scholarly journals Dynamics of entrained air bubbles inside a piezodriven inkjet printhead

2009 ◽  
Vol 95 (22) ◽  
pp. 221902 ◽  
Author(s):  
Sang Joon Lee ◽  
Dae Hee Kwon ◽  
Yong Seok Choi
Keyword(s):  
Air Bubbles ◽  
Entrained Air ◽  
Inkjet Printhead

Air Entrainment and Bubble Generation by a Hydrofoil in a Turbulent Channel Flow

2019 ◽  
Author(s):  
Ichiro Kumagai ◽  
Kakeru Taguchi ◽  
Chiharu Kawakita ◽  
Tatsuya Hamada ◽  
Yuichi Murai
Keyword(s):  
Channel Flow ◽  
Flow Rate ◽  
High Speed ◽  
Air Flow ◽  
Air Entrainment ◽  
Air Bubbles ◽  
Air Flow Rate ◽  
Bubble Generation ◽  
Gas Liquid Flow ◽  
Entrained Air

Abstract Air entrainment and bubble generation by a hydrofoil bubble generator for ship drag reduction have been investigated using a small high-speed channel tunnel with the gap of 20 mm in National Maritime Research Institute (NMRI). A hydrofoil (NACA4412, chord length = 40 mm) was installed in the channel and an air induction pipe was placed above the hydrofoil. The flow rate of the entrained air was quantitatively measured by thermal air flow sensors at the inlet of the air induction pipe. The gas-liquid flow around the hydrofoil was visualized by a backlight method and recorded by a high-speed video camera. As the flow velocity in the channel increased, the negative pressure generated above the suction side of the hydrofoil lowered the hydrostatic pressure in the channel, then the atmospheric air was entrained into the channel flow. The entrained air was broken into small air bubbles by the turbulent flow in the channel. The threshold of air entrainment, the air flow rate, and gas-liquid flow pattern depends on Reynolds number, angle of attack (AOA), and hydrofoil type. We identified at least three modes of air entrainment behavior: intermittent air entrainment, stable air entrainment, and air entrainment with a ventilated cavity. At high flow speed in our experimental condition (9 m/s), a large volume of air bubbles was generated by this hydrofoil system (e.g. air flow rate was 50 l/min for NACA4412 at AOA 16 degrees), which has a high potential to reduce ship drag.

307 Evaluation of cavitation by measurement of oil entrained air bubbles

2015 ◽  
Vol 2015 (0) ◽  
pp. 74-75
Author(s):  
Hiroyuki GOTO ◽  
Sayako SAKAMA ◽  
Ryosuke FUNACHI ◽  
Yutaka TANAKA
Keyword(s):  
Air Bubbles ◽  
Entrained Air

Les effets des caractéristiques du réseau de bulles d'air, du type de mûrissement, du truellage de surface et de la fumée de silice sur la résistance à l'écaillage d'un béton à haute performance

1996 ◽  
Vol 23 (6) ◽  
pp. 1260-1271
Author(s):  
Richard Gagné ◽  
Yvon Latreille ◽  
Jacques Marchand
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
High Performance Concrete ◽  
Surface Finishing ◽  
Air Bubbles ◽  
Concrete Durability ◽  
Freeze Thaw ◽  
Spacing Factor ◽  
Entrained Air ◽  
Scaling Resistance

In Canada, high-performance concretes (HPCs) are increasingly used in construction and repair, particularly for its durability, which is distinctly superior compared with ordinary concrete. The current tendency is to provide for a spacing factor of air bubbles lower than 230 μm in all HPCs that are subjected to freeze–thaw cycles. This choice is basically the outcome of an ongoing controversy as to the necessity of providing a good network of entrained air bubbles to protect HPCs against freeze–thaw cycles. In the future, the optimal use of HPC will depend, among other factors, on a better understanding of minimal requirements regarding the characteristics of air voids to ensure a good behavior of HPCs under freeze–thaw cycles. The results of the investigation reported herein show that a spacing factor lower than approximately 500 μm can be sufficient to ensure a good resistance of HPCs to scaling. It is also shown that surface trawling, slump, and set-retarding agents have only secondary effects on the scaling resistance of HPCs. Silica fume and membrane curing have allowed to improve significantly the scaling resistance of the HPCs under investigation. Key words: high-performance concrete, durability, scaling, set-retarding agent, silica fume, surface finishing, curing, pumping, entrained air, spacing factor.

scholarly journals Shortwave infrared imaging setup to study entrained air bubble dynamics in a MEMS-based piezo-acoustic inkjet printhead

2019 ◽  
Vol 60 (8) ◽  
Author(s):  
Arjan Fraters ◽  
Tim Segers ◽  
Marc van den Berg ◽  
Hans Reinten ◽  
Herman Wijshoff ◽  
...  
Keyword(s):  
Bubble Dynamics ◽  
Infrared Imaging ◽  
Air Bubble ◽  
Entrained Air ◽  
Shortwave Infrared ◽  
Inkjet Printhead ◽  
Imaging Setup

756 Oil degradation by entrained air bubbles

2005 ◽  
Vol 2005 (0) ◽  
pp. 217-218
Author(s):  
Ryushi SUZUKI ◽  
Yutaka TANAKA ◽  
Keiiji BABA
Keyword(s):  
Air Bubbles ◽  
Oil Degradation ◽  
Entrained Air
Sign in / Sign up

Export Citation Format

Share Document