DETERMINATION OF AERODYNAMIC AND MECHANICAL PARAMETERS OF FLEXIBLE DEFORMABLE AIR DUCT Russian patent published in 2016 - IPC F24F13/00 

FIELD: mining.

SUBSTANCE: determination of said parameters comprises the venting of air duct by the blower. Said parameters are revealed in steps. At first step, air duct is vented at two operating modes of the blower so that second mode airflow rate is higher than that at the first mode. Note here that said airflows of both modes are defined as the mean or mean arithmetic flow rates ay air duct inlet and outlet. At second step the ratio (Z) between the specific air drag of air duct (r₀) and air duct material transverse resilience factor (E) is defined by the formula: where δ is air duct wall depth (m); d₀ is air duct initial diameter (m); L is air duct length (m); Q₁, Q₂ are air flow rates in air duct at the first and second operating conditions of the blower, respectively (m³/s); p₁, p₂ are air pressure at the first and second operating conditions of the blower, respectively (kg/m²). Specific air duct drag is calculated by the formula: while air duct material transverse resilience factor is defined by the formula:

EFFECT: higher validity of determination at venting the development gallery of coal mines.