Parametric investigation of twin tube magnetorheological dampers using a new unsteady theoretical analysis

2019 ◽  
Vol 30 (6) ◽  
pp. 878-895
Author(s):  
Mohammad Mehdi Zolfagharian ◽  
Mohammad Hassan Kayhani ◽  
Mahmood Norouzi ◽  
Amir Jalali

In the present work, a new unsteady analytical model is developed for magnetorheological fluid flow through the annular gap which is opened on the piston head of twin tube magnetorheological damper, considering fluid inertia term into the momentum equation. This new unsteady model is based on Stokes’ second problem that is extended for magnetorheological fluid flow between finite oscillating parallel plates under the pressure gradient. A quasi-static analysis is also developed for magnetorheological fluid flow in twin tube damper, to compare its results with present unsteady solution and to show the effect of magnetorheological fluid inertia. The obtained results are validated experimentally and then, a parametric study is presented using both unsteady and quasi-static analysis. The effect of fluid inertia term is investigated on force–displacement and force–velocity loops, magnetorheological fluid velocity profile, pressure drop, phase difference between pressure drop and flow rate and change of plug thickness with time duration. According to the obtained results, quasi-static analysis included considerable error respect to new unsteady analysis as the gap height, magnetorheological fluid density, excitation frequencies and amplitudes are increased and yield stress is decreased. It is found that the plug thickness is considerably affected by inertia term of magnetorheological fluid.

Author(s):  
Ahmad Zaifazlin Zainordin ◽  
Gigih Priyandoko ◽  
Zamri Mohamed

Magnetorheological (MR) damper as a semi-active system for a vehicle suspension is simulated in this study. The proposed design of Magnetorheological (MR) valve consists of meandering flow channel or gaps that fixed in the piston of the damper. The focus of this study is to estimate the performance of proposed MR valve based on actual front suspension parameter of a vehicle. Annular and radial gaps are combined to produce an MR valve with meandering fluid flow path. Furthermore, the damper is filled with Magnetorheological (MR) fluid to energize the damper under the presence of magnetic fields. The magnetic flux density within each gap is obtained via the Finite Element Method Magnetics (FEMM) software. Therefore, the yield stress of MR fluid and magnetic flux relationships both can be predicted. The present paper shows a reduction in pressure drop when the thickness of each gap is increased. Pressure drop is closely affected by the fluid flow rate that enters each gap. This means that the lower flow rate increases the pressure drop of MR valve at various current.


Author(s):  
Irwan Setiawan ◽  
Nurrohman . ◽  
Hablinur Al Kindi

The flow of fluid through the pipe creates fluid friction with pipe walls causing pressure drop and fluid flow velocity affecting the use of energy to drain it. Pressure drop can be affected by several factors such as friction or friction factor, pipe length, pipe diameter and fluid velocity. In this research, it will analyze pressure drop on piping system based on friction, fluid flow characteristics, and fluid velocity. The analysis was done by using two methods, namely experimental method and empirical calculation method. The stages of this study consist of problem analysis, literature study, calibration, data retrieval, empirical data processing and experiments, validation, analysis of results and conclusions. Based on the results of empirical and experimental research, the lowest pressure drop in the experiment and empirical was the 12 LPM discharge copper pipe and the water coolant ratio is 0: 100. This means that the best material pipes used were copper pipes rather than steel and galvanized pipes. The results of the tests and experiments have been tested for validation. The validation value of empirical and experimental data measurement is 91%.


Author(s):  
Sudip Shyam ◽  
Aparesh Datta ◽  
Ajoy Kumar Das

In this study, heat transfer and fluid flow of de-ionized water in two-dimensional parallel plates microchannel with and without micromixers have been investigated for various Reynolds numbers. The effects of heat transfer and fluid flow on height, diameter of micromixer, and also distance between the two micromixers are carried out in the study. Results showed that the diameter of the micromixer does not have much effect on heat transfer with a maximum enhancement of 9.5%. Whereas heat transfer gets enhanced by 85.57% when the height of the micromixer is increased from 100 μm to 400 μm, and also heat transfer gets improved by 11.45% when sb2 is increased from 4L to 5L. The separation and reattachment zone at the entry and exit of the micromixer cause the increase in heat transfer with the penalty of pressure drop. It is also found that increase of Reynolds number increases the intensity of the secondary flows leads to rapid increase in heat transfer and pressure drop. Finally, the optimized structure of micromixer is found out based on maximum heat transfer and minimum pressure drop.


2019 ◽  
Vol 56 (10) ◽  
pp. 1486-1501 ◽  
Author(s):  
Fei Xiao ◽  
Zhiye Zhao

Most existing models for fluid transportation within a single rock fracture tend to use a channel with two smooth parallel plates, whereas real fracture surfaces are usually rough and tortuous, which can produce a flow field significantly different from the smooth plate model. For fluid flow in a rough fracture, there are surface concave areas (SCA), where the fluid velocity is extremely low, contributing little to the fluid transportation. It is of great significance to quantitatively evaluate the impact of rough surfaces on fluid flow. Therefore, a numerical model for simulating Newtonian fluid through rough fractures is proposed, where synthetic surfaces are generated according to statistical analysis of natural rock fractures and can be quantified by several characteristic parameters. Equivalent hydraulic aperture (EHA) is proposed as one quantitative indicator for evaluating the impact of fracture roughness. Systematic studies were conducted for evaluating EHAs of rough fractures, which, combined with characteristic parameters of fractures, are used to build surrogate models for EHA prediction. It is found that the EHA is directly correlated with the fracture roughness, the mean mechanical aperture, and the standard deviation of aperture distribution. The developed surrogate models were verified to have a high accuracy for EHA prediction.


2010 ◽  
Vol 77 (4) ◽  
Author(s):  
Joseph Whiteley ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang

This study presents experimental results on the flow of magnetorheological grease (MRG) through microchannels. MR materials flowing through microchannels create microvalves. The flow is controlled by injecting the MRG through microchannels with controlled adjustable rates. To study the effect of different channel diameters and surface roughnesses, microchannels made of stainless steel, PEEK, and fused silica materials with nominal internal diameters ranging from 1 mm to 0.075 mm (75 μm) are tested. A magnetic field is applied perpendicular to the microchannel flow and is controlled by an input electric current. The pressure drop of the flow is measured across the length of the microchannels. The dynamic pressure drop range and surface roughness effects are also discussed. The Herschel–Bulkley model for non-Newtonian fluid flow is employed to the experimental results with good agreement. The results show a significant pressure drop for different magnetic field strengths.


Author(s):  
O. Burheim ◽  
David A. Vermaas ◽  
Kitty Nijmeijer ◽  
J. G. Pharoah

Reverse Electro-Dialysis, RED, utilises the energy of mixing between two solutions of different salinity by allowing ionic current to pass through the membranes and the two solutions such that cations are transport to the cathode and anions to the anode. [1–4.] The ionic current is converted to electronic current by red-ox reactions at the cathode and the anode. The membranes applied in this process are ionic selective, traditionally of uniform thickness and separated by a non-conductive spacer [5, 6]. Traditionally, non-conductive spacers have been deployed as eddy promoters and membrane spacers in salinity difference power extraction systems, such as Pressure Retarded Osmosis (PRO) and Reverse Electro-Dialysis (RED). For RED, traditional spacers inhibit parts of the ionic current paths in the fluid compartments and magnify the pressure drop imposed by the fluid flow between the membranes. [6] In a strive to lower the pressure drop in the fluid flow compartment and to increase the conductive region between the membranes, it is suggested to manufacture membranes with new shapes and profiles. [6] By modeling transport of mass and momentum in different geometries, spacing, mixing and active membrane area can be optimised with respect to increasing the power extraction. Such work has previously been done for traditional, i.e. non-electrochemical, flow in spacer separated membrane systems. A classical, approach has been to study submerged and non-submerged non-conductive spacer rods in fluid flow between two parallel plates (membranes) for Reynolds numbers (Re) from 50 and upwards. [7–17] This work discusses how spacers united with the reactant surface (membrane) will affect the mixing and the pressure drops of RED systems with Re numbers between 1 and 100, the expected operational Re number range for RED [6, 18, 19]. This is essential for the power production of RED. For a process converting renewable energy present in nature, such as RED, optimising these parameters is detrimental for the exergy yield. In going from a laboratory scale with a 10 × 10 cm2 cross sectional membrane to a large scale of 100 × 100 cm2, the Reynolds number (Re) increases from 10 to 100 simply because the volume flow is proportional to the flow length. Since it is within this range that eddies starts to get promoted by spacers, different mixing properties is expected exist when comparing laboratory and industrial scaled RED systems.


2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.


Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1587
Author(s):  
Dolat Khan ◽  
Ata ur Rahman ◽  
Gohar Ali ◽  
Poom Kumam ◽  
Attapol Kaewkhao ◽  
...  

Due to the importance of wall shear stress effect and dust fluid in daily life fluid problems. This paper aims to discover the influence of wall shear stress on dust fluids of fluctuating flow. The flow is considered between two parallel plates that are non-conducting. Due to the transformation of heat, the fluid flow is generated. We consider every dust particle having spherical uniformly disperse in the base fluid. The perturb solution is obtained by applying the Poincare-Lighthill perturbation technique (PLPT). The fluid velocity and shear stress are discussed for the different parameters like Grashof number, magnetic parameter, radiation parameter, and dusty fluid parameter. Graphical results for fluid and dust particles are plotted through Mathcad-15. The behavior of base fluid and dusty fluid is matching for different embedded parameters.


2018 ◽  
Vol 7 (4.35) ◽  
pp. 148 ◽  
Author(s):  
Nur Irmawati Om ◽  
Rozli Zulkifli ◽  
P. Gunnasegaran

The influence of utilizing different nanofluids types on the liquid cold plate (LCP) is numerically investigated. The thermal and fluid flow performance of LCP is examined by using pure ethylene glycol (EG), Al2O3-EG and CuO-EG. The volume fraction of the nanoparticle for both nanofluid is 2%. The finite volume method (FVM) has been used to solved 3-D steady state, laminar flow and heat transfer governing equations. The presented results indicate that Al2O3-EG able to provide the lowest surface temperature of the heater block followed by CuO-EG and EG, respectively. It is also found that the pressure drop and friction factor are higher for Al2O3-EG and CuO-EG compared to the pure EG.


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