Modeling and simulation of sheets ply separation induced by air flow

2019 ◽  
Vol 37 (4) ◽  
pp. 1133-1153
Author(s):  
Xin He ◽  
XiaoPing Li ◽  
Jinrong Yang
Keyword(s):  
High Speed ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Separation Distance ◽  
Parameter Analysis ◽  
Restoring Force ◽  
Content Type ◽  
Interaction Simulation ◽  
Flow Through ◽  
Main Factor

Purpose The purpose of this paper is to investigate the mechanism of sheets ply separation induced by air flow through numerical simulation with two-way FSI (fluid-structure interaction) simulation using ANSYS and theoretical speculation. Design/methodology/approach The paper primarily establishes a simplified physical model of the sheets ply separation induced by air flow. Then, the force of the air flow acting on the sheet has been analyzed based on the model, and the main factor leading to separation was obtained. Furthermore, the parameter analysis was investigated based on linear stability analysis, from which the factors that affect stable separation are obtained. Finally, a series of numerical simulations are performed to verify the conclusions. Findings This study shows that the main separation factor is the variable air pressure in the gap between the sheets caused by the dynamic pressure air flow. Increasing the inlet velocity of the flow field will increase the separation distance but excessive velocity will lead to instability. The viscous resistance acting on the sheet and the bending stiffness of the sheet are factors that stabilize the system, and the sheet density and the restoring force can lead to instability. Originality/value The paper is one of the first in the literature that investigates the problem of sheets ply separation induced by air flow, which is the primary method for multi-layer separation in sheets de-stacking operations, especially for the high-speed occasion.

scholarly journals Design and Fabrication of Two Step Speed Control of a Cylinder Circuit using Pneumatics

2019 ◽  
Vol 8 (6S2) ◽  
pp. 512-516
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Air Flow ◽  
Control Valve ◽  
Speed Control ◽  
Flow Control Valve ◽  
Push Button ◽  
Low Speed ◽  
Flow Through

The main aim of our project is to design and fabrication of pneumatic two step speed control of a cylinder. Initially the flow from the FRL retracts the cylinder when the push button is in its spring offset position. When it is pushed the flow pilots actuate. The air passes through the flow control and shuttle valve. Then the cylinder extends with high speed as the valve allows more air to enter the cylinder. When the piston reaches the position it operates the cam push button and pilot air flow through this and actuate 5/2 pilot operated valve and reaches flow control valve which permits less air. Then the flow through enters the shuttle valve to cylinder and allows the cylinder to extend at relatively low speed. At the end of extension stroke deactivating push button retracts the cylinder. Thus the speed of cylinder is controlled and project can be achieved

Numerical study of the air flow through an air-conditioning unit on high-speed trains

2019 ◽  
Vol 187 ◽  
pp. 26-35 ◽  
Author(s):  
Xueliang Li ◽  
Fan Wu ◽  
Yu Tao ◽  
Mingzhi Yang ◽  
Robert Newman ◽  
...  
Keyword(s):  
Air Conditioning ◽  
High Speed ◽  
Numerical Study ◽  
Air Flow ◽  
High Speed Trains ◽  
Flow Through

Gas film lubrication method on rotation shaft seal based on contact design

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yue Wang ◽  
Longqing Zou ◽  
Hailong Fu ◽  
Congcong Huang ◽  
Jiaqi Liu
Keyword(s):  
Contact Surface ◽  
Dry Friction ◽  
High Speed ◽  
Dynamic Pressure ◽  
Good Effect ◽  
Shaft Seal ◽  
Content Type ◽  
Rubber Seal ◽  
Spiral Grooves ◽  
Film Lubrication

Purpose Wear failure happens frequently in rubber seal of high-speed rotating shaft because of the dry friction. Some traditional lubrication methods are not effective because of the restrictions on the relative high speed, temperature and others. This paper aims to present a new method of lubrication with gas film for the rotation shaft seal based on the contact design. Design/methodology/approach To obtain the generation condition of gas film and good effect of lubrication in the contact gap between the shaft and its seal, a series of micro-spiral grooves are designed on the contact surface of rubber seal so as to obtain a continuous dynamic pressure difference. Findings The result is that the distribution of the gas film in the micro-gap is continuous under the design of the spiral grooves and the contact with eccentricity because of the deformation of rubber seal, which is verified through the simulation calculation and experiment test. It is confirmed that the lubrication method with gas film through designing micro-spiral grooves on the contact surface is effective, and can achieve self-adaptive air lubrication for the high-speed shaft under the premise of the reliable sealing. Originality/value The method of gas film lubrication is realized through designing a microstructure of spiral grooves on the rubber surface to change the contact status, which can form a mechanism of adaptive lubrication to reduce the dry friction automatically in the contact gap. For the cross-scale difference between the rubber seal and gas film, a new modeling method is presented by building the mapping relation for the split blocks and repairing technique with integrated computer engineering and manufacturing, to reduce the possibility of nonconvergence and improve the efficiency and accuracy of calculation.

Experimental Investigation of Air Vortex Interaction With Porous Screen

2014 ◽  
Author(s):  
Xudong An ◽  
Howard Fultz ◽  
Srinath Iyengar ◽  
Fatemeh Hassanipour
Keyword(s):  
High Speed ◽  
Vortex Flow ◽  
Air Flow ◽  
Vortex Generator ◽  
Ccd Camera ◽  
Injection Velocity ◽  
Custom Made ◽  
Flow Through ◽  
Flow Vortex ◽  
Porous Screen

This study presents the experimental analysis of air flow vortex propagation through porous screens. Our research was conducted with a new and unique experimental setup for measuring and visualizing air vortex flow through porous media. A custom-made, high-precision vortex generator provided a variety of velocity profiles for vortex generation with an unprecedented level of precision. The flow field was captured with the use of a fog generator and a high-speed CCD camera. The porous screens were constructed out of acrylic rods with various orientations, thickness, and porosities from rod separation. The results presented in this paper show the effect of porosity and air injection velocity on the behavior of air flow (separation, accumulation), and the transport phenomena of vortex flow through porous screens.

Characteristics of Squeeze Air Film Between Nonparallel Plates

1983 ◽  
Vol 105 (1) ◽  
pp. 147-152 ◽  
Author(s):  
H. Takada ◽  
S. Kamigaichi ◽  
H. Miura
Keyword(s):  
Pressure Transducer ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Approximate Solutions ◽  
Squeeze Film ◽  
Rectangular Plates ◽  
Flow Through ◽  
Air Film ◽  
Theoretical Results ◽  
Good Agreement

The dynamic pressure in a squeeze film and the air flow through the film were analyzed experimentally and theoretically. The dynamic pressure was measured in a squeeze film between two rectangular plates with a small pressure transducer. Approximate solutions for the rectangular squeeze film were obtained analytically. The results were valid for small excursion ratios. Next, a squeeze film between nonparallel plates (wedge film) was examined. In this case, steady air flow occurred due to the unsymmetry of the pressure distribution. To investigate this fact, the air flow was measured in a spherical squeeze film. The values showed good agreement with the theoretical results.

Some Contributions to Experimental Combustion Research

1969 ◽  
Vol 184 (10) ◽  
pp. 203-211 ◽  
Author(s):  
J. Rödig ◽  
F. Žalud
Keyword(s):  
Combustion Chamber ◽  
Steady Flow ◽  
Diesel Engines ◽  
Evaporation Rate ◽  
Dynamic Pressure ◽  
Air Flow ◽  
Spectrographic Analysis ◽  
Chemical Changes ◽  
Flow Through ◽  
Flow Velocities

Techniques of measuring air flow through inlet ducts of diesel engines and tangential air velocities in the cylinder are investigated. An impulse wheel anemometer and conical pressure pick-up are used to measure steady flow velocities. Air velocities in the combustion chamber are evaluated from dynamic pressure variations indicated by tensometric pick-ups. Chemical changes of the fuel during combustion in the cylinder are studied with the help of spectrographic analysis. The evaporation rate of fuel injected into the cylinder is measured by analysis of fuel luminescence.

scholarly journals Sniffing by a silkworm moth: wing fanning enhances air penetration through and pheromone interception by antennae

2000 ◽  
Vol 203 (19) ◽  
pp. 2977-2990 ◽  
Author(s):  
C. Loudon ◽  
M.A. Koehl
Keyword(s):  
High Speed ◽  
Air Flow ◽  
Wing Fanning ◽  
Sensory Hairs ◽  
Order Of Magnitude ◽  
Flow Through ◽  
Chemical Stimuli ◽  
Air Speed ◽  
Air Penetration ◽  
40 Hz

Many organisms increase the air or water flow adjacent to olfactory surfaces when exposed to appropriate chemical stimuli; such ‘sniffing’ samples fluid from a specific region and can increase the rate of interception of odorant molecules. We used hot-wire anemometry, high-speed videography and flow visualization to study air flow near the feathery olfactory antennae of male silkworm moths (Bombyx mori L.). When exposed to conspecific female sex pheromone, male B. mori flap their wings through a stroke angle of 90–110 degrees at approximately 40 Hz without flying. This behavior generates an unsteady flow of air (mean speed 0.3-0.4 m s(−1)) towards the antennae from the front of the male. A pulse of peak air speed occurs at each wing upstroke. The Womersley number (characterizing the damping of pulsatile flow through the gaps between the sensory hairs on the antennae) is less than 1; hence, pulses of faster air (at 40 Hz) should move between sensory hairs. Calculation of flow through arrays of cylinders suggest that this wing fanning can increase the rate of interception of pheromone by the sensory hairs on the antennae by at least an order of magnitude beyond that in still air. Although wing fanning produces air flow relative to the antennae that is approximately 15 times faster than that generated by walking at top speed (0.023 m s(−1)), air flow through the gaps between the sensory hairs is approximately 560 times faster because a dramatic increase in the leakiness of the feathery antennae to air flow occurs at the air velocities produced by fanning.

MULTIDIMENSIONAL SIMULATIONS AND TEST FIRES OF A HYDROGEN-FUELED RAMJET WITH AN ANNULAR DETONATIVE COMBUSTOR AT APPROACHING AIR FLOW OF MACH 2 AND 1.5

2020 ◽  
Author(s):  
V. S. IVANOV ◽  
◽  
V. S. AKSENOV ◽  
S. M. FROLOV ◽  
P. A. GUSEV ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
High Speed ◽  
Constant Pressure ◽  
Air Flow ◽  
Thermodynamic Cycle ◽  
Aerial Vehicles ◽  
Mach Numbers

Modern high-speed unmanned aerial vehicles are powered with small-size turbojets or ramjets. Existing ramjets operating on the thermodynamic cycle with de§agrative combustion of fuel at constant pressure are efficient at flight Mach numbers M ranging from about 2 to 6.

Sign in / Sign up

Export Citation Format

Share Document