scholarly journals Vane induced two phase flow mixing

2021 ◽  
Vol 850 (1) ◽  
pp. 012022
Author(s):  
K Sowndarya ◽  
S Monica ◽  
M S Abhisheka ◽  
A K Pradikshan ◽  
M Venkatesan
Keyword(s):  
Considerable Change ◽  
Comsol Multiphysics ◽  
Phase Flow ◽  
Micro Channel ◽  
Mixing Index ◽  
Two Phase ◽  
Channel Section ◽  
Flow Mixing ◽  
Multiphase Fluids ◽  
Flow Stream

Abstract Micromixers are used for mixing of multiphase fluids in microchannels. Passive micromixers help in mixing of fluids by having a designed periphery in their structure. In the current study, a Y micro-channel section of 25 mm length with an inlet diameter of 2 mm is considered. Vane shaped micromixers are placed inside the channel to mix fluids of two different concentrations. The vanes are positioned at specific places inside the channel to enhance mixing in the stratified flow stream. The presence of vanes during the flow induces mixing of the stratified fluids without requiring additional components. The study is carried out using COMSOL Multiphysics. The mixing index increases with increase in the number of vanes and no considerable change in velocity is observed downstream of the last vane. Further, when the thickness of the vane is increased, it is found that the mixing index also increases.

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2003 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Micro Channels

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406 × 2.032 mm cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal that the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Annual flow is identified as the dominant flow pattern for conditions relevant to two-phase micro-channel heat sinks, and forms the basis for development of a theoretical model for both pressure drop and heat transfer in micro-channels. Features unique to two-phase micro-channel flow, such as laminar liquid and gas flows, smooth liquid-gas interface, and strong entrainment and deposition effects are incorporated into the model. The model shows good agreement with experimental data for water-cooled heat sinks.

Large Eddy Simulation of Two-Phase Flow Pattern and Transformation Characteristics of Flow Mixing Nozzle

2019 ◽  
Vol 35 (5) ◽  
pp. 693-704
Author(s):  
Jin Zhao ◽  
Zhi Ning ◽  
Ming Lü
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Velocity Ratio ◽  
Inertial Force ◽  
Surface Tension Force ◽  
Viscous Force ◽  
Phase Flow ◽  
Two Phase ◽  
Jet Breakup ◽  
Flow Mixing

ABSTRACTThe two-phase flow pattern of a flow mixing nozzle plays an important role in jet breakup and atomization. However, the flow pattern of this nozzle and its transformation characteristics are still unclear. A diesel-air injection simulation model of a flow mixing nozzle is established. Then the two-phase flow pattern and transformation characteristics of the flow mixing nozzle is studied using a numerical simulation method. The effect of the air-diesel velocity ratio, ratio of the distance between the tube orifice and nozzle hole and the tube diameter (H/D), and the diesel inlet velocity was studied in terms of the jet breakup diameter (jet diameter at the breakup position) and jet breakup length (length of the diesel jet from the breakup position to the nozzle outlet). The results show that the jet breakup diameter decreases with the decrease in H/D or the increase in the air-diesel velocity ratio and diesel inlet velocity. The jet breakup length increases first and then decreases with the increase in H/D and air-diesel velocity ratio; the trend of the diesel inlet velocity is complicated. In addition, a change in the working conditions also causes some morphological changes that cannot be quantitatively analyzed in the diesel-air flow pattern. The transition characteristics of the flow pattern are analyzed, and it is found that the main reason for the change in the flow pattern is the change in the inertial force of the air, surface tension force, and viscous force of diesel (non-dimensional Reynolds number and Weber number describe the transition characteristics in this paper). The surface tension force of diesel decreases and the viscous force of diesel and inertial force of air increase when the air-diesel velocity ratio increases or H/D decreases. However, the effects of the diesel surface tension force and viscous force effect are much smaller than that of the air inertial force, which changes the diesel-air flow pattern from a drop pattern to a vibration jet pattern, broken jet pattern, and then a chaotic jet pattern.

scholarly journals Investigation of Two-Phase Flow Mixing between Two Subchannels. 2nd Report. Verification of Fluctuating Pressure Model without Steady Pressure.

1997 ◽  
Vol 63 (613) ◽  
pp. 3107-3113
Author(s):  
Masanori TAKEMOTO ◽  
Tomoki KONDO ◽  
Takayasu INATOMI ◽  
Sinji SAKAI ◽  
Kazunori WAKAI ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Fluctuating Pressure ◽  
Steady Pressure ◽  
Flow Mixing

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2004 ◽  
Vol 126 (3) ◽  
pp. 288-300 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406×2.032mm2 cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Features unique to two-phase micro-channel flow were identified and employed to validate key assumptions of an annular flow boiling model that was previously developed to predict pressure drop and heat transfer in two-phase micro-channel heat sinks. This earlier model was modified based on new findings from the adiabatic two-phase flow study. The modified model shows good agreement with experimental data for water-cooled heat sinks.

Pressure Drop on Liquid Transportation Using the Characteristics of Gas-Liquid Two-phase Flow in Micro Channel

2002 ◽  
Vol 2002 (0) ◽  
pp. 83-84
Author(s):  
Masahiro AWANE ◽  
Takashi KURAMOTO ◽  
Kenji YOSHIDA ◽  
Tadayoshi MATSUMOTO ◽  
Tomio OKAWA ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase
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