Experimental Study on Planar Unidirectional Permeability of Glass Fiber Preforms at Constant Flow Rate

2010 ◽  
Vol 154-155 ◽  
pp. 494-497
Author(s):  
Shi Lin Yan ◽  
Fei Yan ◽  
Zhong Qi Qiu
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Resin Flow ◽  
Constant Flow ◽  
Flow Rates ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
Transfer Molding ◽  
The One ◽  
Fiber Preforms

During the resin flow of Resin Transfer Molding, the permeability of fiber performs is an important parameter, which reflects the interaction between the resin and fiber. In this paper the Darcy’s law was used as the fundamentals to determine the permeability of fiber performs, an experiment installation was designed, and do some experimental study on the one-dimensional permeability of resin in the multilayer fibrous plaids at a constant flow rate. The installation was designed base on condition of different flow rates and different fiber volumes (or porosity), and compared the results of the permeability of different flow rates. Then analyzed the results, and some content conclusions were obtained.

Unsaturated flow characteristics in dual-scale fibre fabrics at one-dimensional constant flow rate

2016 ◽  
Vol 23 (6) ◽  
pp. 617-624
Author(s):  
Yan Shilin ◽  
Yan Fei ◽  
Li Dequan ◽  
Li Yongjing
Keyword(s):  
Flow Rate ◽  
Unsaturated Flow ◽  
Flow Characteristics ◽  
Constant Flow ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
Liquid Composite Moulding ◽  
Mould Filling ◽  
Set Up ◽  
Dual Scale

AbstractFibre fabrics in liquid composite moulding can be considered as dual-scale porous media. In different gap scales, an unsaturated flow is produced during the mould filling process. This particular flow behaviour deviates from the traditional Darcy’s law, which is used to calculate the filling pressure and will cause errors. To prove the mechanism of this unsaturated flow, an experimental device was set up with a one-dimensional constant flow rate. The influencing factors, such as injected media, flow velocity and fibre fabric, were investigated in this study. Based on the experimental data, several useful conclusions were drawn, providing good references for optimising the process parameters and controlling the product quality.

scholarly journals Programming piston displacements for constant flow rate piston pumps with trigonometric transition functions

2021 ◽  
Vol 12 (1) ◽  
pp. 559-571
Author(s):  
Zhongxu Tian ◽  
Xingxing Lin
Keyword(s):  
Flow Rate ◽  
Analytical Method ◽  
Physical Meaning ◽  
Displacement Function ◽  
Contact Forces ◽  
Constant Flow ◽  
Flow Rates ◽  
Constant Flow Rate ◽  
Transition Functions ◽  
The Given

Abstract. An analytical method for programming piston displacements for constant flow rate piston pumps is presented. A total of two trigonometric transition functions are introduced to express the piston velocities during the transition processes, which can guarantee both constant flow rates and the continuity of piston accelerations. A kind of displacement function of pistons, for two-piston pumps, and two other kinds, for three-piston pumps, are presented, and the physical meaning of their parameters is also discussed. The results show that, with the given transition functions, cam profiles can be designed analytically with parameterized forms, and the maximum accelerations of the pistons are determined by the width of the transition domain and the rotational velocities of the cams, which will affect contact forces between cams and followers.

Computing Transmix in Complex Batch Transfers via the Mixing-Volume-Equivalent-Pipe Concept

2010 ◽  
Author(s):  
Simone Rodrigues de Melo ◽  
Felipe Bastos Freitas Rachid
Keyword(s):  
Parabolic Equation ◽  
Relative Error ◽  
Flow Rate ◽  
Real World ◽  
Initial Value Problem ◽  
Constant Flow ◽  
Initial Value ◽  
Flow Rates ◽  
Constant Flow Rate ◽  
Promising Tool

This paper presents a new concept — the mixing-volume-equivalent-pipe concept (MVEPC) — which is used to compute transmix volumes in complex batch transfers in an easy, quickly and very simple way. By taking advantage of the MVEPC, the mixing volume of a transfer carried out in a complex pipeline, with varying diameters and flow rates, can be calculated as if it had a unique diameter and a constant flow rate. To illustrate the applicability of the proposed methodology, a numerical example is presented for a transfer of typical products. The transmix volumes predicted by the MVEPC are compared with those obtained by solving the nonlinear initial-value problem for the dispersion of matter parabolic equation. The excellent agreement observed between these two methods, with relative error up to a maximum of 2.65%, enables the use of the MVEPC as a promising tool for estimating transmix volumes in real world batch transfer operations.

An anti-settling sample delivery instrument for serial femtosecond crystallography

2012 ◽  
Vol 45 (4) ◽  
pp. 674-678 ◽  
Author(s):  
Lukas Lomb ◽  
Jan Steinbrener ◽  
Sadia Bari ◽  
Daniel Beisel ◽  
Daniel Berndt ◽  
...  
Keyword(s):  
Constant Flow ◽  
Syringe Pump ◽  
Experimental Conditions ◽  
Flow Rates ◽  
X Ray ◽  
Constant Flow Rate ◽  
Significant Impairment ◽  
Working Principle ◽  
After Hours ◽  
Serial Femtosecond Crystallography

Serial femtosecond crystallography (SFX) using X-ray free-electron laser (FEL) sources has the potential to determine the structures of macromolecules beyond the limitation of radiation damage and without the need for crystals of sufficient size for conventional crystallography. In SFX, a liquid microjet is used to inject randomly oriented crystals suspended in their storage solution into the FEL beam. Settling of crystals in the reservoir prior to the injection has been found to complicate the data collection. This article details the development of an anti-settling sample delivery instrument based on a rotating syringe pump, capable of producing flow rates and liquid pressures necessary for the operation of the injector. The device has been used successfully with crystals of different proteins, with crystal sizes smaller than 20 µm. Even after hours of continuous operation, no significant impairment of the experiments due to sample settling was observed. This article describes the working principle of the instrument and sets it in context with regard to the experimental conditions used for SFX. Hit rates for longer measuring periods are compared with and without the instrument operating. Two versions of the instrument have been developed, which both deliver sample at a constant flow rate but which differ in their minimum liquid flow rates and maximum pressures.

Pumpless Fuel Supply Using Pressurized Fuel Regulated by Autonomous Flow-Rate Regulation Valves

2012 ◽  
Vol 9 (3) ◽  
Author(s):  
Il Doh ◽  
Young-Ho Cho
Keyword(s):  
Fuel Cells ◽  
Flow Rate ◽  
Electrical Power ◽  
Initial Pressure ◽  
Flow Regulation ◽  
Present System ◽  
Constant Flow ◽  
Constant Flow Rate ◽  
Fuel Supply ◽  
Fuel Flow

A pumpless fuel supply using pressurized fuel with autonomous flow regulation valves is presented. Since micropumps and their control circuitry consume a portion of the electrical power generated in fuel cells, fuel supply without micropumps makes it possible to provide more efficient and inexpensive fuel cells than conventional ones. The flow regulation valves in the present system maintain the constant fuel flow rate from the pressurized fuel chamber even though the fuel pressure decreases. They autonomously adjust fluidic resistance of the channel according to fuel pressure so as to maintain constant flow rate. Compared to previous pumpless fuel supply methods, the present method offers more uniform fuel flow without any fluctuation using a simple structure. The prototypes were fabricated by a polymer micromolding process. In the experimental study using the pressurized deionized water, prototypes with pressure regulation valves showed constant flow rate of 5.38 ± 0.52 μl/s over 80 min and 5.89 ± 0.62 μl/s over 134 min, for the initial pressure in the fuel chamber of 50 and 100 kPa, respectively, while the other prototypes having the same fluidic geometry without flow regulation valves showed higher and gradually decreasing flow rate. The present pumpless fuel supply method providing constant flow rate with autonomous valve operation will be beneficial for the development of next-generation fuel cells.

Transient Analysis of In-Plane and Through Thickness Flow During VARTM in the Presence of HPM

2014 ◽  
Author(s):  
Debabrata Adhikari ◽  
Suhasini Gururaja
Keyword(s):  
Transient Analysis ◽  
Flow Model ◽  
Resin Flow ◽  
Constant Flow ◽  
High Permeability ◽  
Coupled Flow ◽  
Resin Infusion ◽  
Plane Flow ◽  
Constant Flow Rate ◽  
Vartm Process

Modeling resin flow for a Vacuum Assisted Resin Transfer Molding (VARTM) process involves developing an approach for coupled flow-compaction, porosity-permeability, resin-cure and stress-development phenomena. In the present work, a modified transient incompressible resin flow model has been developed for VARTM without considering the constant flow rate assumption. The use of High Permeability Medium (HPM) during VARTM results in a through-thickness flow in addition to in-plane flow developing due to the pressure gradient. Results have been validated with existing literature. Fill time comparisons for with and without HPM cases have been presented. Some preliminary results of 2D plane flow have also been obtained which show promise in replicating the physics of vacuum assisted resin infusion composite manufacturing process.

On the Dynamics of Compressor Surge

1976 ◽  
Vol 18 (5) ◽  
pp. 234-238 ◽  
Author(s):  
D. H. McQueen
Keyword(s):  
Mass Flow Rate ◽  
Limit Cycle ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Head ◽  
Centrifugal Compressors ◽  
One Dimensional ◽  
Acoustical Properties ◽  
Compressor Surge ◽  
The One

The one-dimensional equations of surge in centrifugal compressors are solved graphically for the pressure head and mass flow rate as functions of time for a variety of situations, and the results are discussed in terms of the acoustical properties of the external piping. Two important parameters affecting the nature of the surge limit cycle are found to be simply related to the acoustic capacitance and acoustic inductance of the system.

Sign in / Sign up

Export Citation Format

Share Document