Direction Of Oil Flow Research Articles

Design and experimental analysis on a single tank energy storage system integrated with a cooking unit using funnel system

The paper presents a new innovation in small scale thermal energy storage system suitable for cooking application. A single tank thermal energy storage system integrated with a cooking unit has been developed and the performance analysed. The system consists of a heat storage tank, a heating chamber referred to as a funnel, and the cooking unit. The heating chamber is a pipe made of cast iron, and on top of the pipe is a cylindrical container made of Aluminium. A heating element of 1.5 kW 220 V was inserted inside the funnel and was used for heating the oil. The top of the funnel allows a cooking pot to be inserted inside it. The funnel can be raised or lowered using screws connected to the top of the tank; this regulates the temperature at which oil begins to overflow into the heat storage tank. The heat storage tank is made of stainless-steel, and contains sunflower oil as a heat storage medium. During charging, a small volume of oil about 2 L was heated inside the funnel, and the temperature rose rapidly to about 150 °C in less than 15 min. The system allows for cooking to begin immediately after charging has been started. As heating continues, the hot oil overflows into the storage tank, and cold oil at the bottom of the tank flows into the funnel where it is heated. The storage tank had 18 L of sunflower oil. During discharge, the direction of oil flow reverses; hot oil flows from the top of the tank into the funnel. The hot and the cold oil do not mix during discharge, and therefore, the heat front is preserved. Cooking tests were demonstrated during charging and discharging cycles. About 453.6 kJ of energy was used in boiling 1.5 L of water in 10 min, and 1.04 MJ was used in boiling 1 kg of dry beans in about 2 h.

Dynamic Heat Dissipation Model of Distributed Parameters for Oil-Directed and Air-Forced Traction Transformers and Its Experimental Validation

A traction transformer with narrow oil channels is usually cooled with the ODAF or "Oil Directed Air Forced" method, where its temperature greatly depends on the Joule heat of windings, the conjugate heat transfer in the transformer, and the secondary heat release via oil cooler, together with the oil flowrate generated by oil pump. Neither the thermal-electric analogy nor the CFD simulation approach is qualified to predict the temporal and spatial temperature variations in this type of transformer. In the current work, the distributed parameter models are built for traction transformers and oil coolers with the assumption of a one-dimensional temperature field in the oil flow direction, respectively. Then, the two models are combined with the lumped parameter ones of oil pumps and pipes via the flow rate, temperature and pressure continuities at their interfaces, resulting in the derivation of the dynamic heat dissipation model of oil-directed and air-forced traction transformers. Additionally, an efficient algorithm is proposed for its numerical solution, and the temperature rise experiment is performed for model validation. Finally, the fundamental of dynamic heat dissipation in traction transformers is investigated with the current numerical model and the effects of ambient temperature are studied.

Influence of different oil flow directions on the friction performance of asymmetric structures in heavy load hydraulic friction pairs

Textures have obvious anti-friction and anti-wear effects, but effective textures often have complex and asymmetric characteristics. Because of the texture’s directional lubrication effect and fluid diode effect, different oil flow directions influence the friction reduction effect of asymmetric texture. Simulations and test methods are used to characterize these effects, and the friction coefficient and wear amount are used as evaluation methods to determine the optimal oil flow direction of asymmetric textures. The results show that an appropriate oil flow direction can significantly change the texture’s friction-reducing ability. The friction reduction efficiency of the texture is highest when the angle between the oil flow direction and the inflow edge of the texture is 60°–90°. When the angle between the oil flow direction and the inflow edge of the texture is 0°–30°, the texture’s anti-friction effect and efficiency are weakened.

Reducing viscosity of waxy crude oil with electric field perpendicular to oil’s flow direction

It has been reported that the application of a high-voltage electric field parallel to the oil flow direction or to a quiescent waxy crude oil can reduce the viscosity of the oil. In this work, an electric field perpendicular to the flow direction is applied to a flowing waxy crude oil in a rheometer equipped with in-situ electric field manipulation, and it is observed that viscosity reduction similar to that obtained with electric field parallel to the flow direction can also be achieved. This, therefore, confirms that the treatment efficacy is insensitive to the direction of the electric field compared to the oil flow direction. Moreover, the non-Newtonian characteristics of the treated crude oil become less significant, and more viscosity reduction is achieved at higher electric field strength and lower oil temperature. After the removal of the electric field, the reduced viscosity gradually recovers and the viscosity reduction disappears after about two days. Though it is found that the electric treatment causes an increase in wax crystal size and aggregation of particles to some extent, we think that weakened interaction between wax particles due to electric field exposure should be the primary reason of the viscosity reduction according to the knowledge of suspension rheology and the mechanism of waxy crude oil rheology.

Mechanical model of yaw damper and its application in the simulation of vehicle system dynamics

Considering the limitation and inaccuracy of conventional simplified Maxwell model of yaw damper in the analyses of vehicle system dynamics, this paper established an accurate mechanical model of both one-way oil flow yaw damper and two-way oil flow yaw damper according to the analyses of their inner structure, and also contrasted two mechanical models of different oil flow direction and simplified Maxwell model in the vehicle system dynamics and analyzed the reason, especially in hunting stability, ride quality and small curve passability. The results show that the mechanical models of AMESim is superior than simplified Maxwell model in the accuracy of simulation.

Investigation of Thermal Behavior of an Oil-Directed Cooled Transformer Winding

In this contribution, the oil speed in horizontal channels of an oil-directed cooled winding is investigated by experimental and numerical methods. The presented winding model offers insight into the horizontal cooling channels perpendicular to the main oil-flow direction. To visualize oil flow, tracing particles were added to the cooling oil and illuminated by high-power light-emitting diodes. The particle velocities were then determined by taking photographs with a defined exposure time. The design of the sophisticated winding model is described in the contribution. In addition to the experimental results, this contribution presents a comparison with respective numerical results from 2-D and 3-D computational fluid dynamics calculations. Finally, numerical results from the winding model concerning the oil-flow distribution inside the winding at various operating conditions are presented. The investigation indicated a strong nonuniform oil-flow distribution on the horizontal channels. The presented results give a deep insight into the oil flow and temperature behavior of windings, enabling the designer to optimize the cooling of the power transformer windings.

Multi-level configuration and optimization of a thermal energy storage system using a metal hydride pair

Metal hydride thermal energy storage (TES) system is an attractive option for the concentrated solar power. In this article, a multi-level configuration is proposed to intensify the discharging process of TES system using MgH2/LaNi5 pair. The discharging process is simulated by establishing a mathematical model, which is solved by COMSOL Multiphysics v5.1. The multi-layer structure of storage units is simplified by the conversion of porosity and thermal conductivity. It is found that the multi-level configuration mitigates the non-uniform reaction along the oil flow direction so as to enhance the overall discharging performance effectively, such as the decrease of discharging time from 17,350 s to 14,688 s and the increase of output temperature by ∼5 °C. Meanwhile, the optimum number of levels is determined between 4 and 5 according to the effect of the number of levels on the discharging performance. Furthermore, it is revealed that the optimum allocation principle of storage materials is to maintain the same discharging time for all the subsystems.

Covariance Matrix Localization Using Drainage Area in an Ensemble Kalman Filter

The Ensemble Kalman filter has been widely researched because of its availability of real-time updating of reservoir models and uncertainty quantification. There have been many studies to solve the two typical problems: overshooting and filter divergence, and to increase its accuracy. One of the methods is covariance localization, which excludes data having relatively low correlation between reservoir parameters and observations. This article proposes covariance matrix localization using a drainage area, which can be easily obtained by checking the direction of oil flow. In applications to synthetic reservoirs, the proposed method gives a better prediction of the permeability distribution by history matching and, therefore, future performances. It also provides reliable results in cases of small ensemble sizes.

Effect of Fracture Inclination on Oil Recovery by Steam Heating in Fractured Reservoirs

The major objectives of this study are investigating the influences of fracture inclination on oil recovery by steam injection processes. The strongest recovery mechanism in steam injection is reduction of viscosity ratio. In this article, steam heating of a naturally fractured reservoir is modeled in terms of a block with a single fracture surrounded by steam. An analytical approach is used, which considers the transient temperature distribution within a single block. A heat integral method is used to obtain the unsteady-state temperature profile. The temperature distribution is used to calculate drainage rate under gravity flow. The solutions obtained are used to determine the effect of fracture inclination and some other parameters on the oil rate in steam injection. The results indicated that a single horizontal fracture in the direction of oil flow (zero inclination angle) recovered the highest oil, while a similar formation with a single vertical fracture perpendicular to oil flow direction (90° inclination angle) produced the lowest oil rate in steam heating. The increases of fracture inclination angle decreases oil recovery during steam heating. In addition, the recovery of oil for matrix with a single horizontal fracture is less dependent on average steam temperature, and this dependency becomes more as fracture inclination approaches to 90° (matrix with vertical fracture).

Modeling Steam-Assisted Gravity Drainage With a Black-Oil Proxy

Summary This paper describes an alternative approach to model steam-assisted gravity drainage (SAGD) with an isothermal black-oil (BO) reservoir simulator. The oil-viscosity reduction caused by heating in the actual SAGD process is emulated by a tuned saturated pseudo-oil viscosity relation in which solution gas/oil ratio (Rs) is used as a “proxy for temperature.” In the BO formulation, fully saturated oil viscosity (μo*) at reservoir pressure equals μo that would be attained at steam-chamber temperature (T*) in the actual SAGD process; initial oil viscosity (μoi) with initial Rs = 0 represents initial oil viscosity at reservoir temperature; and BO gas properties represent steam at T*. After careful analysis of the SAGD process, one finds that oil flows only along a narrow zone along the outer edge of the steam chamber—the “edge oil-flow zone.” The temperature gradient within this narrow zone is perpendicular to the oil-flow direction and is practically impossible to model with any precision because of the large temperature variation and dynamic steam-chamber shape over time. The BO-model solubility gradient also varies, analogous to temperature in a thermal model, from zero to fully saturated (Rs*) with an associated drop in oil viscosity from μoi to μo*. SAGD design requires many hundreds of runs to find operational conditions that maximize economic value (e.g., injector and producer location, rates, pattern spacing, and steam-chamber temperature T*). The proposed BO proxy model runs several times faster than a thermal model while maintaining similar performance behavior. The proxy-model saturated pseudo-oil viscosity μo(p) relation used is found by history matching a full-physics thermal-model performance prediction of oil rate, bottomhole flowing pressure, and cumulative oil for a 2D homogeneous model. We have found a single-constant μo(p) equation that yields a good match to thermal SAGD performance. The tuned pseudo-oil viscosity relation honors the measured initial reservoir and fully heated (at T*) oil viscosities. Its dependence on Rs is not physical, but reflects the use of Rs as a transform variable for temperature, capturing the strong spatial variation of temperature and oil viscosity within the localized steam/oil boundary region in which oil has been mobilized. The pseudo-oil viscosity relation, defined by a single empirical best-fit constant n—for a given T* and a set of thermal properties—appears to be applicable for a wide range of reservoir heterogeneity, injection and production rates, and well placement. Consequently, it should be possible to use the BO proxy model for SAGD optimization of T*, control rates, and injector/producer vertical-depth difference. We also see the potential of using the BO proxy model for solvent-based SAGD, with the pseudo-oil viscosity model depending on both T* and solvent; thermal compositional modeling is yet even slower and less suitable for optimization.

Membrane Emulsification with Oscillating and Stationary Membranes

Membrane emulsification of sunflower oil in aqueous solutions of 2% (v/v) Tween 20 was performed using a stationary disk membrane with a rotating paddle stirrer and, for comparison, a tubular membrane oscillating normal to the direction of oil flow in an otherwise stationary continuous phase. The oscillation frequency ranged from 10 to 90 Hz. The oil was injected through a sieve-type membrane with a 10 μm pore size and 180 μm between pore spacing at low flux rates to minimize any droplet interference. Using the same membrane material under identical peak shear conditions in both systems, smaller and more uniform drops (30−50 μm median sizes) were produced in the oscillating system. In oscillation, the drop size was modeled by a force balance, including a correction for neck formation at the pore surface, but in the rotating paddle system, neck formation did not appear to be relevant. Drop size was not found to be frequency of oscillation dependent, apart from its influence on the shear stress at the membr...

Influences of fracture orientation on oil recovery by water and polymer flooding processes: An experimental approach

The major objectives of this study are to experimentally investigate the influences of fracture orientation on oil recovery by water and polymer flooding processes. Four flood experiments were conducted at simulated reservoir conditions of temperature and pressure. The fifth experiment was carried out using core sample without fracture as a base run to compare the performance of fractured and unfractured formations under water and/or polymer flooding(s). Viscosity variation of actual crude oil and polymer solutions of different concentrations was measured under different temperatures. The results indicated that waterflooding the unfractured carbonate reservoirs provided higher oil recovery than formations of a single fracture. A carbonate reservoir of a single-horizontal fracture in the direction of oil flow (0° inclination angle) recovered the highest oil recovery while a similar formation of a single-vertical fracture perpendicular to oil flow direction (90° inclination angle) produced the lowest one by waterflooding. The increase of fracture inclination angle decreases oil recovery by waterflooding. For polymer flooding after complete waterflooding, the results showed that all fractured carbonate formations of different inclination angles produced higher oil recovery than unfractured ones. The highest oil recovery by polymer flooding was produced from formation of a single fractured of 30° inclination angle, while the lowest recovery was obtained from formation of 90° inclination angle. In addition, the ultimate recovery of combined water and polymer flooding processes in fractured carbonate reservoirs proved that the best recovery was gained from the horizontally fractured formations.

Flow visualization on the linear compressor cascade endwall using oil flows and laser Doppler anemometry

Surface oil flow visualizations were conducted in the VPI&SU Department of AOE Low Speed Linear Cascade Wind Tunnel on the endwall. Oil flow visualizations of the endwall flow features (passage flow, cross flow and tip leakage vortex) for tip gap to chord ratios (t/c) of 1.65% and 3.3% are discussed in detail. For the first time, quantitative comparisons are made between the oil-flow direction and the wall shear stress direction obtained from laser Doppler anemometer experimental results. The oil flow streaks are aligned with the wall shear stress direction, except near separation, which is proved theoretically and experimentally. Wall shear stress directions in the oil-flow images are measured and the separation line in the oil flow is calibrated based on the skin friction results from the LDA measurement.

Upflow versus downflow testing of hydrotreating catalysts

Bench-scale evaluation of hydrotreating catalysts may lead to lower apparent activities than found in commercial operation. Especially for shaped catalysts deviating results are obtained. From bench-scale test results and liquid holdup measurements, it is concluded that these problems are related to the method of testing. The low superficial mass velocities in the test unit lead to inefficient catalyst utilization. It is demonstrated that reversing the direction of oil flow from downflow to upflow gives a much improved catalyst utilization comparable to those in commercial units.

Cavitation erosion of a flat surface near a rotating shaft

To clarify the phenomenon of cavitation erosion in the sliding bearings of internal combustion engines, an apparatus was prepared and tests were conducted on cavitation in the oil between the cylindrical face of a rotating shaft and the tip of a horn attached to an ultrasonic oscillator. This apparatus produces an oil flow and a plus-minus oil pressure between a shaft and a horn tip to simulate erosion and its distribution on bearing surfaces. From patterns of cavitation erosion on the tip of a horn made of an Al-Sn alloy and the pressure distribution on the wedge oil film, it was determined that the region where cavitation bubbles occur and the region where erosion occurs owing to the collapse of the bubbles do not necessarily coincide. Cavitation erosion was found to occur in both the plus and the minus oil film pressure regions and erosion due to bubble collapse occurs in the regions where pressure increases in the direction of oil flow. The test results allow the postulation of the mechanism and the reasons for the occurrence of cavitation erosion on actual sliding bearing surfaces.