scholarly journals Dependence of the Piezoelectric Micropump Operating Mode on Its Geometry

2021 ◽  
Vol 2096 (1) ◽  
pp. 012081
Author(s):  
I Sh Nasibullayev ◽  
E Sh Nasibullaeva ◽  
O V Darintsev
Keyword(s):  
Fluid Flow ◽  
Cross Section ◽  
Cooling System ◽  
Circular Cross Section ◽  
Piezoelectric Actuators ◽  
Operating Mode ◽  
Elastic Tube ◽  
Fluid Flow Rate ◽  
Computer Study ◽  
Channel Parameters

Abstract A mathematical and computer axisymmetric models in which periodic oscillations of ring piezoelectric actuators placed on an elastic tube of circular cross-section leads to radial deformations of the tube is constructed. The result of these displacements is a local compression of the microchannel, which leads to changes in its volume and the corresponding pushing of the fluid. If a non-symmetrical oscillation scheme is used, the average fluid flow over the period will be non-zero and the device can be used as a micropump. The aim of the work is a computer study of the geometric features of an axisymmetric piezoelectric micropump, taking into account the processes of heat transfer by a fluid in the channel. The dependence of the average fluid flow rate on the channel parameters and the frequency of oscillations of the piezoelectric actuators is determined by the method of factorial experiment. The parameters preventing heat backflow have been determinate, which makes it possible to use a device for supplying coolant to a microgripper cooling system.

Length Efficiency of the Etoile Flow Straightener: Numerical Experimentation

2011 ◽  
Author(s):  
Boualem Laribi ◽  
Abdelkader Youcefi ◽  
Elhacene Matene
Keyword(s):  
Reynolds Number ◽  
Fluid Flow ◽  
Velocity Profile ◽  
Cross Section ◽  
Circular Cross Section ◽  
The Other ◽  
Flow Parameters ◽  
Numerical Experimentation ◽  
Valve Position ◽  
Turbulence Intensity Profile

This article presents a numerical investigation of the development and the establishment of the flow in the presence of the Etoile flow straightener recommended in ISO 5167 (ISO 5167. Measurement of fluid flow by means of orifice plates, nozzles and venture plates inserted in circular cross-section conduits running full, 2003). The objective of this study is to examine the effectiveness length of the Etoile flow straightener, recommended by ISO 5167 with length of two pipe diameters, on the development and the establishment of the flow. The flow is produced by air in a 100mm pipe diameter and 40D of length with a Reynolds number of 2.5×105. The disturbance is a valve maintained at 100% and 50% open. The flow parameters examined are velocity profile, turbulence intensity profile, and the gyration of the fluid. Several measuring stations upstream and downstream of the unit are done. The code CFD Fluent is used for this simulation. The results obtained are compared according to directives of the standard ISO 5167. However, they show that for position valve 100% open the various lengths of the Etoile flow straightener do not present differences for the three flow parameters. On the other hand, for the valve position 50% open, the Etoile flow straightener with 2D length which presents the best performances according the standard.

Experimental and numerical investigations of choked air flow and heat transfer in a ball valve for optimization the cross-sectional area

2019 ◽  
Vol 30 (5) ◽  
pp. 2705-2737 ◽  
Author(s):  
Davood Toghraie ◽  
Hojjatollah Heidari Khouzani
Keyword(s):  
Fluid Flow ◽  
Supersonic Flow ◽  
Flow Control ◽  
Cross Section ◽  
Flow Rate ◽  
Ball Valve ◽  
Flow Coefficient ◽  
Fluid Flow Rate ◽  
Content Type ◽  
Percentage Difference

Purpose The purpose of this study is to understand the functional properties of ball valve in a compressible flow and simulation of experimental data collection of ball valve, was completely simulated. Design/methodology/approach Equations are solved according to finite volume and simplified algorithms. By measuring the flow parameters, including pressure and temperature at different points in the simulation circuit, flow coefficients and localized drop in the valve were determined in different openness cases of test valve and compared with experimental results. Determining a graph for flow coefficient variations in terms of the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section. Findings In the supersonic flow, flow coefficients and local drops of the valve are dependent on several parameters, including fluid flow rate. Flow coefficient graphs at different angles of the test valve show that by increasing the valve opening angle, the flow coefficient increases so that it reaches from 1.72 m3/h at a 30° angle to 46.29 m3/h at a 80° angle. It should be noted that these values in the experimental test were obtained 1.53 m3/h and 49.68 m3/h, respectively, and the percentage difference of these values by simulation was obtained for the angle of 30 degrees 11.7% and for the angle of 80°, about 7% per hour at an angle of 80°. Also, the coefficients of localized loss at different angles of test valve show that by increasing the angle of opening of the valve, the amount of localized loss decreases, so that the average value of 1515.2 in the angle of 30° reaches 1.9 at an angle of 80°. The percentage difference of these values by simulation, for the angle of 30° and 3.5% for the angle of 80°, was about 11.1%. Originality/value Determining a graph for flow coefficient variations versus the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section. In the supersonic flow, flow coefficients and local drop coefficients of the valve are dependent on several parameters, including fluid flow rate.

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