scholarly journals Simulation and Validation of Droplet Generation Process for Revealing Three Design Constraints in Electrohydrodynamic Jet Printing

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 94 ◽  
Author(s):  
Yanqiao Pan ◽  
Liangcai Zeng
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
High Performance ◽  
Droplet Generation ◽  
Generation Process ◽  
Design Constraints ◽  
Whole Process ◽  
Velocity Magnitude ◽  
Electrohydrodynamic Jet Printing ◽  
Jet Printing

Droplet generation process can directly affect process regulation and output performance of electrohydrodynamic jet (E-jet) printing in fabricating micro-to-nano scale functional structures. This paper proposes a numerical simulation model for whole process of droplet generation of E-jet printing based on the Taylor-Melcher leaky-dielectric model. The whole process of droplet generation is successfully simulated in one whole cycle, including Taylor cone generation, jet onset, jet break, and jet retraction. The feasibility and accuracy of the numerical simulation model is validated by a 30G stainless nozzle with inner diameter ~160 μm by E-jet printing experiments. Comparing numerical simulations and experimental results, period, velocity magnitude, four steps in an injection cycle, and shape of jet in each step are in good agreement. Further simulations are performed to reveal three design constraints against applied voltage, flow rate, and nozzle diameter, respectively. The established cone-jet numerical simulation model paves the way to investigate influences of process parameters and guide design of printheads for E-jet printing system with high performance in the future.

Numerical Simulation on Flow Field of Bladeless Fan

2014 ◽  
Author(s):  
Li Guoqi ◽  
Lin Peifeng ◽  
Cui Baoling ◽  
Jin Yingzi ◽  
Hu Yongjun ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Fluid Motion ◽  
Internal Flow ◽  
External Flow ◽  
Computational Domain ◽  
Static Characteristics ◽  
Whole Process ◽  
Velocity Magnitude ◽  
Flow Field Characteristics

With the advent of bladeless fan, technological revolutions begin to hit the industrial design world of fan. However, there is none of the developed methods on bladeless fan. To explore the excellent blowing performance of bladeless fan, numerical simulation on flow field of bladeless fan was carried out in this paper. Based on the simplified model of bladeless fan, the whole process that the airflow passes through the turbine from the inlet to the outlet slit and exit far field at last, were simulated. By comparing the flux of inlet and the flux of far outlet, the causes of flux increasing are analyzed. After analyzing static characteristics of the flow field, it shows that pressure difference is very obvious. The results obtained from velocity distribution and the characteristics of the pathlines near diffuser section and turbine, were described and analyzed. The results show that the internal flow field characteristics of bladeless fans, which we concern. The external flow field characteristics of bladeless fan was studied in the same way. And it is found that the velocity magnitude of the outlet slit and Coanda surface is much larger than other area and different positions play different roles. A general analysis on inside computational domain and outside computational domain, denotes the details about fluid motion. The research could offer reference to improvement of bladeless fan.

Modeling and Experimental Validation of Droplet Generation in Electrohydrodynamic Inkjet Printing for Prediction of Printing Quality

2021 ◽  
Author(s):  
Liangkui Jiang ◽  
Pavithra Premaratne ◽  
Yanhua Huang ◽  
Zhan Zhang ◽  
Hantang Qin
Keyword(s):  
Fluid Dynamics ◽  
Simulation Model ◽  
Inkjet Printing ◽  
High Performance ◽  
Optimization Techniques ◽  
Generation Mechanism ◽  
Droplet Generation ◽  
Duty Ratio ◽  
Printing Quality ◽  
Long Time

Abstract Electrohydrodynamic (EHD) Inkjet printing is one type of micro/nano scale additive manufacturing technique. The droplet generation mechanism plays an important role in electrohydrodynamic (EHD) inkjet printing due to its significant effects on process control, printing quality, and printing performance. The large variation of printing system design used in EHD printing and the limited process optimization techniques resulted in a complex experimental procedure to determine a working condition, and it takes a long time to finish such experiments. It is also challenging to understand the droplet generation mechanism’s fluid dynamics under a multiphysical field in EHD printing. The development of computational fluid dynamics (CFD) and the recent advancements in high performance computing can be utilized to alleviate the aforementioned challenges. In this study, a numerical simulation model was developed to model the droplet generation mechanism in EHD printing based on Taylor-Melchar leaky-dielectric model. This model successfully simulated a single printing cycle, including Taylor cone formation, cone-jet generation, jet break, and jet retraction. A further simulation study demonstrated accurate predictions of the droplet volume and the jetting diameter under different working conditions (e.g., voltages and duty ratio of pulsed AC voltage). Experiments validated the simulation model and its prediction results. Such advancement in modeling can be used to optimize the printing process as well as guide the quick selection of printing conditions given a new ink.

Fundamental Examination of Numerical Simulation Model for Pressure Rise due to Underwater Arc

2014 ◽  
Vol 134 (7) ◽  
pp. 604-613 ◽  
Author(s):  
Toshiya Ohtaka ◽  
Tomo Tadokoro ◽  
Masashi Kotari ◽  
Tadashi Amakawa
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Pressure Rise

Evaluation of an improvement in runoff control by means of a construction of an infiltration sewer pipe under a porous asphalt pavement

1997 ◽  
Vol 36 (8-9) ◽  
pp. 397-402
Author(s):  
Yasuhiko Wada ◽  
Hiroyuki Miura ◽  
Rituo Tada ◽  
Yasuo Kodaka
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Asphalt Pavement ◽  
Considerable Effect ◽  
Rainfall Infiltration ◽  
Sewer Pipe ◽  
Porous Asphalt ◽  
Runoff Control

We examined the possibility of improved runoff control in a porous asphalt pavement by installing beneath it an infiltration pipe with a numerical simulation model that can simulate rainfall infiltration and runoff at the porous asphalt pavement. From the results of simulations about runoff and infiltration at the porous asphalt pavement, it became clear that putting a pipe under the porous asphalt pavement had considerable effect, especially during the latter part of the rainfall.

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

scholarly journals Study on the regional characteristics during foam flooding by population balance model

2020 ◽  
pp. 014459872098361
Author(s):  
Zhongbao Wu ◽  
Qingjun Du ◽  
Bei Wei ◽  
Jian Hou
Keyword(s):  
Numerical Simulation ◽  
Simulation Model ◽  
Oil Recovery ◽  
Population Balance ◽  
Growth Zone ◽  
Balance Model ◽  
Population Balance Model ◽  
Liquid Ratio ◽  
One Dimensional ◽  
Foam Flooding

Foam flooding is an effective method for enhancing oil recovery in high water-cut reservoirs and unconventional reservoirs. It is a dynamic process that includes foam generation and coalescence when foam flows through porous media. In this study, a foam flooding simulation model was established based on the population balance model. The stabilizing effect of the polymer and the coalescence characteristics when foam encounters oil were considered. The numerical simulation model was fitted and verified through a one-dimensional displacement experiment. The pressure difference across the sand pack in single foam flooding and polymer-enhanced foam flooding both agree well with the simulation results. Based on the numerical simulation, the foam distribution characteristics in different cases were studied. The results show that there are three zones during foam flooding: the foam growth zone, stable zone, and decay zone. These characteristics are mainly influenced by the adsorption of surfactant, the gas–liquid ratio, the injection rate, and the injection scheme. The oil recovery of polymer-enhanced foam flooding is estimated to be 5.85% more than that of single foam flooding. Moreover, the growth zone and decay zone in three dimensions are considerably wider than in the one-dimensional model. In addition, the slug volume influences the oil recovery the most in the foam enhanced foam flooding, followed by the oil viscosity and gas-liquid ratio. The established model can describe the dynamic change process of foam, and can thus track the foam distribution underground and aid in optimization of the injection strategies during foam flooding.

High-resolution additive direct writing of metal micro/nanostructures by electrohydrodynamic jet printing

2021 ◽  
Vol 543 ◽  
pp. 148800
Author(s):  
Wuhao Zou ◽  
Haibo Yu ◽  
Peilin Zhou ◽  
Ya Zhong ◽  
Yuechao Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Direct Writing ◽  
Electrohydrodynamic Jet Printing ◽  
Jet Printing
Sign in / Sign up

Export Citation Format

Share Document