Single-Phase Laminar-Flow Heat Transfer and Two-Phase Oscillating-Flow Heat Transport in Microchannels

2004 ◽  
Vol 25 (3) ◽  
pp. 31-43 ◽  
Author(s):  
SHIGEFUMI NISHIO
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Transport ◽  
Single Phase ◽  
Oscillating Flow ◽  
Two Phase ◽  
Flow Heat

Single-Phase Laminar-Flow Heat Transfer and Two-Phase Oscillating-Flow Heat Transport in Microchannels

2003 ◽  
Author(s):  
Shigefumi Nishio
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Single Phase ◽  
Local Equilibrium ◽  
Oscillating Flow ◽  
Thermal Systems ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Flow Heat ◽  
Inner Diameter

The present review article focuses on the research field of heat transfer of single-phase laminar-flow and two-phase self-exciting oscillating-flow in microchannels. First, to make prominent the special features of Micro Thermal Systems (MTSs), the definition of the term “Nano Thermal Systems” (NTSs) is discussed from the viewpoint of local equilibrium. Next, to show the special features of flow and heat transfer in microchannels, some thermal functions appearing in microchannels are introduced. Further, focusing on flow and heat transfer characteristics of single-phase laminar liquid-flow in microchannels, researches in the literature and recent results at IIS (Institute of Industrial Science, the University of Tokyo) are introduced, and it is shown that the results obtained for tubes larger than 0.1mm in inner diameter are in good agreement with the conventional analyses. Finally, Japanese researches and recent results at IIS on micro SEMOS heat pipes (mSEMOSs) are introduced and it is shown that a mSEMOS of 0.5mm in inner diameter can transport a significant amount of heat.

Performance Evaluation of Liquid Flow With PCM Particles in Microchannels

2005 ◽  
Vol 127 (8) ◽  
pp. 931-940 ◽  
Author(s):  
K. Q. Xing ◽  
Y.-X. Tao ◽  
Y. L. Hao
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Phase Change ◽  
Performance Index ◽  
Single Phase ◽  
Suspension Flow ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase

A two-phase, non thermal equilibrium-based model is applied to the numerical simulation of laminar flow and heat transfer characteristics of suspension with microsize phase-change material (PCM) particles in a microchannel. The model solves the conservation of mass, momentum, and thermal energy equations for liquid and particle phases separately. The study focuses on the parametric study of optimal conditions where heat transfer is enhanced with an increase in fluid power necessary for pumping the two-phase flow. The main contribution of PCM particles to the enhancement of heat transfer in a microsize tube is to increase the effective thermal capacity and utilize the latent heat effect under the laminar flow condition. An effectiveness factor εeff is defined to evaluate the heat transfer enhancement compared to the single-phase flow heat transfer and is calculated under different wall heat fluxes and different Reynolds numbers. The comparison is also made to evaluate the performance index, i.e., the ratio of total heat transfer rate to fluid flow power (pressure drop multiplied by volume flow rate) between PCM suspension flow and pure water single-phase flow. The results show that for a given Reynolds number, there exists an optimal heat flux under which the εeff value is the greatest. In general, the PCM suspension flow with phase change has a significantly higher performance index than the pure-fluid flow. The comparison of the model simulation with the limited experimental results for a MCPCM suspension flow in a 3mmdia tube reveals the sensitivity of wall temperature distribution to the PCM supply temperature and the importance of characterizing the phase change region for a given tube length.

Performance Evaluation of Liquid Flow With NPCM in Microchannels

Volume 4 ◽  
2004 ◽  
Author(s):  
K. Q. Xing ◽  
Y.-X. Tao ◽  
Y. L. Hao
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Phase Change ◽  
Performance Index ◽  
Single Phase ◽  
Suspension Flow ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase

A two-phase, non-thermal-equilibrium based model is applied to the numerical simulation of laminar flow and heat-transfer characteristics of suspension with nano-size phase change material (NPCM) particles in a microchannel. The model solves the conservation of mass, momentum and thermal energy equations for liquid and particle phases separately. The study focuses on the parametric study of optimal conditions where heat transfer is enhanced with an increase in fluid power necessary for pumping the two-phase flow. The main contribution of NPCM particles to the enhancement of heat transfer in a micro-size tube is to increase the effective thermal capacity and utilize the latent heat effect under the laminar flow condition. An effectiveness factor εeff is defined to evaluate the heat transfer enhancement compared to the single phase flow heat transfer and is calculated under different wall heat fluxes and different Reynolds numbers. The comparison is also made to evaluate the performance index (PI); i.e., the ratio of total heat transfer rate to fluid flow power (pressure drop multiplied by volume flow rate) between NPCM suspension flow and pure water single-phase flow. The results show that for a given Reynolds number, there exists an optimal heat flux under which the εeff value is the greatest. In general, the NPCM suspension flow with phase change has a significantly higher performance index than the pure-fluid flow.

scholarly journals Single-Phase Laminar Flow Heat Transfer From Confined Electron Beam Enhanced Surfaces

2015 ◽  
Vol 36 (14-15) ◽  
pp. 1165-1176 ◽  
Author(s):  
Arben Ferhati ◽  
Tassos G. Karayiannis ◽  
John S. Lewis ◽  
Ryan J. McGlen ◽  
David A. Reay
Keyword(s):  
Heat Transfer ◽  
Electron Beam ◽  
Laminar Flow ◽  
Single Phase ◽  
Flow Heat
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