a. kibar

Flow distribution uniformity in manifolds is important in various engineering applications. In this study, the effect of manifold design on flow distribution is examined using both experimental and numerical methods. A comparison was made between a straight manifold and a gradually decreasing cross-sectional design considering two different inlet diameters. In addition, the staggered manifold case with the most homogeneous outlet was compared with the conical manifold under the same conditions. The results demonstrate that the gradually decreasing manifold design significantly improves the flow rate uniformity compared with the straight manifold. This improvement is achieved by reducing the flow rate differences between the distribution branches, leading to a more balanced fluid distribution. The gradual reduction in the cross-sectional area allows the fluid to traverse at lower velocities in regions with higher resistance, effectively minimizing flow rate discrepancies and pressure drops. In addition, the effect of varying the inlet diameter on flow rate uniformity was investigated, revealing that larger inlet diameters contribute to improved flow distribution. The outlet uniformity of the staggered manifold matches the effective performance of the conical manifold, demonstrating similar performance at a lower cost. The results highlight the importance of designing an appropriate manifold, considering factors such as inlet diameter, channel geometry, and staggered ratio, to achieve efficient and uniform fluid distribution.

A liquid jet impinging on stationary and rotating superhydrophobic and hydrophilic convex surfaces is experimentally investigated. The effects of the rotation and wettability of the surface and the inertia and impingement rate of the jet on the flow, and the reflection and deflection behavior of the impinging jet are examined. This study examines the effect of air film formation at the constantly regenerating interface between a superhydrophobic surface and a liquid jet. For this purpose, two copper pipes and one plexiglass pipe, which had outer diameters of 8, 22, and 50 mm, were used for the convex surfaces. The copper pipes were coated with a superhydrophobic coating with a 157° apparent contact angle. The uncoated plexiglass pipe had a 73° apparent contact angle. The Reynolds and Weber numbers ranged from 1082 to 3443 and from 3.90 to 35.12, respectively. The liquid jet was sent to the rotating convex surfaces at different impingement rates. The experimental results show that the impinging liquid jet is reflected off the stationary superhydrophobic surface. This reflection behavior is not nearly distributed from the rotation of the superhydrophobic convex surface. The distribution increases slightly with an increase in the Reynolds or Weber numbers, the diameter of the convex surface, and the impingement rate. Nevertheless, the impingement liquid jet is deflected off the stationary hydrophilic surface. This deflection increases considerably with the rotation of the convex surface. The renewal of the air film between the superhydrophobic surface and the liquid significantly reduces the viscous drag force. Therefore, the impinging liquid jet cannot be dragged by the rotating superhydrophobic convex surface.

Hydraulic systems are extensively used in industries. However, these systems must be free of contaminants to ensure their durability. When the contaminants entering the system are not removed with a suitable filter, sensitive parts such as pumps, motors, and actuators would be damaged. Therefore, hydraulic filters are critical elements in hydraulic systems. In this study, the flow and pressure drop in hydraulic filters were investigated experimentally and numerically. Although the main function of this device is to filter oil, it has many other functions in the system. Experiments were performed at eight Reynolds numbers in the range of 1250 ‒ 2350 at a constant viscosity. In the experiments, the pressure between the inlet and outlet of the filter was measured differently. The numerical results were used for detailed analysis of the flow after experimental verification. The analyses were performed using eight Reynolds numbers at laminar boundaries to examine the flow in the hydraulic filter. The results show that all surface areas of the filter element are not used homogeneously for fluid passage. The resultant pressure drop is due to the Dean vortex formed at the outlet of the hydraulic filter. The findings of this study can help better understand the flow recirculation regions that produce pressure drops and contaminant accumulation regions throughout a hydraulic filter from the inlet to the outlet of the flow path.

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.