A Study of Aerodynamics Around Rotating Blades in a Lawnmower Deck

2002 ◽  
Author(s):  
P. A. Hagen ◽  
W. Chon ◽  
R. S. Amano
Keyword(s):  
High Speed ◽  
Flow Behavior ◽  
Video Camera ◽  
Element Analysis ◽  
Pressure Transducers ◽  
Discharge Velocity ◽  
Vapor Injection ◽  
High Speed Video Camera ◽  
Particle Feeding ◽  
Visualization Techniques

The objective of this study is to investigate the flow behavior within a triple-blade lawnmower deck. The test section was constructed for velocity measurement with an open bottom and side-discharge. Velocity measurements were collected at several different tangential and axial sections inside the deck. The flow behaviors are observed using Laser Doppler Velocimetry (LDV) and a high-speed video camera capturing 2000 frames per second. Several different visualization techniques have been attempted: particle feeding, water vapor injection, tuft method, and others. To further enhance the experimental accuracy, fresh sod was fed into the system simulating normal cutting conditions. Along with the extensive velocity analysis, strain and static pressure were also examined at various surface locations along the blade using linear strain gages, piezoresistive pressure transducers, and Finite Element Analysis (FEA) methods. Validation of the above analyses was performed using Computational Fluid Dynamics (CFD) investigation. It has been observed that the deck and blade configurations share equal significance in the resultant flow profiles.

Experimental Study of Aerodynamics Around Rotating Blades in a Lawnmower Deck

2002 ◽  
Author(s):  
P. A. Hagen ◽  
W. Chon ◽  
R. S. Amano
Keyword(s):  
High Speed ◽  
Flow Behavior ◽  
Video Camera ◽  
Strain Gages ◽  
Velocity Measurements ◽  
Discharge Velocity ◽  
Vapor Injection ◽  
High Speed Video Camera ◽  
Particle Feeding ◽  
Visualization Techniques

The objective of this study is to investigate the flow behavior within a triple-blade lawnmower deck by means of experimental techniques. The test section was constructed for velocity measurement with an open bottom and side-discharge. Velocity measurements were collected at several different tangential and axial sections inside the deck. The flow behaviors are observed using both a Laser Doppler Velocimetry (LDV) and a high-speed video camera capturing 2000 frames per second. Several different visualization techniques have been attempted: particle feeding, water vapor injection, tuft method, and others. To further enhance the experimental accuracy, fresh sod was fed into the system simulating normal cutting conditions. Along with the extensive velocity analysis, strain and static pressure were also examined at various surface locations along the blade using linear strain gages and a piezoresistive pressure transducer. It has been observed that the deck and blade configurations share equal significance in the resultant flow profiles.

Experimental Study on Pressure Transients With Cavitation in Low Pressure Water-Hydraulic Pipeline

2018 ◽  
Author(s):  
Dan Jiang ◽  
Cong Ren ◽  
Qing Guo
Keyword(s):  
High Speed ◽  
Gas Bubbles ◽  
Video Camera ◽  
Low Pressure ◽  
Pressure Pulsations ◽  
Pressure Transients ◽  
Pressure Transducers ◽  
High Speed Video Camera ◽  
Pressure Water ◽  
Water Hydraulic

In this study, pressure transients are triggered by a steel ball, which is released from an upstream reservoir to hit a valve seat and shut off water flow in a horizontal straight copper pipeline. The pressure pulsations, cavitation and gas bubbles growth and collapse in the low pressure water-hydraulic pipeline are recorded by two pressure transducers and a high speed video camera, respectively. In addition, the influences of initial volume of gas bubbles in water and instant leakage in valve are investigated. The experimental results indicate that increasing initial gas bubble volume in water and the instant leakage of the valve will help to reduce magnitudes and numbers of pressure peaks during pressure transients. Then methods to reduce pressure pulsations in pipelines are put forward.

Image Analysis of Carry-Under by Falling Liquid Flow

2010 ◽  
Author(s):  
Tomohiko Ohtsuka ◽  
Naoki Haraguchi ◽  
Hiroyasu Ohtake ◽  
Yasuo Koizumi
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Flow Behavior ◽  
Wave Length ◽  
Video Camera ◽  
Water Jet ◽  
Water Pool ◽  
Nozzle Outlet ◽  
Pool Surface ◽  
High Speed Video Camera

Bubble carry-under into the water pool was examined. In experiments, a water jet from a nozzle of 5 mm in diameter plunged into the water pool. The distance between the nozzle outlet and the pool surface was 246 mm. Flow behavior in the water pool and also the state of the water jet surface were recorded with a high speed video camera. Following conclusions were obtained. When the flow rate of the water jet was small, the water jet disintegrated into small drops on the way from the nozzle outlet to the pool surface. The wave appearing position moved downward as the flow rate was increased. When the wave length reached the Kelvin-Helmholtz critical wave length, the water jet disintegrated into drops. When flow rate of the water jet was increased, the surface of the water jet became smooth and no perturbation was observed. The carry-under was not observed in this situation. When the flow rate of the water jet was further increased, large waves came to appear on the water jet surface. The wave appearing position moved upward as the flow rate was increased. Even if the wave length on the water jet reached the Kelvin-Helmholtz critical wave length, the water jet did not disintegrate into drops and the water jet plunges into the pool with large waves on the water jet. The penetration depth in this case was deep and the volume of the bubble carry-under was large compared with the case that the water jet disintegrated into drops.

Numerical Simulation and Experiment of Motion of Rice Seed in Pneumatic Seed-Metering Device

2012 ◽  
Vol 249-250 ◽  
pp. 657-662
Author(s):  
Ya Xin Yu ◽  
Yuan Yuan Yang ◽  
Bin Zheng ◽  
Fei Zhang
Keyword(s):  
High Speed ◽  
Theoretical Models ◽  
Video Camera ◽  
Rice Seed ◽  
Working Process ◽  
Straight Pipe ◽  
Element Analysis ◽  
High Speed Video Camera ◽  
Simulation And Experiment ◽  
Seed Metering Device

A new-style pneumatic precision seed-metering device for super rice seed was proposed. This paper analyzed the working process for seed-metering device. The movement of rice seed in the “L” tube was simulated by finite element analysis software. The speed distribution, pressure distribution of air in the “L” tube and the trajectory of rice seed were solved. Results of the analyses indicated that there were partial reflux at the entrance and elbow; while the airflow moved steadily at the straight pipe. Based on the fabricated device, the motion trajectory was studied by high speed video camera. Experiment was used to analyze the effect of parameters. The results showed that the experimental trajectory was in accordance with theoretical models.

scholarly journals Detonation effects of shallow buried explosive in sandy soil on target plate acceleration in a small-scale blast test

2018 ◽  
Vol 192 ◽  
pp. 02028
Author(s):  
Hassan Zulkifli Abu ◽  
Ibrahim Aniza ◽  
Mohamad Nor Norazman
Keyword(s):  
Sandy Soil ◽  
High Speed ◽  
Early Stage ◽  
Time History ◽  
Video Camera ◽  
Small Scale ◽  
Target Plate ◽  
Air Blast ◽  
High Speed Video Camera ◽  
The Impact

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

In Situ Observation Method for Quantitative Evaluation of Solidification Phenomena and Solidification Cracks during Welding

2014 ◽  
Vol 782 ◽  
pp. 3-7
Author(s):  
Kenji Shinozaki ◽  
Motomichi Yamamoto ◽  
Kohta Kadoi ◽  
Peng Wen
Keyword(s):  
High Speed ◽  
Video Camera ◽  
Solidification Cracking ◽  
In Situ Observation ◽  
High Speed Video Camera ◽  
Varestraint Test ◽  
Solidification Cracks ◽  
Observation Method ◽  
Solidification Crack

Solidification cracking during welding is very serious problem for practical use. Therefore, there are so many reports concerning solidification cracking. Normally, solidification cracking susceptibility of material is quantitatively evaluated using Trans-Varestraint test. On the other hand, local solidification cracking strain was tried to measure precisely using in-situ observation method, called MISO method about 30 years ago. Recently, digital high-speed video camera develops very fast and its image quality is very high. Therefore, we have started to observe solidification crack using in site observation method. In this paper, the local critical strain of a solidification crack was measured and the high temperature ductility curves of weld metals having different dilution ratios and different grain sizes to evaluate quantitatively the effects of dilution ratio and grain size on solidification cracking susceptibility by using an improved in situ observation method.

Study on Magnetic Barrel Machine Equipped with Three-Dimensional Arrangement of Magnets

2007 ◽  
Vol 329 ◽  
pp. 761-766 ◽  
Author(s):  
Y. Zhang ◽  
Masato Yoshioka ◽  
Shin-Ichiro Hira
Keyword(s):  
High Speed ◽  
Permanent Magnets ◽  
Three Dimensional ◽  
Video Camera ◽  
High Speed Video ◽  
High Speed Video Camera ◽  
The Media ◽  
Set Up

At present, a commercially available magnetic barrel machine equipped with permanent magnets has some faults arising from constructional reason. That is, grinding or finishing ability is different from place to place in the machining region, resulting in the limitation on the region we can use in the container of workpieces. Therefore, in this research, authors made the new magnetic barrel machine equipped with three dimensional (3D) magnet arrangement to overcome these faults. The grinding ability of the new 3D magnetic barrel machine converted was experimentally examined, and compared with that of the traditional magnetic barrel machine. As a result, it was shown that we can use much broader region in the new 3D machine. It was also shown that the grinding ability became higher. The distribution of barrel media in action was recorded by means of a high speed video camera. It was clarified that the media rose up higher and were distributed more uniformly in the container by the effect of the magnet block newly set up. It was supposed that this must be the reason for the above-mentioned improvement of grinding ability.

Grease soap particles passing through an elastohydrodynamic contact under side slip conditions

2000 ◽  
Vol 214 (4) ◽  
pp. 317-325 ◽  
Author(s):  
P Eriksson ◽  
V Wikström ◽  
R Larsson
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Previous Investigation ◽  
Video Camera ◽  
Slip Conditions ◽  
High Speed Video ◽  
Elastohydrodynamic Contact ◽  
High Speed Video Camera ◽  
Pure Rolling ◽  
Minimum Film Thickness

In a previous investigation, grease thickener fibres were tracked as they passed through an elastohydrodynamic (EHD) contact in pure rolling using interferometry in a standard ball-and-disc apparatus. In order to capture single thickener fibres, a high-speed video camera was used. Here, the experiments have been repeated introducing different amounts of side slip for different rolling speeds and a faster video camera capable of capturing 4500 frames/s. The contact was lubricated with a continuous supply of grease. Two greases, based on the same synthetic poly(α-olefin) but thickened with Li-12-OH and lithium complex soap respectively, were studied. It was observed that the thickener fibres were stretched both before entering the contact and as they passed through it. Fibres seem to avoid the minimum film thickness regions and, if they enter, the film is restored immediately after passage.

Sign in / Sign up

Export Citation Format

Share Document