Experimental and Numerical Investigation of Flow in ‎Hydraulic Elbows

Abstract

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.

Air Flow Analysis and Effect of Angle on Rotation Vane Blade Through 90-Degree by Computational Fluid Dynamic

“…The graph indicates that the pressure loss rises dramatically with Reynolds number for both rotating vane blade angles. The pressure changed from section A-A to section B-B as a result of centrifugal forces, friction on the pipe bend wall, and the angle of rotation of the vane blade [5,30]. The largest pressure drop happened at the lower end of the pipe cross-section (P2), while the least pressure drop happened at the higher end of the pipe cross-section (P9).…”

“…The 90° pipe bend is often employed in pipeline systems to divert flow to specific places [1,2]. It is used in a variety of engineering applications, including the oil industry, transportation systems, water supply systems, air conditioning systems, and hydraulic systems [3][4][5]. As the fluids travel through the pipe bend, the turbulent flow of high-velocity fluids contacts the pipe bend's wall, and centrifugal force is created based on the bend curvature, resulting in the development of secondary flows [2].…”

Head losses and experimental loss coefficient in 45^o and 90^o elbows of PVC pipes with small diameters for single-phase flow and moderate Reynolds numbers

“…Research on head losses or loss coefficient in elbows has not ceased in recent years, which can be seen in the experimental work carried out by Silverio [2], Musa [5], Yogaraja [6] and Arteaga [12]. Likewise, recent research has been reported where numerical models are applied to estimate head losses in elbows, such as the work reported by Selim [13], Mańko [14], Meng [15] and Chang [16]. However, limited information is available on small-diameter fittings, and these studies necessitate calibration or comparison with experimental data for validation, highlighting the importance of laboratory research.…”