Oil Dynamic Viscosity Research Articles

Application of analytical models for assessment of crude oil dynamic viscosity at different thermobaric conditions

The article describes author approach to application of approximating model based on experimental evidences. This model allows a user to realize assessment of crude oil dynamic viscosity applying only thermobaric conditions. The authors conduct a case study of suggested approach for the purpose of analysis of dynamic viscosity during oil production in an actual field of the Vankorskaya group. The given example presents real experimental data for viscous oil sample, on the basis of which a two-parameter numerical model of dynamic viscosity as function of gas content at different thermobaric conditions is simulated. The benefit of suggested data display mode is the possibility of its direct incorporation in hydro-dynamic simulation for correct assessment of crude oil dynamic viscosity.

A Study on the Thermal Properties of Oil-Film Viscosity in Squeeze Film Dampers

Considering the variation in temperature of the oil film in squeeze film dampers (SFDs) caused by squeezing, a more comprehensive analysis of SFD can be obtained. Aiming to investigate the viscosity thermal effect of the oil film in SFDs, this study established a 3D CFD solution model. Based on the total energy model, the viscosity thermal effect was performed. With the mixture multi–phase flow model, the Zwart–Gerber–Belamri (Z–G–B) cavitation model, and the use of the additional mass coefficient, the two–phase flow phenomenon in SFDs was discussed. The oil film at various temperatures and the temperature distribution of different oil types under different working conditions were analyzed. Furthermore, the influence of the SFD thermal effect on the two–phase flow phenomenon were particularly carried out. Meanwhile, the simulation results of the SFD thermal effect were experimentally verified. The results revealed that the maximum temperature of the SFD oil film was enhanced with the increase in the eccentricity ratio and precession frequency. The temperature of the oil film was closely related to the oil dynamic viscosity. The dynamic viscosity of the oil was reduced, which was caused by the SFD thermal effect, thus leading to decreased oil–film damping, enlarging the vaporization level and the range of vapor cavitation, as well as the ingested air amount. CFD simulation results of the thermal effect were in good agreement with the experimental data, which verified the accuracy of the proposed model.

Research on the Depletion and Recovery Characteristics of Fault-Karst Reservoirs

A fractured-vuggy carbonate reservoir is a special reservoir formed by long-term physical, chemical, and geological processes. Its reserves are large in scale and widely distributed, showing the characteristics of free flow-seepage coupling. Conventional simulation is usually simplified by equivalent permeability, which cannot reflect the actual development characteristics. Given this, the flow in caves and fractures is treated with free flow, using the Navier–Stokes equation. The seepage simulation is used for other areas, and the Darcy formula is used. Finally, the simulation results are obtained by coupling, and the influence of oil production speed, fracture-cavity size, fracture-cavity location, dynamic viscosity, permeability, and other factors on bottom pressure is analyzed to effectively guide the field development. The results show that the production pressure of fractured-vuggy reservoirs diffuses from the central fractured-vuggy area to the surrounding matrix, and the pressure increases from the fractured-vuggy area to the surrounding matrix. The flow velocity in the seepage area is relatively stable and flows gently into the middle fracture cavity from all directions. There will be eddy current in the free-flow area. Different factors have different effects on the development. The oil production speed and oil dynamic viscosity are positively correlated with it, while the formation permeability is negatively correlated with it. The size and location distribution of fracture cavity will also have a certain impact. Simulation in advance can effectively avoid some reservoir development problems.

3D Numerical Study of the Electrokinetic Motion of a Microparticle Adsorbed at a Horizontal Oil/Water Interface in an Infinite Domain.

This work builds a three-dimensional (3D) simulation model and studies the electrokinetic velocity of a microparticle adsorbed at a horizontal oil/water interface in an infinite domain. The effects of the interface zeta potentials, the electric field, the oil dynamic viscosity, and the contact angle between the particle and the oil/water interface are investigated in detail. The results show that in an infinite oil/water interface system, both the negatively charged mobile oil/water interface and the negatively charged particle adsorbed to it move toward the positive electrode of the DC electric field, and the particle velocity increases along with the contact angle, the electric field strength, and the absolute values of negative zeta potential of both the particle and the oil/water interface. When the oil/water interface is positively charged with a relatively small zeta potential, the negatively charged microparticle also moves in the opposite direction of the electric field. The larger the oil dynamic viscosity, the smaller the electrokinetic velocity of the microparticle at the interface. Additionally, the numerical simulation results are compared with the reported experiment results under the same conditions, and they have good agreement.

Tandem tapered roller bearings no-load torque loss in a rear axle gear transmission

The main no-load power loss source of a rear axle is the pre-loaded pinion tapered roller bearings, as concluded in a previous work. Therefore, the pinion roller bearings torque loss was studied in detail, where the influence of several parameters was considered, such as, the starting torque of the pinion tapered roller bearings, the oil level, the lubricant viscosity and the rotational speed.Due to the nature of the assembly of the pinion shaft assembly, pre-load in the tapered roller bearings is difficult to measure, however the starting torque of this assembly can be easily measured.For this reason, in this work a rolling bearing torque loss empirical equation was developed, where it uses as input parameters the starting torque, the oil dynamic viscosity, operating speed and the rolling bearing mean diameter and width.

Theoretical rheological models for olive oil

This paper proposes new rheological models for olive oil. The purpose of this study was to find an exponential dependence between temperature and dynamic viscosity of olive oil, using one equation. Equation constants lnη0, A1 and t1 were determined by fitting exponential. The olive oil have investigated using a Haake VT 550 Viscotester developing shear rates ranging between 3 and 120 s-1 and measuring viscosities from 104 to 106 mPa·s when the HV1 viscosity sensor is used.
 Olive oil dynamic viscosity decreases with increasing temperature at constant shear rate. Plotting the ln dynamic viscosity depending on temperature shows an exponential decline.
 

MODEL MATHEMATICAL OF DEPENDENCE DYNAMIC VISCOSITY-TEMPERATURE FOR COCONUT OIL

This article proposes new rheological models for coconut oil. The purpose of this study was to find an exponential dependence between temperature and dynamic viscosity of coconut oil, using one equation. Equation constants η0, A1 and t1 were determined by fitting exponential. Coconut oil dynamic viscosity decreases with increasing temperature at constant shear rate. Plotting the dynamic viscosity depending on temperature shows an exponential decline.

Development of a New Multifunctional Inhibitor for Protecting Oil Industry Equipment From Corrosion

In order to protect oil industry borehole equipment and the product transport system from corrosion, and also to improve oil recovery in highly viscous oil deposits a new reagent is developed based on acidol, technical-grade isopropyl alcohol, and technical-grade phosphatide. Laboratory studies show that the reagent reduces the oil dynamic viscosity by a factor of 2.9, and is also effective as an inhibitor (the degree of overall corrosion protection is 94–96 %), while the protective effect of general corrosion is 94–96 %. Industrial testing shows that as a results of action of the reagent in the bottom-hole formation zone oil production increases on average by 22 %, and the degree of protection from overall corrosion is 90 %. Measurements also show a reduction in flow pressure in product transport pipelines 20 % from 0.12 to 0.096 MPa.

Churning power losses of a gearbox with spiral bevel geared transmission

Abstract To predict the churning power losses in a gearbox with spiral bevel geared transmission, based on the Computational Fluid Dynamics (CFD) method, a numerical simulation model for the splash lubrication of the intermediate gearbox of a helicopter including gear box housing, a spiral bevel gear pair and an oil guide device is established and validated by the churning power losses prediction of experiments showing a good agreement. With the model, churning power losses of a gearbox with spiral bevel geared transmission are obtained; influences of gear rotational speed, oil fill level, oil temperature, oil dynamic viscosity, oil density, and tilt angle of the helicopter, on the churning power losses are analyzed.

Electro-magneto-hydrodynamic lubrication

Abstract The topic of the presented paper aims to demonstrate a new principle of hydrodynamic lubrication in mechanical, thermal and electro-magnetic fields. Up till now, when dealing with the hydrodynamic theory lubrication, many authors of scientific papers have assumed the constant oil dynamic viscosity value without variations caused by temperature crosswise the film thickness. Simultaneously, due to the numerous AFM measurements, it appears that oil temperature gradients and oil viscosity changes in the bearing gap height directions cannot be omitted. Therefore, in this paper, the problem of the viscosity changes across the lubricant thin layer was resolved as the main novelty in principles of mechanical thermal lubrication. The method of solving the mentioned problem was manifested by a general model of semi-analytical solutions of isothermal electro-magneto-elastohydro-dynamic and non-Newtonian, lubrication problem formulated for two deformable rotational surfaces in curvilinear, co-ordinates.

Influence of mass temperature on gear scuffing

Abstract A new scuffing parameter for gears lubricated with mineral base oils is developed, proposing the existence of gear mass temperatures which are critical for each lubricant (viscosity grade). The introduction of the total cycle of the gear for mass temperatures calculation is supported by a theoretical background that was clearly established without empirical formulation and without any geometrical gear specificity which provides consistent physical support to the proposed scuffing parameter. The oil dynamic viscosity at the critical mass temperatures is constant, allowing the prediction of critical temperatures for other viscosity grades of the mineral gear oils without the need of additional scuffing tests.

THE PROBLEMS OF HYDRODYNAMIC NON-ISOTHERMAL LUBRICATION

The classical hydrodynamic theory of slide bearing lubrication has been constituted on the assumption of constant pressure and viscosity perpendicular to the thin oil layer thickness. These fundamental assumptions are in contradiction to contemporary achievements connected with new devices such as micro-bearing, nano-bearing, magnetic bearings, artificial joints in humanoid robots, micro-motors. Therefore, new methods of measurements and calculations using AFM and a new mathematical computer programs are needed. Energy conservation equations after boundary layer simplifications confirm the fact that temperature gradient variations across the film thickness have the same order of magnitude as the variations in longitudinal or circumferential directions. The fact that temperature gradient variations across the bearing gap height can be significantly large are evident, despite the temperature differences across the film thickness that are negligibly small. This statement cannot be compliant with the assumption of a constant viscosity value in the gap height direction. It has been proven that hydrodynamic pressure is not constant across the film thickness for non-Newtonian oils with Rivlin Erickson constitutive equations. For pseudo-plastic non-Newtonian oils, the apparent dynamic viscosity significantly decreases with shear rate increases. However, for pseudo-plastic oils, the shear rate increments during the oil flow are strictly connected with the average flow velocity increments. Therefore, the apparent dynamic viscosity depends strongly on the oil velocity gradients. It is evident that flow velocity gradients across the film thickness have intensive variations, particularly in regions where gap height attains the least value. In these places, the dynamic viscosity attains the largest variations in gap height directions. If gap height in micro-bearing is smaller than one micrometre, than the largest oil dynamic viscosity increments caused by the velocity variations across the film thickness are located near the superficial layer of the movable journal surfaces in the case of the hydrodynamic lubrication by rotation, but in the neighbourhood where each of two come near lubricated surfaces during the squeezing. Hence, in these places, dynamic viscosity increases across the film thickness and attains the local maximum values. A gap height smaller than one micrometre has the largest oil dynamic viscosity increments caused by the adhesion force variations across the film thickness located near the motionless sleeve surfaces. In a similar manner, the influences on the viscosity variations caused by the cluster points of concentrations of nano particles as oil inhibitors or oil additives smaller than 5 nm occurring in micro-bearing gaps and the cluster concentration regions of collagen fibres occurring in human joint gap are observed. This paper describes and comments on the above-mentioned problem of oil viscosity changes in the gap height direction, and it presents the apparent dynamic viscosity functions for Newtonian and non-Newtonian oils as well indicates the largest viscosity variations in bearing gap height direction and gives examples of initial calculation results.

Study of the effect of temperature and gas condensate addition on the viscosity of heavy oils

Abstract Heavy and extra heavy oils have been the focus of attention since the conventional oil reserves are becoming more scarce in the world. To explore and process these oils is a challenging task because of their high viscosity and high density, which can lead to many problems during their flow and processing. In this study, the effect of temperature and gas condensate addition over the dynamic viscosity of four Brazilian heavy oils was analyzed with API density varying from 13.7 to 21.6. In addition, the effect of gas condensate addition over the densities of these samples was studied. The elevation of temperature around 20 °C led to levels from 70 to 77% of oil dynamic viscosity reduction. Condensate addition significantly reduced oil viscosities by as much as 98% (in comparison to the crude oil viscosities) in the concentration of 32% (v/v) of condensate. At a condensate concentration of 14% (v/v) the percent viscosity reduction was about 90% for the studied oils, meaning that condensate addition over this value may be unnecessary to reach the desirable objective of reducing the oil viscosity. Additionally, models that represent the influence of temperature and condensate addition over the studied oils were built.

Feasibility of Observing Small Differences in Friction Mean Effective Pressure between Different Lubricating Oil Formulations Using a Small, Single-Cylinder Motored Engine Rig

The feasibility of using a motored single-cylinder 517 cc diesel engine to observe small frictional differences between oil formulations is investigated. Friction mean effective pressure (FMEP) is measured and compared for an SAE 10W-30 and an SAE 5W-20 oil in three stages of production: base oil, commercial oil without a friction and wear reducing additive, and fully formulated commercial oil. In addition, a commercial SAE 5W-30 engine oil is investigated. Friction mean effective pressure is plotted versus oil dynamic viscosity to compare the lubricant FMEP at a given viscosity. Linear regressions and average friction mean effective pressure are used as a secondary means of comparing FMEP for the various oil formulations. Differences between the oils are observed with the base oil having higher friction at a given viscosity but a lower average FMEP due to the temperature distribution of the test and lower viscosities reached by the base oil. The commercial oil is shown to have both a higher FMEP at a given viscosity and a higher average FMEP than the commercial oil without a friction and wear reducing additive. The increase in friction for the oil without a friction and wear reduction additive indicates that the operational regime of the engine may be out of the bounds of the optimal regime for the additive or that the additive is more optimized for wear reduction. Results show that it is feasible to observe small differences in FMEP between lubricating oil formulations using a small, single-cylinder motored engine.

An integrated supplier selection and procurement planning model using product predesign and operational criteria

The literature of supply chain management and concurrent engineering indicates that many benefits can be achieved if suppliers are involved in product design and development. This paper proposes a single product, multiple sourcing model for evaluating and ranking potential suppliers using a multi-criteria decision making tool, the analytic hierarchy process (AHP). In addition to the criteria related to the operational aspects of the production process, such as quality and price, AHP considers other criteria related to the early stage of product design, such as end customer requirements satisfaction, technical product specifications, and supplier flexibility. The integration between operational criteria and predesign criteria, gives the decision makers the opportunity to select the suppliers that have the potential to satisfy their future demand of raw materials, components, subassemblies or services effectively and efficiently, as well as the capability to satisfy the end customers’ requirements by positively affecting the design of the finished products. The output from AHP is then used in a two-stage optimization model where a utility function that includes suppliers’ relative weights is first maximized to select the best suppliers, then a cost function is minimized to determine the amounts of raw materials, components, subassemblies or services to be ordered from every selected supplier. An application to the lubricants industry is carried out where predesign criteria such as base oil dynamic viscosity and kinematic viscosity are taken into account in the supplier selection phase to show the effectiveness of the model.

Thermal simulation modeling of a hydrostatic machine feed platform

Hydrostatic guideways are widely applied into precision and ultra-precision machine tools. Meanwhile, the oil film heat transfer causes thermal disturbance to the machine accuracy. Therefore, it is necessary to study the mechanism of the oil film heat transfer and the heat-transfer-reducing method to improve the machine accuracy. This paper describes a comprehensive thermal finite element (FE) simulation modeling method for the hydrostatic machine feed platform to study methods of reducing machine thermal errors. First of all, the generating heat power of viscous hydraulic oil flowing between parallel planes is calculated based on the Bernoulli equation. This calculation is then employed for the simulation load calculations for the closed hydrostatic guideways, which is adopted by the hydrostatic machine feed platform. Especially, in these load calculations, the changing of oil film thickness (resulted from external loads) and the changing of oil dynamic viscosity (influenced by its temperature) are taken into account. Based on these loads, thermal FE simulation modeling of the hydrostatic machine feed platform is completed to predict and analyze its thermal characteristics. The reliability of this simulation modeling method is verified by experiments. The studies demonstrate that the hydrostatic machine thermal error degree is determined by the oil film heat transfer scale, and this scale is mainly influenced by the relative oil supply temperature to ambient temperature (quantitative comparison of oil supply temperature and ambient temperature). Furthermore, the reduction of the absolute value of this relative oil supply temperature can reduce the oil film heat transfer scale and improve the machine accuracy.

Excessive Additive Effect On Engine Oil Viscosity

The main goal of this paper is excessive additive (for oil filling) effect on engine oil dynamic viscosity. Research is focused to commercially distribute automotive engine oil with viscosity class 15W–40 designed for vans. There were prepared blends of new and used engine oil without and with oil additive in specific ratio according manufacturer’s recommendations. Dynamic viscosity of blends with additive was compared with pure new and pure used engine oil. The temperature dependence dynamic viscosity of samples was evaluated by using rotary viscometer with standard spindle. Concern was that the oil additive can moves engine oil of several viscosity grades up. It is able to lead to failure in the engine. Mathematical models were used for fitting experimental values of dynamic viscosity. Exponential fit function was selected, which was very accurate because the coefficient of determination R2 achieved high values (0.98–0.99). These models are able to predict viscosity behaviour blends of engine oil and additive.

Temperature Relations of Selected Engine Oils Dynamic Viscosity

Abstract This article focuses on temperature relations of dynamic viscosity for selected engine oils. The effect of temperature on new and used oil dynamic viscosity was investigated. Measurements were performed on three different motor oil samples. All the three motor oil samples were synthetic. The first oil sample was new, the second sample was used for 15,000 km, and the third sample was used for 30,000 km. There were made two measurements of samples in one week. Dynamic viscosity was measured using a digital rotational viscometer Anton Paar DV-3P. The principle of measurement is based on the dependence of sample resistance to probe rotation. The results of measurements are shown as graphical relationships between dynamic viscosity and temperature. Decreasing exponential functions in temperature relationships were used for all the samples. The highest difference between the first and second measurement was observed in the new oil, and very small differences were found in other oils. Due to different types of oils and different stage of usage, the results could not be compared.

Temperature and Adhesion Influence on the Microbearings Operating Parameters

In presented paper are elaborated the preliminary problems of thermo-hydrodynamic theory of lubrication for dependences between temperature, adhesive forces, and oil dynamic viscosity, in micro-scale inside super thin cylindrical boundary layer arising between two cooperating grooved cylindrical surfaces. In cylindrical micro-bearings are visible the large gradients of temperature changes and adhesion changes in very thin gap height direction. Hence the oil dynamic viscosity changes significantly in gap height direction. This fact implies the visible oil flow velocity changes and friction forces and the hydrodynamic pressure changes during the micro-bearing exploitation. Up to now the influence of adhesion forces simultaneously with temperature on oil viscosity changes and next on hydrodynamic pressure and load carrying capacity changes in cylindrical micro-bearing gap were not considered in analytical and numerical way.

Termofyzikálne a reologické vlastnosti vzoriek biomazív

This article deals with thermal properties of selected biooils (Plahyd S – biooil No1 and Plahyd N – biooil No2) and rheologic properties of rapeseed oil. Plahyd S is a synthetic, rapidly biodegradable fluid which is based on sustainable raw materials. It is exceptionally suitable for applications in mobile and stationary hydraulic systems. Plahyd N is multigrade hydraulic oil based on rapeseed oil used in agricultural and construction machinery. For thermal parameters measurements was used Hot wire method. The experiment is based on measuring of the temperature rise vs. time evaluation of an electrically heated wire embedded in the tested material. The thermal conductivity is derived from the resulting change in temperature over a known time interval. Dependency of material resistance against the probe rotation was used at measurement of rheologic properties with instrument viscometer Anton Paar DV-3P. For two samples of biooils – Plahyd N and Plahyd S were determined basic thermophysical parameters – thermal conductivity, thermal diffusivity and volume specific heat. For each biooil samples were made two series of measurements. In the first series were measured thermal conductivity and thermal diffusivity at constant room temperature 20 °C. Every thermophysical parameter was measured 10 times for each sample. The results were statistically processed. For biooil No1 thermal conductivity was 0.325 W*m -1 .K-1 , it was higher value than we obtained for biooil No2 – 0.224 W*m -1 .K-1 . The similar results were obtained for thermal diffusivity of biooil No1 2.140.10-7 m 2 *s -1 and biooil No2 2.604.10-7 m 2* s -1 . For samples with constant temperature were calculated basic statistical characteristics as: standard deviation for ? – biooil No1 (±0.056 W*m -1*K -1 ) and biooil No2 (± 0.054 W*m -1*K -1 ); probable error of the arithmetic average for ? – biooil No 1 (±0.012 W*m - 1*K -1 ) and biooil No 2 (±0.005 W*m -1*K -1 ); relative probable error in % for ? – biooil No1 (±3.69 %) and biooil No2 (±2.23 %). The same statistical characteristics were calculated for thermal diffusivity. In the second series of measurements were measured relations of thermal conductivity and thermal diffusivity to the temperature in temperature range (20 – 29) °C. From results was evident that all measured dependencies are nonlinear. For both thermophysical parameters were obtained polynomial functions of the second degree described by the polynomial coefficients. Type of function was selected according to statistical evaluation based on the coefficient of determination for every thermophysical parameter graphical dependency. In temperature dependency of rapeseed oil dynamic viscosity was used decreasing exponential function, which is in accordance with Arrhenius equation. The results obtained by the implementation of thermophysical and rheologic measurements on samples of biooils could be compared with the values presented in the literature.