Effect of gas slip on the behavior of the aerostatic guideway

2017 ◽  
Vol 69 (4) ◽  
pp. 447-454 ◽  
Author(s):  
Dongju Chen ◽  
Jihong Han ◽  
Chen Huo ◽  
Jinwei Fan ◽  
Qiang Cheng
Keyword(s):  
Load Capacity ◽  
Dynamic Stiffness ◽  
Velocity Slip ◽  
Flow Equation ◽  
Flow State ◽  
Content Type ◽  
Maximum Value ◽  
Slip Effects ◽  
Bearing Stiffness ◽  
The Impact

Purpose This paper aims to better understand the dynamic characteristics of an aerostatic slider caused by a gas film, and the impact of a gas film slip on the load capacity, stiffness and dynamic stiffness of the guideway is studied. Design/methodology/approach In theory, the Navier velocity slip model is introduced for fluid continuous flow equation to calculate the flow state in the micro-state; in experimental techniques, the stiffness experiment of the guideway by digital inductance meter is performed under different loadings, which are used to inspect the simulation results. Findings The maximum value of bearing stiffness in the condition of considering that the gas slip is larger than that of not considering the gas slip, and the gas film clearance of maximum bearing stiffness in the condition of considering the gas slip is less than that of not considering the gas slip. This is verified by the measurement of the stiffness of the guideway. Originality/value This paper mostly studies the influence of the gas slip effects on the performance of the aerostatic guideway, which will make a certain contribution to the guideway stability and the machining precision of the machine tool.

Effect of velocity slip in a narrow rough porous journal bearing

2003 ◽  
Vol 217 (1) ◽  
pp. 59-70 ◽  
Author(s):  
K Gururajan ◽  
J Prakash
Keyword(s):  
Porous Material ◽  
Coefficient Of Friction ◽  
Strong Interaction ◽  
Journal Bearing ◽  
Load Capacity ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Qualitative And Quantitative ◽  
Slip Effects ◽  
Thin Walled

The paper examines the effect of velocity slip in a thin-walled infinitely short rough porous journal bearing operating under steady conditions in a hydrodynamic regime. The analysis extends earlier work [1] in which the tangential velocity at the surface of the porous material was neglected. The problem is solved analytically together with associated boundary conditions. It is found that there exists a strong interaction between roughness and slip effects. A comparison with the case of an infinitely long journal bearing [2] shows that there are significant qualitative and quantitative differences in load capacity and coefficient of friction. However, the slip-induced variations in friction force are similar to those for an infinitely long journal bearing.

Numerical analysis of the dynamic performance of aerostatic thrust bearings with different restrictors

2018 ◽  
Vol 233 (3) ◽  
pp. 406-423 ◽  
Author(s):  
Hailong Cui ◽  
Yang Wang ◽  
Xiaobin Yue ◽  
Yifei Li ◽  
Zhengyi Jiang
Keyword(s):  
Load Capacity ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Dynamic Mesh ◽  
Eccentricity Ratio ◽  
Thrust Bearings ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping ◽  
The Impact ◽  
The Relationship

This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.

Hall and ion slip current’s impact on magneto-sodium alginate hybrid nanoliquid past a moving vertical plate with ramped heating, velocity slip and Darcy effects

2020 ◽  
Vol 17 (1) ◽  
pp. 65-101 ◽  
Author(s):  
A. Ali ◽  
Soma Mitra Banerjee ◽  
S. Das
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Sodium Alginate ◽  
Velocity Slip ◽  
Physical Parameters ◽  
Shear Stresses ◽  
Transform Method ◽  
Content Type ◽  
Slip Effects ◽  
Ion Slip

PurposeThe purpose of this study is to analyze an unsteady MHD Darcy flow of nonNewtonian hybrid nanoliquid past an exponentially accelerated vertical plate under the influence of velocity slip, Hall and ion slip effects in a rotating frame of reference. The fluids in the flow domain are assumed to be viscously incompressible electrically conducting. Sodium alginate (SA) has been taken as a base Casson liquid. A strong uniform magnetic field is applied under the assumption of low magnetic Reynolds number. Effect of Hall and ion-slip currents on the flow field is examined. The ramped heating and time-varying concentration at the plate are taken into consideration. First-order homogeneous chemical reaction and heat absorption are also considered. Copper and alumina nanoparticles are dispersed in base fluid sodium alginate to be formed as hybrid nanoliquid.Design/methodology/approachThe model problem is first formulated in terms of partial differential equations (PDEs) with physical conditions. Laplace transform method (LTM) is used on the nondimensional governing equations for their closed-form solution. Based on these results, expressions for nondimensional shear stresses, rate of heat and mass transfer are also determined. Graphical presentations are chalked out to inspect the impacts of physical parameters on the pertinent physical flow characteristics. Numerical values of the shear stresses, rate of heat and mass transfer at the plate are tabulated for various physical parameters.FindingsNumerical exploration reveals that a significant increase in the secondary flow (i.e. crossflow) near the plate is guaranteed with an augmenting in Hall parameter or ion slip parameter. MHD and porosity have an opposite effect on velocity component profiles for both types of nanoliquids. Result addresses that both shear stresses are strongly enhanced by the Casson effect. Also, hybrid nanosuspension in Casson fluid (sodium alginate) exhibits a lower rate of heat transfer than usual nanoliquid.Social implicationsThis model may be pertinent in cooling processes of metallic infinite plate in bath and hybrid magnetohydrodynamic (MHD) generators, metallurgical process, manufacturing dynamics of nanopolymers, magnetic field control of material processing, synthesis of smart polymers, making of paper and polyethylene, casting of metals, etc.Originality/valueThe originality of this study is to obtain an analytical solution of the modeled problem by using the Laplace transform method (LTM). Such an exact solution of nonNewtonian fluid flow, heat and mass transfer is rare in the literature. It is also worth remarking that the influence of Hall and ion slip effects on the flow of nonNewtonian hybrid nanoliquid is still an open question.

scholarly journals Upshot of heterogeneous catalysis in a nanofluid flow over a rotating disk with slip effects and Entropy optimization analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ramzan ◽  
Saima Riasat ◽  
Jae Dong Chung ◽  
Yu-Ming Chu ◽  
M. Sheikholeslami ◽  
...  
Keyword(s):  
Velocity Slip ◽  
Rotating Disk ◽  
Interfacial Area ◽  
Slip Parameter ◽  
Similarity Transformations ◽  
First Order Kinetics ◽  
Permeable Media ◽  
Slip Effects ◽  
Flow Through ◽  
The Impact

AbstractThe present study examines homogeneous (HOM)–heterogeneous (HET) reaction in magnetohydrodynamic flow through a porous media on the surface of a rotating disk. Preceding investigations mainly concentrated on the catalysis for the rotating disk; we modeled the impact of HET catalysis in a permeable media over a rotating disk with slip condition at the boundary. The HOM reaction is followed by isothermal cubic autocatalysis, however, the HET reactions occur on the surface governed by first-order kinetics. Additionally, entropy minimization analysis is also conducted for the envisioned mathematical model. The similarity transformations are employed to convert the envisaged model into a non-dimensional form. The system of the modeled problem with ordinary differential equations is analyzed numerically by using MATLAB built-in bvp4c function. The behavior of the emerging parameters versus the thermal, concentration, and velocity distributions are depicted graphically with requisite discussion abiding the thumb rules. It is learned that the rate of the surface catalyzed reaction is strengthened if the interfacial area of the permeable media is enhanced. Thus, a spongy medium can significantly curtail the reaction time. It is also noticed that the amplitude of velocity and thermal profile is maximum for the smallest value of the velocity slip parameter. Heat transfer rate declines for thermophoresis and the Brownian motion parameter with respect to the thermal slip parameter. The cogency of the developed model is also validated by making a comparison of the existing results with a published article under some constraints. Excellent harmony between the two results is noted.

Sport consumer flow and shopping well-being in online shopping

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Bomin Paek ◽  
Alan Morse ◽  
Minjung Kim ◽  
Hoyoon Jung
Keyword(s):  
Online Shopping ◽  
Empirical Finding ◽  
Well Being ◽  
Shopping Behavior ◽  
Equation Modeling ◽  
Flow State ◽  
Website Quality ◽  
Content Type ◽  
Mediating Role ◽  
The Impact

PurposeDue to the increased growth of Internet users, the examination of compelling online shopping behavior has emerged as a vital topic in developing positive consumer behaviors. However, there is a dearth of studies into how consumers of sport merchandise in the online setting spend their time and what types of factors contribute toward their positive shopping experience. To fill this gap, the purpose of this current study is to investigate the impact and complexity of sport commerce websites by providing the precondition of flow (e.g. convenience, content, aesthetics, interactivity and customization), as well as the consequences of flow (e.g. website satisfaction and shopping well-being).Design/methodology/approachThis study examines relationships among perceived website quality, flow, web satisfaction, and shopping well-being by using structural equation modeling. This current study is based on online sport fans who have recent online shopping experiences of licensed sport products (n = 331).FindingsResults of this present study show that flow plays a mediating role between perceived website quality and web satisfaction, which in turn is positively associated with consumers' shopping well-being.Originality/valueThis current study supports a mediating role of flow state in sport consumer perceptions of website quality and satisfaction; it expands existing knowledge through determining the factors that facilitate flow state and website satisfaction in online shopping. This empirical finding offers important implications regarding the function of flow as an essential factor via the optimization of website services and sport consumers' attitudes.

Wet Compression Analysis Including Velocity Slip Effects

2010 ◽  
Author(s):  
A. J. White ◽  
A. J. Meacock
Keyword(s):  
Gas Turbines ◽  
Velocity Slip ◽  
Design Flow ◽  
Compression Process ◽  
Relaxation Effects ◽  
Slip Effects ◽  
Industrial Gas Turbines ◽  
Wet Compression ◽  
Dry Climates ◽  
The Impact

Injection of water droplets into industrial gas turbines in order to boost power output is now common practice. The intention is usually to saturate and cool the intake air, especially in hot and dry climates, but in many cases droplets carry over into the compressor and continue to evaporate. Evaporation within the compressor itself (often referred to as “overspray”) is also central to several advanced wet cycles, including the Moist Air Turbine (MAT) and the so-called TOPHAT cycle. The resulting wet compression process affords a number of thermodynamic advantages, such as reduced compression work, and increased mass flow rate and specific heat capacity of the turbine flow. Against these benefits, many of the compressor stages will operate at significantly off-design flow angles, thereby compromising aerodynamic performance. The current paper describes wet compression calculations including velocity slip and many of the associated phenomena (e.g., blade deposition and film evaporation). The calculations also allow for a poly-dispersion of droplet sizes and droplet temperature relaxation effects (i.e., the full droplet energy equation is solved rather than assuming that droplets adopt the wet-bulb temperature). The latter is important for sprays produced by “flashing” since the resulting droplets are initially much hotter than the surrounding gas. The method has been applied to a “generic” twelve stage compressor to ascertain to the impact slip effects have on the wet compression process.

Effect of roundness error on the performance of novel gas foil conical bearings

2020 ◽  
Vol 72 (7) ◽  
pp. 895-904
Author(s):  
Hongyang Hu ◽  
Ming Feng ◽  
Tianming Ren
Keyword(s):  
Peer Review ◽  
Dynamic Properties ◽  
Load Capacity ◽  
Dynamic Stiffness ◽  
Friction Torque ◽  
Roundness Error ◽  
Content Type ◽  
Stiffness Model ◽  
Static Performance ◽  
Stiffness And Damping

Purpose The purpose of this paper is to study the effect law of roundness error on the properties of gas foil conical bearing (GFCB), and the performance of bearings with different non-circular sleeve shapes are calculated. Design/methodology/approach For the bump-type GFCB, the nonlinear bump foil stiffness model and 1-D beam top foil stiffness model are built. On this basis, the finite element method and finite difference method are used to solve the Reynolds equation and the film thickness equation coupled, and the static and dynamic properties of GFCB are calculated. The effect law of sleeve roundness error on the static performance under different conditions is obtained. Moreover, the dynamic stiffness and damping characteristics under different errors are also studied. Findings The roundness error will decrease the load capacity and friction torque of GFCB, and increase the attitude angle. The error effect is more dramatic when there is larger eccentric, small nominal clearance, larger error value and more error lobes, and the static performance exhibits a periodic change in the circumferential direction. The roundness error can also decrease the direct stiffness and cross-coupled damping of GFCB, while the cross-coupled stiffness increases largely, which will reduce the bearing stability. Originality/value The roundness error adversely affects the static and dynamic characteristics of GFCB, which should be concerned by bearing designers, researchers and academicians. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0019/

Coupling effects of the impact factors in micro-scale on the performance of aerostatic guideway

2018 ◽  
Vol 70 (5) ◽  
pp. 846-855 ◽  
Author(s):  
Dongju Chen ◽  
Lihua Dong ◽  
Ri Pan ◽  
Jinwei Fan ◽  
Qiang Cheng
Keyword(s):  
Bearing Capacity ◽  
Effective Viscosity ◽  
Velocity Slip ◽  
Coupling Effects ◽  
Content Type ◽  
Micro Scale ◽  
First Order ◽  
Rarefaction Effect ◽  
Static Performance ◽  
The Impact

PurposeThe purpose of this study is to investigate the coupling effects of the velocity slip, rarefaction effect and effective viscosity of the gas film on the performance of the aerostatic guideway in micro-scale and improve the analysis precision of the static performance of aerostatic guideway.Design/methodology/approachThe corresponding model of the gas film flow with consideration of the velocity slip, rarefaction effect and effective viscosity of the gas film in micro-scale is proposed. By solving the corresponding model, the bearing capacity and the stiffness of the aerostatic guideway are obtained through the pressure distributions of the air cavity. Through comparing the bearing capacity and the stiffness in different situations, the couple effects of the three factors are analyzed. Finally, the experimental results about the stiffness are obtained and the contrast between the simulation stiffness and the tested stiffness is achieved.FindingsThrough comparing the coupling effects of the micro scale factors under different conditions on the performance of the aerostatic guideway, it was found that when comparing the effects of a single factor, the effect of the first-order slip is the largest. When two factors are randomly combined, velocity slip and viscosity of the gas film is the largest, but these coupling effects are less than the effect of considering three factors simultaneously.Originality/valueIt is essential to consider the first-order velocity slip, the flow factor Q and the effective viscosity when analyzing the static performance of the aerostatic guideway in micro-scale. This makes studying the performance of the aerostatic guideway in micro-scale feasible and improves the machine’s accuracy.

Impact of Brownian motion and thermophoresis on bioconvective flow of nanoliquids past a variable thickness surface with slip effects

2019 ◽  
Vol 15 (1) ◽  
pp. 103-132 ◽  
Author(s):  
Anantha Kumar K. ◽  
Sugunamma V. ◽  
Sandeep N. ◽  
Ramana Reddy J.V.
Keyword(s):  
Mass Transfer ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Variable Thickness ◽  
Heat Sink ◽  
Physical Parameters ◽  
Content Type ◽  
And Brownian Motion ◽  
Slip Effects ◽  
The Impact

Purpose The purpose of this paper is to scrutinize the heat and mass transfer attributes of three-dimensional bio convective flow of nanofluid across a slendering surface with slip effects. The analysis is carried out subject to irregular heat sink/source, thermophoresis and Brownian motion of nanoparticles. Design/methodology/approach At first, proper transmutations are pondered to metamorphose the basic flow equations as ODEs. The solution of these ODEs is procured by the consecutive application of Shooting and Runge-Kutta fourth order numerical procedures. Findings The usual flow fields along with density of motile microorganisms for sundry physical parameters are divulged via plots and scrutinized. Further, the authors analyzed the impact of same parameters on skin friction, heat and mass transfer coefficients and presented in tables. It is discovered that the variable heat sink/source parameters play a decisive role in nature of the heat and mass transfer rates. The density of motile microorganisms will improve if we add Al-Cu alloy particles in regular fluids instead of Al particles solely. A change in thermophoresis and Brownian motion parameters dominates heat and mass transfer performance. Originality/value To the best of the knowledge, no author made an attempt to investigate the flow of nanofluids over a variable thickness surface with bio-convection, Brownian motion and slip effects.

The More Control, the Better?

2014 ◽  
Vol 26 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Jeeyun Oh ◽  
Mun-Young Chung ◽  
Sangyong Han
Keyword(s):  
Mixed Design ◽  
Negative Effects ◽  
Story Structure ◽  
Content Type ◽  
High User ◽  
User Control ◽  
Rigorous Research ◽  
Control Versus ◽  
The Media ◽  
The Impact

Despite of the popularity of interactive movie trailers, rigorous research on one of the most apparent features of these interfaces – the level of user control – has been scarce. This study explored the effects of user control on users’ immersion and enjoyment of the movie trailers, moderated by the content type. We conducted a 2 (high user control versus low user control) × 2 (drama film trailer versus documentary film trailer) mixed-design factorial experiment. The results showed that the level of user control over movie trailer interfaces decreased users’ immersion when the trailer had an element of traditional story structure, such as a drama film trailer. Participants in the high user control condition answered that they were less fascinated with, absorbed in, focused on, mentally involved with, and emotionally affected by the movie trailer than participants in the low user control condition only with the drama movie trailer. The negative effects of user control on the level of immersion for the drama trailer translated into users’ enjoyment. The impact of user control over interfaces on immersion and enjoyment varies depending on the nature of the media content, which suggests a possible trade-off between the level of user control and entertainment outcomes.

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