Mongkolwongrojn, Mongkol
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Preferred name
Mongkolwongrojn, Mongkol
Alternative Name
Mongkolwongrojn, M.
Main Affiliation
Email
mongkol.mo@kmitl.ac.th
18 results
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Item type:Publication, Transient EHL of two surfaces under elliptical contact with non-Newtonian lubricant(2012-02-23); Panichakorn, JesdaThis paper presents the effects of a sudden load change and sudden speed change on the performance characteristics of two surfaces under elliptical contact with elastohydrodynamic lubrication. The non-Newtonian lubricant for the research work are modeled based on Carreau viscosity model. The time dependent modified Reynolds equation and elastic equation were formulated for compressible fluid. Perturbation method, Newton Raphson method and full adaptive multigrid method were implemented and solved to obtain the film pressure, film thickness profiles and friction coefficient in the contact regime at various applied loads and speeds. Simulation results show the friction coefficient increase significantly under sudden loads. The minimum film thickness and friction coefficient both decrease significantly as speed is decreased. © (2012) Trans Tech Publications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of surface roughness in TEHL with non-Newtonian liquid/solid lubricants under sudden load change(2008-05-16); Aiumpornsin, ChatchaiThis paper describes the influence of surface roughness on thermoelastohydrodynamic (TEHL) lubrication characteristics of a sliding line contact under sudden load change. The surface roughness is a harmonic wave in the transverse direction. The time-dependent Reynolds equation with non-Newtonian liquid-solid fluids has been formulated using a power law model. The constitutive equation of the liquid-solid lubricants was formulated based on experimental data. The simultaneous systems of modified Reynolds, elasticity and energy equations with initial conditions were solved numerically. The static and dynamic characteristics of the thermoelastohydrodynamic line contact with rough surfaces under sudden load change have been investigated numerically to determine the distribution of pressure, film thickness and temperature. The transient response of the lubricated line contact between a infinitely long cylinder surface and a flat plate was simulated under a heavy step load function. This simulation showed a significant effect of surface roughness and solid particles on thermoelastohydrodynamic lubrication under sudden load change. Copyright © 2007 by ASME. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of Al2O3 nanoparticles additives on thermo-elastohydrodynamic with Newtonian lubricant(2013-10-04) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Thermoelastohydrodynamic analysis of journal bearings with non-Newtonian Carreau fluids(2010-06-24); Aiumpornsin, C.The paper focuses on the solution of a numerical model to explore the journal bearing performance under transient thermal elastohydrodynamic lubrication with non-Newtonian lubricants based on Carreau viscosity model. The newly derived time-dependent modified Reynolds equation and the adiabatic energy equation have been formulated using a non-Newtonian Carreau viscosity model. The simultaneous systems consisting of the modified Reynolds equation, elasticity equation and energy equation with initial conditions were solved numerically using the multi-grid multi-level method with full approximation technique. The analysis showed that the fluid characteristics as defined by the Carreau model, led to large differences in minimum film thickness and maximum temperature rise for bearing liners with low elastic modulus. Copyright © 2009 by ASME. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of speed-up and speed-down on internal stresses of wound rolls in web handling process(2012-02-23); Jeenkour, PutthaIn web winding process, the effects of speed-up and speed-down on internal stresses of wound roll have been investigated. The air-entrainment can be obtained theoretically using the modified nonlinear Hakiel model. In this research work, air-entrainment model established by Hamrock and Dowson was applied to estimate the initial air film layers into a wound roll in the winding system with a nip-roller. Moreover, the characteristics of a wound roll were examined under varying tension and varying speed conditions. The numerical results showed the radial stress, tangential stress, and friction force distributions at central inside a wound roll under the condition for a wound roll without wrinkle and slippage phenomena. © (2012) Trans Tech Publications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Study swaging process for reduction swage effect in hard disk drive(2013-04-15) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Theoretical analysis of flying characteristics for air-helium filled HDD(2014-01-01); Kuanoon, KunchitThis paper presents the flying characteristics of air-helium filled hard disk drive for a self-acting two rails flat slider bearing. Numerical scheme based on the finite difference with multigrid multi-level technique were implemented for the ultra-low flying height sliders. The characteristics of air-helium filled HDD have been examined in this research work. The results shown that the change of flying height is significantly for various fraction of air-helium filled, at various operating conditions such as temperature velocity and mass of slider. Increase of velocity, flying height increase. Increase both the temperature and the mass load, flying height decrease. Increasing of fraction in helium gas, the flying height decreases rapidly for 40% to 60% of fraction in helium filled. The flying height for air-helium filled magnetic flat slider head equal to 1.3 nm at trailing edge with mass load 12 mN and velocity 20 m/s. The spacing for helium filled hard disk drive is lower than 3 nm when compared with conventional air filled hard disk drive. © (2014) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effects of slider geometry change on helium filled HDD(2014-01-01); Kuanoon, KunchitThis paper describes the static characteristics of helium filled hard disk drive for a s two rails flat slider gas bearing. Numerical scheme based on the finite difference with multigrid multi-level technique were implemented for the ultra-low flying height sliders. The effect of slider geometry change in both crown and camber on flying height have been examined in this research work. The results show that the flying height change is significantly with a few nanometers change in crown and camber. The flying height of helium filled magnetic flat slider head equal to 3.5 nm at trailing edge. The spacing for helium filled hard disk drive is lower than 4 nm when compared with conventional air filled hard disk drive. The increase of slider crown, the flying height increases rapidly but the increase of slider camber, the flying height decreases continuously. © (2014) Trans Tech Publications, Switzerland. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effect of solid particle on TEHL under line contact with solid-liquid lubricant(2012-04-04) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Elastohydrodynamic lubrication of cylindrical roller in line contact(2004-09-27); Yawong, SomnukElastohydrodynamic lubrication is defined as thin film lubrication considering the elastic deformation of material under contact stress. This paper presents the application of finite difference and Newton Raphson method to calculate the Reynolds equation of a cylindrical roller on flat surface numerically. The lubricant is a compressible fluid and operated at isothermal condition. Calculation results show that the film pressure of the lubricants in line contact under elastohydrodynamic lubrication is decreased when the increase of load, on the other hand, the film thickness will be increase as the velocity increase. At severe conditions, the film pressure will be increased approach the Hertzian contact pressure. At constant load and velocity the film pressure increase gradually at lubricant inlet and reach the maximum pressure to form pressure spike at minimum film thickness.