Numerical Simulation of Bubble Coalescence Based on VOF Method

2011 ◽  
Vol 148-149 ◽  
pp. 814-817
Author(s):  
Zhi Yong Yang ◽  
Jian Dong Li ◽  
Guo Hua Zhang
Keyword(s):  
Performance Improvement ◽  
Bubble Coalescence ◽  
Initial Time ◽  
Vertical Position ◽  
Volume Of Fluid Method ◽  
Group Research ◽  
And Performance ◽  
Different Diameters ◽  
Two Bubbles ◽  
Center Distance

This paper takes bubbles of bubble shell as research object, mainly studies two bubbles arranged in a vertical position. Applying VOF (volume of fluid) method to simulate interaction between two bubbles, analyses the effect of center distances and diameters on deformation and coalescence of bubbles. Results show that coalescence time of two bubbles with same diameters increases as the center distance increases. To two bubbles with different diameters, when the bigger bubble located beneath at the initial time, the smaller bubble moves upward first and then moves downward before two bubbles coalesce. When the smaller bubble located beneath at the initial time, bubble coalescence cannot happen. This paper is the basis of bubble group research, it is of positive significance to the bubble group research and performance improvement of bubble shell.

Efficiency of pay for performance program on the brazilian judiciary

2014 ◽  
Author(s):  
Luis Cláudio de Jesus-Silva ◽  
Antônio Luiz Marques ◽  
André Luiz Nunes Zogahib
Keyword(s):  
Performance Improvement ◽  
Pay For Performance ◽  
Field Research ◽  
The State ◽  
Quantitative Approach ◽  
The Internet ◽  
Court Of Justice ◽  
And Performance ◽  
Compensation Program ◽  
Structured Questionnaire

This article aims to examine the variable compensation program for performance implanted in the Brazilian Judiciary. For this purpose, a survey was conducted with the servers of the Court of Justice of the State of Roraima - Amazon - Brazil. The strategy consisted of field research with quantitative approach, with descriptive and explanatory research and conducting survey using a structured questionnaire, available through the INTERNET. The population surveyed, 37.79% is the sample. The results indicate the effectiveness of the program as a tool of motivation and performance improvement and also the need for some adjustments and improvements, especially on the perception of equity of the program and the distribution of rewards.

Current progress and performance improvement of Pt/C catalysts for fuel cells

2020 ◽  
Vol 8 (46) ◽  
pp. 24284-24306
Author(s):  
Xuefeng Ren ◽  
Yiran Wang ◽  
Anmin Liu ◽  
Zhihong Zhang ◽  
Qianyuan Lv ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Conversion ◽  
Performance Improvement ◽  
Electric Energy ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Carnot Cycle ◽  
High Energy Conversion Efficiency ◽  
And Performance

Fuel cell is an electrochemical device, which can directly convert the chemical energy of fuel into electric energy, without heat process, not limited by Carnot cycle, high energy conversion efficiency, no noise and pollution.

scholarly journals Parameter Determination and Ion Current Improvement of the Ion Current Sensor Used for Flame Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 697
Author(s):  
Hanqing Xu ◽  
Weijun Fan ◽  
Jianwei Feng ◽  
Peiliang Yan ◽  
Shuchan Qi ◽  
...  
Keyword(s):  
Contact Area ◽  
High Reliability ◽  
Ion Current ◽  
Parameter Determination ◽  
Current Sensor ◽  
Vertical Position ◽  
Excitation Voltage ◽  
Burner Exit ◽  
And Performance ◽  
Flame Monitoring

Flame monitoring of industrial combustors with high-reliability sensors is essential to operation security and performance. An ion current flame sensor with a simple structure has great potential to be widely used, but a weak ion current is the critical defect to its reliability. In this study, parameters of the ion current sensor used for monitoring flames on a Bunsen burner are suggested, and a method of further improving the ion current is proposed. Effects of the parameters, including the excitation voltage, electrode area, and electrode radial and vertical positions on the ion current, were investigated. The ion current grew linearly with the excitation voltage. Given that the electrodes were in contact with the flame fronts, the ion current increased with the contact area of the cathode but independent of the contact area of the anode. The smaller electrode radial position resulted in a higher ion current. The ion current was insensitive to the anode vertical position but largely sensitive to the cathode vertical position. Based on the above ion current regularities, the sensor parameters were suggested as follows: The burner served as a cathode and the platinum wire acted as an anode. The excitation voltage, anode radial and vertical positions were 120 V, 0 mm, and 6 mm, respectively. The method of further improving the ion current by adding multiple sheet cathodes near the burner exit was proposed and verified. The results show that the ion current sensor with the suggested parameters could correctly identify the flame state, including the ignition, combustion, and extinction, and the proposed method could significantly improve the magnitude of the ion current.

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