Comprehensive assessment of viscous heat generation in rarefied gas microflows

2021 ◽  
Author(s):  
Nam T. P. Le ◽  
Bang V. Dinh ◽  
Quang L. Dang ◽  
Anh V. Dang ◽  
Y. Q. Nguyen
Author(s):  
C. Rajalingham ◽  
B. S. Prabhu ◽  
R. B. Bhat ◽  
G. D. Xistris

Abstract The viscous heat generation in the lubricant film of a hydrodynamic journal bearing causes a rise in temperature of the fluid film. Considering the influence of the temperature variation along and across the film, the performance of a journal bearing is investigated under adiabatic conditions for different values of thermal conductivity of the lubricant. In this analysis, the temperature of the journal surface has been chosen to ensure that there is no net heat transfer from the lubricant The results show that the variation of temperature across the film affects bearing performance significantly and that an increase in lubricant thermal conductivity enhances bearing performance.


1991 ◽  
Vol 46 (5-6) ◽  
pp. 1385-1392 ◽  
Author(s):  
A.F. Flores ◽  
J.C. Gottifredi ◽  
G.V. Morales ◽  
O.D. Quiroga

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401881306
Author(s):  
XZ Zhu ◽  
J Liu ◽  
DP Sun

The internal mixer is an important devise for processing the polymer nanocomposites acting as a chemical reactor. In this article, based on the computational fluid dynamics method, the fluid transportation and heat transfer analysis of sol–gel reaction processing for Polypropylene (PP)/TiO2 nanocomposites in the internal batch mixers with single-winged and two-winged Cam rotors were simulated. First, the Lagrangian coherent structure analysis was used to understand the fluid transport properties in the mixers. Then the effect of rotational speeds (ratios) and barrel temperatures on the heat transfer characteristics in the mixers with different rotors was analyzed. Also, the changes of viscous heating and torques of rotors with different thermal conditions in the mixers were discussed. Especially, the relationship between the fluid transportation and heat transfer characteristics was explored. The results show that a big rotor speed ratio can induce great fluid transportation in the left and right mixer chambers based on the Lagrangian coherent structure analysis, and the fluid near the horseshoe map has great folding effect and temperature magnitude. The viscous dissipation, viscous heat generation, and rotor torques in the mixers increase with increasing the rotational speeds and decrease with increasing the barrel temperatures. The mixer with two-winged rotors has higher average temperature, viscous dissipation, viscous heat generation and the torques of rotors values of reactive fluid than that with single-winged rotors.


AIAA Journal ◽  
2017 ◽  
Vol 55 (2) ◽  
pp. 474-483 ◽  
Author(s):  
Nam T. P. Le ◽  
Ngoc Anh Vu ◽  
Le Tan Loc

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