Location

Rolla, MO

Session Start Date

6-11-1999

Session End Date

6-17-1999

Keywords and Phrases

Equivalent Roughness; Friction Drag; ERM; Flow Direction of Diagonal Airway

Abstract

Some roadways, which do not behave as "wholly rough pipe" as we expected, will have different impact on airflow in a mine ventilation network because of the low Reynolds numbers. For a "non-Wholly-rough" roadway, its resistance factor (R) or the friction factor (¦) is not only dependent upon the relative roughness but also dependent upon the Reynolds number, which varies directly as the flow rate. In this case, R or ¦ is no longer a constant independent of flow rate. Thus, in order to correctly calculate the friction drag of the same roadway for different flow rates, ¦ must be correctly calculated firstly by an appropriate method. After introducing the concept of Equivalent Roughness of mine roadway, the Colebrook formula can serve as this method. Known from the conventional method for calculating the friction drag of mine roadway, the method introduced in this paper is called the Equivalent Roughness Method (ERM). By using the ERM to analyze the airflow direction of the diagonal airway in a simple diagonal network, a new calculating example is presented.

Department(s)

Mining and Nuclear Engineering

Appears In

U.S. Mine Ventilation Symposium

Meeting Name

8th U.S. Mine Ventilation Symposium

Publisher

University of Missouri--Rolla

Publication Date

6-11-1999

Document Version

Final Version

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Jun 11th, 12:00 AM Jun 17th, 12:00 AM

Equivalent Roughness and Its Application in Calculating Friction Drag of Mine Roadway

Rolla, MO

Some roadways, which do not behave as "wholly rough pipe" as we expected, will have different impact on airflow in a mine ventilation network because of the low Reynolds numbers. For a "non-Wholly-rough" roadway, its resistance factor (R) or the friction factor (¦) is not only dependent upon the relative roughness but also dependent upon the Reynolds number, which varies directly as the flow rate. In this case, R or ¦ is no longer a constant independent of flow rate. Thus, in order to correctly calculate the friction drag of the same roadway for different flow rates, ¦ must be correctly calculated firstly by an appropriate method. After introducing the concept of Equivalent Roughness of mine roadway, the Colebrook formula can serve as this method. Known from the conventional method for calculating the friction drag of mine roadway, the method introduced in this paper is called the Equivalent Roughness Method (ERM). By using the ERM to analyze the airflow direction of the diagonal airway in a simple diagonal network, a new calculating example is presented.