Oil Flow Rate Research Articles

Thermal-Fluid-Solid Coupling in Thermal Characteristics Analysis of Rolling Bearing System Under Oil Lubrication

Abstract It is necessary to use the thermal network method for thermal analysis of the bearing, but there are still some shortcomings. In this paper, a novel thermal network model of the bearing transient temperature is developed considering the thermal-fluid-solid coupling effects. First, the quasi-static analysis of the bearing is carried out considering the thermal expansion effect, and the heat generation, heat transfer, and heat dissipation are studied. Then, the coupling effects between the oil characteristics, heat generation, structure parameters, and temperature (thermal-fluid-solid) during the operation of the bearing are discussed, and the transient thermal network model of the bearing-shaft-bearing housing system is established. Test results indicate that the existing models (without thermal-fluid-solid coupling) have large temperature deviation, while the proposed model in this paper considering the thermal-fluid-solid coupling effects is much more accurate. Finally, the effects of rotational speed, load, oil temperature, and oil flowrate on the temperature rise are all achieved and discussed.

Emission Rate Estimation of Fuel Oil in A Combustion System Using Empirical Method

This work highlighted the prediction of the emission rates of the products of combustion using a fuel oil of specific gravity of 0.9. The two reaction pathways of complete combustion and incomplete combustion were used differently to ascertain the emission rates. Ultimate analysis were conducted on the fuel oil to show the percentage composition of elements using ASTM 3178 method for carbon and hydrogen, Kjedahl method for nitrogen, ASTM D1552 for sulphur and the differences used to compute that of oxygen. The estimated percentages of the various elements were the stoichiometrically used to compute the emissions rates at standard conditions. The basis of the computation was a fuel oil flow rate of 10Tonnes/h and the following emission rates were predicted for the complete combustion reaction pathway: 31,246Kg/h for CO2, 65Kg/h for H2O, 158Kg/h for NO2 and 20Kg/h for SO2 while 9,940Kg/h for CO2, 15,623Kg/h for CO, 11,700Kg/h for H2O, 11Kg/h for H2S and 158Kg/h for NO2 were predicted for the incomplete combustion pathway. The study noted that this predictive path should be taken where effective devices or logistics are not in place to measure emissions from combustion systems.

Emission Rate Estimation of Fuel Oil in A Combustion System Using Empirical Method

This work highlighted the prediction of the emission rates of the products of combustion using a fuel oil of specific gravity of 0.9. The two reaction pathways of complete combustion and incomplete combustion were used differently to ascertain the emission rates. Ultimate analysis were conducted on the fuel oil to show the percentage composition of elements using ASTM 3178 method for carbon and hydrogen, Kjedahl method for nitrogen, ASTM D1552 for sulphur and the differences used to compute that of oxygen. The estimated percentages of the various elements were the stoichiometrically used to compute the emissions rates at standard conditions. The basis of the computation was a fuel oil flow rate of 10Tonnes/h and the following emission rates were predicted for the complete combustion reaction pathway: 31,246Kg/h for CO2, 65Kg/h for H2O, 158Kg/h for NO2 and 20Kg/h for SO2 while 9,940Kg/h for CO2, 15,623Kg/h for CO, 11,700Kg/h for H2O, 11Kg/h for H2S and 158Kg/h for NO2 were predicted for the incomplete combustion pathway. The study noted that this predictive path should be taken where effective devices or logistics are not in place to measure emissions from combustion systems.

An experimental investigation on the effects of mineral oil flow rate on CPU immersion cooling

The aim of this research is to analyze the effect of using immersion cooling with different flow rate and fan rotation on decreasing the temperature on CPU. The study used three variables of flow rate: 0.5, 1 and 1.5lpm. in addition, three other variables of fan rotation, 400, 600, and 800 rpm, were used as well. Data collection was by means of benchmark software to load the CPU to work maximum and the logging software to record the temperature. The results show that the immersion cooling could potentially be utilized as the new and more effective cooling system. The most optimum variable to decrease the temperature was 1, 5 lpm with fan rotation at 800 rpm. It decreased the maximum temperature from 60 °C to 47 °C, a deviation of 13 °C lower compared to the conventional fan cooling system with air as a medium. The study established that the higher the flow rate and the fan rotation, the higher temperature can be decrease. Therefore, immersion cooling can be the solution to decrease the consumption of energy on IT sector on a bigger scale.

Experimental characterization of thermal-hydraulic performance of a microchannel heat exchanger for waste heat recovery

Given size and performance advantages, microchannel heat exchangers are becoming increasingly important for various energy recovery and conversion processes. In this study, detailed experimental measurements were conducted to characterize flow and heat transfer performance of a microchannel heat recovery unit (HRU) manufactured using standard photochemical etching and diffusion bonding processes. According to the global flow and temperature measurement, the HRU has delivered the predicted thermal performance under various oil and air flow rates. As expected, the heat transfer effectiveness varies between 88% and 98% for a given air and oil flow rates while it increases with air inlet temperature due to the improved thermal conductivity. However, significant flow mal distribution is identified among the air channels according to the in-depth flow distribution measurement using hot wire. The flow measurement also indicates visible misalignment of the air channels caused by the manufacturing processes. In addition, the excessive pressure drops occurred for both air and oil channels indicating reduced flow areas due to the photochemical etching process. The results of this experimental study can hopefully provide insights in improving designs of microchannel heat exchangers using the same manufacturing processes.

Investigation of Heat Management in High Thermal Density Communication Cabinet by a Rear Door Liquid Cooling System

In this paper, a rear door oil-cooling heat exchanger for data center cabinet-level cooling has been proposed. In order to solve the heat dissipation problem of high heat density data center, this paper applied the mature transformer oil cooling technology to the data room. The heat dissipation of liquid-cooled cabinets and traditional air-cooled cabinets was compared, and the heat dissipation performance of the oil-cooled system was theoretically and experimentally investigated. To investigate the heat dissipation system, the cabinet operating temperature, circulating oil system temperature and cabinet exhaust temperature, cabinet heat density, oil flow rates and fan power were analyzed. It was found that the average cooling efficiency of the liquid-cooled cabinet increased by 66% compared with the average cooling efficiency of the conventional air-cooled cabinet. The operating temperature in air-cooled cabinets is as high as 55 °C, and the operating temperature in liquid-cooled cabinets does not exceed 50 °C. Among which, the maximum heat dissipation efficiency of the liquid-cooled cabinets can reach 58.8%. The oil temperature could reach 46.9 °C after heat exchange, and the exhaust air of the cabinet could reach 42.8 °C, which could be used to prepare domestic water and regenerative desiccant. The results from established calculation model agreed well with the testing results and the model could be used to predict the heat dissipation law of the oil cooling system under different conditions. The research has proposed the potential application of the oil-cooled in cabinet-level cooling, which can help realize saving primary energy and reducing carbon emission.

To the issue of choosing the well pump operation mode under unsteady drainage

The article discusses the unsteady drainage as one of the ways to increase oil recovery. With this well operation process, optimal periods of pump switching are determined to increase the oil flow rate and reduce the watercut. The object of study is the "reservoir — well — pump" system. The purpose of the study is to ensure efficient operation of wells. We use the descriptive method, including the analysis of transient processes of the "reservoir — well — pump" system on a simulation bench, interpretation of transient graphs, and comparison and generalization of the results. The research results showed the dependence of the pressure change on the pump operation mode, i.e. the dependence of the formation parameter on the change in the flow resistance of the "reservoir — well — pump" system. For each transient process, the optimal period of pump operation was determined equal to 3 τ, which will ensure efficient well production mode.

Role of Shearing Dispersion and Stripping in Wax Deposition in Crude Oil Pipelines

Wax deposition during crude oil transmission can cause a series of negative effects and lead to problems associated with pipeline safety. A considerable number of previous works have investigated the wax deposition mechanism, inhibition technology, and remediation methods. However, studies on the shearing mechanism of wax deposition have focused largely on the characterization of this phenomena. The role of the shearing mechanism on wax deposition has not been completely clarified. This mechanism can be divided into the shearing dispersion effect caused by radial migration of wax particles and the shearing stripping effect caused by hydrodynamic scouring. From the perspective of energy analysis, a novel wax deposition model was proposed that considered the flow parameters of waxy crude oil in pipelines instead of its rheological parameters. Considering the two effects of shearing dispersion and shearing stripping coexist, with either one of them being the dominant mechanism, a shearing dispersion flux model and a shearing stripping model were established. Furthermore, a quantitative method to distinguish between the roles of shearing dispersion and shearing stripping in wax deposition was developed. The results indicated that the shearing mechanism can contribute an average of approximately 10% and a maximum of nearly 30% to the wax deposition process. With an increase in the oil flow rate, the effect of the shearing mechanism on wax deposition is enhanced, and its contribution was demonstrated to be negative; shear stripping was observed to be the dominant mechanism. A critical flow rate was observed when the dominant effect changes. When the oil flow rate is lower than the critical flow rate, the shearing dispersion effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. When the oil flow rate is higher than the critical flow rate, the shearing stripping effect is the dominant effect; its contribution rate increases with an increase in the oil flow temperature. This understanding can be used to design operational parameters of the actual crude oil pipelines and address the potential flow assurance problems. The results of this study are of great significance for understanding the wax deposition theory of crude oil and accelerating the development of petroleum industry pipelines.

Experimental analysis on the behavior of water drops dispersed in oil within a centrifugal pump impeller

This paper aims to investigate the behavior of water drops in a continuous oil medium inside a centrifugal pump impeller working at eight operational conditions (up to 1200 rpm and 2.8 m3/h) with two-phase liquid-liquid flows. Water-in-oil dispersions were produced with low water cuts of about 1% in volume, thus the dispersed phase became arranged as water drops. Experiments for pump performance and flow visualization were conducted using a high-speed camera and a pump prototype with a transparent shell. Flow images revealed that the large water drops usually deform, elongate, and break up into smaller ones, especially at high pump rotations and oil flow rates, while small water drops tend to keep their spherical geometry without deformations and fragmentations. A sample of drops were tracked and their equivalent diameters, residence times, and velocities were calculated. The tracking indicated that the water drops travel random trajectories in the channels, generally undergoing a deceleration along their pathway. Furthermore, the residence times and the average velocities of water drops strongly depend on the flow conditions. For the conditions tested, the water drops presented equivalent diameters between 0.1 and 5.0 mm, average velocities from 0.4 to 1.7 m/s, and residence times between 30 and 152 ms. For a more complete analysis, the results achieved in this study are constantly compared with results available in literature regarding oil drops in oil-in-water dispersions.

Numerical simulation and deacidification of nanomagnetic enzyme conjugate in a liquid–solid magnetic fluidized bed

The conventional deacidification method is difficult to achieve a better refining effect due to the high acid value in the rice bran crude oil, and the enzymatic esterification deacidification method can effectively reduce the acid value without generating chemical waste. In this study, the free lipase was immobilized on a magnetic polymer carrier Fe3O4/SiOx-g-P (GMA: glycidyl methacrylate) to obtain a immobilized lipase with a particle size of 105.30 ± 1.1 nm and an enzyme activity of 6580 ± 9.6 PLU/g (PLU: enzyme activity unit). Based on the batch deacidification process parameters, a multi-stage magnetic fluidized bed continuous circulation deacidification system was designed, and then the motion law of nanomagnetic immobilized lipase particles in liquid–solid magnetic fluidized bed was simulated by computer. When the iterative step was 5 × 10−5 s, the open porosity of the porous plate was 35.0%, the rice bran oil flow rate was 3.0 mm/s, and the magnetic field strength was 25.0 mT, which was beneficial to the deacidification reaction of rice bran oil. Under the conditions of magnetic immobilized lipase dosage of 4.0%, the phytosterol dosage of 22.0%, the molecular sieve dosage of 10%, the esterification temperature of 78.0 °C and the FFA (free fatty acid) content in rice bran oil decreased to 1.5%, after 48 h of reaction. The conversion rate is 92.8%, which provides a theoretical basis for the subsequent guidance of magnetic fluidized bed enzymatic continuous deacidification.

Potential for the wellbore zone development using the dynamic impact

To increase the effect of acid formation treatment (increase in production/injectivity, an overhaul period, reduction of costs of geological and technical works), the authors suggest using a dynamic impact on the wellbore zone (WZ) by using acid creating the rinsing effect with the help of swab equipment and an acid aggregate when waiting for the acid reaction. The article aims to analyze the potential for the application of dynamic impacts on the WZ. The differences of the technology from other impact methods were studied. The main parameters of the wells before and after the dynamic WZ treatment were determined using three indicators: a fluid flow rate, an oil flow rate and a water cut rate. The economic effect of the technology was compared with the effect of the clay-acid treatment (CAT) technology and complex vibrational depression chemical effects (CVDCE). The technology can be used at other NGDUs in order to improve the profitability of field development.

Study of Geologically Consistent History Matching Peculiarities by Means of Gradient-Free Optimization Methods

This paper presents some results and distinctive features of the algorithm for automated history matching of 3D reservoir flow models using gradient-free methods. Widely used Nelder-Mead method was chosen for optimization. In order to preserve geological consistency of a model within the history matching process, control parameters are comprised of “porosity-to-permeability” relation parameters, anisotropic (semi)variogram parameters, and reservoir properties at pilot points. The control parameters are used at each iteration of the history matching process to generate porosity and permeability distributions based on static well data and perform flow simulations. Test studies were conducted for a specially developed synthetic model representing a inhomogeneous five-spot well pattern element. Oil flow rates at production wells and water flow rate at the injection well, as well as bottomhole pressures of all wells were chosen as measured dynamic data in the objective function. The influence of initial guess of parameter values and relative weights in the objective function on the quality of reconstruction of the ‘true’ solution and convergence rate were evaluated. Problems of gradient-free optimization methods application and specific features of residuals normalization in the objective function, as well as influence of pilot points are discussed.

METHOD OF GAS PRESSURE OPTIMIZATION IN PRODUCING WELL ANNULUS

The process of oil production using sucker rod-pumping installations, especially with high gas content of formation fluid, is accompanied by accumulation of oil gas in the annulus of wells. The growth of the annular gas pressure causes an increase in the back pressure on the reservoir and a number of other negative consequences, to exclude which various technologies are used to pump out gas from the annular space of production wells. The article considers the problem of optimizing the gas pressure in the annulus by pumping gas with a compressor at a constant speed. The design of the suspended plunger compressor driven by the balance of the pumping unit and the method for calculating the technological parameters of the compressor based on the balance of the compressor supply and the volumetric flow rate of the separated gas into the annulus are proposed. A two-stage algorithm for calculating the parameters of the optimal technological mode of well operation has been developed. As an optimization criterion, joint fulfillment of the following conditions was proposed: ensuring the permissible volume fraction of gas at the inlet, minimum pump immersion under the dynamic level, and maximizing the flow rate of the well. To assess the effectiveness of the proposed well operation technology and to calculate the increase in well flow rate during compressor operation, a mathematical model of a multiphase stationary gas-liquid mixture flow in a wellbore operated by a pumping pump unit, taking into account the equilibrium processes of separation and dissolution of oil gas, the effects of oil and gas phase slip, is proposed. The calculation results confirm that the use of compressors for pumping gas from the annulus allows one to obtain a significant increase in the flow rate of liquid and oil, which depends on the parameters and properties of the pumped product, the operational characteristics of the formation and barothermal conditions.

Experimental and theoretical investigations on transition of lubrication conditions for a five-pad tilting-pad journal bearing with eccentric pivot up to highest surface speeds

Abstract Lubrication conditions of tilting-pad journal bearings strongly depend on the combination of bearing design, lubricant flow rate, and operating boundary conditions. A five-pad tilting-pad journal bearing is investigated experimentally for surface speeds ranging from 25 to 140 m/s and specific bearing loads between 1.0 and 4.0 MPa at different fresh oil flow rates. Comparisons to theoretical analyses indicate speed-dependent transition from fully flooded to partially filled conditions in certain space between pad regions. These conditions are discussed in detail and a semi-empirical model to approximate this behavior is proposed and validated with the test data.

Investigating Minimum Quantity Lubrication in Unidirectional Cf/SiC composite grinding

The influences of minimum quantity lubrication (MQL) on the grinding performance of unidirectional carbon fibre-reinforced ceramic matrix (Cf/SiC) composites were investigated in this paper. The experimental results indicate that MQL can significantly improve surface quality and reduce grinding forces. In addition, MQL has a low cost and does not generate considerable pollution. According to the lubrication mechanism of MQL, the effects of nozzle direction, air pressure, oil flow rate and nozzle distance on the grinding performance of unidirectional Cf/SiC composites were carefully investigated in this research. Excellent surface quality and low grinding forces can be achieved when the nozzle direction, air pressure, oil flow rate and nozzle distance are 15°, 5 bar, 100 ml/h and 80 mm, respectively. The surface topographies show that smooth fibre separation, fibre breaking, fibre outcropping, fibre pullout and matrix cracks are the main failure forms of the ground surface. The histogram reflects that the proportion of fibre pullout is the highest, whereas that of fibre outcropping is lowest. In the MQL grinding process, a large amount of heat is removed by water vapour, which can significantly reduce the grinding temperature. Meanwhile, effective oil films form in the contact areas between the grits and the material surface. The above factors are advantageous for improving the grinding performance of unidirectional Cf/SiC composites. The objective of this research was to investigate the influences of MQL for unidirectional Cf/SiC composites, validate these interpretations with experimental results and provide reasonable recommendations for guaranteeing the machining accuracy of Cf/SiC composites.

CO2 Laser Fabrication of PMMA Microfluidic Double T-Junction Device with Modified Inlet-Angle for Cost-Effective PCR Application.

The formation of uniform droplets and the control of their size, shape and monodispersity are of utmost importance in droplet-based microfluidic systems. The size of the droplets is precisely tuned by the channel geometry, the surface interfacial tension, the shear force and fluid velocity. In addition, the fabrication technique and selection of materials are essential to reduce the fabrication cost and time. In this paper, for reducing the fabrication cost Polymethyl methacrylate (PMMA) sheet is used with direct write laser technique by VERSA CO2 laser VLS3.5. This laser writing technique gives minimum channel width of about , which limit miniaturizing the droplet. To overcome this, modification on double T-junction (DTJ) channel geometry has been done by modifying the channel inlets angles. First, a two-dimensional (2D) simulation has been done to study the effect of the new channel geometry modification on droplet size, droplets distribution inside the channel, and its throughput. The fabricated modified DTJ gives the minimum droplet diameter of , while DTJ channel produced droplet diameter of at the same conditions. Moreover, the modified double T-junction (MDTJ) decreases the variation in droplets diameter at the same flow rates by than DTJ. This low variation in the droplet diameter is suitable for repeatability of the DNA detection results. The MDTJ also enhanced the droplet generation frequency by more than the DTJ channel. The uniformity of droplet distribution inside the channel was enhanced by compared to the DTJ channel geometry. This fabrication technique eliminates the need for a photomask and cleanroom environment in addition shortening the cost and time. It takes only for fabrication. The minimum generated droplet diameter is within with more than droplets per second (at . oil flow rate). The device is a high-throughput and low-cost micro-droplet formation aimed to be as a front-end to a dynamic droplet digital PCR (ddPCR) platform for use in resource-limited environment.

Experimental Investigation on Oil Spray Cooling With Hairpin Windings

Hairpin windings are gaining increasing popularity in recent years due to their advantages in improving electrical machine performance while reducing manufacturing time and costs. Their geometrical features introduce new challenges and opportunities on thermal management. In particular, spray cooling is increasingly being used, since hairpin windings open up regular and accurately defined gaps in the end-windings compared to the traditional random windings. To date, technical literature on the effectiveness of spray cooling with hairpin windings is lacking, with no practical guidelines available to researchers. In this article, taking an existing hairpin-wound stator, a test rig is developed to investigate the cooling ability of different spray cooling setups on the end-windings. Three types of commercial spray nozzles are chosen to carry out a series of experiments, varying the oil flow rate, pressure, outlet velocity, and number of nozzles. The winding temperature and heat transfer coefficients are presented and discussed. Furthermore, the efficiency of spray cooling is reviewed based on the experimental results. Finally, suggestions on designing similar cooling setups and increasing the cooling efficiency are also provided.

Control over parameters of ESCP unit to improve efficiency in bringing wells to stable production using a frequency-controlled drive on R. Trebs oil field

The article deals with the results of technological process of bringing an oil well to stable production; the well is equipped with an electric submersible centrifugal pump unit, its drive function is changed by a frequency-controlled drive. The paper presents data obtained while bringing an oil well to stable production: the liquid flow rate, oil flow rate, operating current, submersible electric motor loading, current frequency, water content of the products. The authors describe the process and specific aspects of bringing an oil well to stable production, conditions necessary for the process, variation of operation parameters. Recommendations were developed to ensure optimal operation of oil wells equipped with electric submersible centrifugal pump units considering technological and economic costs.

A MILP model for the detailed scheduling of multiproduct pipelines with the hydraulic constraints rigorously considered

Multiproduct pipelines are the most effective and important way to transport refined products from refineries to the downstream market. The detailed scheduling of a multiproduct pipeline with the hydraulic constraints considered plays a vital role in the pipeline's safe and economic operation. Aiming at this issue, this paper proposes a continuous-time mixed-integer nonlinear programming (MINLP) model taking the sum of the pumps’ running and start/stop costs as the objective function. Based on a method proposed in a previous study for the rigorous description of the hydraulic loss changes in multiproduct pipelines, the pipeline hydraulic constraints and pump-related functions are considered directly and rigorously in the model. Other actual field processing constraints, such as the pipeline shutdown and contaminated oil flowrate, are also considered. To deal with the nonlinear relationship between the flowrate and pressure/volume, a piecewise linearization method is adopted, and the pipeline flowrate is graded according to the divided intervals. Finally, the application of the established model is successfully conducted on a real-world multiproduct pipeline through two case studies. A comparison with a previous discrete-time model is also performed to verify this model's applicability, accuracy, and superiority.

Experimental Study of Friction Factor for Iraqi Crude Oil by Using Nano-Al2O3 as Drag Reduction Agent (DRA)

Objectives: The aim of the present work is to study the effect of adding Nano-Al2O3 on the experimental friction factor and pressure drop for Iraqi crude oil. Methods/Statistical Analysis: The effect of three pipe diameters (0.5, 0.75 and 1 inch), five values of Reynolds number and Nano-Al2O3concentration (0.002–0.01 wt %) on the friction factor were studied. Findings: The results illustrated that the friction factor is generally decreased with increasing of Nano-Al2O3 concentration and crude oil flow rate. Application/Improvements: There is very low available literature on the drag reduction process by using Nano-Al2O3 as drag reduction agent for Iraqi crude oil.