scholarly journals The investigation of the velocity slip and the temperature jump effect on the heat transfer characteristics in a microchannel

2022 ◽  
pp. 101791
Author(s):  
Alexander S. Lobasov ◽  
Andrey V. Minakov ◽  
Valeri Y. Rudyak
Keyword(s):  
Heat Transfer ◽  
Temperature Jump ◽  
Velocity Slip ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Scale Effects and Slip Microflow Characteristics of Evaporating Thin Films in a Microchannel

2009 ◽  
Author(s):  
J. J. Zhao ◽  
X. F. Peng ◽  
Y. Y. Duan
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Wall Temperature ◽  
Temperature Jump ◽  
Scale Effects ◽  
Channel Width ◽  
Heat Transfer Characteristics ◽  
Slip Coefficient ◽  
Transfer Characteristics ◽  
Solid Liquid

Micro flow, phase change and heat transfer characteristics of an evaporating thin film in a microchannel was investigated using an augmented Young-Laplace model and the kinetic theory for transverse flow in a solid-liquid-vapor triple contact line region. A model considering both wall slip and wall temperature jump was developed to explore scale effects of channel width. The results show that the average heat transfer coefficient and Reynolds number in thin film regions decrease with decreasing channel width, indicating worse flow and heat transfer characteristics. The scale effects are caused by increased far-field liquid film curvature and film thickness and consequently lower liquid superheat and lower evaporation pumping capability. Original models describing wall-affected ordered adsorbed flowing liquid microlayer and variable slip coefficient were established to give the solid-liquid interfacial resistance and wall temperature jump. Microflow and microlayer near a wall increase wall thermal resistance and thus leads to worse film spreading and heat transfer characteristics, which are significant in thin film regions. The microflow model with variable slip coefficient is logical, more reasonable in results and better than the microflow model with constant slip coefficient.

Investigation Into the Similarity Solution for Boundary Layer Flows in Microsystems

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Suhil Kiwan ◽  
M. A. Al-Nimr
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Temperature Jump ◽  
Velocity Slip ◽  
Skin Friction Coefficient ◽  
Heat Transfer Characteristics ◽  
Boundary Layer Flows ◽  
Flow And Heat Transfer

An investigation toward the existence of a complete similarity solution for boundary layer flows under the velocity slip and temperature jump conditions is carried out. The study is limited to the boundary layer flows resulting from an arbitrary freestream velocity U(x)=Uoxm and wall temperature given by Tw−T∞=Cxn. It is found that a similar solution exists only for m=1 and n=0, which represents stagnation flow on isothermal surface. This case has been thoroughly investigated. The analysis showed that three parameters control the flow and heat transfer characteristics of the problem. These parameters are the velocity slip parameter K1, the temperature jump parameter K2, and Prandtl number. The effect of these parameters on the flow and heat transfer of the problem has been studied and presented. It is found that the slip velocity parameter affects both the flow and heat transfer characteristics of the problem. It is found that the skin friction coefficient decreases with increasing K1 and most of changes in the skin friction takes place in the range 0<K1<1. The skin friction coefficient is found to be related to K1 and Rex according to the relation: Cf=3.38Rex−0.5(K1+1.279)−0.8 for 0<K1<5 with an error of ±4%. On the other hand, the correlation between Nu, K1, K2, and Pr has been found by the equation Nu=[(0.449+1.142K11.06)∕(0.515+K11.06)](K2+1.489Pr−0.44)−1, for 0<K1, K2<5, 0.7≤Pr≤5 within a maximum error of ±3%.

Slip Flow Heat Transfer in Annular Microchannels With Constant Heat Flux

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
Zhipeng Duan ◽  
Y. S. Muzychka
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Knudsen Number ◽  
Temperature Jump ◽  
Slip Flow ◽  
Velocity Slip ◽  
Heat Transfer Characteristics ◽  
Uniform Wall ◽  
Flow Heat ◽  
Uniform Wall Heat Flux

Microscale fluid dynamics has received intensive interest due to the emergence of microelectromechanical systems technology. When the mean free path of the gas is comparable to the channel’s characteristic dimension, the continuum assumption is no longer valid and velocity slip and temperature jump may occur at the duct walls. Slip flow heat transfer in annular microchannels has been examined. The effects of velocity slip and temperature jump on the hydrodynamically and thermally fully developed heat transfer characteristics for laminar flow have been studied analytically. The analysis is carried out for both uniform wall heat flux on one wall, adiabatic on the other wall, and uniform wall heat flux on both walls. The results indicate that the slip flow Nusselt numbers are lower than those for continuum flow and decrease with an increase in Knudsen number for most practical engineering applications. The effects of Knudsen number, radius ratio, and heat flux ratio on heat transfer characteristics are discussed, respectively.

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