The Effects of Gap Size on Flooding in Vertical Narrow Rectangular Channels

2012 ◽  
Vol 616-618 ◽  
pp. 959-963
Author(s):  
Xi Chuan Li ◽  
Zhong Ning Sun
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Current Flow ◽  
Liquid Flow Rate ◽  
Flow Characteristics ◽  
Gap Size ◽  
Gas Velocity ◽  
Two Phase ◽  
Rectangular Channels ◽  
Counter Current

In this paper, counter-current gas--liquid two-phase flow and onset of flooding in vertical narrow rectangular channels were studied. In order to study the flow pattern, during counter-current flow and determine conditions associated with the onset of flooding, the flow pattern and pressure drop were investigated by visual experiments. The results show that the flow characteristics and the tendency of pressure drop in vertical narrow rectangular channels were similarly with the conventional channels. However, the maximum of pressure drop appeared at the completed carrying up of flooding in vertical narrow rectangular channels, and it appeared at the onset of flooding in conventional channels. Flooding gas velocities decrease as the gap size decreases; The gas velocity required for flooding increases as the gap size increases at the same liquid flow rate.

Pressure drop for two phase counter-current flow in a packed column with a novel internal

2003 ◽  
Vol 94 (3) ◽  
pp. 179-187 ◽  
Author(s):  
Minghan Han ◽  
Hongfei Lin ◽  
Yanhui Yuan ◽  
Dezheng Wang ◽  
Yong Jin
Keyword(s):  
Pressure Drop ◽  
Current Flow ◽  
Packed Column ◽  
Two Phase ◽  
Counter Current Flow ◽  
Counter Current

Validation of Models for Two-Phase Pressure Drop in Porous Media With Volumetric Heat Sources

2006 ◽  
Author(s):  
Patrick Scha¨fer ◽  
Rudi Kulenovic
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Current Flow ◽  
Flow Boiling ◽  
Two Phase ◽  
Porous Bed ◽  
Explicit Consideration ◽  
Current Flows ◽  
Interfacial Drag ◽  
Counter Current

An experimental investigation on flow-boiling in inductively heated porous media (particle bed of oxidized stainless steel spheres, 3 mm resp. 6 mm diameter) has been carried out. As coolant demineralized water was used. The main focus of the experiments is to determine the dryout heat flux and the pressure drop of the two-phase flow under various conditions. In the boiling experiments the inflow rate of the coolant was varied from 0 mm/s (self driven flow with water supply from the waterpool above the porous bed, “counter-current-flow”) to 7.2 mm/s (forced inflow condition at the bottom of the porous bed, “co-current-flow”). The experimental results are used to validate dryout models applied in reactor safety. The model verifications show clearly that models without the explicit consideration of the interfacial drag can only be utilized for co-current flows and are unsuitable for counter-current flows. Against it models with the explicit consideration of the interfacial drag show at least qualitative agreement for both, counter-and co-current flows.

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.

scholarly journals Flow Pattern and Pressure Drop Characteristics on Gas/Liquid Two-phase Flow in a Serpentine Capillary Tube

2007 ◽  
Vol 2 ◽  
pp. 25-32 ◽  
Author(s):  
Toru SUKAWA ◽  
Tomoya HASEGAWA ◽  
Kenji YOSHIDA ◽  
Isao KATAOKA
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Capillary Tube ◽  
Phase Flow ◽  
Two Phase
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