Condensation heat transfer characteristics of vapor flow in vertical small-diameter tube with variable wall temperature

2002 ◽  
Vol 45 (1) ◽  
pp. 81 ◽  
Author(s):  
Xiaoze DU
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Small Diameter ◽  
Condensation Heat Transfer ◽  
Vapor Flow ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Variable Wall Temperature ◽  
Variable Wall

Numerical Simulation on Heat Transfer Characteristics of Turbulent Gas Flow in Micro-Tubes

2011 ◽  
Author(s):  
Kyohei Isobe ◽  
Chungpyo Hong ◽  
Yutaka Asako ◽  
Ichiro Ueno
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Wall Temperature ◽  
Gas Flow ◽  
Tube Diameter ◽  
Turbulence Energy ◽  
Stagnation Temperature ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Turbulent Gas Flow

Numerical simulations were performed to obtain for heat transfer characteristics of turbulent gas flow in micro-tubes with constant wall temperature. The numerical methodology was based on Arbitrary-Lagrangian-Eulerinan (ALE) method to solve compressible momentum and energy equations. The Lam-Bremhorst Low-Reynolds number turbulence model was employed to evaluate eddy viscosity coefficient and turbulence energy. The tube diameter ranges from 100 μm to 400 μm and the aspect ratio of the tube diameter and the length is fixed at 200. The stagnation temperature is fixed at 300 K and the computations were done for wall temperature, which ranges from 305 K to 350 K. The stagnation pressure was chosen in such a way that the flow is in turbulent flow regime. The obtained Reynolds number ranges widely up to 10081 and the Mach number at the outlet ranges from 0.1 to 0.9. The heat transfer rates obtained by the present study are higher than those of the incompressible flow. This is due to the additional heat transfer near the micro-tube outlet caused by the energy conversion into kinetic energy.

scholarly journals Condensation Heat Transfer Characteristics of R-1234yf with the Variation of Tube Diameter

2021 ◽  
Vol 41 (4) ◽  
pp. 161-171
Author(s):  
Sung-Hoon Seol ◽  
Jung-In Yoon ◽  
Joon-Hyuk Lee ◽  
Seung-Yun Cha ◽  
Su-Jeong Ha
Keyword(s):  
Heat Transfer ◽  
Tube Diameter ◽  
Condensation Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics
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