Research Papers

Obstructed View Factor Calculations for Multiple Obstructions in Closed Cavities

[+] Author and Article Information
Fiaz Mahmood

School of Nuclear Science and Technology,
Xian Jiaotong University,
No. 28, Xianning West Road,
Xi'an 710049, Shaanxi, China

Huasi Hu

School of Nuclear Science and Technology,
Xian Jiaotong University,
No. 28, Xianning West Road,
Xi'an 710049, Shaanxi, China
e-mail: huasi_hu@mail.xjtu.edu.cn

1Corresponding author.

Manuscript received October 29, 2017; final manuscript received September 13, 2018; published online January 24, 2019. Assoc. Editor: Asif Arastu.

ASME J of Nuclear Rad Sci 5(1), 011012 (Jan 24, 2019) (5 pages) Paper No: NERS-17-1218; doi: 10.1115/1.4041563 History: Received October 29, 2017; Revised September 13, 2018

The inertial confinement fusion (ICF) program has been mainly concentrating on the indirect drive approach for the last three decades, due to relaxed requirements on driver-beam uniformity and reduced sensitivity to hydrodynamic instabilities. The optimal designs are important for maximum conversion of driving energy to X-rays, and finally, symmetrical irradiation of the capsule. The view factor (VF) evaluation is an important parameter providing significant radiation heat transport information in specific geometries. The present study is aimed at the VF calculations for closed cavities. The VF calculations include the case of energy transfer from one infinitesimal surface element of the enclosure to other similar infinitesimal surface elements of the cavity. Similarly, the obstructed VF is also calculated when multiple obstructions are present in the cavity. Two distinct computer programs are developed by programming in FORTRAN-90 to evaluate unobstructed VF and obstructed VF for a square geometry. The calculations are based on the crossed strings method, which is more reliable for simple geometries. The shadow effect method is used for the obstructed VF calculations. The results of the developed programs are benchmarked using the summation rule. In the case of no obstacles in the cavity, VF calculations solely obey the summation rule. However, in the presence of obstacles in the cavity, obstructed VF calculations showed the acceptable difference in comparison with the summation rule.

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Grahic Jump Location
Fig. 1

The radiative exchange between two infinitesimal surface elements

Grahic Jump Location
Fig. 2

The crossed strings method for arbitrary two-dimensional configurations

Grahic Jump Location
Fig. 3

Schematic of geometry without obstructions showing radiation emission and transmission

Grahic Jump Location
Fig. 4

Hierarchy of the program for VF calculations

Grahic Jump Location
Fig. 5

Schematic of geometry with obstructions showing radiation emission and transmission

Grahic Jump Location
Fig. 6

Hierarchy of the program for obstructed VF calculations



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