Bubble Collapse and Flow Characteristics in Bubble Flow in a Venturi Tube

Bubble is the heart of the microfluidic chip, which takes a significant role in drug release, biological detection and so on. In this case, bubble flow characteristics in microfluidic chip are the key to realize its function. In this paper, bubble flow characteristics in the microfluidic chip have been studied with high speed photography system by controlling the wettability and the heat flux of the microelectrode surface. The result shows that bubble flows faster on the electrode with hydrophobic surface. In addition, loading current to the electrode with hydrophilic surface could also speed up the movement of bubble, and the flow rate of bubble increases with the increasing heat flux of the electrode.

Download Full-text

Effect of Flow Characteristics in the Downstream of Butterfly Valve on the Flow Rate Measurement using Venturi Tube

10.1063/1.3464901 ◽

2010 ◽

Author(s):

Seok Ho Yoon ◽

Jungho Lee ◽

Cheong Hwan Yu ◽

San-Jin Park ◽

Chang-Hwan Chung ◽

...

Keyword(s):

Flow Rate ◽

Flow Characteristics ◽

Venturi Tube ◽

Rate Measurement ◽

Butterfly Valve ◽

Flow Rate Measurement

Download Full-text

Prediction of Residual Stress Improvement by Water Jet Peening Using Cavitating Jet Simulation With Bubble Flow Model

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 1, Symposia – Parts A, B, and C ◽

10.1115/fedsm-icnmm2010-30419 ◽

2010 ◽

Cited By ~ 1

Author(s):

Masashi Fukaya ◽

Ren Morinaka ◽

Noboru Saitou ◽

Hisamitsu Hatou ◽

Yoshiaki Tamura ◽

...

Keyword(s):

Residual Stress ◽

Flat Plate ◽

Power Plants ◽

Compressive Residual Stress ◽

Flow Model ◽

Water Jet ◽

Bubble Collapse ◽

Bubble Flow ◽

Bubble Pressure ◽

Cavitating Jet

We developed the new method for predicting a region of compressive residual stress on the weld surface after water jet peeing (WJP), which is a preventive maintenance technology for nuclear power plants. A cavitating jet is impinged on the weld surfaces of structures in a nuclear reactor. Bubble collapse impact causes plastic deformation of the weld surface, and changes the residual stress from tensile to compressive. Compressive residual stress prevents the occurrence of stress corrosion cracking (SCC) on the weld surface. A cavitating jet vertically injected into a submerged flat plate was investigated. Tensile stress was introduced onto the surface of the stainless steel plate by grinding before WJP in the experiment. We numerically simulated impulsive bubble pressure that varied by microseconds in the cavitating jet with the “bubble flow model”. The bubble flow model simulates the abrupt time-variations in the radius and inner pressure of bubbles based on the Rayleigh-Plesset equation in a cavitating flow. The cavitation collapse energy was estimated based on the bubble pressure. The cavitation collapse energy was compared with the measured compressive residual stress on the flat plate after WJP. The radial range of the compressive residual stress from the jet center axis is one of the most important measures of performance of WJP. The radial range of the cavitation collapse energy corresponded to that of compressive residual stress with a prediction error of +/− 20% under different conditions of jet velocity and the distance between the jet nozzle and plate surface. The results confirmed that the method we developed for predicting the region of compressive residual stress after WJP was valid.

Download Full-text