Semester

Spring

Date of Graduation

2002

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mining Engineering

Committee Chair

Lloyd English.

Abstract

Coal mines require very effective and proper ventilation systems not only to keep the levels of explosive, harmful gases and dust to a safe level but also to deliver enough fresh air for miners to breathe. Depending upon the size of the mine and the quantity of gases and dust in this mine, it could be ventilated by using a single fan or several fans. There are two types of fans used in mines: vane axial and centrifugal.;In multiple-fan systems, each individual fan influences the performance of the whole system, including the other fans. Each fan in the system has its own mine characteristic curve or subsystem curve. Thus the present of an axial flow fan or fans inside each subsystem turns the resistance factor of the subsystem into a variable. Thus the relationship between the airflow and the pressure consumed through the subsystem does not strictly follow Atkinson equation. The shape of the subsystem curve and the number of the operating points in the system depend on the number and type of fans inside the subsystem. The shape of this subsystem characteristic curve could have sharp turning points and its shape may not be fixed as in the single fan system.;Both the implemented Hardy Cross method and damped Newton-Raphson method using switching parameters are found to be good tools to trace these subsystem characteristic curves. The modified Hardy Cross method is faster and more flexible than the modified damped Newton-Raphson method, especially when solving large networks.

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