Numerical simulation of a z-shaped ventilation elbow and reduction of its resistance

Abstract

Abstract The paper presents the results of a numerical study of the flow in a Z-shaped elbow. Dependencies are found for the local drag coefficient of such a unit, the coupling effect coefficient, the lengths of the influence zones and the outlines of the vortex zones on the distance between the individual components in this unit. The dependence for the LDC, as well as the coupling effect coefficient, agrees quite well with the known experimental data, which indicates the validity of the numerical model. Using the found outlines of the vortex zones, numerical models of energy-efficient profiled Z-shaped elbows were developed and investigated. Graphical dependence of the LDC of such a duct unit on the distance between the single elbows is developed. The resulting dependence shows a decrease in resistance by 70 % compared with the standard design. For a whole ventilation system, it will lead to energy savings spent on the drive of the fans, and therefore to reduce operating costs. Using of a large number of such energy-efficient duct elements will allow replacing the fan with a less powerful one, which will lead to reduction in capital costs for construction.