The modeling of these complex transcritical phenomena for large-scale configurations is so far not possible. To address this issue, we propose the Regularized-Interface Method (RIM) as a unified formulation that can describe both sub- and supercritical processes as well as the transition between them. The proposed method is derived via filtering of the nanoscale interface-resolving formulation based on van der Waals' linear gradient theory. Thus, this approach allows for the consistent modeling of interfacial dynamics that vanishes at supercritical conditions, while significantly reducing the temporal and spatial resolution constraints of the original nanoscale formulation. The resulting RIM formulation is examined in interface-capturing simulations of sub-, trans-, and supercritical fuel injection processes, involving droplets and jets. These results highlight the importance of resolving spatio-temporal transitions from subcritical interfacial dynamics to supercritical mixing in high-pressure multiphase simulations, in contrast to commonly employed diffused-interface methods, where interfacial dynamics are often neglected.

Needle-free jet injector treatment with bleomycin is efficacious in patients with severe keloids: a randomized, double-blind, placebo-controlled trial.

Severe keloids are difficult to treat. Corticosteroid injections with needles are painful and associated with frequent recurrences. Therefore, more effective, safe and patient friendly alternative treatments are urgently needed. To assess the efficacy, tolerability, and patient satisfaction of intralesional bleomycin treatment using a needle-free electronic pneumatic jet injector (EPI) in severe keloids. Patients with severe keloids were included in this double-blind, randomized placebo-controlled trial with split-lesion design. Three EPI treatments with bleomycin or saline, were administered every four weeks in respectively the intervention and control side. Outcome measures were change in scar volume assessed by 3D-imaging, Patient and Observer Scar Assessment Scale (POSAS), skin perfusion with laser speckle contrast imaging (LSCI), spilled volume, procedure related pain, adverse events, and patient satisfaction. Fourteen patients (9 female, 5 men) were included. The estimated mean keloid volume was significantly reduced with 20% after EPI-assisted bleomycin, compared to a slight increase of 3% in the control side (p<0.01). The estimated mean POSAS patient and observer scores decreased with respectively 26% and 28% (p = 0.02; p = 0.03). LSCI showed no significant change in perfusion. EPI treatment was preferred over previous needle injections in 85% of patients. The estimated mean spilled volume after EPI was around 50%, and NRS pain scores were moderate. Adverse events included bruising, hyperpigmentation, and transient superficial necrosis. Three EPI-assisted bleomycin treatments are efficacious and well-tolerated in severe keloids. Moreover, EPI treatment was preferred by most patients and may serve as a patient-friendly alternative treatment.

Phased transition from methane to hydrogen in internal combustion engines: Utilizing hythane and direct injection jet ignition for enhanced efficiency and reduced emissions

A strategic pathway to decarbonizing internal combustion engines and advancing toward sustainable energy includes the transition from conventional fuels to methane combustion, followed by methane-hydrogen mixtures, and ultimately to hydrogen-only combustion. This progression leverages the miscibility of hydrogen and methane, enabling the use of Hythane, a fuel blend that combines the advantages of both gases. Methane's widespread availability and existing infrastructure facilitate a cost-effective transition, while its combustion produces lower emissions compared to gasoline and diesel. Hydrogen's high reactivity and clean combustion properties enhance engine efficiency and reduce emissions, making it a crucial component in this phased transition. Challenges in homogeneous charge compression ignition (HCCI) combustion of CH₄-H₂ mixtures, such as controlling ignition timing and managing stable combustion, are addressed by the direct injection jet ignition (DIJI) technique. DIJI creates stratified air-fuel mixtures that ensure rapid and complete combustion, minimizing quenching and reducing heat losses. This study presents a comprehensive analysis of the combustion properties of methane and hydrogen, the benefits of phasing the transition with the availability of green hydrogen, and the technical challenges and solutions in developing HCCI and DIJI combustion systems for Hythane. The research underscores the potential of DIJI to enhance engine performance, efficiency, and emissions control, paving the way for a sustainable energy future in transportation.