Plume Angle Research Articles

Modeling non-monotonic variation of plume angle with superheat index of flash boiling spray

There is an urgent need for modeling angles and widths of liquid jet with internal phase change, but existing semi-empirical models rely strongly on coefficient fitting and lack a thorough understanding of the additional phase-change physics. In the present work, we proposed a theoretical model to predict the non-monotonic variation of plume angle with the defined superheat index of flash boiling spray. Assuming that the plume angle is determined by the trajectories of tiny droplets in the perimeter of the spray, this model identifies the angle with the inverse tangent of the ratio of the streamwise and crosswise velocities of the tiny droplets. The streamwise velocity is determined by solving a one-dimensional two-phase flow within the channel, and the crosswise velocity is determined by modeling the burst of an equivalent bubble at the exit of the nozzle. Compared with the existing semi-empirical models, this model is free of fitting parameters, and it agrees well with the experimental data from a rectangular microchannel with discrepancies being sufficiently discussed. This model has the potential of being applied to modeling the plume angle of flash boiling sprays with different nozzle geometries in various atomization practices.

Effects of Nozzle Retraction Elimination on Spray Distribution in Middle-Posterior Turbinate Regions: A Comparative Study.

The standard multi-dose nasal spray pump features an integrated actuator and nozzle, which inevitably causes a retraction of the nozzle tip during application. The retraction stroke is around 5.5 mm and drastically reduces the nozzle's insertion depth, which further affects the initial nasal spray deposition and subsequent translocation, potentially increasing drug wastes and dosimetry variability. To address this issue, we designed a new spray pump that separated the nozzle from the actuator and connected them with a flexible tube, thereby eliminating nozzle retraction during application. The objective of this study is to test the new device's performance in comparison to the conventional nasal pump in terms of spray generation, plume development, and dosimetry distribution. For both devices, the spray droplet size distribution was measured using a laser diffraction particle analyzer. Plume development was recorded with a high-definition camera. Nasal dosimetry was characterized in two transparent nasal cavity casts (normal and decongested) under two breathing conditions (breath-holding and constant inhalation). The nasal formulation was a 0.25% w/v methyl cellulose aqueous solution with a fluorescent dye. For each test case, the temporospatial spray translocation in the nasal cavity was recorded, and the final delivered doses were quantified in five nasal regions. The results indicate minor differences in droplet size distribution between the two devices. The nasal plume from the new device presents a narrower plume angle. The head orientation, the depth at which the nozzle is inserted into the nostril, and the administration angle play crucial roles in determining the initial deposition of nasal sprays as well as the subsequent translocation of the liquid film/droplets. Quantitative measurements of deposition distributions in the nasal models were augmented with visualization recordings to evaluate the delivery enhancements introduced by the new device. With an extension tube, the modified device produced a lower spray output and delivered lower doses in the front, middle, and back turbinate than the conventional nasal pump. However, sprays from the new device were observed to penetrate deeper into the nasal passages, predominantly through the middle-upper meatus. This resulted in consistently enhanced dosing in the middle-upper turbinate regions while at the cost of higher drug loss to the pharynx.

Comparative study of nasal cavity drug delivery efficiency with different nozzles in a 3D printed model.

Nasal sprays are widely used in treating nasal and sinus diseases; however, there are very few studies on the drug delivery efficiency of nasal sprays. In this study, the drug delivery efficiency of three different nasal spray devices was evaluated in vitro using a 3D printed cast model of nasal cavity. Three nasal spray devices with different nozzles and angles of administration were used in the 3D model of the nasal cavity and paranasal sinuses. The spraying area (SA), maximal spraying distance (MSD), and spraying distribution scores on the nasal septum and lateral nasal wall were recorded. Different nasal spray devices have their own characteristics, including volume of each spray, SA, and plume angle. The SA of the three nozzles on the nasal septum increased with an increasing angle of administration. When the angle of administration was 50°, each nozzle reached the maximal SA. There was no statistically significant difference in MSD among the three nozzles at the three angles. The total scores for each nozzle using the three different spraying angles were as follows: nozzle A, 40°>30°>50°; nozzle B, 30°>40°>50°; and nozzle C, 30°>40°>50°. The total scores for different nozzles using the same angle were statistically significantly different and the scores for nozzle C were the highest. Nozzle C had the minimum plume angle. None of the three nozzles could effectively delivered drugs into the middle meatus at any angle in this model. The design of the nozzle affects drug delivery efficiency of nasal spray devices. The ideal angle of administration is 50°. The nozzle with smaller plume angle has higher drug delivery efficiency. Current nasal spray devices can easily deliver drugs to most areas of the nasal cavity, such as the turbinate, nasal septum, olfactory fissure, and nasopharynx, but not the middle meatus. These findings are meaningful for nozzle selection and device improvements.

Positive and negative secondary species emission behavior for an ionic liquid electrospray

Ionic liquid electrosprays can emit a polydisperse population of charged droplets, clusters, and molecular ions at high velocity. Secondary species emission (SSE) is a term that encompasses many concurrent impact and emission phenomena that occur when electrosprayed primary species strike a surface, resulting in a diverse population of secondary electrons, ions, clusters, and droplets. This Letter examines the spatial dependency of SSE behavior across an [EMI]Im electrospray beam using microscopy of the target surface and experimental quantification of SSE yields as a function of the plume angle. Microscopy of the beam target confirms our prediction of shock-induced desorption when operating at elevated beam voltages. SSE yield measurements show that, upon impact with a surface, incident primary species that consist of entirely positive charge will produce both positive and negative SSE. Furthermore, the results show that the SSE yields for an ionic liquid electrospray have strong spatial and energy dependencies. These findings have significant implications for understanding and predicting ionic liquid electrospray thruster lifetime and performance and focused ion beam applications.

Influence of the upstream axial magnetic mirror field on the plume characteristics in the full cylindrical Hall thruster

Full cylindrical Hall thruster holds considerable promise in terms of its low wall erosion rate and long-lifetime performance advantages. As far as we know, its upstream magnetic mirror field plays a fundamental role in the determination of plasma behavior and hence the thruster performance. In this paper, a series of upstream axial magnetic mirror fields with different axial gradient values were generated by adjusting the inverse-electromagnetic coil currents near the upstream channel and its effect on the plume characteristics were investigated. The experiment results indicate that under a low magnetic mirror field with 44.8 G/mm gradient value, a bulb-like plasma discharge region emitting a visible high-intensity light is discovered near the thruster exhaust, its plume manifests a hollow profile with a plume angle of 77°. In contrast, as the axial gradient value of magnetic mirror field increases from 44.8 G/mm to 72.5 G/mm, this bulb-like plasma region near exhaust shrink gradually to disappear along with the plume angle decreasing to 65°. Meanwhile, the anode efficiency enhances significantly (from 16% to 28%) correspondingly. According to the analysis of ion current, electron current and ion energy distribution, the observed strong plasma discharge near the thruster exhaust should be intimately related with the extension of the ionization region towards exit due to the weak electron confinement under the low magnetic mirror field. However, the larger upstream magnetic mirror field could diminish the leaking of local electrons towards the anode efficiently, which could not only intensify the ionization, but also induce the shrink of the ionization region axially towards the upstream channel and the clearer separation of acceleration region from the ionization region. Ultimately, the enhanced propellant utilization and current utilization, higher ion energy and the collimated plume are achieved. This work provides a feasible way to recognize the ionization and acceleration process under the mirror-like magnetic field of the miniaturized full cylindrical Hall thruster.

The first micro thrust measurement of the ultrasonic electric propulsion system

The Ultrasonic Electric Propulsion system is mainly used in space missions within the limits of 50 kg, and employs capillary standing waves as emitters to extract charged droplets in electric field. Due to multi-physics field such as ultrasonic vibration, liquid mechanics and electrostatic field in the Ultrasonic Electric Propulsion system, its thrust prediction always faces a big challenge. In this work, the thrust of Ultrasonic Electric Propulsion system is first measured by a measurement platform, and the test results are 565.23 μN, 715.65 μN and 842.73 μN with an accuracy in the order of 10% at 5 kV, 7 kV and 9 kV, and a flow rate of 5 ml/h and ultrasonic vibration frequency of 120 kHz. The test results also indicate that the thrust value increases with extraction voltage in the same flow rate with propellant and vibration frequency. Besides, the vacuum emission plume of Ultrasonic Electric Propulsion system is first investigated by a high-speed imaging technique, which reveals different emission conditions at different time such as parabolic emission trajectory and varied plume angles.

Mode transition of the cylindrical Hall thruster with the near-anode cusp magnetic field

There are two distinct discharge modes in a 200 W cylindrical Hall thruster with the near-anode cusp magnetic field. In mode I, a divergent plume is observed at a low discharge voltage. When the discharge voltage rises over 280 V, an apparent discharge mode transition occurs along with the sharp decreasing of discharge current (by 9.9%) and electron current (by 26%) and apparent narrowing of plume angle (by 12%), bringing a convergent plume (mode II). In mode I, the most probable ion energy of ion energy distribution function declines monotonically with the increasing of plume angle. However, a non-monotonic variation characteristic of most probable ion energy is indicated in mode II, which suggests that there are two ionization regions in this mode. These novel mode transition phenomena should be attributed to the unique near-anode cusp magnetic field. In low discharge voltage conditions (mode I), as the energies of the electron population are low, they are trapped in the near-axial magnetic mirror field, and a cylindrical ionization region along thruster axis is established. When the discharge voltage rises over the threshold voltage occurring mode transition, the energies of the electron population are enhanced and the energetic electrons could escape from the mirror field and reach the upstream crossed electric and magnetic fields. As a result, an additional ionization region related to E × B drift is formed in the upstream region. The competitive relationship between the upstream ionization related to E × B drift and the near-axial ionization related with magnetic mirror field should be the leading cause of mode transition.

Near-infrared measurement of temperature fields formed by mixed convection from a small heating sphere in water

This study proposed a method for reconstructing three-dimensional (3D) non-axisymmetric temperature fields in water formed by mixed convection surrounding a small heating sphere. The proposed method is based on the temperature dependence of the absorption coefficient of water at a wavelength of 1150 nm in the near-infrared (NIR) region. The absorbance images of a 10-mm-thick water cell containing a 1-mm diameter steel sphere heated via electromagnetic induction were acquired using a two-orthogonal-direction NIR imaging system. The 3D reconstruction was implemented by applying a non-axisymmetric inverse Abel transform to the absorbance images. In addition, particle tracking velocimetry (PTV) was applied to the same images to visualize and quantify the flow field. The results indicated that the temperature distribution within the plume was distorted compared to an axisymmetric one, and the plume shape, length, and angle were dependent on the forced flow and heating power. Further, employing a thermal balance model with temperature distributions, the heat production rates were determined and discussed based on the plume characteristics. The PTV results revealed a mixed convection field inconsistent with the plume shape, which was also verified by comparison with numerical simulations.

CFD-guided optimization of the injector and injection parameters for light-duty GCI engine

In this study, computational fluid dynamics (CFD) and machine learning (ML) were used to investigate the effects of and optimize the injector design parameters for light-duty gasoline compression ignition (GCI) engine. This study was performed at part- (6 bar) and high-load (22 bar) indicated mean effective pressure (IMEP) conditions. The effects of number of nozzles (nNoz), spray angle (SA) and plume angle (PA) while maintaining total nozzle area (TNA) and start of injection (SOI) were first investigated. The increased nNoz and PA enhanced fuel/air mixing, especially in the bowl region, by even spray distribution at part-load condition, but the effects are negligible at high-load mixing-driven combustion due to high in-cylinder temperature and pressure at the time of main injection. On the other hand, SA had significant effect on the air utilization and hence engine performance and emissions at both part- and high-load conditions. The best design from this manual parametric study produced a balanced air utilization between piston bowl and squish region resulting from the fuel spray targeting the upper lip of the bowl. The second phase of this study focused on the optimization of the injector and injection parameters including nNoz, SA, nozzle hole diameters (dNoz) and SOI using design of experiment (DoE) approach. 32 DoE cases were generated and best design was selected at each load point. It was found that the SA and SOI are the most influential injection parameters. Specifically, two optimum SOI regimes at part-load conditions have been identified. These are a) early injection resulting in retarded combustion and low pressure rise rate and b) late injection yielding high combustion efficiency and low hydrocarbon emission. At high-load condition, SOI right before top dead center (TDC) is most preferable and early injection should be avoided to minimize pressure rise rate. The narrow SA (90 degrees (deg) in this study) as well as wide SA were found to produce optimum performance. Subsequently, ML algorithm was used to further optimize the injector and injection parameters. As a result of this optimization study, 10.7% reduction of fuel consumption at part-load and 7.5% reduction at high-load were achieved.

Under pressure: turbulent plumes in a uniform crossflow

Direct numerical simulation is used to investigate the integral behaviour of buoyant plumes subjected to a uniform crossflow that are infinitely lazy at the source. Neither a plume trajectory defined by the centre of mass of the plume $z_c$ nor a trajectory defined by the central streamline $z_{U}$ is aligned with the average streamlines inside the plume. Both $z_c$ and $z_{U}$ are shown to correlate with field lines of the total buoyancy flux, which implies that a model for the vertical turbulent buoyancy flux is required to faithfully predict the plume angle. A study of the volume conservation equation shows that entrainment due to incorporation of ambient fluid with non-zero velocity due to the increase in the surface area (the Leibniz term) is the dominant entrainment mechanism in strong crossflows. The data indicate that pressure differences between the top and bottom of the plume play a leading role in the evolution of the horizontal and vertical momentum balances and are crucial for appropriately modelling plume rise. By direct parameterisation of the vertical buoyancy flux, the entrainment and the pressure, an integral plume model is developed which is in good agreement with the simulations for sufficiently strong crossflow. A perturbation expansion shows that the current model is an intermediate-range model valid for downstream distances up to $100\ell _b$ – $1000 \ell _b$ , where $\ell _b$ is the buoyancy length scale based on the flow speed and plume buoyancy flux.

Response Surface Methodology (RSM) Approach for Optimizing the Actuator Nozzle Design of Pressurized Metered-Dose Inhaler (pMDI)

Recently, a remarkable scientific interest in the inhalation therapy for respiratory disease was spiked attributed to the growing prevalence of asthma, chronic obstructive pulmonary disease (COPD), and coronavirus disease 2019 (COVID-19) pandemic. A pressurized metered-dose inhaler (pMDI) is the best option by providing fast and efficient symptomatic relief within the lung. However, the rapid development of new inhalation devices could be critical in this competitive environment, and optimizing the inhalation devices could be costly and time-consuming. Therefore, the computational fluid dynamic (CFD) approach was used to shorten the development time. In this study, response surface methodology (RSM) in ANSYS version 19.2 was introduced to discover the optimal design for the actuator nozzle to increase the performance of pMDI. Three (3) parameters (orifice diameter, length, and actuator angle) were optimized, and the best design was selected according to the analysis of particle tracking. The analysis of spray plume was also conducted and compared to analyze the spray plume characteristic produced by three designs. The result showed that RSM generated three (3) models for the new design of the actuator nozzle (Design A, Design B, and Design C). Among three (3) designs, actuator nozzle design C showed the highest injection particle number (232457) and the only one that produced maximum particles velocity magnitude in the acceptable ranges (35.67m/s). All three designs showed a similar pattern as maximum particle velocity magnitude decreased along the axial length until they match the air velocity (0.03-0.04 m/s). Furthermore, the spray plume length, angle, and width were observed to increase linearly with the decreasing maximum particle velocity magnitude. Thus, this study suggested that design C might have the potential as a new actuator nozzle to develop future pMDI to relieve the respiratory condition.

Nasal Spray Formulations Based on Combined Hyalurosomes and Glycerosomes Loading Zingiber officinalis Extract as Green and Natural Strategy for the Treatment of Rhinitis and Rhinosinusitis.

A total green nanotechnological nasal spray has been manufactured and proposed as an alternative treatment of rhinitis and rhinosinusitis. It was obtained by combining the strengthening effect of liposomes on barrier function, the hydrating and lubricating properties of sodium hyaluronan and the anti-inflammatory and antioxidant activities of the extract of Zingiber officinalis. To this purpose, the extract was loaded in special phospholipid vesicles immobilized with hyaluronic acid (hyalurosomes), which were further enriched with glycerol in the water phase. Liposomes and glycerosomes were prepared as well and used as reference. Vesicles were oligolamellar and multicompartment, as confirmed by cryogenic transmission electron microscopy (cryo-TEM) observation, small in size (~140 nm) and negatively charged (~−23 mV). Spray characteristics were evaluated by using the Spraytec® and instant images, from which the plume angle was measured. The range of the droplet size distribution and the narrow spray angle obtained suggest a good nebulization and a possible local deposition in the nasal cavity. In vitro studies performed by using human keratinocytes confirmed the high biocompatibility of vesicles and their ability to effectively counteract oxidative damage on cells induced by hydrogen peroxide. The overall collected data suggest that our vesicles are suitable as nasal spray.

Liquid Film Translocation Significantly Enhances Nasal Spray Delivery to Olfactory Region: A Numerical Simulation Study

Previous in vivo and ex vivo studies have tested nasal sprays with varying head positions to enhance the olfactory delivery; however, such studies often suffered from a lack of quantitative dosimetry in the target region, which relied on the observer’s subjective perception of color changes in the endoscopy images. The objective of this study is to test the feasibility of gravitationally driven droplet translocation numerically to enhance the nasal spray dosages in the olfactory region and quantify the intranasal dose distribution in the regions of interest. A computational nasal spray testing platform was developed that included a nasal spray releasing model, an airflow-droplet transport model, and an Eulerian wall film formation/translocation model. The effects of both device-related and administration-related variables on the initial olfactory deposition were studied, including droplet size, velocity, plume angle, spray release position, and orientation. The liquid film formation and translocation after nasal spray applications were simulated for both a standard and a newly proposed delivery system. Results show that the initial droplet deposition in the olfactory region is highly sensitive to the spray plume angle. For the given nasal cavity with a vertex-to-floor head position, a plume angle of 10° with a device orientation of 45° to the nostril delivered the optimal dose to the olfactory region. Liquid wall film translocation enhanced the olfactory dosage by ninefold, compared to the initial olfactory dose, for both the baseline and optimized delivery systems. The optimized delivery system delivered 6.2% of applied sprays to the olfactory region and significantly reduced drug losses in the vestibule. Rheological properties of spray formulations can be explored to harness further the benefits of liquid film translocation in targeted intranasal deliveries.

Determination of Spray Pattern and Plume Geometry of Combined Budesonide and Formoterol Fumarate pressurized Metered Dose Inhalation Aerosol

Budesonide and formoterol fumarate pressurized metered-dose inhaler (pMDI) is combined aerosol dosage form. The label claim of this combined dosage form is 100 mcg of Budesonide and 6 mcg of Formoterol Fumarate per actuation. It is prescribed for the treatment of asthma and chronic obstructive pulmonary disease (COPD). Formoterol fumarate is an anti-asthmatic drug (Bronchodilator), and Budesonide is Anti Inflammatory drug (Glucocortico steroid).The objective of plume geometry and spray pattern study is to monitor the consistency and quality of a device when actuated. The plume and pattern study aims to develop a formulation with robust device which can deliver an accurate amount of drug directly to the lungs of a patient. The chemistry manufacturing and controls (CMC) guideline outlined the basic data required for spray pattern and plume geometry measurement for different pMDI devices. In 2013, draft guidance on bioavailability and bioequivalence (BABE) of pMDI published, which provides details on plume geometry and spray pattern, image collection and evaluation.In the present study, the spray patterns were collected at 2 distances 3 and 6 cm from the actuator device's exit. The spray pattern Ovality results at 3 cm show 2.52% variation and at 6 cm results show 4.31% variation. Method precision, ruggedness and robustness study for Spray pattern also performed at 6 cm distance from actuator orifice. The plume geometry was collected at 6 cm distance from the exit of an actuator device. Plume geometry results show that Plume height is found in the range 16.20 cm to 18.98 cm, Plume angle is found from 17.7–24.9°, and Plume width is found between 3.68 to 4.57 cm.

Coupled in-nozzle flow and spray simulation of Engine Combustion Network Spray-G injector

A coupled Eulerian-Lagrangian approach was employed to Engine Combustion Network (ECN) Spray-G simulations. The Eulerian in-nozzle flow simulation was conducted with a small plenum attached to the nozzles, and the results were fed to the Lagrangian spray simulation. For Eulerian simulation, the homogeneous relaxation model (HRM) coupled with the volume of fluid (VOF) method was used. HRM proved to be good at predicting the phase change phenomena due to vaporization mechanisms, that is, both cavitation and flash boiling. As a one-way coupling, quantities such as rate of injection (ROI), mass injected through each hole, discharge coefficient, spray plume angle and half cone angle predicted from the Eulerian simulations were used as the initial and boundary conditions for the subsequent Lagrangian spray simulations using the blob injection model. Non-flashing (Spray-G1) and flashing (Spray-G2) spray was simulated, and the results were validated quantitatively against the published data in terms of the liquid and vapor penetration lengths, and good agreements were obtained. Furthermore, the simulation predicted the liquid and gas axial velocity and sauter mean diameter for Spray-G1 condition in agreement with the droplet size and particle image velocimetry (PIV) measurements from literature.

Experimental and numerical study of the effects of nozzle taper angle on spray characteristics of GDI multi-hole injectors at cold condition

With today’s stringent legislative requirements, every combustion/emission contributing component must be researched and optimized in modern gasoline direct injection (GDI) engines. However, a limited amount of research on the taper angle of gasoline injector nozzles can be found. In this study, three GDI fuel injectors are investigated to study the effects of nozzle taper angle on spray characteristics. All of the injectors have the same inlet diameter, and the only difference is the nozzle taper angle. Fuel pressure was set at 200 bar and fuel temperature was at room temperature. A numerical method was used to study the internal nozzle flow, and various optical techniques were applied to investigate the spray characteristics. It was found that adjusting the nozzle taper angle didn’t induce any noticeable difference in the static flow rate, which was linear with the square root of the pressure differential across the orifice plate. As a result, the initial tip penetration was proportional to the injection timing, and nearly independent with the nozzle taper angle. For well-developed sprays, larger nozzle taper angle resulted in shorter penetration and faster breakup. Increasing the nozzle taper angle resulted in larger space between internal flow and the nozzle wall, which enhanced air entrainment into the nozzle. Consequently, flow radial velocity at the nozzle exit increased, which was beneficial to spray breakup and atomization. Larger nozzle taper angle resulted in wider fuel plume, larger plume angle, broader and shorter global spray, which increased the possibility of plume interaction. Smaller fuel drops were measured from the injectors with larger taper angle. Finally, it shows that adjusting the taper angle of the nozzle offers an additional degree of freedom when trying to optimize the spray characteristics of an injector for improved fuel atomization, engine combustion performance and emissions reduction.

Particle deposition in the paranasal sinuses following endoscopic sinus surgery

Optimizing intranasal distribution and retention of topical therapy is essential in the management of patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). Computational fluid dynamics analysis has not previously been used to investigate sinus nasal spray delivery in the complete post-operative sinonasal geometries of patients who have undergone FESS. Models of sinonasal cavities were created from postoperative magnetic resonance imaging scans in four patients, three of whom underwent a comprehensive FESS, the other a modified endoscopic Lothrop procedure. Spray simulations were conducted at different flow rates (5 L/min, 10 L/min and 15 L/min) using sixteen particle sizes ranging from 4 μm to 70μm, spray velocity of 10 m/s and plume angle of 15°. Two different spray insertion angles were compared. Airflow distribution in the sinuses was closely related to the patient's nasal geometry and surgical intervention, in particular a unique crossflow between nasal chambers was present for the Lothrop patient. Sinus deposition was generally more effective with inhalational transport of low-inertia particles outside of the range produced by many standard nasal sprays or nebulizer. This was true except in the Lothrop patient, since previous surgery had been performed removing most of the septum where high-inertia particles would normally deposit. For sinuses receiving minimal airflow, particle penetration was diminished and successful deposition in the region became more restricted by device parameters. Further research is needed to validate these findings and explore other spray variables in a wider spectrum of patients to ascertain a multi-level approach to optimizing drug delivery in the sinuses.

A modified USP induction port to characterize nasal spray plume geometry and predict turbinate deposition under flow

There is currently no in vitro technique for assessing plume geometry of nasal sprays under airflow conditions. However, a majority of FDA approved nasal products recommend that patients inhale during actuation. Therefore, a reproducible in vitro test that measures plume angles under physiologically relevant inhalation flow rates would be useful. The purpose of this study was to adapt the recently described Plume Induction Port Evaluator (PIPE) apparatus for nasal sprays under flow and correlate these with nasal cast deposition patterns.Mass Median Plume Angles (MMPAs) of four nasal spray formulations with increasing viscosities were determined using the PIPE apparatus in the absence and presence of airflow. MMPAs were then correlated to drug deposition within 3D printed nasal casts using airflow. We evaluated different inhalation instructions obtained from the package insert of nasal products.MMPAs significantly reduced (narrower angles) when using flow for the three formulations with the lowest viscosities. An increase in the turbinate deposition was observed in the nasal casts when just one of the nostrils was closed during inhalation, except by the highest viscosity formulation. The turbinate deposition numerically correlated with changes in the plume angles observed using PIPE.

A Simplified Geometric Model to Predict Nasal Spray Deposition in Children and Adults.

A mathematical approach was developed to estimate spray deposition patterns in the nasal cavity based on the geometric relationships between the emitted spray plume and the anatomical dimensions of the nasal valve region of the nasal cavity. Spray plumes were assumed to be spherical cones and the nasal valve region was approximated as an ellipse. The effect of spray plume angle (15-85°) on the fraction of the spray able to pass through the nasal valve (deposition fraction) was tested for a variety of nasal valve (ellipse) shapes and cross-sectional areas based on measured dimensions from pediatric and adult nasal cavities. The effect of the distances between the tip of the nasal spray device and the nasal valve (0.2-1.9cm) on the deposition fraction was also tested. Simulation results show that (1) decreasing spray plume angles resulted in higher deposition fractions, (2) deposition fraction was inversely proportional to the spray distance and the nasal valve (ellipse) major/minor axis ratio, and (3) for fixed major/minor axis ratios, improved deposition occurred with larger nasal valve cross-sectional areas. For a typical adult nasal valve, plume angles of less than 40° emitted from a distance of 1cm resulted depositions greater than 90% within the main nasal cavity, whereas for a 12-year-old child, only the most narrow plume angles (< 20°) administered resulted in significant deposition beyond the nasal valve.

The influence of plume angle and energy on the mass separation of plasma beam

Plasma optical mass separation is an important innovation in the field of isotopes separation. The magnetic field in the separation region only plays the role of magnetizing plasma and guiding the beam flow direction. The ion trajectory in the separation region containing only radial electric field is the focus of the current research. The plume angle and energy of the plasma beam also determine the effect of beam mass separation. Based on the equation of motion of the ion in the electric field and the mechanism of obtaining the circumferential velocity in the azimuthator, the trajectories of the lithium ions at different plume angles and different energies are analysed, and the parameters of plume angle and energy with the best separation effect are obtained, which provides parameters for the engineering implementation of the multi-mass beam separation structure. The research results can be applied to the development of some devices, such as the mass separator, the mass spectrum analyser and material purification. At the same time, it has certain reference significance for the related field’s research of the special configuration electromagnetic field controlling multi-mass beam flow.