Numerical model of the flow in the exhaust unit "opening – elbow"

The object of research is the unit of the ventilation system, "exhaust opening - elbow." Ventilation systems designed in buildings for various purposes are usually highly branched, leading to significant pressure losses, the largest of which is due to local resistance in duct fitting elements. The design features of the premises and the significant dimensions of the ventilation ducts lead to the need to route the air ducts with fitting elements installed side-by-side. In such cases, one element has a mutual influence on another, with a change in comparison with separate ones, both in the coefficients of local resistance and the total pressure loss, which is not considered when performing aerodynamic calculations nowadays. Method. The article investigates the ventilation system unit, consisting of an elbow and an exhaust opening, spaced significantly large apart for testing purposes. Outlines of the vortex zones and the local drag coefficients of individual elements included in the unit are determined in the study. Results. As a result, outlines of the vortex zones at the inlet of the exhaust opening and in the elbow were obtained. The local drag coefficients for the exhaust opening and elbow were calculated. The obtained results were compared with known experimental and numerical data. The comparison of the obtained results showed that the settings used in this study led to adequate results in determining the outlines of the vortex zones and the local drag coefficients. The chosen model will be further used to study the influence of the elbow-exhaust opening distance on flow characteristics.