Coupled radiation-convection heat transfer of high-temperature participating medium in heated/cooled tubes

2003 ◽  
Vol 33 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Xin-Lin Xia ◽  
Yong Huang ◽  
He-Ping Tan ◽  
De-Peng Ren
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Convection Heat Transfer ◽  
Convection Heat

Numerical Analysis of Convection Heat Transfer on High-Temperature Rotating Disk at Bottom Surface of Air Flow Duct

2014 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami ◽  
Katsuaki Shirai
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Rotation Speed ◽  
Air Flow ◽  
Convection Heat Transfer ◽  
Rotating Disk ◽  
Bottom Surface ◽  
Convection Flow ◽  
Convection Heat ◽  
Flow Duct

Convection heat transfer distribution on a high-temperature rotating disk in a horizontal air flow duct was analyzed by three-dimensional computational fluid dynamics (CFD) code. The temperature of the disk was 1000°C, and the rotation speed was 60–480 rpm. The temperature of the inlet air was 25°C, and the velocity was 0–1 m/s. The air flow pattern was affected by natural convection caused by temperature difference, forced convection flow along the disk surface, rotation flow induced by the disk, and volume expansion of gas. The calculated results show that the ratio of the maximum and minimum values of the average heat flux along the circumstance direction on the disk was large when the rotation speed and air velocity were small.

Study of Convection Heat Transfer in a Very High Temperature Reactor Flow Channel: Numerical and Experimental Results

2016 ◽  
Vol 196 (3) ◽  
pp. 661-673 ◽  
Author(s):  
Francisco I. Valentín ◽  
Narbeh Artoun ◽  
Ryan Anderson ◽  
Masahiro Kawaji ◽  
Donald M. McEligot
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Convection Heat Transfer ◽  
Flow Channel ◽  
Experimental Results ◽  
Convection Heat ◽  
Very High Temperature Reactor ◽  
High Temperature Reactor ◽  
Very High

Forced and Mixed Convection Heat Transfer at High Pressure and High Temperature in a Graphite Flow Channel

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Francisco I. Valentín ◽  
Narbeh Artoun ◽  
Masahiro Kawaji ◽  
Donald M. McEligot
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
High Pressure ◽  
High Temperature ◽  
Mixed Convection ◽  
Convection Heat Transfer ◽  
Reynolds Numbers ◽  
Lower Wall ◽  
Convection Heat ◽  
Flow Laminarization

High pressure/high temperature forced and mixed convection experiments have been performed with helium and nitrogen at temperatures and pressures up to 893 K and 64 bar, respectively. The test section had a 16.8 mm ID flow channel in a 108 mm OD graphite column. Flow regimes included turbulent, transitional, and laminar flows with the inlet Reynolds numbers ranging from 1500 to 15,000. Due to strong heating, the local Reynolds number decreased by up to 50% over the 2.7 m test section. In addition, heat transfer degradation and flow laminarization caused by intense heating led to Nusselt numbers 20–50% lower than the values given by the modified Dittus–Boelter and modified Gnielinski correlations. Flow laminarization criteria were considered based on a dimensionless acceleration parameter (Kv) and buoyancy parameter (Bo*). Upward turbulent flows displayed higher wall temperatures than downward flows, due to the impact of flow laminarization which is not expected to affect buoyancy-opposed flows. Laminar Reynolds number flows presented an opposite behavior due to the enhancement of heat transfer for buoyancy-aided flows. At low Reynolds numbers, downward flows displayed higher and lower wall temperatures in the upstream and downstream regions, respectively, than the upward flow cases. In the entrance region of downward flows, convection heat transfer was reduced due to buoyancy leading to higher wall temperatures, while in the downstream region, buoyancy-induced mixing caused higher convection heat transfer and lower wall temperatures.

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