Numerical Simulation and Experimental Study of the Drag Reduction of 90° Elbows for Ventilation and Air Conditioning Tubes in An Arc Form

Abstract

Ventilation and air conditioning (VAC) tubes and technologies have been widely applied in modern architecture. In tube systems, local drag generally accounts for 40% of the total drag losses. Thus, optimizing the existing system components is extremely important in improving energy utilization, saving energy, and reducing emissions. Among the local drag components of the systems, 90° elbows are essential. In this study, the drag reduction of 90° elbows in an arc form is numerically simulated and experimentally studied. Factors influencing drag losses are analyzed. Several optimal design schemes for such components are given, and the effect of drag reduction of various optimization schemes is verified by experiments.The optimized elbows can effectively reduce local drag opposite VAC tubes by 9%–10%.