scholarly journals Evaluation of Magnus Force on Check Ball Behavior in a Hydraulic L Shaped Pipe

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 191
Author(s):  
Shinji Kajiwara
Keyword(s):  
Flow Pattern ◽  
Opposite Direction ◽  
Rotational Speed ◽  
Hydraulic System ◽  
Translational Motion ◽  
Check Valve ◽  
Inlet Pipe ◽  
Magnus Force ◽  
Magnus Effect ◽  
Computer Aided

This paper presents the effect of the rotational speed of a check ball in a hydraulic L-tube on the translational motion caused by the Magnus effect. A spring-driven ball check valve is one of the most important components of a hydraulic system and controls the position of the ball to prevent backflow. To simplify the structure, the springs must be eliminated. To this end, it is necessary to clarify the flow pattern of the check ball in an L-shaped pipe and the rotational and translational behaviors of the ball. In this study, the position of the inlet pipe and the availability of the check were determined using Computer Aided Engineering (CAE) tools. By moving the position of the inlet pipe from the top to the bottom of the housing, the direction of the rotation of the ball was reversed, and the behavior changed significantly. It was found that the Magnus force, which causes the ball to levitate by rotating it in the opposite direction to the flow, acts to shorten the floating time.

Damping of Self-Excited Pressure Pulsations in Petrodiesel Pipeline

2014 ◽  
Vol 630 ◽  
pp. 375-382 ◽  
Author(s):  
Daniel Himr ◽  
Vladimir Haban
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Control Valve ◽  
Sampling Frequency ◽  
Pressure Pulsations ◽  
One Dimensional ◽  
Fuel Storage ◽  
Excited Oscillation ◽  
Subsequent Measurement ◽  
And Control

A pumping station in a fuel storage suffered from pressure pulsations in a petrodiesel pipeline. Check valves protecting the station against back flow made a big noise when disc hit a seat. Due to employees complaints we were asked to solve the problem, which could lead to serious mechanical problems. Pressure measurement in the pipeline showed great pulsations, which were caused by self-excited oscillation of control valves at the downstream end of pipeline. The operating measurement did not catch it because of too low sampling frequency. One dimensional numerical model of the whole hydraulic system was carried out. The model consisted of check valve, pipeline and control valve, which could oscillate, so it was possible to simulate the unsteady flow. When the model was validated, a vessel with nitrogen was added to attenuate pressure pulsations. According to the results of numerical simulation, the vessel was installed on the location. Subsequent measurement proved noticeably lower pulsations and almost no noise.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

scholarly journals The impact of rotational speed and water volume on textile translational motion in a front-loading washer

2018 ◽  
Vol 89 (16) ◽  
pp. 3401-3410 ◽  
Author(s):  
Hong Liu ◽  
R Hugh Gong ◽  
Pinghua Xu ◽  
Xuemei Ding ◽  
Xiongying Wu
Keyword(s):  
Residence Time ◽  
Rotational Speed ◽  
High Speed ◽  
Translational Motion ◽  
Processing System ◽  
Water Volume ◽  
Motion Path ◽  
Rotational Axis ◽  
Passive Region ◽  
The Impact

Textile motion in a front-loading washer has been characterized via video capturing, and a processing system developed based on image geometric moment. Textile motion significantly contributes to the mass transfer of the wash solution in porous materials, particularly in the radial direction (perpendicular to the rotational axis of the inner drum). In this paper, the velocity profiles and residence time distributions of tracer textiles have been investigated to characterize the textile dynamics in a front-loading washer. The results show that the textile motion varies significantly with the water volume and rotational speed, and that the motion path follows certain patterns. Two regions are observed in the velocity plots: a passive region where the textile moves up with low velocity and an active region where the textile falls down with relatively high speed. A stagnant area in the residence time profile is observed. This corresponds to the passive region in the velocity profile. The stagnant area affects the mechanical action, thus influencing washing efficiency and textile performance. The findings on textile dynamics will help in the development of better front-loading washers.

scholarly journals Spectral Flow, Magnus Force and Mutual Friction Via the Geometric Optics Limit of Andreev Reflection

1997 ◽  
Vol 12 (06) ◽  
pp. 1123-1123
Author(s):  
Michael Stone
Keyword(s):  
Andreev Reflection ◽  
Relaxation Processes ◽  
Spectral Flow ◽  
Mutual Friction ◽  
Geometric Optics ◽  
Magnus Force ◽  
The Core ◽  
Magnus Effect ◽  
Pinning Potential ◽  
Stationary Vortex

The notion of spectral flow has given new insight into the motion of vortices in superfluids and superconductors. For a BCS superconductor the spectrum of low energy vortex core states is largely determined by the geometric optics limit of Andreev reflection. We use this to follow the evolution of the states when a stationary vortex is immersed in a transport supercurrent. If the core spectrum were continuous, spectral flow would convert the momentum flowing into the core via the Magnus effect into unbound quasi-particles — thus allowing the vortex to remain stationary without a pinning potential or other sink for the inflowing momentum. The discrete nature of the states, however, leads to Bloch oscillation which thwart the spectral flow. The momentum can escape only via relaxation processes. Taking these into account permits a physically transparent derivation of the mutual friction coefficients.

Instability of the Flow in a Mixed-Flow-Type Vaneless Diffuser System

2003 ◽  
Author(s):  
Hiromu Tsurusaki
Keyword(s):  
Rotational Speed ◽  
Velocity Ratio ◽  
Inlet Pipe ◽  
Vaneless Diffuser ◽  
Unstable Flow ◽  
Mixed Flow ◽  
Flow Angle ◽  
Fast Speed ◽  
Flow Through ◽  
Speed Mode

This study was carried out in order to investigate the unstable flow through a mixed-flow-type vaneless diffuser system. The testing equipment consists of a vaneless diffuser, an inlet pipe, and a swirl flow generator. Pressure fluctuations of the flow through the diffuser were measured. In the experiment, the velocity ratio (axial velocity/peripheral velocity) at the diffuser inlet, diffuser width, inlet pipe length, hub diameter, and mixed flow angle of the diffuser were varied. The internal flow condition existing when the unstable flow occurred is discussed in terms of turbulent flow analysis. The main findings of this study are as follows. The unstable flow is excited when the aforementioned velocity ratio is lowered under a critical value. The source of the unstable flow is the mixed flow vaneless diffuser. The rotational speed of the cell and the intensity of pressure fluctuation are influenced remarkably by diffuser width. The inlet pipe acts as an attenuator for the unstable flow of the diffuser. A prediction equation for rotational speed of the cell is proposed. Prediction of back flow in the diffuser is useful for prediction of the onset of unstable flow. Unstable flow with a fast-speed mode was measured when the diffuser had a small hub and a small mixed flow angle. The fast-speed mode is believed to arise from instability in the inlet pipe system.

Sedimentation Behavior of Mixed Powder Slurry under High-Speed Centrifugal Force

2009 ◽  
Vol 631-632 ◽  
pp. 361-366
Author(s):  
Hiroyuki Y. Suzuki
Keyword(s):  
Flow Pattern ◽  
Rotational Speed ◽  
High Speed ◽  
Mixed Powder ◽  
Initial Flow ◽  
Sedimentation Behavior ◽  
Compaction Behavior ◽  
Acceleration Rate ◽  
Dispersing Medium ◽  
Slight Amount

Compaction behavior of two component slurry during High-speed Centrifugal Compaction Process (HCP) was observed. Slight amount of iron oxide powder is mixed into alumina slurry, then the slurry was sedimented in a centrifuge under rotational speed of up to 11,500 rpm. A “Y” letter shaped flow pattern was emerged in the cross section of the compact. The pattern was clearer with higher rotational speed, but indifferent to acceleration rate of rotation. A similar pattern was simulated when we presume bidirectional initial flow in centrifugal field, which indicated that the combination of Corioli’s force and bidirectional flows of powder and dispersing medium caused such flow pattern.

scholarly journals Methodological Advances in the Design of Photovoltaic Irrigation

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2313
Author(s):  
Martín Calero-Lara ◽  
Rafael López-Luque ◽  
Francisco José Casares
Keyword(s):  
Rotational Speed ◽  
Hydraulic System ◽  
Water Distribution ◽  
Energy Requirement ◽  
Water Distribution Network ◽  
Irrigation Network ◽  
Daily Work ◽  
Photovoltaic Power ◽  
Irrigation Time ◽  
Energy Balances

In this study, an algorithm has been developed that manages photovoltaic solar energy in such a manner that all generated power is delivered to the system formed by a pump and irrigation network with compensated emitters. The algorithm is based on the daily work matrix that is updated daily by considering water and energy balances. The algorithm determines an irrigation priority for the sectors of irrigation of the farm based on programmed irrigation time and water deficits in the soil and synchronises the energy produced with the energy requirement of the hydraulic system according to the priority set for each day, obtaining the combinations of irrigation sectors appropriate to the photovoltaic power available. It takes into account the increment/decrease in the pressure of the water distribution network in response to increases/decreases in photovoltaic energy by increasing/decreasing the rotational speed of the pump, thus increasing/decreasing the power transferred to the system. The application to a real case of a 10-hectare farm divided into four sectors implies an efficient use of the energy of 26.15% per year and savings in CO2 emissions of 6.29 tonnes per year.

scholarly journals Investigation of Diesel Injector Flow Pattern Based On Computer-aided Design

CFD letters ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 13-23
Author(s):  
Mohd Azahari Razali ◽  
Rais Hanizam Madon ◽  
Md Norrizam Mohmad Ja’at ◽  
Azwan Sapit ◽  
Hamidon Salleh ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Computer Aided Design ◽  
Computer Aided ◽  
Aided Design
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