Experimental investigation of turbulent flow through a square-sectioned duct and 90ᵒ square elbow by using circular turbulator

Abstract

The ducting system is made up of 90° elbows and a few other fittings and accessories in addition to straight ducts. The friction loss, separation loss, and secondary flow loss are the main causes of the pressure decrease in an elbow, and they all increase with the presence of elbows. Utilizing too much energy to propel the flow is a cost associated with pressure loss. The aim of this research is to investigate turbulent flow via 90° square elbows and a square-sectioned duct through experimental methods by adding a circular turbulator (CT) close to the elbow wall's inner radius. The Reynolds numbers (ReDh) used in this research are 1.6×104, 4.8×104, and 9.5×104, with average flow velocities of 2 m/s, 6 m/s, and 12 m/s. Circular turbulators are added to the inner walls with angular positions (α) of 5°, 10°, 15°, and 20°. The results showed that the turbulence intensity increased toward the inner radius wall of the elbow in ducting with CT. For this study, the flow within the ducting with the CT is generally more turbulent than the flow inside the ducting without the CT. By including CT, it was possible to reduce the overall pressure loss in ducting with an elbow. The pressure reduction at two ReDh values (1.6×104 and 4.8×104) was only lessened by CT positioned at α=10°, 15°, and 20° out of the four CT placements. Conversely, CT positioned at α=5° can only effectively mitigate pressure decrease at ReDh=1.6×104. CT installation cannot lessen the pressure drop that happens in the ducting at a value of ReDh=9.5×104. CT placement at the three α values often helps to lower the pressure drop in the ducting. Using the CT, positioned at α=15°, is the greatest strategy to reduce the overall pressure decrease