A MULTISCALE MODELING APPROACH TO UNDERSTAND MECHANISM OF DEPOSIT CONTROL BY LUBRICANT DETERGENTS AND DISPERSANTS

Download

Esra Kan Tez.pdf

Date

2022-7-29

Author

Kan, Esra

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

309
views

170
downloads

With the recent developments in high performance computing power, molecular modeling calculations to design and improve new generation additives for engine oils have reached a level that can support and guide experimental results. Control of insoluble nanoparticle aggregations in oil and on the engine pistons is the most important key performance parameter for lubricant oil additives. General consensus about the mechanism of deposit build-up is the self-aggregation of nanosized insoluble structures. Detergents and dispersants are the major additives to prevent aggregation in lubricant formulations provided by Lubrizol Corporation. Together with the base oil, they play a significant role to disperse and stabilize insoluble particles to control deposit formation. In this study, multiscale modeling methods were used to elucidate molecular mechanism of deposit control via detergents and dispersants by using density functional theory, molecular dynamics simulations of cells constructed by statistical sampling of large number of molecular configurations and coarse-grained simulations. The aim of this study is to understand the role of different groups such as bis-succinimide amine center and two polyisobutylene tails in dispersants as well as anionic sulfonate head group and alkyl tails in detergents. It was demonstrated that the mechanism of deposit control can be explained by the interactions between constituents such as hydrogen bonding and hydrophobic-hydrophilic forces. We showed that nanoparticle aggregation is mitigated by intercalation of dispersant and detergent polar groups between the insoluble nanoparticles followed by the extension of hydrophobic tails into the oil phase that decreases coalesce further by forming a repulsive layer against the other nanoparticles.

Subject Keywords

Dispersant, Detergent, Multiscale Modeling, Molecular Dynamics Simulation, Coarse-Grained Simulation

URI

https://hdl.handle.net/11511/98615

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

A COMBINED EXPERIMENTAL AND COMPUTATIONAL STUDY FOR THE DESIGN OF A LOW WATER CONSUMPTION COOLING TOWER Dogan, Burak; Yilmaz, Ibrahim; Polat, Ozgur; Karabulut, Oytun; Ural, Ahmet; Uludağ, Yusuf; ARADAĞ ÇELEBİOĞLU, SELİN (2014-06-27) In this study, a combined experimental and computational study for the design of a low water consumption cooling tower is performed. The purpose of the study is to reduce the water consumption without decreasing the efficiency of a typical cooling tower. To achieve this aim, it is necessary to enhance the homogeneity of mist/air mixture. For this purpose, firstly, an experimental set-up including a small scale wind tunnel is installed which provides opportunity to examine different inlet and outlet configur...
SIMULATION AND OPTIMIZATION OF 3 EXISTING ETHYLBENZENE DEHYDROGENATION REACTORS IN SERIES ONAL, I; YALCIN, N; UYGUN, E; OZTURK, H (1990-01-01) A computer model was developed to simulate the performace of three commercial reactors in series for dehydrogenation of ethylbenzene to styrene. The model can be used to predict the performance of dehydrogenation catalysts in the commercial reactors. In the model program, flow of the reactant stream through the catalyst bed is treated as one-dimensional plug flow. The kinetic rate parameters were obtained by using the Conjugate Direction method as a multivariable search technique so as to minimize the su...
A methodology to assess suitability of a site for small scale wet and dry CSP systems Uzgoren, Eray; Timur, Eray (2015-06-25) This study presents a methodology to assess suitability of a site for small scale concentrated solar power (CSP) systems for its energy conversion efficiency and make-up water requirement. Energy conversion efficiency of CSPs relies not only on the level of direct solar radiation but also on the performance of the cooling system. Regions with high solar potential have to deal with heat rejection at elevated temperatures which causes reduced energy conversion efficiencies due to high condenser temperatures. ...
A stochastic approach in reserve estimation Kök, Mustafa Verşan (Informa UK Limited, 2006-12-01) Geostatistics and more especially stochastic modeling of reservoir heterogeneities are being increasingly considered by reservoir analysts and engineers for their potential in generating more accurate reservoir models together with usable measures of spatial uncertainty. Geostatistics provides a probabilistic framework and a toolbox for data analysis with an early integration of information. The uncertainty about the spatial distribution of critical reservoir parameters is modeled and transferred all the wa...
A fabrication process based on structural layer formation using Au-Au thermocompression bonding for RF MEMS capacitive switches and their performance Cetintepe, Cagri; Topalli, Ebru Sagiroglu; Demir, Şimşek; Aydın Çivi, Hatice Özlem; Akın, Tayfun (2014-10-01) This paper presents a radio frequency micro-electro-mechanical-systems (RF MEMS) fabrication process based on a stacked structural layer and Au-Au thermocompression bonding, and reports on the performance of a sample RF MEMS switch design implemented with this process. The structural layer consists of 0.1 mu m SiO2/0.2 mu m SixNy/1 mu m Cr-Au layers with a tensile stress less than 50 MPa deposited on a silicon handle wafer. The stacked layer is bonded to a base wafer where the transmission lines and the iso...

Citation Formats

E. Kan, “A MULTISCALE MODELING APPROACH TO UNDERSTAND MECHANISM OF DEPOSIT CONTROL BY LUBRICANT DETERGENTS AND DISPERSANTS,” M.S. - Master of Science, Middle East Technical University, 2022.