scholarly journals Needle-Free Jet Injectors’ Geometry Design and Drug Diffusion Process Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Yunfei Wang ◽  
Long Yue ◽  
Lechuan Hu ◽  
Jing Wang
Keyword(s):  
Diffusion Process ◽  
Process Analysis ◽  
Subcutaneous Tissue ◽  
Nozzle Geometry ◽  
Drug Diffusion ◽  
Free Jet ◽  
Cylindrical Nozzle ◽  
Geometry Design ◽  
Nozzle Geometries ◽  
Jet Injectors

In order to study the injection and diffusion process of the drug in the subcutaneous tissue of a needle-free jet injectors (NFJIs) in detail and understand the influence of different nozzle geometry on the diffusion process of the drug, in this paper, numerical simulations were performed to study the diffusion process of the drug in the subcutaneous tissue of NFJIs with cylindrical nozzle. On this basis, the differences of the drug diffusion process with different nozzle geometries were analyzed. The results show that the drug diffused in the shape of ellipsoid in the subcutaneous tissue. The penetration of the drug into the subcutaneous tissue is deeper under the condition of conical nozzle and conical cylindrical nozzle at the same time. However, it takes longer to spread to the interface between skin and subcutaneous tissue in reverse.

An Attempt to Improve the Deposition Efficiency of AI2O3 Coating by HVOF Spraying

2000 ◽  
Author(s):  
Y. Shimizu ◽  
K. Sugiura ◽  
K. Sakaki ◽  
A. Devasanapathi
Keyword(s):  
Hardness Test ◽  
Deposition Efficiency ◽  
Nozzle Geometry ◽  
Hvof Spraying ◽  
Fuel Gas ◽  
Dense Microstructure ◽  
Alumina Particles ◽  
Coating Characteristics ◽  
Nozzle Geometries ◽  
Spraying Process

Abstract High Velocity Oxy-Fuel (HVOF) method using propylene as a fuel gas was employed to spray alumina particles. In order to improve the coating characteristics such as the deposition efficiency and the hardness, three HVOF gun nozzles of varying geometry were designed and tested experimentally. The spraying process was also simulated numerically for each of the nozzle geometries to understand their effectiveness in influencing the velocity and temperature of the sprayed particles. The coating was characterized using optical and scanning electron microscopy (SEM), micro-vickers hardness test and X-ray diffractometry (XRD). Results showed that with the use of a convergent and divergent type gun nozzle, similar to that of a Laval nozzle, the extent of melting of the alumina particles could be increased. This was exhibited by an increase in the deposition efficiency to the extent of 45%. However, the sharp changes in the convergent and divergent nozzle geometry, resulted in fusion and agglomeration of alumina particles leading to spitting during the spraying process. The results clearly showed that alumina coatings of excellent hardness in the range of 920-1290 HV, with a relatively dense microstructure could be obtained in HVOF method irrespective of the gun nozzle geometry, provided the spraying parameters are properly controlled.

Nozzle Geometry Effect on Twin Jet Flow Characteristics

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Muthuram A ◽  
Thanigaiarasu S ◽  
Rakesh Divvela ◽  
Rathakrishnan Ethirajan
Keyword(s):  
Mach Number ◽  
Flow Characteristics ◽  
Nozzle Geometry ◽  
Ambient Atmosphere ◽  
Free Jets ◽  
Twin Jets ◽  
Equivalent Area ◽  
Nozzle Configuration ◽  
Jet Nozzle ◽  
Nozzle Geometries

AbstractEffect of nozzle geometries on the propagation of twin jet issuing from nozzles with circle-circle, circle-ellipse, circle-triangle, circle-square, circle-hexagon and circle-star geometrical combinations was investigated for Mach numbers 0.2, 0.4, 0.6 and 0.8. In all the cases, both jets in the twin jet had the same Mach number. All the twin jets of this study are free jets, discharged into stagnant ambient atmosphere. The result of the twin jets issuing from circle-circle nozzle is kept as the reference in this study. For all the twin jet nozzles, the inter nozzle spacing; the distance between the nozzle axes (S) was 20 mm and all the nozzles had an equivalent area of 78.5 mm2. Thus for all the cases of the present study, S/D ratio is 2. The results show that the mixing of the combined jet, after the merging point is strongly influenced by the combined effect of the nozzle geometry and jet Mach number. Among the six different twin jet nozzle configuration studied, circle-square combination is found to be the most superior mixing promoter.

Effects of nozzle geometry on kinetics in free-jet expansions

1984 ◽  
Vol 88 (20) ◽  
pp. 4474-4478 ◽  
Author(s):  
Hylton R. Murphy ◽  
David R. Miller
Keyword(s):  
Nozzle Geometry ◽  
Free Jet

Impact of Mechanical Chevrons on Supersonic Jet Flow and Noise

2009 ◽  
Author(s):  
K. Kailasanath ◽  
Junhui Liu ◽  
Ephraim Gutmark ◽  
David Munday ◽  
Steven Martens
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Near Field ◽  
Supersonic Jet ◽  
Initial Step ◽  
Nozzle Geometry ◽  
Jet Flows ◽  
Flow Conditions ◽  
Nozzle Geometries ◽  
The Impact

In this paper, we present observations on the impact of mechanical chevrons on modifying the flow field and noise emanated by supersonic jet flows. These observations are derived from both a monotonically integrated large-eddy simulation (MILES) approach to simulate the near fields of supersonic jet flows and laboratory experiments. The nozzle geometries used in this research are representative of practical engine nozzles. A finite-element flow solver using unstructured grids allows us to model the nozzle geometry accurately and the MILES approach directly computes the large-scale turbulent flow structures. The emphasis of the work is on “off-design” or non-ideally expanded flow conditions. LES for several total pressure ratios under non-ideally expanded flow conditions were simulated and compared to experimental data. The agreement between the predictions and the measurements on the flow field and near-field acoustics is good. After this initial step on validating the computational methodology, the impact of mechanical chevrons on modifying the flow field and hence the near-field acoustics is being investigated. This paper presents the results to date and further details will be presented at the meeting.

Visual Investigation of an Ejector Motive Nozzle

2010 ◽  
Author(s):  
Christian Tischendorf ◽  
Christian Lucas ◽  
Juergen Koehler ◽  
Wilhelm Tegethoff
Keyword(s):  
Energetic Efficiency ◽  
Refrigeration Cycle ◽  
Shape Parameters ◽  
Flow Conditions ◽  
Compressibility Effect ◽  
Free Jet ◽  
Key Issues ◽  
Ejector Nozzle ◽  
Physical Effects ◽  
Nozzle Geometries

Previous investigations by other authors, e.g. Lorentzen [1], have shown that in a conventional refrigeration cycle significant throttling losses occurs. With the help of an ejector, these losses can be reduced. As a result, the energetic efficiency (COP) of the refrigerant system will be improved. Investigations show that CO2 ejector cycles are feasible and that some systems have already been commercialized successfully. The key issues in the optimization of the ejector used in a refrigeration cycle are the geometries of the different ejector parts. To optimize the geometry, a deeper understanding of the physical effects and the flow conditions within the ejector are essential. So far there are only a few investigations published on this issue, e.g. Elbel [2], investigated the flow in the mixing section of the ejector. This paper presents experimental results for different ejector nozzle geometries and operational condiditons. The motive nozzle was investigated separately from the other ejector parts. Investigated were multi-hole nozzles and the effect of the jet shape. Parameters were chosen according to the typical conditions in ejector refrigeration systems. Based on these conditions, the free jet exiting the motive nozzle was observed. To investigate the jet shape, an new experimental setup was designed. The motive jet was visually observed in a glass cylinder. The combination of both the contraction and compressibility effect on mass flow rate was also investigated.

scholarly journals Novell Application of CFD for Rocket Engine Nozzle Optimization

2018 ◽  
Vol 47 (2) ◽  
pp. 131-135
Author(s):  
Csaba Jéger ◽  
Árpád Veress
Keyword(s):  
Simulation Model ◽  
Rocket Engine ◽  
Pressure Ratio ◽  
Geometry Optimization ◽  
Optimization Procedure ◽  
Geometric Optimization ◽  
Nozzle Geometry ◽  
Nozzle Contour ◽  
Nozzle Geometries ◽  
Optimization Loop

Numerical analyses, validation and geometric optimization of a converging-diverging nozzle flows has been established in the present work. The optimal nozzle contour for a given nozzle pressure ratio and length yields the largest obtainable thrust for the conditions and thus minimises the losses. Application of such methods reduces the entry cost to the market, promote innovation and accelerate the development processes. A parametric geometry, numerical mesh and simulation model is constructed first to solve the problem. The simulation model is then validated by using experimental and computational data. The optimizations are completed for conical and bell shaped nozzles also to find the suitable nozzle geometries for the given conditions. Results are in good agreement with existing nozzle flow fields. The optimization loop described and implemented here can be used in the all similar situations and can be the basis of an improved nozzle geometry optimization procedure by means of using a multiphysics system to generate the final model with reduced number sampling phases.

A New Concept of Needle-Free Jet Injector by the Impact Driven Method

2017 ◽  
Vol 11 (1) ◽  
Author(s):  
Prachya Mukda ◽  
Kulachate Pianthong ◽  
Wirapan Seehanam
Keyword(s):  
High Speed ◽  
Liquid Jet ◽  
High Speed Photography ◽  
Free Jet ◽  
Impact Peak ◽  
Lower Pain ◽  
Jet Velocity ◽  
Commercial Device ◽  
Jet Injectors ◽  
The Impact

Currently, most of commercial needle-free jet injectors generate the liquid jet by a method called “driving object method” (DOM); however, the reliability and efficiency are still questioned. This paper proposes a new concept of jet generation method, known as “impact driven method” (IDM). A prototype of an IDM jet injector is designed, built, tested, and compared to a commercial device (Cool.click, Tigard, OR). Fundamental characteristics, i.e., the exit jet velocity and impact pressure, are measured. Jet injection processes are visualized both in air and in 20% polyacrylamide by high speed photography. In this study, from the prototype of the IDM jet injector, a maximum jet velocity of 400 m/s and impact peak pressure of 68 MPa can be obtained. It is clear that the IDM jet injector provides a double pulsed liquid jet, which is a major advantage over the commercial jet injector. Because, the first pulse gives a shorter erosion stage, and then, immediately the second pulse follows and provides a better penetration, wider lateral dispersion, and considerably less back splash. Hence, lower pain level and higher delivery efficiency should be achieved. It can be concluded that the IDM concept is highly feasible for implementation in real applications, either for human or animal injection. However, the control and accuracy of IDM still needs to be carefully investigated.

Experimental Improvement of Ejector Performance Through Numerical Optimization of Nozzle Geometry

2013 ◽  
Author(s):  
Navid Sharifi ◽  
Majid Sharifi
Keyword(s):  
Optimization Procedure ◽  
Nozzle Geometry ◽  
Cfd Models ◽  
Steam Ejector ◽  
Nominal Pressure ◽  
Fixed Constant ◽  
Nozzle Geometries ◽  
The One ◽  
Suction Flow ◽  
The Given

Ejectors are widely used in different applications such as refrigeration, propulsion, evacuation and aerospace. They use a pressurized flow as a motive stream to entrain a secondary flow or suction flow. In the current study, a malfunctioning steam ejector is studied experimentally to identify the sources of low compression ratio. This ejector was designed to operate under a motive pressure of 6 bar. However, the required vacuum in the system was not attained unless the pressure of motive steam was increased to 8 bar. The steam ejector was coupled with other unit operating facilities and hence, the ejector replacement was very costly. Therefore, the fastest and the most inexpensive way of improving the device performance was considered as replacing just the primary nozzle and without any further change in ejector’s geometry. To achieve the required vacuum under the available motive pressure (i.e. 6 bar), a CFD–based optimization procedure was performed and different nozzle shapes were numerically investigated. The CFD Models were constrained to a fixed constant throat since the optimized nozzle shall not consume more flow rate than the former one. Ten different nozzle geometries were scrutinized in this numerical simulation and the one, which yields the highest entraining performance under the given boundary condition (i.e. motive flow pressure of 6 bar), was selected as the most optimized nozzle and manufactured. After installing the designed nozzle, an improved entrainment capability was observed and a desired vacuum level was attained under the nominal pressure of 6 bar.

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