Abstract
The optimal design of pipe outlets is an essential objective for many engineering projects. For the first time, this paper reports the results of a laboratory investigation on the effect of using a passive rotor (added at the pipe outlet) on the outlet performance. Different sizes and numbers of blades of rotors were considered. Through the Tracker software package, video and image processing techniques were applied to capture the temporal variations of the tank water depth and the passive rotor’s angular speed. In addition, a normalized average drainage rate (NADR) parameter is defined to quantify the changes in the tank drainage rate as a result of passive rotor utilization. It is noted that adding a 4-bladed symmetric passive rotor will increase NADR by up to 9.0%. The study also shows that the highest increase in NADR is attained when the rotor diameter size is approximately 1.73 times the pipe outlet’s diameter for the case of symmetric 4-blade rotors, and the corresponding average tip rotor speed ratio is 1.65. It is also found that using an asymmetric 3-blade rotor has a negative impact on the NADR due to the significant perturbation produced by the rotor asymmetry.
Highlights
This paper proposes the use of a passive rotor at the pipe outlet to enhance the system non-intrusive measurement for the temporal variations of the water depth in the tank, the performance of a tank-pipe-outlet system
The hydraulic effect of introducing a passive rotor to a tank-pipe-outlet system was investigated experimentally to assess its effect on the tank drainage rate and the hydraulic performance of the outlet
Video analysis and image processing were performed using the Tracker package to determine the temporal variations of the tank water depth and the corresponding rotor’s angular speed
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. It has been found that a single-port diffuser is more efficient in diluting the effluent by the ambient water under the condition that free mixing is maintained. This interaction could result in a significant reduction in the dilution efficiency of all the diffusers as a set at large [13,14] Another innovative way that could be proposed to enhance the mixing and dilution of the discharged effluent is to add a rotor at the disposal port outlet. The main objectives of the study in hand are to investigate experimentally, for the first time, the effect of using a passive rotor at the outlet of a tank-pipe-outlet system on the time of emptying, the water depth decline trend, and the temporal variations of the effluent discharge.
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