Citation

Zhang L, Chen S, Zhao L, Wang J, Lu Y. China Saf. Sci. J. 2021; 31(12): 78-84.

Copyright

(Copyright © 2021, China Occupational Safety and Health Association, Publisher Gai Xue bao)

DOI

10.16265/j.cnki.issn1003-3033.2021.12.011

PMID

unavailable

Abstract

In order to make the calculation of flow pressure loss in goaf simple and reasonable, a new physical model of porous media was proposed. Then, it was cut to construct a minimum flow unit according to principles of equal porosity and single-cycle flow. For the unit, hydrodynamic differential equations were used to quantify relationship between pressure loss per unit length and sphere diameter, gas density and initial velocity, and a simplified one-dimensional minimum flow unit's pressure loss calculation formula was obtained. Finally, the formula was verified on flow field test platform in a goaf, and 26 actual measurements of initial velocity and pressure loss were completed for 4 entrance sections respectively. As section wind speed increased, measured pressure loss also increased, while the ratio of measured loss to the calculated one decreased first and then stabilized. This ratio was defined as correction coefficient, and its average value was obtained. The results show that the simplified formula is derived based on the minimum flow unit, and by further correcting the formula with correction coefficient, a pseudo three-dimensional calculation formula can be obtained, thereby realizing simple calculation of gas flow pressure loss in goaf. © 2021 China Safety Science Journal. All rights reserved.

Language: zh