Effect of hydrodynamic impact and cavitation on oil flow characteristics

2019 ◽  
pp. 46-50
Author(s):  
V.N. Petrov ◽  
◽  
F.M. Galimov ◽  
L.A. Akhmetzyanova ◽  
S.V. Petrov ◽  
...  
Keyword(s):  
Flow Characteristics ◽  
Hydrodynamic Impact ◽  
Oil Flow

scholarly journals THREE DIMENSIONAL SIMULATION OF OIL FLOW CHARACTERISTICS IN LUBRICATION SYSTEM OF ROTARY TILLAGE ENGINE

2021 ◽  
pp. 163-172
Author(s):  
Junxiang Gao ◽  
Xiaoliang Gao ◽  
Wei Zou
Keyword(s):  
Pressure Drop ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Lubricating Oil ◽  
Flow Index ◽  
Lubrication System ◽  
Pump Rotor ◽  
Oil Pump ◽  
Oil Flow ◽  
Dimensional Simulation

Taking the lubrication system of rotary tillage engine as the research object, this paper makes a three-dimensional simulation study on the oil flow characteristics in the lubricating oil passage. The oil supply of the oil pump shall be greater than the circulating oil required by the lubrication system to ensure the lubrication of the rotary cultivator. Lubrication system is an important part to ensure the reliability and durability of rotary cultivator. The key component to achieve its performance is the oil pump. The geometric model of lubricating oil flow field in rotary tiller lubrication system is established by using FLUENT software. The results show that the pressure drop in the lubricating oil passage of the main bearing is the largest under the same working conditions. In the oil passage of the cylinder head, the pressure drop of the front main oil passage is the largest and the oil discharge is the largest. Add 1.6mm oil pump rotor on the basis of the thickness of the original oil pump rotor, the oil flow at the connecting rod nozzle reaches the flow index of the original rotary cultivator, and there is no cylinder pulling phenomenon of the rotary cultivator.

Effects of Core Flow Swirl on the Flow Characteristics of a Scalloped Forced Mixer

2011 ◽  
Author(s):  
Zhijun Lei ◽  
Ali Mahallati ◽  
Mark Cunningham ◽  
Patrick Germain
Keyword(s):  
Pressure Ratio ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Pressure Probe ◽  
Streamwise Vortices ◽  
Core Flow ◽  
The Core ◽  
Flow Swirl ◽  
Swirl Angle ◽  
Oil Flow

This paper presents a detailed experimental investigation of the influence of core flow swirl on the mixing and performance of a scaled turbofan mixer with 12 scalloped lobes. Measurements were made downstream of the mixer in a co-annular wind tunnel. The core-to-bypass velocity ratio was set to 2:1, temperature ratio to 1.0, and pressure ratio to 1.03, giving a Reynolds number of 5.2 × 105, based on the core flow velocity and equivalent hydraulic diameter. In the core flow, the background turbulence intensity was raised to 5% and the swirl angle was varied using five vane geometries from 0° to 30°. Seven-hole pressure probe measurements and surface oil flow visualization were used to describe the flowfield and the mixer performance. At low swirl angles, additional streamwise vortices were generated by the deformation of normal vortices due to the scalloped lobes. With increased core swirl, greater than 10°, the additional streamwise vortices were generated mainly due to radial velocity deflection, rather than stretching and deformation of normal vortices. At high swirl angles, stronger streamwise vortices and rapid interaction between various vortices promoted downstream mixing. Mixing was enhanced with minimal or no total pressure and thrust losses for the inlet swirl angles less than 10°. However, the reversed flow downstream of the center-body was a dominant contributor to the loss of thrust at the maximum core flow swirl angle of 30°.

Comparison of Turbine Tip Leakage Flow for Flat Tip and Squealer Tip Geometries at High-Speed Conditions

2004 ◽  
Vol 128 (2) ◽  
pp. 213-220 ◽  
Author(s):  
Nicole L. Key ◽  
Tony Arts
Keyword(s):  
Reynolds Number ◽  
High Speed ◽  
Flow Characteristics ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Cascade Arrangement ◽  
Oil Flow ◽  
Blade Tip ◽  
Tip Velocity

The tip leakage flow characteristics for flat and squealer turbine tip geometries are studied in the von Karman Institute Isentropic Light Piston Compression Tube facility, CT-2, at different Reynolds and Mach number conditions for a fixed value of the tip gap in a nonrotating, linear cascade arrangement. To the best knowledge of the authors, these are among the very few high-speed tip flow data for the flat tip and squealer tip geometries. Oil flow visualizations and static pressure measurements on the blade tip, blade surface, and corresponding endwall provide insight to the structure of the two different tip flows. Aerodynamic losses are measured for the different tip arrangements, also. The squealer tip provides a significant decrease in velocity through the tip gap with respect to the flat tip blade. For the flat tip, an increase in Reynolds number causes an increase in tip velocity levels, but the squealer tip is relatively insensitive to changes in Reynolds number.

Hydraulic Spool Valve Metering Notch Characterization Using CFD

2003 ◽  
Author(s):  
Roger Yang
Keyword(s):  
Flow Characteristics ◽  
Post Processing ◽  
Hydraulic Oil ◽  
Simulation Procedure ◽  
Discharge Coefficients ◽  
Oil Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Spool Valves ◽  
Spool Valve ◽  
Mode A

This paper presents some results from an attempt to characterize hydraulic oil flow inside spool valves with different spool metering notches using Computational Fluid Dynamics (CFD). Hydraulic spool valve oil flow under different conditions has been simulated using a commercially available CFD software program. The fluid flow is assumed steady-state, incompressible, isothermal and normally in a turbulent mode. A complete simulation procedure is presented from parametric geometry creation with a 3-D solid CAD program through final post-processing of CFD results. Main focus of this study is to explore the effects of geometric parameters of notches on important hydraulic oil flow characteristics, such as flow force and discharge coefficients. Formulas, intended for predicting such flow forces and discharge coefficients at different stage of spool notch openings, have been generalized and summarized under certain conditions based on a CFD result database from groups of same types of notches. Results comparison to experimental data is also presented.

Film Flow Characteristics of Droplet Cooling in a Simplified Bearing Chamber

2013 ◽  
Author(s):  
E. D. Kay ◽  
H. Power ◽  
S. Hibberd
Keyword(s):  
Gas Turbines ◽  
Flow Characteristics ◽  
Temperature History ◽  
Design Parameters ◽  
Flow Conditions ◽  
Internal Surfaces ◽  
Aero Engine ◽  
Oil Flow ◽  
Oil Films ◽  
Engine Bearing

Droplet-cooled oil films develop on the internal surfaces of an aero-engine bearing chamber and are a primary mechanism in removing heat from the chamber as oil is continuously collected and externally cooled and recycled. Predicting the internal oil temperature and oil temperature history is an important thermal problem which becomes more apparent with potential increases in operating temperatures of gas turbines. Studying interacting oil flow and thermal processes within a simplified bearing chamber geometry provides useful information on the trends and characteristics which can arise under different applied flow conditions (e.g. mass flow rate of oil through the system) and insight to the effect chamber design parameters may have on oil degradation and cooling of chamber walls. Thin oil films develop on the walls of a bearing chamber as oil is injected or shed from bearings and impinges on the walls under a strong airflow set in motion by rotating components. Typically the film is also subject to a heat flux from the hot chamber walls and the droplets provide an important cooling effect through “heat-to-oil” mechanisms. We present a mathematical model for the depth-averaged flow and associated heat transfer by thin oil films on the walls of a simplified aero-engine bearing chamber. Cases corresponding to generic flow conditions relevant to an aero-engine bearing chamber are presented. Characteristics of the film and the efficacy of the flow regime to transfer heat from the chamber is explored through calculating residence times and time histories of oil particles as they make a transit of the internal system.

The Flow Dynamics of an Air-Driven Hydraulic Pump

2015 ◽  
Author(s):  
Yan Shi ◽  
Tiecheng Wu ◽  
Andrew R. Plummer ◽  
Maolin Cai
Keyword(s):  
Volume Flow Rate ◽  
Flow Characteristics ◽  
Area Ratio ◽  
Air Pressure ◽  
Hydraulic Systems ◽  
Hydraulic Pump ◽  
Oil Flow ◽  
System Input ◽  
Output Characteristics ◽  
Set Up

Air-driven hydraulic pumps are widely used to pump high-pressure oil for small hydraulic systems, where it is uneconomic to set up a conventional hydraulic power pack. To obtain good performance of a small hydraulic system, input air flow and output oil flow characteristics of the air-driven hydraulic pump should be properly understood. In this paper, based on a mathematical model which has been experimentally verified, the model of an air-driven hydraulic pump is proposed. Using the software MATLAB/Simulink for simulation, the dynamic characteristics of the pumps are obtained. To set a foundation for the optimization of the pump, the influence of key parameters on the output characteristics of the pump was studied. Through analysis, it can be obtained that, firstly, with an increase in the input air pressure, output oil pressure and area ratio, the ratio of output to input volume flow rate decrease approximately linearly. Moreover, when the output oil pressure was fixed, an energy-saving method to enhance the output oil flow is to enlarge the area ratio of the pump. Furthermore, the output oil flow can be increased rapidly through increasing the input air pressure, but that may result in an increase in compressed air consumption. This research is of use in the performance and design optimization of air-driven hydraulic pumps.

scholarly journals Heat and mass transfer of oils in baffled and finned ducts

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 267-276
Author(s):  
Younes Menni ◽  
Houari Ameur ◽  
Ali Chamkha ◽  
Mustafa Inc ◽  
Bandar Almohsen
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Turbulent Regime ◽  
Model Case ◽  
Transfer Rates ◽  
Oil Flow ◽  
High Reynolds ◽  
Function Number ◽  
Volume Method ◽  
Calculation Software

This analysis intends to simulate the forced-convection and oil flow characteristics in the turbulent regime (Re = 5000-25000) through rectangular-shaped ducts with staggered, transverse, solid, and flat baffle plates. The study is achieved by using a calculation software based on the finite volume method (FLUENT) with selected SIMPLE, Quick, and k-? model. Two various models of baffled ducts are simulated in this analysis under steady flow conditions. In the first model (Case A), a duct with one upper fin and two lower baffles is examined. However and in the second model (Case B), a duct with two upper fins and one lower baffle is treated. The con?tour plots of stream-function, number of Nusselt, and coefficient of skin friction are addressed. As expected, the heat transfer rates raised in the second case (Case B), due to the presence of the lower second obstacle that directs the entire oil current towards the hot upper part of the second duct at very high velocities, resulting thus in enhanced heat transfer rates, especially in the case of high Reynolds number values.

scholarly journals Heat and mass transfer of oils in baffled and finned ducts

2020 ◽  
Vol 24 (Suppl. 1) ◽  
pp. 267-276
Author(s):  
Younes Menni ◽  
Houari Ameur ◽  
Ali Chamkha ◽  
Mustafa Inc ◽  
Bandar Almohsen
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Turbulent Regime ◽  
Model Case ◽  
Transfer Rates ◽  
Oil Flow ◽  
High Reynolds ◽  
Function Number ◽  
Volume Method ◽  
Calculation Software

This analysis intends to simulate the forced-convection and oil flow characteristics in the turbulent regime (Re = 5000-25000) through rectangular-shaped ducts with staggered, transverse, solid, and flat baffle plates. The study is achieved by using a calculation software based on the finite volume method (FLUENT) with selected SIMPLE, Quick, and k-? model. Two various models of baffled ducts are simulated in this analysis under steady flow conditions. In the first model (Case A), a duct with one upper fin and two lower baffles is examined. However and in the second model (Case B), a duct with two upper fins and one lower baffle is treated. The con?tour plots of stream-function, number of Nusselt, and coefficient of skin friction are addressed. As expected, the heat transfer rates raised in the second case (Case B), due to the presence of the lower second obstacle that directs the entire oil current towards the hot upper part of the second duct at very high velocities, resulting thus in enhanced heat transfer rates, especially in the case of high Reynolds number values.

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