Effects of low-Re pulsatile flow on friction characteristics in bare square array rod bundles

2018 ◽  
Vol 120 ◽  
pp. 630-641 ◽  
Author(s):  
Ayodeji Adebisi Ala ◽  
Sichao Tan ◽  
Abdelgadir Eltayeb ◽  
Zhengpeng Mi
Keyword(s):  
Pulsatile Flow ◽  
Rod Bundles ◽  
Friction Characteristics ◽  
Square Array

Experimental study of transient friction characteristics and velocity distribution of pulsatile flow in rod bundles

2020 ◽  
Vol 140 ◽  
pp. 107124 ◽  
Author(s):  
Xing Li ◽  
Peiyao Qi ◽  
Sichao Tan ◽  
Dongyang Li ◽  
Yitung Chen ◽  
...  
Keyword(s):  
Experimental Study ◽  
Velocity Distribution ◽  
Pulsatile Flow ◽  
Rod Bundles ◽  
Friction Characteristics

An Analysis of Heat Transfer to Axial Dispersed Flow between Rod Bundles under Reactor Emergency Cooling Conditions

1980 ◽  
Vol 102 (3) ◽  
pp. 508-512 ◽  
Author(s):  
S. Wong ◽  
L. E. Hochreiter
Keyword(s):  
Heat Transfer ◽  
Diameter Ratio ◽  
Circular Pipe ◽  
Rod Bundles ◽  
Dispersed Flow ◽  
Rod Bundle ◽  
Cooling Conditions ◽  
Flow Heat ◽  
Square Array ◽  
The Heat Transfer Coefficient

Analysis is carried out for dispersed flow heat transfer under reactor emergency cooling conditions. The present formulation explicitly reveals an extra dependence of the heat transfer coefficient and Nusselt number on the mean vapor temperature for droplet dispersed flow which is not found in single phase flow heat transfer. The heat transfer results obtained from three different geometries—an infinite square array of cylindrical rods, an annulus and a circular pipe—are compared; all have the same hydraulic diameter. It is found that, within the framework of the present analysis, results for the annulus and the rod bundles agree well when the pitch-to-diameter ratio is 1.5 or greater. The circular pipe is in general a poor approximation for rod bundle geometries except at a pitch-to-diameter ratio of about 1.3 which is typical of present day light water reactor fuel assemblies.

Simulation of low-Re pulsatile flow through bare 5 x 5 square arrayed rod bundles

2020 ◽  
Vol 129 ◽  
pp. 103487
Author(s):  
Ayodeji A. Ala ◽  
Sichao Tan ◽  
Abdelgadir Eltayeb ◽  
Thompson Appah
Keyword(s):  
Pulsatile Flow ◽  
Rod Bundles ◽  
Flow Through

Natural Convection Heat Transfer From Vertical 7x7 Rod Bundles in Liquid Sodium

2017 ◽  
Author(s):  
Koichi Hata ◽  
Katsuya Fukuda ◽  
Tohru Mizuuchi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Liquid Sodium ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Rod Bundles ◽  
Nusselt Numbers ◽  
Rod Bundle ◽  
Square Array

Natural convection heat transfer from vertical 7×7 rod bundle in liquid sodium was numerically analyzed to optimize the thermal-hydraulic design for the bundle geometry with equilateral square array, ESA. The unsteady laminar three dimensional basic equations for natural convection heat transfer caused by a step heat flux were numerically solved until the solution reaches a steady-state. The PHOENICS code was used for the calculation considering the temperature dependence of thermo-physical properties concerned. The 7×7 test rods for diameter (D = 7.6 mm), heated length (L = 200 mm) and L/d (= 26.32) were used in this work. The surface heat fluxes for each cylinder were equally given for a modified Rayleigh number, (Rf,L)ij and (Rf,L)Nx×Ny,S/D, ranging from 3.08×104 to 4.28×107 (q = 1×104∼7×106 W/m2) in liquid temperature (TL = 673.15 K). The values of S/D, which are ratios of the diameter of flow channel for bundle geometry to the rod diameter, for vertical 7×7 rod bundle were ranged from 1.8 to 6 on the bundle geometry with equilateral square array. The spatial distribution of average Nusselt numbers for a vertical single cylinder of a rod bundle, (Nuav)ij, and average Nusselt numbers for a vertical rod bundle, (Nuav,B)Nx×Ny,S/D, were clarified. The average value of Nusselt number, (Nuav)ij and (Nuav,B)Nx×Ny,S/D, for the bundle geometry with various values of S/D were calculated to examine the effect of array size, bundle geometry, S/D, (Rf,L)ij and (Rf,L)Nx×Ny,S/D on heat transfer. The bundle geometry for the higher (Nuav,B)Nx×Ny,S/D value under the condition of S/D = constant was examined. The general correlations for natural convection heat transfer from a vertical Nx×Ny rod bundle with the equilateral square and triangle arrays including the effects of array size, (Rf,L)Nx×Ny,S/D and S/D were derived. The correlations for vertical Nx×Ny rod bundles can describe the theoretical values of (Nuav,B)Nx×Ny,S/D for each bundle geometry in the wide analytical range of S/D (= 1.8 to 6) and the modified Rayleigh number ((Rf,L)Nx×Ny,S/D = 3.08×104 to 4.28×107) within −9.49 to 10.6 % differences.

Protective Effects of Pulsatile Flow during Cardio-Pulmonary Bypass

2016 ◽  
Vol 64 (S 02) ◽  
Author(s):  
A. Salameh ◽  
L. Kuehne ◽  
M. Grassl ◽  
M. Gerdom ◽  
S. von Salisch ◽  
...  
Keyword(s):  
Pulsatile Flow ◽  
Protective Effects ◽  
Cardio Pulmonary Bypass ◽  
Pulmonary Bypass

A Study of Doppler Waveform Using Pulsatile Flow Model

1997 ◽  
Vol 37 (2) ◽  
pp. 225 ◽  
Author(s):  
Hye Won Chung ◽  
Myung Jin Chung ◽  
Jae Hyung Park ◽  
Jin Wook Chung ◽  
Dong Hyuk Lee ◽  
...  
Keyword(s):  
Pulsatile Flow ◽  
Flow Model ◽  
Doppler Waveform
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