Natural Convection Heat Transfer from Horizontal Rod Bundles in Liquid Sodium
Project/Area Number  07680529 
Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
エネルギー学一般・原子力学

Research Institution  KYOTO UNIVERSITY 
Principal Investigator 
HATA Koichi Institute of Advanced Energy, Kyoto University Research Associate, エネルギー理工学研究所, 助手 (60115912)

CoInvestigator(Kenkyūbuntansha) 
TAKEUCHI Yuto Institute of Advanced Energy, Kyoto University Research Associate, エネルギー理工学研究所, 助手 (90179606)
SHIOTSU Masahiro Graduate School of Energy Science, Kyoto University Professor, エネルギー科学研究科, 教授 (20027139)

Project Period (FY) 
1995 – 1996

Project Status 
Completed(Fiscal Year 1996)

Budget Amount *help 
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥1,900,000 (Direct Cost : ¥1,900,000)

Keywords  Liquid Sodium / Natural Convection Heat Transfer / Horizontal Rod Bundles / Theoretical Equations for Laminar Natural Convection Heat Transfer / Two Parallel Horizontal Test Cylinders / Correlations for Two Cylinders / Combined Correlation for Five Cylinders in Vertical Array / Correlation for Horizontal Rod Bundles / 自然対流熱伝達 / 水平円柱バンドル発熱体 / 自然対流熱伝達表示式 / 4角配列形状 / 千鳥配列形状 / 等密度配列形状 / 5本組発熱体表示式 
Research Abstract 
Natural convection heat transfer coefficients on two parallel horizontal test cylinders in liquid sodium were obtained experimentally and theoretically for various setting angles, gamma, between vertical direction and the plane including both of these cylinder axis, over the range of zero to 90ﾟ. Both test cylinders are 7.6 mm in diameter and 50 mm in heated length with the ratio of the distance between each cylinder axis to the cylinder diameter, S/D,of2. Theoretical equations for laminar natural convection heat transfer from the two horizontal cylinders were numerically solved for the same conditions as the experimental ones by using the PHOENICS code. The surface heat fluxes for each cylinder were equally given for a modified Rayleigh number, R_f, ranging from 0.0637 to 63.1 (q=1*10^47*10^6 W/m^2). The average Nusselt numbers Nu on the cylinders obtained experimentally were compared with the corresponding theoretical values on the Nu versus modified Rayleigh number R_f [=Gr^<**>Pr^
… More
2/ (4+9Pr^<1/2>+10Pr)] graph. The theoretical values of Nu on two cylinders except those for R_f<4at gamma=0ﾟ are in agreement with the experimental data at each gamma with the deviations less than 15 %. Correlations for two cylinders were obtained as functions of S/D and gamma based on the theoretical solutions. A combined correlation for five cylinders in a vertical array based on the correlations for two cylinders was developed. The values by the correlation agree with the theoretical solution for the five cylinders for R_f ranging from 4.7 to 63 within 10% difference. Natural convection heat transfer from horizontal rod bundles in Nx*Ny arrays (Nx, Ny=59) was numerically analyzed for three types of the bundle geometry (inline rows, two kinds of staggered rows). S_x/D and S_y/D for the rod bundle which are ratio of the distance between center axs on the abscissa and the ordinate to the rod diameter were ranged from 1.6 to 2.5 on each bundle geometry. The average value of Nusselt number, Nu_<av>, for three types of the bundle geometry with various values of S_x/D and S_y/D were calculated to examine the effect of the array size, S/D and R_f on heat transfer. The Nu_<av> becomes lower with the decrease in the value of R_f and higher with the increase in the value of S_x/D and S_y/D.The values of Nu_<av> with the same combinations of S_x/D and S_y/D values are almost in agreement independent of the bundle geometry. The bundle geometry for the higher Nu_<av> value under the condition of (S_x/D) * (S_y/D)=4 was examined by changing the ratio of S_x/S_y. A correlation for Nu_<av> for three types of bundle geometry above mentioned including the effects of S_x/D and S_y/D was developed. The correlation can describe the theoretical values of Nu_<av> for three types of the bundle geometry in Nx*Ny arrays (Nx, Ny=59) for S_x/D and S_y/D ranging from 1.6 to 2.5 within 10% difference. Less

Report
(3results)
Research Output
(9results)