PIV Measurement of Flow Field in a Rotary Engine

The steady streaming (SS) phenomenon is gaining increased attention in the microfluidics community, because it can generate net mass flow from zero-mean vibration. We developed numerical simulation and experimental measurement tools to analyze this vibration-induced flow, which has been challenging due to its unsteady nature. The validity of these analysis methods is confirmed by comparing the three-dimensional (3D) flow field and the resulting particle trajectories induced around a cylindrical micro-pillar under circular vibration. In the numerical modeling, we directly solved the flow in the Lagrangian frame so that the substrate with a micro-pillar becomes stationary, and the results were converted to a stationary Eulerian frame to compare with the experimental results. The present approach enables us to avoid the introduction of a moving boundary or infinitesimal perturbation approximation. The flow field obtained by the micron-resolution particle image velocimetry (micro-PIV) measurement supported the three-dimensionality observed in the numerical results, which could be important for controlling the mass transport and manipulating particulate objects in microfluidic systems.

Download Full-text

Characteristics of Dynamic Forces Generated by a Flapping Butterfly and its Wake Structure

Volume 1C, Symposia: Gas-Liquid Two-Phase Flows; Gas and Liquid-Solid Two-Phase Flows; Numerical Methods for Multiphase Flow; Turbulent Flows: Issues and Perspectives; Flow Applications in Aerospace; Fluid Power; Bio-Inspired Fluid Mechanics; Flow Manipulation and Active Control; Fundamental Issues and Perspectives in Fluid Mechanics; Transport Phenomena in Energy Conversion From Clean and Sustainable Resources; Transport Phenomena in Materials Processing and Manufacturing Processes ◽

10.1115/fedsm2017-69285 ◽

2017 ◽

Author(s):

Masaki Fuchiwaki ◽

Kazuhiro Tanaka

Keyword(s):

Flow Field ◽

Butterfly Wing ◽

Vortex Loop ◽

Insect Wing ◽

Fluid Forces ◽

Insect Wings ◽

Piv Measurement ◽

Dynamic Forces ◽

Butterfly Wings ◽

The Relationship

A typical example of the flow field around a moving elastic body is that around butterfly wings. Butterflies fly by skillfully controlling this flow field, and vortices are generated around their bodies. The motion of their elastic wings produces dynamic fluid forces by manipulating the flow field. For this reason, there has been increased academic interest in the flow field and dynamic fluid forces produced by butterfly wings. A number of recent studies have qualitatively and quantitatively examined the flow field around insect wings. In some such previous studies, the vortex ring or vortex loop formed on the wing was visualized. However, the characteristics of dynamic forces generated by the flapping insect wing are not yet sufficiently understood. The purpose of the present study is to investigate the characteristics of dynamic lift and thrust produced by the flapping butterfly wing and the relationship between the dynamic lift and thrust and the flow field around the butterfly. We conducted the dynamic lift and thrust measurements of a fixed flapping butterfly, Idea leuconoe, using a six-axes sensor. Moreover, two-dimensional PIV measurement was conducted in the wake of the butterfly. The butterfly produced dynamic lift in downward flapping which became maximum at a flapping angle of approximately 0.0 deg. At the same time, the butterfly produced negative dynamic thrust during downward flapping. The negative dynamic thrust was not produced hydrodynamically by a flapping butterfly wing because a jet was not formed in front of the butterfly. The negative dynamic thrust was the kicking force for jumping and the maximum of this kicking force was about 6.0 times as large as the weight. On the other hand, the butterfly produced dynamic thrust in upward flapping which was approximately 6.0 times as large as the weight of the butterfly. However, the attacking force by the abdomen of the butterfly was included in the dynamic thrust and we have not yet clarified quantitatively the dynamic thrust produced by the butterfly wing.

Download Full-text

Combined effect of intake angle and chamber structure on flow field and combustion process in a small-scaled rotary engine

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2021.117652 ◽

2021 ◽

pp. 117652

Author(s):

Run Zou ◽

Jinxiang Liu ◽

Huichao Jiao ◽

Jingjing Zhao ◽

Nana Wang

Keyword(s):

Flow Field ◽

Combustion Process ◽

Combined Effect ◽

Rotary Engine

Download Full-text

Finite Element Numerical Simulation and PIV Measurement of Flow Field inside Metering-in Spool Valve

Chinese Journal of Mechanical Engineering ◽

10.3901/cjme.2009.01.102 ◽

2009 ◽

Vol 22 (01) ◽

pp. 102 ◽

Cited By ~ 4

Author(s):

Dianrong GAO

Keyword(s):

Numerical Simulation ◽

Finite Element ◽

Flow Field ◽

Piv Measurement ◽

Finite Element Numerical Simulation ◽

Spool Valve

Download Full-text

PIV measurement and study on turbulence generator flow field of medium consistency pump

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/163/1/012120 ◽

2018 ◽

Vol 163 ◽

pp. 012120

Author(s):

D X Ye ◽

X D Lai ◽

H Li

Keyword(s):

Flow Field ◽

Piv Measurement ◽

Turbulence Generator

Download Full-text

Numerical Study on Flow Field in a Peripheral Ported Rotary Engine Under the Action of Apex Seal Leakage

Journal of Fluids Engineering ◽

10.1115/1.4049117 ◽

2020 ◽

Author(s):

Baowei Fan ◽

Yuanguang Wang ◽

Jianfeng Pan ◽

Yaoyuan Zhang ◽

Yonghao Zeng

Keyword(s):

Velocity Field ◽

Flow Field ◽

Combustion Chamber ◽

Numerical Study ◽

Particle Image Velocimetry Data ◽

Calculation Model ◽

Flow Area ◽

Rotary Engine ◽

Unidirectional Flow ◽

Rotary Engines

Abstract Apex seal leakage is one of the main defects restricting the performance improvement of rotary engines. The aim of this study is to study the airflow movement in a peripheral ported rotary engine under the action of apex seal leakage. For this purpose, a 3D dynamic calculation model considering apex seal leakage was firstly established and verified by particle image velocimetry data. Furthermore, based on the established 3D model, the flow field in the combustion chamber under the four apex seal leakage gaps (0.02, 0.04, 0.06 and 0.08 mms) and the three engine revolution speeds (2000, 3500, and 5000 RPMs) was calculated. By comparing with the flow field under the condition without leakage, the influences of the existence of apex seal leakage on the velocity field, the turbulent kinetic energy and the volumetric efficiency in the combustion chamber were investigated. Thereinto, the influences of the existence of apex seal leakage on the velocity field is that at the intake stroke, a vortex formed in the middle of the combustion chamber under the condition without apex seal leakage, was intensified by the apex seal leakage action. At the compression stroke, irrespective of the condition with or without apex seal leakage, all vortexes in the combustion chamber are gradually broken into a unidirectional flow. However, there is an obvious "leakage flow area" at the end of combustion chamber due to the existence of apex seal leakage.

Download Full-text

Feasibility Study on Application of a Self-Formed Flow Field Downstream of Elbows to Divertor Cooling

Volume 5: Fuel Cycle, Radioactive Waste Management and Decommissioning; Reactor Physics and Transport Theory; Nuclear Education, Public Acceptance and Related Issues; Instrumentation and Controls; Fusion Engineering ◽

10.1115/icone21-16105 ◽

2013 ◽

Author(s):

Shoichi Kodate ◽

Tatsuya Kubo ◽

Shinji Ebara ◽

Hidetoshi Hashizume

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Reynolds Stress ◽

Swirling Flow ◽

Pipe Wall ◽

Three Dimensional ◽

High Heat ◽

Turbulent Pipe Flow ◽

High Heat Transfer ◽

Piv Measurement

In this study, the characteristic of the swirling flow was analyzed in detail in terms of flow field by means of a visualization experiment using matched refractive index PIV measurement to evaluate the applicability of the swirling flow generated downstream of a three-dimensionally connected dual elbow to the divertor cooling. The dual elbow used in the experiment comprises two 90-degree elbows with the same curvature connected directly in three-dimensional configuration. From the experiment, it was found that strong swirling velocity component appears locally near the pipe wall downstream of the second elbow. Moreover, although the strength of the swirling flow changed gradually as it flowed downstream, it attenuated little even 8D downstream of the dual elbow, where D was the diameter of the piping. Therefore, this swirling flow is expected to survive for a considerable distance downstream of the elbow, and the applicability of this flow field to divertor cooling can be promising. Furthermore turbulence quantities such as Reynolds stress were analyzed in terms of heat transfer performance. Since there were some regions where larger Reynolds stress than a developed turbulent pipe flow was observed near the pipe wall, high heat transfer is expected there.

Download Full-text

PIV Measurement of Flow Field around Film Boiling in He II

Physics Procedia ◽

10.1016/j.phpro.2015.06.101 ◽

2015 ◽

Vol 67 ◽

pp. 596-601 ◽

Cited By ~ 1

Author(s):

Masahide Murakami ◽

Suguru Takada ◽

Masakazu Nozawa

Keyword(s):

Flow Field ◽

Film Boiling ◽

Piv Measurement

Download Full-text

Aerodynamics of Flapping Wing at Low Reynolds Numbers: Force Measurement and Flow Visualization

ISRN Mechanical Engineering ◽

10.5402/2011/162687 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Abhijit Banerjee ◽

Saurav K. Ghosh ◽

Debopam Das

Keyword(s):

Reynolds Number ◽

Flow Field ◽

Flow Visualization ◽

Force Measurement ◽

Reynolds Numbers ◽

Flapping Flight ◽

Water Tank ◽

Cross Sectional ◽

Piv Measurement ◽

The Difference

Flow field of a butterfly mimicking flapping model with plan form of various shapes and butterfly-shaped wings is studied. The nature of the unsteady flow and embedded vortical structures are obtained at chord cross-sectional plane of the scaled wings to understand the dynamics of insect flapping flight. Flow visualization and PIV experiments are carried out for the better understanding of the flow field. The model being studied has a single degree of freedom of flapping. The wing flexibility adds another degree to a certain extent introducing feathering effect in the kinematics. The mechanisms that produce high lift and considerable thrust during the flapping motion are identified. The effect of the Reynolds number on the flapping flight is studied by varying the wing size and the flapping frequency. Force measurements are carried out to study the variations of lift forces in the Reynolds number (Re) range of 3000 to 7000. Force experiments are conducted both at zero and finite forward velocity in a wind tunnel. Flow visualization as well as PIV measurement is conducted only at zero forward velocity in a stagnant water tank and in air, respectively. The aim here is to measure the aerodynamic lift force and visualize the flow field and notice the difference with different Reynolds number (Re), and flapping frequency (f), and advance ratios (J=U∞/2ϕfR).

Download Full-text