Measurement uncertainty of discharge air velocity by graphical integration in closed conduits using Pitot tubes

Abstract

This paper addresses the measurement uncertainty in the determination of the discharge air velocity, using Pitot static tubes, for the flow-rate measurement in closed conduits related to ventilation installations. This indirect measurement method is supported in local air velocity measurements performed in known positions in the conduit’s cross-section. Graphical integration between extreme measuring points is one of the available techniques used for the calculation of the discharge air velocity. This paper illustrates a Monte Carlo simulation procedure for the measurement uncertainty propagation from the input quantities – local air velocities, measurement positions, conduit dimension and inner wall roughness – to the output quantity – discharge air velocity.