Oil Temperature Distribution Research Articles

Prediction of PAN oxidation in a gas turbine bearing chamber using coupled chemical kinetics and CFD simulation of lubricant flow

A Computational Fluid Dynamics (CFD) model, using COMSOL 6.1, was developed in this work to simulate the oil temperature distribution within a bearing housing, to provide a means of predicting the most probable zones for PAN oxidation. Three different zones in the radial direction and two distinct zones in the axial direction were specified with different temperature profiles. It was also found that the rotational speed of the rotor and oil outlet pressure can significantly influence the temperature distribution. Oil inlet temperature was the other factor that had a minor impact on the temperature profile. Furthermore, the highest temperatures were observed in the bulk oil in the area surrounding the rotor. A chemical reaction analysis, which was performed using MATLAB R2022a, was performed to estimate the rate of PAN oxidation. According to the final results; higher rotational speeds increase the rate of oxidation. Moreover, a reduction in revolution speed extends the time required to completely consume the original PAN content. These findings were also used to demonstrate where varnish deposits start to form. Multiple temperature zones were used instead of the average temperature to carefully check the mutual relation between the revolution speed and temperature, and accurately calculate the rate of PAN oxidation reaction.

Development of a 2-dimensional thermal calculation method to estimate silicone oil's temperature distribution in viscous torsional vibration dampers

AbstractHigh-performance internal combustion engines are subject to severe torsional vibrations which result from uneven gas and inertial loads. Fatigue damage occurs if the frequency of these undesired oscillations matches the resonance frequency of the crankshaft and the driven engine elements. This phenomenon can be avoided by the application of visco-dampers whose working fluid is high-viscosity silicone oil. Since silicone oil is exposed to a significant amount of heat load during operation, it is essential to calculate the temperature distribution in a relatively easy, quick, and cost-efficient way for lifetime estimation purposes. The aim of this article is to develop a reliable, fast, and accurate finite difference-based numerical method for steady-state thermal calculations for arbitrary damper sections. The developed MATLAB code calculates the temperature field of the damping fluid together with all components in a radial cross-section at given operational conditions. The accuracy of the developed thermal calculation method has been tested in a 3-dimensional – 2-dimensional two-step verification process by finite element and finite volume-based advanced engineering software in ANSYS environment. Furthermore, the original Iwamoto equation available in the literature has been updated to provide more accurate surface temperature results based on the simulations' outcome gained by the finite volume method.

Modeling of stationary mode for pipeline operation during hot oil pumping

The objective of this work is to build and analyze a mathematical model of steady-state operation of a pipeline that conducts hot oil pumping in a particular section. Mathematical modeling of pipeline operation during hot pumping makes it possible to determine the pumping flow rate, temperature and pressure distribution along the length of the pipeline. The object and subject of the study is a horizontal pipeline route between two pumping stations with preheating of oil at the beginning of the section. Within the framework of this work, the dependence of oil viscosity on temperature was determined, and the following graphs were obtained: graph of oil temperature distribution in the considered pipeline section, graph of pressure distribution in the pipeline in the considered section, graph of hydraulic resistance coefficient distribution according to the Leibenzon model, graph of pressure distribution in the pipeline in the considered section according to the combined model of Shukhov and Leibenzon. The graphs obtained allowed us to assert that taking into account the real rheological properties of oil leads to a change in the law of pressure distribution along the pipeline route and to a significant change in the length of the linear section of the pipeline, where a significant pressure drop occurs.

Modeling of stationary mode for pipeline operation during hot oil pumping

The objective of this work is to build and analyze a mathematical model of steady-state operation of a pipeline that conducts hot oil pumping in a particular section. Mathematical modeling of pipeline operation during hot pumping makes it possible to determine the pumping flow rate, temperature and pressure distribution along the length of the pipeline. The object and subject of the study is a horizontal pipeline route between two pumping stations with preheating of oil at the beginning of the section. Within the framework of this work, the dependence of oil viscosity on temperature was determined, and the following graphs were obtained: graph of oil temperature distribution in the considered pipeline section, graph of pressure distribution in the pipeline in the considered section, graph of hydraulic resistance coefficient distribution according to the Leibenzon model, graph of pressure distribution in the pipeline in the considered section according to the combined model of Shukhov and Leibenzon. The graphs obtained allowed us to assert that taking into account the real rheological properties of oil leads to a change in the law of pressure distribution along the pipeline route and to a significant change in the length of the linear section of the pipeline, where a significant pressure drop occurs.

The “Golden Zone” temperature distribution of oil and gas occurrence examined using a global empirical database

We present here a straightforward empirical correlation between petroleum occurrence in sedimentary basins and reservoir temperature that can be integrated with other methods of analysis to reduce exploration risk. Global amounts of recoverable oil, gas, and gas-condensate in 1175 well characterized reservoirs from 954 of the world's largest fields, constituting 54% of the world's documented recoverable conventional oil and 50% of gas, are examined in terms of present-day reservoir temperature. Most volumes (74%) occur within the range of 60–120 ± 2 °C (140–248 ±4 °F), corresponding with the isotherm-bounded depth interval in petroliferous basins previously defined as the “Golden Zone” for exploration. Only 6% of the global total occurs at higher temperatures and 20% at lower temperatures. The decrease <58 °C is gradual in most regions, whereas the drop-off of discovered volumes >122 °C is precipitous. The low-temperature limit is suggested to reflect both poor sealing capacity of diagenetically immature shales and biodegragation, but many low-temperature accumulations survive because of uplift from previous maximum burial. The high-temperature limit is interpreted as resulting mainly from diagenetically induced overpressure that causes seal failure and remigration. Similarity between the distributions of both oil and gas with temperature indicates that the controlling processes are unrelated to petroleum generation. The distributions are also similar for sandstone and carbonate reservoirs and for reservoirs with shale, evaporite, and carbonate seals, indicating little lithologic influence. Although the ultimate controls can be debated and are certainly in need of continuing study, the observed temperature dependence of petroleum volumes is entirely empirical and can be used as an independent exploration risk factor. Nevertheless, the proportions of total estimated ultimate recovery above and below the Golden Zone temperature limits vary significantly between major petroleum-producing regions, so local calibration is essential.

Numerical simulation of temperature distribution of heat flow on reservoir tanks connected in a series

The flow of temperature distribution through a medium in thermodynamic studies plays an important role in understanding physical phenomena in chemical science and petroleum engineering, while temperature distribution indicates the degree of reaction that must be undergone to obtain the final product. Therefore, this paper aims to present and apply the exponential matrix algorithm (EMA), differential transformation algorithm (DTA), and Runge-Kutta (RK5) to simulate the temperature distribution in five heating tanks in series. successive preheating of multicomponent oil solutions. A mathematical model of the energy balance equations of the reservoir is considered. Two computer experiments were performed to test and investigate the relationship between two constant parameters appearing in the model. Numerical simulation of saturated steam Tsteam temperature of 500 °C and 1000 °C used to heat the tanks and initial temperature T035°Cand100°C of the first tank feed oil are considered. The fluids in the reservoirs were considered homogeneous throughout the experiment and changes in the cell configuration at two constant parameters were presented in the 2D plot control with the use of the MAPLE 18 software package. The study revealed the nature of the temperature distribution that the higher temperature distribution is obtained when heat is transferred from the first tank to the fifth tank and the reverse reaction occurs in all five reservoirs when ψ = 0.0025 and ω = 0.0025 respectively. Numerical results obtained are prototypes of oil temperature distribution performed under laboratory conditions in a thermodynamic experiment.

A Reduced Radiator Model for Simplification of ONAN Transformer CFD Simulation

In this paper, a reduced computational fluid dynamics (CFD) model is proposed for determining the total heat dissipation and the oil temperature distribution of transformer radiators in oil natural air natural (ONAN) cooling mode. In the reduced radiator CFD model, the air flow simulation is replaced with an optimized air heat transfer coefficient ( <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>h</i><i>_air</i></b> ) equation. An experimentally verified full radiator CFD model, which includes the air flow simulation, has been introduced as a benchmark model for evaluating the validity of the reduced model. It was found that one <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{h}}_{{\boldsymbol{air}}}}$</tex-math></inline-formula> can provide sufficient accuracy in simulating the air convection effect of transformer radiators. An <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{h}}_{{\boldsymbol{air}}}}$</tex-math></inline-formula> equation was derived through a parametric study using the full radiator CFD model. The performance of the proposed <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{h}}_{{\boldsymbol{air}}}}$</tex-math></inline-formula> equation was compared with the existing empirical equations, and its validities for different insulating liquids and different ambient temperatures were proven by additional CFD modelling. This <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\boldsymbol{h}}_{{\boldsymbol{air}}}}$</tex-math></inline-formula> equation can be transformed into a dimensionless form to help the radiator design and facilitate the complete-cooling-loop (CCL) based transformer CFD modelling.

Morton effect prediction with validation using a CFD based CNN for pad inlet temperatures

The Morton Effect (ME) is a thermal-fluid–structure interaction instability occurring in rotating machinery supported by hydrodynamic journal bearings. The mechanism of ME consists of a bowed rotor or mass imbalance induced shaft synchronous whirl vibration in the bearing, which causes local, asymmetric heating of the journal, which causes shaft bending, potentially leading to increasing vibration. This study presents an original ME simulation approach that includes a CFD (Computational Fluid Dynamics) bearing groove model, embedded in a deep learning algorithm for computational efficiency and non-expert usage. The groove model provides a 2D oil temperature distribution at the leading edge of the bearing pads, yielding a more accurate journal axisymmetric temperature distribution which is the source of the ME. The paper provides validation of the approach by test result correlation, and illustrates the effects of parameter variation and configuration variation, by examining various oil injection types. The approach may be used for correcting ME occurring in existing machinery, or for designing machinery to avoid the ME.

Viscous interference torque analysis of liquid floated gyroscope based on multi-source data learning

The liquid floated gyroscope (LFG) is a core instrument of the inertial navigation system, which is used to obtain the angular motion information of the carrier. Under the thermal effect of electronic components, the floating oil inside the instrument flows slowly, thereby introducing a viscous interference torque (VIT) acting on the floater surface, which will affect the output accuracy of the instrument. Since the magnitude of VIT is extremely small, there is currently no effective means to obtain its accurate value. Therefore, this work aims to combine the advantages of experiment and simulation and then proposes a feasible method to predict the VIT. First, a gas–liquid–solid three-phase coupled heat transfer model of the LFG was established, and the relative error between the calculated temperature and the test temperature of the calibration point is 3.5%. The computational fluid dynamics method was adopted to calculate the VIT under different oil temperature distributions; the backpropagation neural network algorithm was selected to build a network model between the temperature distribution and the VIT, and the model fitting accuracy was 0.99. Then, the actual temperature distribution of the gyro oil was obtained through experiments, which was taken as an input of the neural network to predict the VIT. The relative error between the predicted and simulation values under the same conditions was 4.18%. The proposed method provides a feasible scheme to predict the microscopic VIT that is difficult to measure, which provides a theoretical reference for the accuracy improvement of LFGs.

Анализ зависимости распределения температуры нефти по радиусу нефтепровода при остановке перекачки

Анализ зависимости распределения температуры нефти по радиусу нефтепровода при остановке перекачки

Temperature field distribution analysis for cargo oil on microwave heating process

This paper uses microwave technology to study the heating process of cargo oil in tanker side cabin under the static environment. The research is aimed to improve the heat transfer efficiency of cargo oil and solve the problems of uneven temperature distribution and energy consumption during the heating process of traditional crude-oil in oil tank. Based on the theory of microwave heating and heat transfer, the finite element simulation software is used to couple the microwave and temperature field during the cargo oil is heated to simulate the changing characteristics of the temperature field in static environment, and then verify the numerical results of the existing experiments. The simulation results show that the numerical results of this model agree well with the experimental data, and the error is in the range of 6.21-13.84%. Therefore, the accuracy of the numerical method can be verified. During the heating process, the absorption of microwave energy has a positive correlation with the electric field intensity distribution. The microwave field shows a ?strong point? distribution characteristic. Heat transfer is accompanied by natural-convection and heat conduction, and the oil temperature distribution is more balanced under the combined effect, which shows that the microwave heating of oil tankers have certain feasibility. The results of this study can provide a theoretical basis for studying the heat transfer law of oil tanker cargo steam and microwave combined heating process.

A prediction model of mechanical loss in a turbocharger considering oil temperature distribution of bearing

A prediction model of mechanical loss in a turbocharger considering oil temperature distribution of bearing

Influence of piston ring profiles and oil temperature distribution on cylinder liner lubrication of a marine two-stroke engine

In the paper a comprehensive model of a piston-ring-cylinder (PRC) system has been presented. The local thickness of the oil film can be compared to height of the combined surface roughness of a cylinder liner and piston rings. Equations describing the mixed lubri-cation problem based on the empirical mathematical model formulated in works of Patir, Cheng and Greenwood, Tripp have been ap-plied. The main parts of the model have been experimentally verified abroad by the author at the marine engine designing centre. In contrast to the previous papers of the author concerning the PRC system of combustion engines, new calculation results for a ma-rine two-stroke engine have been presented. Firstly the right selection of barrel-shaped sliding surface of piston rings has been analysed. Secondly the influence of oil temperature distribution along the cylinder liner on the lubrication of the PRC system has been assessed. The developed model and software can be useful for optimization of the PRC system design.

CALCULATION OF CFD-THERMAL MODELS OF OIL-COOLED TRANSFORMER EQUIPMENT

The purpose of the study is to ensure designing of full-function and stable CFD-simulation procedure for integrated thermal models of the transformers and the reactors, as well as to receive the approval of method of quality and abilities using the calculation examples of full-scale models of the equipment, along with autonomous models of coil-type windings having various design versions of heat-transfer intensification. Research Methods. Computational Fluid Dynamics (CFD) method of mathematical simulation of nonlinear processes as concerns hydrodynamics and heat transfer in the transformer equipment using finite-element analysis is employed. The results obtained. The paper presents the main elements of technique for creation of mathematical models; it also contains the examples of CFD-calculations as referred to axisymmetrical integrated models of furnace transformer and gapped-core shunt reactor, as well as the models of windings having design approaches of heat exchange intensification owing to «labyrinth» (partitions) and «alternation» (of number and locations) of axial cooling ducts. Scientific novelty. Scientific value of applied methodological approach lies in the fact that the developed models are the integrated ones, i.e., they consider geometry, loss, thermal parameters not only of the windings, but also of the main structural elements and cooling system. This ensures the quality and the accuracy of simulation of heat-and-mass transfer processes in complex structure of oil ducts and coils in the windings, enables to avoid erroneous «zigzag» oil flow movement through the groups of coil regular structures (without labyrinth and «alternation» of number and locations of axial ducts under conditions of transformer oil natural cooling as was deduced in the certain studies. Practical significance. Integrated models ensure calculation of oil temperature distribution within active part, including winding fields, oil temperature field between the tank and the windings, temperatures at oil outlet from the tank (top) and oil inlet into the tank (bottom). Calculations allow estimation of mean temperature distribution over the crosssection of winding coils, mean winding temperatures by means of averaging of the temperatures within the coils, detection of location and maximum temperature on the surface of conductors relevant to the most heated coil. The latter is treated as winding hot spot temperature (HST) and used to evaluate the aging of the contacting insulation. Determination of winding hot spot locations and temperatures (HST) is used as support data for installation areas of fiber optic probes for measurement during type testing, as well as in operational monitoring systems of the equipment. The results presented above are practically applied for industrial designing and testing of transformers and reactors.

Thermo-fluid Dynamic Analysis of a CSP Solar Field Line During Transient Operation

Abstract Concentrating Solar Power (CSP) technology allows to produce high temperature thermal energy from solar radiation. The thermal energy can be converted into electricity or it can be directly used for industrial processes. Most of the available simulation models of CSP plants evaluate the behavior of the solar field in stationary conditions, neglecting transient thermo-fluid-dynamic effects. Nevertheless, the study of the dynamic behavior of the solar field is a very challenging and interesting task and allows obtaining useful information for the design and the effective management strategies of CSP plants. This paper presents a thermo-fluid-dynamic analysis of asolar field line of the CSP plant currently under construction in Ottana, Sardinia (Italy), which uses thermal oil as heat transfer fluid. Dynamics of the system due to solar irradiance variations have been evaluated by using an axisymmetric unsteady 2D numerical model developed in Comsol® to evaluate the oil temperature distribution along the receiver tube for different operating conditions. The results have been compared with those obtained with a simpler, non-stationary one-dimensional model, developed in Matlab® environment. The comparative analysis show very similar results for the two models and demonstrate that the dynamic effects on the temperature distribution along the solar field line are not negligible.

A coupled internal–external flow and conjugate heat transfer simulations and experiments on radiators of a transformer

Experimental and numerical studies are reported on radiator–fan assembly, for ONAN (Oil Natural and Air Natural) and ONAF (Oil Natural and Air Forced) cooling configurations. In-house radiator test facility is developed for the experiments, and commercial software is used for the simulations. Simulations considered oil inside and air outside the radiator, and the conjugate (conduction–convection–radiation) heat transfer. Present study is done on a group of 5 radiators (of 2.5m height), each with 27 fins, and 2 fans (of 1m diameter). Good agreement, between the numerical and the experimental results, are reported for heat dissipation from the radiators. Numerical study is done to study the effect of the vertical as compared to a horizontal air flow on the thermal performance. Significant effect of the flow direction is reported on the oil flow and temperature distribution inside the radiators, with 6.1% more heat dissipation by the horizontal as compared to vertical air flow. An average oil temperature distribution inside the radiators along the height follows an exponential decay distribution, in contrast to the traditional linear profile assumption for all configurations of transformer cooling. The study is useful for transformer designers and manufacturers, leading to an improvement in the thermal design.

Effects of the radial temperature gradient and axial conduction of drilling fluid on the wellbore temperature distribution

Therefore, in this study, based on energy balance principle between wellbore and formation, a temperature model of drilling fluid layers was established under different grid units of wellbore condition. Meanwhile, the axial thermal conductivity temperature model of drilling fluid was established by introducing axial conduction items of drilling fluid, followed by using discrete and solving of implicit finite difference method to these mathematical models. The calculation results indicated that the error temperature of the radial and axial of drilling fluid wellbore temperature which was caused of radial temperature gradient were 0.15 and 0.2 ℃ respectively, whereas axis thermal conductivity of drilling fluid has little effect on wellbore temperature distribution. Therefore, the above results confirmed that it can ignore both of them to influence wellbore temperature distribution by established the wellbore-formation coupled transient heat transfer model. Moreover, it is the first proved the correctness of model assumptions from previous scholars based on the mathematical modeling methods, and then further provides the reliable theoretical basis for down-hole temperature distribution of oil and gas well and geothermal well.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

Numerical simulation of a buried hot crude oil pipeline under normal operation

A physical model is proposed to study the heat transfer and oil flow of a buried hot oil pipeline under normal operation. With certain physically reasonable assumptions, the governing equations for the thermal analyses are derived. An approach combining unstructured-finite-volume [1] and finite difference methods is applied to solve the governing equations, in which the soil domain was discretized by unstructured grids. Numerical simulations in a wide range of operating conditions are conducted. The operating conditions cover 5 months (April, May, June, October and November) with throughputs ranging from 15,007 tons per day to 27,451 tons per day and outlet temperatures varying from 40.6 °C to 64.8 °C. Measured data are provided for comparison. A good agreement between numerical simulations and field measurement suggests that the proposed numerical scheme is a suitable method to simulate the heat transfer and oil flow of buried hot crude oil pipelines. We also analyze a number of influential factors on the temperature distribution of oil along the pipeline.

Forecasting the oil temperatures along the proposed China–Russia Crude Oil Pipeline using quasi 3-D transient heat conduction model

Abstract The China–Russia Crude Oil Pipeline (CRCOP) faces significant challenges due to differential frost heaving and thaw settlement resulting from significant variations of oil temperatures along the pipeline. Oil temperature distribution along the pipeline during the long-term operation period is a very important factor in pipeline foundation design under future climate warming and various frozen soil conditions. It is important for the assessment and prediction of differential frost heave and thaw settlement of the pipeline foundations soils, forecasting the development of the seasonal and inter-annual frozen and thawed cylinders around the operating pipeline, stress–strain analysis of the pipeline, and mitigation of subsequent frost hazards. A quasi three-dimensional computational model was developed to predict the oil temperature along the pipeline. It was verified by analytic solutions of the minimum oil temperatures along the route provided by the Daqing Oilfield Engineering (DOE) Co. The oil temperatures were predicted and analyzed for two proposed annual oil flow rates of 15 million tons (0.3 mbpd) and 30 million tons (0.6 mbpd) with and without mitigative measures (only pipe insulation was considered here) during the operation period. Also, the inter-annual variations of oil temperature at key typical locations were investigated to understand the impact of climate warming. The results indicated that the maximum oil temperature cools southwards, but the minimum oil temperature warms southwards (with the inlet oil temperatures from − 6 to +10 °C). However, the average annual oil temperature decreases southwards in the northern part of the pipeline, then it starts to slowly increase. The amplitudes of oil temperature change will decrease southwards. Oil temperatures will slightly increase with elapsing time due to the imposed boundary conditions of climate warming. The oil temperatures with a lower flow rate vary more significantly than that with a higher flow rate because the oil temperature with a low flow rate is more affected by the thermal regime of the surrounding soils and the external environments. Insulation around the pipeline tends to reduce the oil temperature variations along the pipeline during pipeline operation period. Therefore, pipe insulation can effectively reduce the development of frozen and thawed cylinders in the permafrost zone. The phase change of water in soils around the pipeline has a distinct influence on the oil temperature during the freeze–thaw transition periods. The oil temperature tends to be equal to the ambient ground temperature around the pipeline with southward distance and with elapsing operation time. The pipeline oil temperature is controlled by the incoming oil temperature and the surrounding ground temperature before the equalization. It would be mainly controlled by the ground temperature around the pipeline afterwards.