scholarly journals Fluid flow and heat transfer within ducts of a cross-shaped cross-section. 1st report Numerical calculation of laminar flow field.

1986 ◽  
Vol 52 (477) ◽  
pp. 2243-2247
Author(s):  
Akira NAKAYAMA ◽  
Hitoshi KOYAMA
2013 ◽  
Vol 561 ◽  
pp. 460-465
Author(s):  
Dong Hui Zhang ◽  
Jiao Gao

The objective of this paper is to study the characteristic of a circular tube with a built-in arc belt on fluid flow and heat transfer in uniform wall temperature flows. Numerical simulations for hydrodynamically laminar flow was direct ran at Re between 600 and 1800. Preliminary results on velocity and temperature statistics for uniform wall temperature show that, arc belt can swirl the pipe fluid, so that the fluid at the center of the tube and the fluid of the boundary layer of the wall can mix fully, and plays the role of enhanced heat transfer, but also significantly increases the resistance of the fluid and makes the resistance coefficient of the enhanced tube greater than smooth tube. The combination property PEC is all above 1.5.


Author(s):  
CJ Ho ◽  
GN Sou ◽  
CM Lai

This paper presents a numerical study of transient buoyancy-induced fluid flow and heat transfer between two horizontal, differentially heated pipelines inside a circular, air-filled enclosure. Numerical simulations based on the finite difference method were conducted to investigate the flow mode transition of the buoyant airflow and its effects on the heat transfer characteristics of the pipelines. The results indicate that the fluid flow complexity and the heat transfer of air between the pipelines are strongly affected by the Rayleigh number. When Ra = 6 × 105 and 1.2 × 106, both the flow field and the temperature distribution exhibit periodic variations with different patterns. The former ( Ra = 6 × 105) is a complete alteration of the flow direction from clockwise to counterclockwise, whereas the latter is a variation in the flow field strength that varies between strong and weak. The latter has a lower variation frequency than that of the former.


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