Inlet Oil Research Articles

Analysis of Pressure Pulsation in Aviation Gear Pump

In order to analyse the influence of gear parameters on the internal pressure pulsation of the aviation gear pump, the flow field analysis software PumpLinx is used to calculate the internal flow field of the aviation gear pump. By setting monitoring points inside the gear pump under different gear parameters, the pressure pulsation results at different positions under different gear parameters are obtained and analysed. The results show that the larger the modulus, the greater the pressure pulsation in the oil inlet area, oil trapped area and the oil outlet area; the greater the number of teeth, the greater the pressure pulsation in the oil trapped area, and the smaller the impact on the oil inlet area and oil outlet area; the larger the index circle pressure angle, the smaller the pressure pulsation in the trapped oil area, and the smaller the impact on the oil inlet area and the oil outlet area. The analysis results provide a reference for further optimizing the internal pulsation and oil trapping problems of aviation gear pumps.

Numerical simulation of the heat losses through the steam injection in enhanced oil recovery process

In this study, a numerical investigation of the effect of using a new insulation of Yttrium oxide with thermal painting of (5 wt.%) on the heat losses from steam injected in the enhanced oil recovery process. ANSYS Fluent v.16 was used in the simulation. Results were obtained for inlet oil velocity of 5 m/s, temperature of 313 K, and inlet steam velocity of 0.1 m/s, temperature of 373 K. The length of tube is 0.5 m. Pressure through the oil decreases along the distance, while through the steam seems to be unchanged. The insulation does not affect on the pressure distribution. Velocity through the oil decreases along the distance and decreases slightly through the steam. Using the insulation lead to reduce the velocity of oil. Steam temperature decreases through before using the insulation and slightly decrease after using the insulation. Using the insulation leads to make the temperature of steam along the distance greater than the temperature before using the insulation. The pressure through the oil decreases along the distance, while through the steam seems to be unchanged. The insulation does not affect on the pressure distribution. The velocity through the oil decreases along the distance and decreases slightly through the steam by 7.14%. Using the insulation lead to reduce the velocity of oil. Using the insulation leads to make the temperature of steam along the distance greater than the temperature before using the insulation by 9.42%.

An experiment investigation of temperature control performance for machine tool oil coolers with hot-gas bypass temperature control scheme and inverter temperature control scheme

Following the machine tool with demands of high-speed, high-precision machining and multi-axis, the heat generation of machine tool will lead to thermo growth of spindle, thermal error, etc. Therefore, the machine tool oil cooler has been frequently adopted for thermal management of heat generation for machine tool. However, it will be quite challenging to develop high-precision machining without suitable temperature control scheme. And, the machine tool oil cooler with on-off control is difficult to control the oil temperature accurately. Therefore, in this paper, the machine tool oil cooler with hot-gas bypass temperature control scheme and inverter temperature control scheme based on the PID control logic have been proposed to solve the oil temperature control problem for machine tool oil cooler. Furthermore, the temperature control performance (i.e. thermo growth of spindle, oil temperature control accuracy, and EER) of hot-gas bypass temperature control scheme and inverter temperature control scheme has been compared by means of experiment. The experimental results shows that the inlet oil temperature control accuracy can be maintained ±0.2 °C during spindle operation by using the hot-gas bypass temperature control scheme (HGB cooler) and inverter temperature control scheme (INV cooler). Furthermore, the thermo growth of spindle of HGB cooler is about 14 % smaller than the INV cooler because of hot-gas bypass temperature control scheme with thermal compensation function. However, the total power consumption of HGB cooler is about 0.18 kW higher than the INV cooler. Hence, the energy efficiency ratio (EER) of INV cooler reveals about 10.9 % higher than the HGB cooler at steady state. Furthermore, when oil flow rate declined to about half, the temperature difference between initial and final steady state temperature of the spindle is increased around 94.3 %, and the thermo growth of spindle is increased 58.7 %.

Effect of the inlet oil temperature on vibration characteristics of the high-speed turbocharger rotor system

The inlet oil temperature of the rotor system with high-speed and light-load turbocharger will change during operation, which will change the vibration characteristics of the rotor system and even cause vibration accidents. Taking a certain type of high-speed and light-load turbocharger rotor system as the research object, the changes in oil film viscosity, friction power consumption, oil film temperature rise, and ring speed ratio with the inlet oil temperature of floating ring bearings are analyzed. A dynamic finite-element model of the turbocharger rotor–floating-ring-bearing system is constructed, and the finite-element model is verified through the critical speed and colormap spectrogram. The Newmark integral method is used to analyze the nonlinear transient response of the rotor system, and the influence of the inlet oil temperature on the vibration response characteristics of the rotor system is studied. The results show that an increase in the inlet oil temperature leads to a decrease in the internal and external oil film viscosities, frictional power consumption, temperature rise, and an increase in the ring speed ratio. When the inlet oil temperature increases from 50 °C to 130 °C, the amplitude of the inner oil film oscillation will gradually decrease, but the amplitude of the outer oil film vortex will gradually increase, and the journal speed point where the inner oil film oscillation and the outer oil film vortex will appear about 30% in advance. In summary, the rotor vibration is better when the inlet oil temperature is about 90 °C. The conclusion of this paper can provide a theoretical reference for selecting the operating parameters of the rotor system with the least vibration for high-speed light-load turbochargers.

The Pressure Control of High-pressure Tubing

This article mainly studies the pressure control of high-pressure tubing. Based on the theoretical basis of the pressure formula, a pressure variation model based on the pressure formula is established and solved by the enumeration method within the range. In the process of solving the model of the open time of the one-way valve in the problem, first, establish a model of the pressure change of the inlet and outlet oil. Using integral thinking, we get the oil density under each pressure. Based on the tubing pressure requirements in the corresponding time period together with the relationship between the net mass of the inlet and outlet oil per unit time, the relationship between the opening time of the inlet valve and the pressure is obtained by using the principle of the inlet valve opening time to control the inlet mass. The results of the corresponding pressure requirements are obtained through the enumeration method within the range.

Development of Degassing Device for Transformer oil Based on Headspace Degassing Method

By analyzing the type and content of gas in oil, the latent faults in equipment can be found as soon as possible, and the faults can be monitored at any time. In this paper, a degassing device based on headspace degassing method is designed. The oil circuit adopts the way of oil pump and battery valve to complete the oil inlet and oil discharge. Through stirring, the dissolved gas in the oil can reach the dynamic balance in the gas-liquid two-phase, so as to realize the rapid and effective separation of the gas in the oil. At the same time, after degassing, the oil can be sent back to the body. In addition, the degassing verification of the device is carried out, and the effect is good. In the next step, the device can be integrated with the gas detection equipment to form a sealed cabinet detection equipment, which is of great significance for the technical realization and engineering application of online monitoring and live detection of power equipment.

Dual Source Integrated Driving for Hydraulic Excavator Swing System

Generally, during the accelerating process of construction machinery large inertia hydraulic swing system, a lot of kinetic energy is accumulated, and it will be eventually dissipated through the relief valve orifice during the decelerating process, which results in serious energy waste and large overflow loss. In order to solve this problem, a new dual source hydraulic motor with non-uniform flow distribution is proposed, which can drive high-frequency swing mechanism efficiently. The new dual source hydraulic motor has two groups of oil inlet and outlet, corresponding to two groups of different displacement. The two groups of inlet and outlet are respectively connected with the energy recovery unit and the main driving unit. During the starting process, the energy recovery unit assists the main driving unit to drive the swing mechanism together, so that the main drive unit output torque and overflow loss are reduced; during the braking process, the energy recovery unit recovers the braking energy. Finally, the integrated control of braking energy direct recovery and utilization is realized. In the research, the 38 t hydraulic excavator is taken as the research object. Firstly, the multi-body dynamics electro-hydraulic simulation model of the dual source integrated driving hydraulic excavator swing system is established, and the accuracy of the model is verified by experiments. Then the effects of the accumulator working pressure and the dual source hydraulic motor displacement ratio on the working performance of the system were simulated. The simulation results show that with the displacement ratio increasing, the accelerating time, the maximum angular velocity and decelerating time increase. Compared with the original system, when the displacement ratio $\alpha $ is 0.6, the comprehensive performance of the system is the best, and the hydraulic pump output energy is reduced by 48.6% and 46.6% respectively in the process of full load and no-load operation.

Effect of the Geometry of the Inlet Boundary of a Lubricating Film on the Stress State in the Subsurface Layer of an Elastohydrodynamic Contact of a Profiled Roller

In this paper we formulate and solve numerically the elastohydrodynamic problem about a heavy loaded contact of elastic bodies in the form of a profiled roller. Such contacts are typical for roller bearings and gears. The effect of the geometry of the inlet boundary of the lubricating film on the contact parameters (pressure, thickness of the lubricating film, and subsurface stresses distributions) is studied. A mathematical model of the problem is based on the stationary nonlinear integro-differential equations with boundary conditions for the pressure and on the inequalities. From numerical solutions it follows that the peculiarities of the geometry of the inlet boundary of a lubricating film cause significant qualitative and quantitative variations in distributions of pressure, thickness of the lubricating film in the contact zone, and octahedral stresses in the subsurface layer. It is shown that an increase in the number of irregularities of the inlet oil meniscus leads to an increase in the number of extremums of octahedral stresses.

Experimental study on the design of light phase outlets for a novel axial oil-water separator

Oil-water separation plays a serious role in oil exploitation to reduce the production cost. Centrifugal separation is one of the feasible methods due to its large capacity, high separation efficiency and low maintenance cost. Besides, the centrifugal separation equipment can be divided into tangential inlet separators and axial inlet separators. The ones with tangential inlet have received a large number of investigation on structure optimization but some shortcomings limit the further improvement of separation performance. In this paper, an axial separator with multiple-stage separation was introduced and investigated experimentally with water flow rate range from 3 to 7 m3/h and inlet oil fraction below 10%. Additionally, the schedule for Light Phase Outlets (LPOs) was studied experimentally and theoretically to ensure high separation efficiency and low split ratio. The results show that the multiple stage separator can keep high separation performance that the oil concentration in HPO is below 200 ppm while the split ratio ranged from 0.2 to 0.45 within experimental conditions. Besides, the reasonable schedule can lead an obvious drop in split ratio with high separation performance. Additionally, based on the analysis of flow field characteristic, the LPOs positioned in the two sides of the oil core can ensure the discharge of oil droplets in high swirl flow field and the LPO located downstream has better potential to separate small size droplets.

Statistical analysis and mathematical modeling of modified single slope solar still

ABSTRACT Conventional single slope solar still integrated with a parabolic trough collector in addition to packaged glass ball layer was used in water desalination. Experimental work carried and data obtained were used in modeling the influential parameters affecting water desalination using principal component analysis to reduce parameters’ numbers. These parameters were then applied in constructing a Response Surface Model (RSM). System’s Performance has been predicted in terms of temperatures; saline water temperatures (Tw), glass cover temperatures (Tg), dry bulb temperature (Tdb), and wet bulb temperature (Twb) inside the conventional solar still. Along with the above temperatures, ambient air temperature (Ta), Oil inlet temperature (Toi) and solar intensity (I). The impact of these parameters can highly effect the water desalination yield. The RSM is developed to predict the impact of these parameters. Principal Component Analysis (PCA) reduced and categorized the number of effective parameters to three components containing the parameters (Tw, Twb, and Tdb), (I, Ta, and Tg) and (Ta, Toi, and I) respectively. These combinations were then tested using the two different RSM optimized models; Modified Reduced Quadratic and Two-Factor Interaction (2FI) model. These models were tested by monitoring nine statistical indices namely: RMSE, P-value, F-value, R2, R2 adj, R2 pred, BIC, PRESS, and AICc. Results obtained for this model showed minimum RMSE value and higher values of R2, R2 adj and R2 pred as well as lowest values for BIC and AICc. Concluding supremacy of (I, Ta, and Tg) Modified Reduced 2FI model over the others.

Pengaruh Modifikasi Pipa Masukan Bahan Bakar Oli Bekas Berbentuk Spiral Terhadap Performansi Burner Tornado Api

The need for fuel in Indonesia is a serious problem in human life in the future. Various efforts are being made to find alternative fuels. One that is currently being researched as an alternative fuel is lubricating oil (oil). Several studies have been carried out in the context of developing this used fuel oil. Used oil when using the standard burner used in previous studies has an impact on the amount of smoke and low temperature, because the oil that goes to the burner is still pure oil. This research tries to modify the oil input flow in the form of a circular spiral. The difference between the burners that will be made with previous studies is in the oil intake hose. The oil inlet pipe in this study will be made in a spiral shape. The results showed that the modification using a spiral pipe had a higher temperature of 397 0 C compared to without using a spiral pipe which was 381 0 C. In addition, the heating rate using this spiral pipe is greater, namely 302400 Joules. So it can be concluded that the burner performance with spiral pipe modification is higher than without using spiral pipe

Experimental study on a compact axial separator with conical tube for liquid-liquid separation

Centrifugal technology for two-phase flow separation is widely used in industrial fields. However, the liquid-liquid separation is more difficult than solid-liquid and gas-liquid separation due to its relative small density difference and emulsion caused by droplets breakup. And the current hydrocyclones for liquid-liquid separation have some shortcomings limiting further improvement of separation efficiency. Axial separators with static swirler emerged as an effective alternative method. In this paper, a compact axial separator with conical tube was introduced and investigated experimentally using oil as the dispersed phase and tap water as the continuous phase. A high-speed camera was used to verify the advantages of conical tube compared to a cylindric tube by oil droplets trajectories. Additionally, the separation performance and pressure drop on different inlet flow rate and oil fraction was studied. In the experiment, the split ratio was changed by controlling the valve in HPO pipe, and the results show that separation efficiency can be improved by increasing the split ratio to ensure the drain of oil core.

Analysis of Oil-Air Two-Phase Flow Characteristics inside a Ball Bearing with Under-Race Lubrication

Under-race lubrication can increase the amount of lubricating oil entering a bearing and greatly improve lubrication and cooling effects. The oil-air two-phase flow characteristics inside a ball bearing with under-race lubrication play a key role in lubrication and cooling performance. The motions of ball bearing subassemblies are complicated. Ball spin affects the oil volume fraction. In this paper, the coupled level set volume of fluid (CLSVOF) method is used to track the oil-air two-phase flow inside the ball bearing with under-race lubrication. The influence of various factors on the oil volume fraction inside the ball bearing with under-race lubrication is investigated, particularly rotating speeds, inlet velocity and the size of oil supply apertures under the inner ring. The influence of the ball spinning is analyzed separately. The result demonstrates that, on account of the centrifugal force, lubricating oil is located more on the outer ring raceway at rotational speeds of 5000 r/min, 10,000 r/min, 15,000 r/min and 20,000 r/min. The oil volume fraction inside the bearing gradually increases at an oil inlet velocity of 5 m/s, 10 m/s and 15 m/s. The circumferential distribution of oil is also similar. As the diameter of the oil supply aperture increases from 1.5 mm to 2 mm, the oil volume fraction increases inside the ball bearing. However, the oil volume fraction slightly decreases from 2 mm to 2.5 mm of oil supply aperture diameter. Ball spin does not affect the circumferential distribution trend of the lubricating oil, but slightly reduces the oil volume fraction. Furthermore, ball spin causes the surface fluid to rotate around its rotation axis and increases the speed.

Numerical Investigation of the Minimum Gap Impact on the Screw Compressor Efficiency

The screw compressor is a positive displacement machine, with two rotors - driver and driven. In this paper, the influence of minimum gap, between the rotors of an oil injection screw compressor, on the efficiency was investigated. Two cases were analysed, in which the minimum gap ranged from 40 to 60μm, respectively 20 to 40μm. The geometrical model, the physical properties and the initial values represent the input data for the used thermodynamic model. Starting from the 3D CAD model, the computational domain for the stator part was defined, which is composed of three subdomains: suction side, oil inlet and pressure side. The grids for the stator were generated with Ansys Meshing, whereas the meshes for the rotor subdomains were made using the TwinMesh software. In the end, smoothing functions were used to increase the mesh quality. To simulate the flow through the screw compressor, the commercial software of CFD ANSYS CFX was used, employing the SST turbulence model. In the analysis the rotational speed was 6000rpm, with a suction pressure of 2bar and a discharge of 10bar. Using the “opening” type limit conditions with the required pressure, both the air flow variation and the oil flow variation were determined.

Numerical simulation of gas-liquid mixed top blowing to enhance momentum diffusion

The presence of magnetic iron in slag increases the viscosity of the matte-slag mixture, impeding the precipitation and separation of matte from the slag. Magnetic iron can be reduced by injecting diesel oil into the molten bath and the resulting reaction enhanced by adding nitrogen to the spray lance. This study establishes a three-dimensional mathematical unsteady flow model of a y-shaped pipe containing a gas-liquid mixture, which is top-blown to enhance momentum agitation. By changing the inlet velocity of the y-pipe branch while maintaining a constant oil inlet speed, eight working conditions with different oil-gas ratios were established. These were used to investigate the effect of changing the two-phase flow pattern in the vertical tube with the inlet gas-liquid ratio. The simulation results agree well with published water model results. Experimental and simulation results show that when the ratio of oil to gas is 1:2, due to tangential disturbance of the branch gas relative to the main oil phase,rotational flow forms during the mixed descent process. After entering the molten bath, the circumferential gas-liquid mixing disturbance forms the optimum effect of swirling flow diffusion in the molten bath. The complex flow pattern formed by the nonlinear momentum diffusion of diesel mixed with bubbles can effectively improve the reduction rate of magnetic iron in the molten bath, thus reducing copper content in the slag.

Study on the Law of Diesel Oil Carrying Water in Lanzhou–Chengdu–Chongqing Product Oil Pipeline Based on Large Eddy Simulation

Water accumulation at the bottom of the product oil pipeline will lead to corrosion damage to the pipeline. The study on water carrying laws of refined oil could provide a reference for the safe operation of the pipeline. In this paper, the actual size of Lanzhou–Jiangyou section of Lanzhou–Chengdu–Chongqing pipeline was taken as the pipeline size. The volume of fluid (VOF) model of oil-water two-phase flow based on large eddy simulation (LES) was established. The numerical simulation of the water-carrying behavior of the product oil in the inclined pipeline was carried out. The LES-based two-phase flow model can capture the characteristics of stratified flow, wavy stratified flow, and dispersed flow under various operating conditions. The model was applied to simulate the water carrying process under various oil inlet velocities and the inclined pipe angles. The results show that as the pipeline inclined angle is 10~20° and the oil inlet velocity is 0.66 m/s, the flow patterns in the pipeline mainly include stratified flow and wavy stratified flow. As the oil inlet velocity is 0.88~1.55 m/s, the flow patterns in the pipe are mainly stratified flow, wavy stratified flow, and dispersed flow. As the inclined angle of the pipeline is 30~40°, the flow patterns in the pipeline mainly include stratified flows, wavy stratified flows, and dispersed flows. Finally, with the increase of flow time, water can be carried completely from the pipeline through the oil. With the increase of oil inlet velocity, the water carrying capacity of oil gradually increases. With the increase of pipeline inclination, the water carrying capacity of oil firstly increases and then decreases.

Pressure Control of High-Pressure Oil Pipe

In this paper, to realize the pressure stability control of high-pressure oil pipe, the dynamic differential equation of fuel oil inlet and outlet is established based on the theory of mass conservation. According to the change of the pressure in the high-pressure tubing, an optimization model is established to achieve precise control of the working time of each part of the high-pressure oil pipe.

Investigation on the characteristics of oil supply system for a hermetic variable speed rotary compressor

Abstract A hermetic variable speed rotary compressor has a substantially vertically oriented drive shaft, by which the oil is driven upwards and delivered to the lubricating components. To avoid oil starvation or excessive oil supply over a wide range of working speed, it is essential to understand the flow characteristics in such a centrifugal oil pump. In this study, a novel test rig has been built to perform the measurements of oil flow rate under various operating conditions. Several key design parameters in relation to the flow rate such as oil inlet diameter, oil viscosity and oil level height in oil sump have been discussed in detail. The results indicate that the oil flow rate increases up to the speed at which the flow stagnation appears and then starts to slightly decrease with the speed. The stagnation speed decreases with the oil inlet diameter but increases with an augment in oil level height. The oil viscosity does not considerably affect the stagnation speed. Based on the simulated results, it is found that the gas region at oil inlet expands and the effective oil flow area reduces when the rotational speed is high enough. Such behavior of oil flow could be one potential explanation to the occurrence of flow rate stagnation.

Numerical study of transient flow dynamics in a core-type transformer windings

The transient hydraulic behaviour in a given pass of a low voltage Core-type power transformer winding was simulated using Computational Fluid Dynamics in order to study and characterize the dynamic response of oil flow to a sinusoidal type perturbation on the oil inlet velocity. Different parameters were tested, namely the oil temperature, the oil inlet velocity and the duration of the sinusoidal perturbation.The dynamic friction factor was calculated as a function of the Reynolds number. For fast perturbations, the discrepancies between the calculated dynamic and the steady-state friction factor are observed only during the short-term period of the perturbation. For smooth and longer perturbations, the system slowly redistributes the oil flow through the radial channels and differences to initial steady-state are not as noticeable. Overall, the curve fit obtained for steady-state conditions is valid for transient conditions. Furthermore, the results show that, in order to develop a new Thermal Hydraulic Network Model (THNM) Dynamic simulator, only the hydraulic resistance needs to be considered.

Numerical simulation of stratified waxy crude oil and water flows across horizontal pipes in the presence of wall heating

In the present work, a 3D numerical study was carried out to investigate the stratified flow of waxy crude oil-water through a horizontal pipe with a contraction-expansion placed in its midsection. Moreover, a uniform heat flux was applied to the pipeline wall to investigate its effect on the overall pressure drop across the pipeline and the two-phase flow pattern. Waxy crude oils are highly viscous fluids, and they exhibit non-Newtonian viscoplastic flow behavior. The governing equations of such non-Newtonian multiphase flows were discretized and solved using the finite volume method on a structured numerical grid. The volume of fluid (VOF) method was utilized to capture the oil-water interface. Waxy crude oil flowed in the laminar regime while a turbulent water flow field was assumed, and it was modeled using the well-known SST k-ω turbulence model. The effect of several parameters, such as heat flux, wax content of the crude oil, and oil inlet velocity, have been studied comprehensively. The results revealed that the overall pressure drop was extremely sensitive to the wax content. Moreover, the simulation results indicated that using a relatively low uniform heat flux can reduce the pressure drop, up to 25%. Finally, it is shown that by increasing oil velocity at the inlet, pressure drop monotonically increased.