Experimental Observation and Numerical Simulation for Injection Characteristics of Piezoelectric Inkjet Printhead

• Main Authors: M.-L., Chiu, 邱明立
• Other Authors: H.-P., Cheng
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/52455737871793543257

碩士 === 國立臺北科技大學 === 冷凍與低溫科技研究所 === 92 === In the research study, the commonly used analytical software in computational fluid dynamics, CFD-RC, for statistical analysis on the droplet injection by piezoelectric inkjet printhead, and accompanied with experimental observation to analyze the injection of droplets. This study defined liquid form and external gas form f piezoelectric inkjet as incompressible fliuid, governing equation as the conservation of mass and momentum, and used Volume-Of-Fluid (VOF) to describe the size and motion path of the droplets. Finite Volume method was used to disperse the governing equation, and Pressure Based SIMPLEC algorithm was used for solution. The numerical simulation studied the effect of fluid characteristics, diameter of the nozzle, cavity size, and voltage waveform, and found out that the viscocity coefficient of the water and ink was very close to the surface tension. As a result, the shape and speed of injected droplets were very similar. Given fixed viscosity coefficient of the work fluid, the droplet speed increases as the surface tension rises. Given fixed surface tension of work fluid, larger the viscosity coefficient leads to slower injection speed. Under different piezoelectric substrate, the “push-stop-push” method generated higher injection speed. The experimented discussed the effect of time length of driving waveform on the speed and volume of injection droplets. The results showed that for different driving waveform, longer the time length leads to slower droplet injection speed and larger volume.