Proposal of a Simpler Procedure for Flow Rate Estimation in Square Cross Section Ducts

Focus of the present work is the evaluation of the air flow rate in a pipe of squared cross section through the direct measurement of the mean velocity at a fixed location of the section. To this aim, an extension of the methodology already utilized for circular section pipes is here proposed. The method simplifies and improves the procedure suggested by the technical standard EN 12599. Specifically, it has been possible to state a geometrical position in the cross section where to straight measure the mean flow velocity in order to evaluate the flow rate. Here, it is shown that the proposed methodology allows the estimation of the flow rate with higher accuracy than the normed one does, estimating errors less than those accepted in common practice.