|This program is designed for the use of Mechanical Engineers who design air
distribution or exhaust systems for Heating Ventilating and Air Conditioning systems.
The calculator, in either english or metric, allows users to input a desired flow rate, a limiting velocity, air pressure, air temperature, the length of the duct, and the duct material. The program then calculates the duct cross sectional area, the circular duct diameter, rectangular duct equivalents (with aspect ratios of 1.0 through 4.0), air density, fluid viscosity, Reynold's number, relative roughness, the Moody friction factor, the Colebrook friction factor, the pressure loss, and the duct friction loss per unit of duct length.
The program uses the Moody equation, the Colebrook equation, the Darcy-Weisbach equation, the perfect gas laws, and the Huebscher equation.
Slide-rule type duct calculators designed for standard air and galvanized steel ductwork do not allow users to correct for non-standard air conditions, or for other types of duct material. The Air Duct Calculator allows users to input any type of duct material, and can input any air temperature and pressure. The program will then calculate air density and air viscosity for precise pressure loss calculations.