Experimental and Numerical Investigation of Flow in ‎Hydraulic Elbows

Elbow fittings are common in hydraulic and pipeline systems. These components cause a significant ‎pressure drop in the total pressure of a system. The banjo elbow is advantageous in areas low to the ‎ground and where flexible connection angles are needed. However, this elbow yields a larger pressure ‎drop than a standard elbow. Additionally, the position of the internal bolt in the banjo elbow cannot be ‎determined prior to installation, which corresponds to a wide range of possible pressure drop. In this ‎study, the pressure drop through a 3/8” banjo elbow is investigated for different positions of the internal ‎bolt, experimentally and numerically. Experiments and simulations were carried out on hydraulic oil with ‎four different Reynolds numbers ranging from 3111 to 6222 and at nine bolt connection angles ranging ‎from 0° to 60°. Experiments were repeated with the standard elbow of the same size to compare the ‎pressure drops to those of the banjo elbow. Pressure was measured at both the inlets and outlets of the ‎elbows. The results suggest that the connection angle of the internal bolt is an important factor in the ‎pressure drop and minor head loss through a banjo elbow. For Reynolds numbers of 3111 and 6222, an ‎improvement in minor head loss by 33% and 58%, respectively, was achieved by adjusting the ‎connection angle of the internal bolt in the banjo elbows.