552 Heat Transfer and Flow Characteristics of Air-Surfactant Solution Two-Phase Vertical Flow

2009 ◽  
Vol 2009.58 (0) ◽  
pp. 327-328
Author(s):  
Koichi ARAGA ◽  
Shinnichi ITOGAWA ◽  
Keiji MURATA
2007 ◽  
Vol 2007 (0) ◽  
pp. 255-256
Author(s):  
Koichi ARAGA ◽  
Masato ARIMURA ◽  
Shinnichi ITOGAWA ◽  
Keiji MURATA

Author(s):  
Mei Zheng ◽  
Wei Dong ◽  
Zhiqiang Guo ◽  
Guilin Lei

The runback water flow and heat transfer on the surface of aircraft components has an important influence on the design of anti-icing system. The aim of this paper is to investigate the water flow characteristics on anti-icing surface using numerical method. The runback water flow on the anti-icing surface, which is caused by the impinging supercooled droplets from the clouds, is driven by the aerodynamic shear forces and the pressure gradient around the components. This is a complex model of flow and heat transfer that considers flow field, super-cooled droplets impingement and runback water flow simultaneously. In this case of gas-liquid two phase flow, the Volume-of-Fluid (VOF) method is very suitable for the solution of thin liquid film flow so that it is applied to simulate the runback water flow on anti-icing surfaces in this paper. Meanwhile, the heat and mass transfer of the runback water flow are considered in the calculation using the User-Defined Functions (UDFs) in ANASYS FLUENT. The verification is conducted by the comparison with the results of the experimental measurement and the mathematical model calculation. The effect of the airflow velocity and contact angle on the water flow are also considered in the numerical simulation.


2019 ◽  
Vol 16 (11) ◽  
pp. 1950164 ◽  
Author(s):  
Kh. S. Mekheimer ◽  
A. Z. Zaher ◽  
A. I. Abdellateef

Catheterization has an imperative rule in heat transfer investigations, which are frequently applied to analyze and deal with the heart transfer studies. Here, the entering of a catheter adjusts the flow of the blood and it affects the hemodynamic status in the artery region. In practical clinical cases, catheters cannot be precisely concentric with the artery. The impartial of this work is to investigate the behavior of a blood streaming characteristics, in the case of injecting the catheter eccentrically all the way through a stenotic overlapping artery. In this paper, we consider the heat transfer within the presence of blood corpuscle which has been characterized by a macroscopic two-phase model (i.e. a suspension of erythrocytes in plasma). The model here considers the blood fluid as a liquid fluid with adjourned particles in the gap bounded by the eccentric cylinder. The inside cylinder is identically rigid demonstrating the movable thin catheter and kept at constant temperature, where the outer cylinder is a taper cylinder demonstrating the artery that has overlapping stenosis and it is cooled and maintained at zero temperature. The coupled differential equations for both fluid (plasma) and particle (erythrocyte) phases have been solved. The expressions for the flow characteristics, namely, the flow rate, the impedance (resistance to flow), the wall shear stress and the temperature distribution, have been derived. The model is very useful in medicine, where the hemodynamic speed is higher for eccentric case than that of concentric one. Also, the temperature distribution and the entropy generation in the state of eccentric position are higher than in the case of the concentric position. A significant increase in the magnitude of the impedance and the wall shear stress occurs for an increase in the hematocrit, C for diseased blood.


Author(s):  
Sira Saisorn ◽  
Somchai Wongwises ◽  
Piyawat Kuaseng ◽  
Chompunut Nuibutr ◽  
Wattana Chanphan

The investigations of heat transfer and fluid flow characteristics of non-boiling air-water flow in micro-channels are experimentally studied. The gas-liquid mixture from y-shape mixer is forced to flow in the 21 parallel rectangular microchannels with 40 mm long in the flow direction. Each channel has a width and a depth of 0.45 and 0.41 mm, respectively. Flow visualization is feasible by incorporating the stereozoom microscope into the camera system and different flow patterns are recorded. The experiments are performed under low superficial velocities. Two-phase heat transfer gives better results when compared with the single-phase flow. It is found from the experiment that heat transfer enhancement up to 53% is obtained over the single-phase flow. Also, the change in the configuration of the inlet plenum can result in the different two-phase flow mechanisms.


2018 ◽  
Vol 103 ◽  
pp. 151-164 ◽  
Author(s):  
Yingwei Wu ◽  
Simin Luo ◽  
Liu Wang ◽  
Yandong Hou ◽  
G.H. Su ◽  
...  

Author(s):  
Guangwen Jiang ◽  
Jianmin Gao ◽  
Xiaojun Shi ◽  
Wang Zhao ◽  
Yunlong Li

The heat and flow characteristics of mist/steam two-phase flow in U-shaped internal cooling passage of gas turbine blade are studid numerically in this paper. The standard k-ε model was used as the turbulence model combined with the DPM model to calculate the influence of mist/steam mass ratio and mist diameter on flow and heat transfer of U-passage with different shaped ribs. The result indicates that under the same working condition, the U-shaped channel with 45 deg. V-shaped ribs has better heat transfer performance than other channels and heat transfer non-uniformity of the U-shaped channel with 75 deg. ribs is the worst among all channels studied in this paper. The heat transfer performance of the U-shaped channel with V-shaped ribs is higher than that of the channel with paralleled ribs. As for the mist/steam cooling in U-shaped passage with same ribs structure, heat transfer non-uniformity increases with the increasing of heat transfer performance. When mists diameter increases from 5μm to 15μm, the heat transfer performance of the Second-Flow-Passage increases obviously and the heat transfer non-uniformity increases at the same time. The heat transfer performance has not been further enhanced when the mists diameter continuously increases after mist diameter are larger than 10μm.


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