Two-phase flow maldistribution in minichannel heat-sinks under non-uniform heating

2014 ◽  
Vol 78 ◽  
pp. 527-537 ◽  
Author(s):  
Seok Ho Yoon ◽  
Navid Saneie ◽  
Yoon Jo Kim
Keyword(s):  
Two Phase Flow ◽  
Heat Sinks ◽  
Phase Flow ◽  
Uniform Heating ◽  
Two Phase ◽  
Flow Maldistribution

TWO-PHASE FLOW MALDISTRIBUTION IN A MINI-MANIFOLD SYSTEM

2010 ◽  
Vol 22 (1) ◽  
pp. 95-114 ◽  
Author(s):  
Iztok Zun ◽  
Jurij Gregorc ◽  
Matjaz Perpar
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Maldistribution ◽  
Manifold System

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.

The influence of non-uniform heating on two-phase flow instability in subchannel

2019 ◽  
Vol 345 ◽  
pp. 7-14
Author(s):  
Sipeng Wang ◽  
Bao-Wen Yang ◽  
Hu Mao ◽  
Yu-chen Lin ◽  
Guanyi Wang
Keyword(s):  
Two Phase Flow ◽  
Flow Instability ◽  
Phase Flow ◽  
Uniform Heating ◽  
Two Phase

The Influence of Non-Uniform Heating on Two-Phase Flow Instability in Parallel Channels

2013 ◽  
Author(s):  
Xiaodong Lu ◽  
Linglan Zhou ◽  
Hong Zhang ◽  
Yingwei Wu ◽  
Guanghui Su ◽  
...  
Keyword(s):  
Heat Flux ◽  
Two Phase Flow ◽  
Flow Instability ◽  
System Stability ◽  
System Control ◽  
Phase Flow ◽  
Uniform Heating ◽  
Two Phase ◽  
System Pressure ◽  
Parallel Channels

The two-phase flow instability in parallel channels heated by uniform and non-uniform heat flux has been theoretically studied in this paper. Based on the homogeneous flow model in two-phase region, the system control equations of parallel channels were established. Semi-implicit finite-difference method and staggered mesh method were used to discretize the system control equations and the difference equations were solved with a chasing method. The cosine profile and uniform constant heat flux represent the non-uniform and uniform heating condition, respectively. The marginal stability boundaries (MSB) of parallel channels and the three-dimensional instability spaces (or instability reefs) of different heat flux models were obtained. For cosine profile heating, the stability of parallel channels increases with the increase of the system pressure and inlet resistant coefficient. In high inlet subcooling region, cosine heat flux can strengthen the system stability. However, in low inlet subcooling region, the negative effect to system stability will be caused by non-uniform heating. The increase of inlet resistant coefficient will move the turning point of the MSB to high inlet subcooling number.

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.

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