| The main purpose of this thesis is to study various mine ventilation network analysis methods theoretically and experimentally. Many of the well-known algorithms for mine ventilation network analysis are collected and compared. New ideas or modifications to the existing algorithms that may offer greater efficiency than those of the existing algorithms are proposed. The variations of the performance characteristics of all these procedures due to the changes in the characteristics of networks are studied.;A mine ventilation network analysis procedure is divided into three steps: (1) mesh selection, (2) mesh ordering, and (3) numerical solution. Three methods of mesh selection, three methods of mesh ordering, and four methods of numerical solution are discussed in this thesis. As a result, 36 combinations of a mesh selection method, a mesh ordering method, and a numerical solution method are compared. The Hardy Cross method, the Newton-Raphson method, the linear theory method, and the second-order approximation method are the four methods of numerical solution compared. The minimum-resistance spanning tree method, the shortest-path method, and the minimum-resistance-path method are the three methods compared for mesh selection. The three methods of mesh ordering are the random ordering method, the bandwidth reduction method, and the profile reduction method.;A method of generating a set of "random" networks that can be used for comparison of different algorithms is suggested. Then the evaluation of the varoius combinations is performed by analyzing randomly generated ventilation networks. Both the total computing time and the number of iterations are used as the measures for the efficiency of a network analysis program with emphasis being given to the total computing time. Also, a number of different random networks are used for the experiment to eliminate the bias caused by the differences in the characteristics of the networks. The stability of a network analysis method as well as the average performance is discussed. The coefficient of variation is used as a measure for the stability. |
