scholarly journals Steady-State Flow Characteristics and End Clearance Optimization of Internal Gear Grease Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Xinjian Li ◽  
Lingfeng Tang ◽  
Ming Qian
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Flow Characteristics ◽  
High Viscosity ◽  
Effect Of Temperature ◽  
Working Pressure ◽  
Side Plate ◽  
Clearance Flow ◽  
Fluent Software ◽  
Internal Gear

The internal gear grease pump is a mechanical device used for transfer of high viscosity fluid. The existing clearance between the end faces of the internal or external gear and the floating side plate might cause pump leakage during operation. In order to obtain the optimal end clearance of the internal gear grease pump, the rheological features of the lubricating lithium-based grease for various temperatures are explored via rotating rheometer. Shear force and apparent viscosity are chosen as monitored experimental parameters. The experimental data is fitted to obtain grease rheological features at various temperatures. The end clearance flow field model and the leakage model are established. Fluent software is employed for solving the flow field model and exploring the effect of temperature, end clearance, and speed on grease leakage. Superior grease flow performance is observed with an increase in temperature, which makes it to easier for the grease to leak from the end clearance. With an increase in the end clearance and the working pressure of the pump, an increase in leakage is also observed. Furthermore, it is found that rotational speed also affects the pump leakage. The leakage mechanism is obtained by combining the rheological features of the grease at the end clearance. The mathematical model method is utilized to solve for the optimal value of the end clearance.

In 16V265H Locomotive Diesel Engine Nozzle Flow Field Simulation Analysis

2014 ◽  
Vol 983 ◽  
pp. 368-373
Author(s):  
Shi He Li ◽  
Ming Hai Li ◽  
Xiao Du
Keyword(s):  
Flow Field ◽  
Fuel Injection ◽  
Simulation Analysis ◽  
Flow Characteristics ◽  
Experimental Conditions ◽  
Nozzle Pressure ◽  
Fluent Software ◽  
Level Of Selection ◽  
Distribution Of Flow ◽  
Locomotive Diesel

The investigation of the flow characteristics inside the nozzle becomes more and more important because the flow status in the nozzle and fuel injection significantly influence the emission and economy of diesel engines. Due to limited experimental conditions, we can make use of computer simulation, UG models can be used to predict the flow pattern inside the injectors and promote the level of selection and design of injectors. In this investigation, the UG model is calculated by FLUENT software after considering the compressibility and the viscosity of the fuel. By studying, we can predict the distribution of flow field inside the nozzle, analysis the rationality of the design of nozzle, determine the appropriate boundary conditions, mainly includes the nozzle pressure chamber and the needle tip structure, points out that the improvement direction.

scholarly journals Analysis of Three-Dimensional Flow Field Inside the Pilot Stage of the Deflector Jet Servo Valve

2021 ◽  
Author(s):  
Shuanglu Li ◽  
YaoBao Yin ◽  
JiaYang Yuan ◽  
ShengRong Guo
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Static Characteristics ◽  
Servo Valve ◽  
Free Jet ◽  
Dimensional Flow ◽  
Deflector Jet

Abstract Current two-dimensional flow field model has some defects in describing the pilot stage’s flow field and static characteristics of the deflector jet servo valve(DJSV) because the three-dimensional(3D) jet of the flow field is ignored. In order to overcome the shortcomings, a new flow field model is proposed and the energy transfer process of the pilot stage is obtained. In this model, the flow field is divided into five regions: pressure jet region, free jet region, mixed collision region, secondary jet region and pressure recovery region. Especially, three-dimensional turbulent jet is adopted in the free jet region for the first time to describe the structure of the flow field, and the jet entrainment model is proposed in pressure recovery region to describe the coupling relationship between the pressure in the receiving chamber and the jet flow which has never been considered before. The static characteristics of the pilot stage, such as pressure-flow characteristics, pressure characteristics and flow characteristics are obtained, and the relationship between zero-position valve coefficients and the key structural parameters of the pilot stage is analyzed. The results show that main structural parameters that affect the pressure gain include the length of receiving chamber, the width of guide groove outlet and the width of the wedge; The thickness of jet-pan has the most significant influence on flow gain. The flow field structure and the static characteristics are verified respectively by finite element analysis(FEA) and experimental results, and the results show that the pilot stage mathematical model has good reliability which is beneficial to understand the working mechanism of the pilot stage provide theoretical basis for parameter optimization.

Thermo-flow characteristics and air flow field leading of the air-cooled condenser cell in a power plant

2011 ◽  
Vol 54 (9) ◽  
pp. 2475-2482 ◽  
Author(s):  
WanXi Zhang ◽  
LiJun Yang ◽  
XiaoZe Du ◽  
YongPing Yang
Keyword(s):  
Power Plant ◽  
Flow Field ◽  
Air Flow ◽  
Flow Characteristics

scholarly journals Study on the 3D Hydrodynamic Characteristics and Velocity Uniformity of a Gravity Flow Circular Flume

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 927
Author(s):  
Yi Zhang ◽  
Longxi Han ◽  
Lina Chen ◽  
Chenfang Wang ◽  
Bo Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Environmental Science ◽  
Structural Characteristics ◽  
Longitudinal Velocity ◽  
Flow Characteristics ◽  
Science Research ◽  
Hydrodynamic Characteristics ◽  
Straight Channel ◽  
Uniformity Coefficient ◽  
Annular Flume

Flumes have been widely used in water conservancy science and environmental science research. It is of great significance to obtain the hydrodynamic characteristics and flow field uniformity in the flume. In this study, a new type of annular flume was taken as an example. The 3D flow field was simulated by using a commercial computational fluid dynamics (CFD) code, and was also measured by acoustic doppler velocimeter (ADV) to verify the simulation results. The average relative error range was between 8.37% and 9.95%, the simulated results basically reflected the actual situation of the flow field. On this basis, the structural characteristics of flow field were analyzed. A new calculation method of flow velocity uniformity was presented according to the flow characteristics of natural open channels. The velocity uniformity in the straight channel was calculated and analyzed based on this method, and the influence of speed on the velocity uniformity was further discussed. The length of uniform section was negatively correlated with the rotational speed (average velocity), which was between 39 cm and 101 cm in the straight, and the uniformity coefficient was less than 10%. Finally, the water flow characteristics in the straight channel without wheel were compared with the natural open channel flow. The longitudinal velocity was well fitted with the Prandtl logarithmic distribution formula (R2 > 0.977), and the application feasibility of the flume was analyzed. This study can provide technical support for the development and application of annular flume.

scholarly journals Bathtub Vortex Profile and Flow Field Model with Circulation.

1998 ◽  
Vol 64 (620) ◽  
pp. 972-978 ◽  
Author(s):  
Seigo SAKAI ◽  
Haruki MADARAME ◽  
Koji OKAMOTO
Keyword(s):  
Flow Field ◽  
Field Model ◽  
Bathtub Vortex

Effects of Valve Disc on Flow Characteristics Inside a Swing Check Valve During Opening and Closing Processes

2021 ◽  
Author(s):  
Yi-xiang Xu ◽  
Qiang Ru ◽  
Huai-yu Yao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Flow Field ◽  
Working Conditions ◽  
Power Plants ◽  
Flow Characteristics ◽  
Check Valve ◽  
Opening Angle ◽  
Piping System ◽  
Total Moment ◽  
Valve Disc ◽  
Opening And Closing

Abstract The check valve is one of the most important devices for safety protection of the piping system in thermal and nuclear power plants. As the key component of the check valve, the valve disc accounts for a major effect on the flow characteristics especially during the opening and closing processes. In this paper, a typical swing check valve is taken as the research object. In order to make a comparative study, three working conditions of 30% THA (Turbine Heat Acceptance), 50% THA and 100% THA are selected. Focusing on the effects of valve disc, how does the valve disc motion interact with the flow field around the valve disc is analyzed with the help of the dynamic mesh technology. The results show that under the combined action of fluid force and gravity, the check valve can be opened and closed quickly. During the opening process, the maximum total moment of the disc appears between 45° ∼ 50° opening angle, and during the closing process the maximum total moment occurs when the disc fully closed. The flow field near the valve disc has similar variation rules with the rotation of the valve disc in the three working conditions, and the pressure near the valve disc reaches the maximum value at the moment of opening and closing. This study can provide some suggestions for the further optimal design of similar swing check valve.

scholarly journals Flow Field Investigation in the Exit Region of a Radial Inflow Turbine Using LDV

1994 ◽  
Author(s):  
D. Muthuvel Murugan ◽  
Widen Tabakoff ◽  
Awatef Hamed
Keyword(s):  
Flow Field ◽  
Field Investigation ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Complex Flow ◽  
Tip Clearance Flow ◽  
Exit Region ◽  
Flow Investigation ◽  
Clearance Flow ◽  
Radial Inflow Turbine

Detailed flow investigation in the downstream region of a radial inflow turbine has been performed using a three component Laser Doppler Velocimetry. The flow velocities are measured in the exit region of the turbine at off-design operating conditions. The results are presented as contour and vector plots of mean velocities, flow angles and turbulent stresses. The measured parameters are correlated to the rotor blade rotation to observe any periodic nature of the flow. The measurements reveal a complex flow pattern near the tip region at the rotor exit due to the interaction of the tip clearance flow. The degree of swirl of the flow near the tip region at the rotor exit is observed to be high due to the gross under turning of the flow near the tip region. The effect of the rotor on the exit flow field is observed in the proximity of the rotor exit.

Study on the Gas Distribution Characters of the Outsize CO2 Absorber of the Flue Gas in the Coal-Fired Power Plant

2014 ◽  
Vol 962-965 ◽  
pp. 1476-1479
Author(s):  
Bing Cheng Liu ◽  
Wen Feng Dong ◽  
De Biao Zhou ◽  
Qian Liang ◽  
Qing Ling Li
Keyword(s):  
Flow Field ◽  
Flue Gas ◽  
Annular Flow ◽  
Theoretical Foundation ◽  
Co2 Absorption ◽  
Technological Parameters ◽  
Absorption Column ◽  
Gas Distributor ◽  
Column Wall ◽  
Fluent Software

In the article the flow field in the twin-tangential annular flow gas distributor was simulated based on the standard k-ε turbulent model with FLUENT software according to various distance L between sleeve and column wall and differing numbers of baffles, after comprehensively analyzing, got the best technological parameters with misdistribution factor and pressure drop. Based on the analysis of the flow field discipline of the twin-tangential annular flow gas distributor and the two-line vane gas distributor, and the systematic comparison of the performance of these two kinds of gas distributors in the flue gas CO2 absorption column, the research will provide the important theoretical foundation for the choosing and designing of the distributor of the flue gas CO2 absorber.

scholarly journals Numerical Simulation and Experimental Study on Flow Field in a Swirl Nozzle

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yicheng Sun ◽  
Yufan Fu ◽  
Baohui Chen ◽  
Jiaxing Lu ◽  
Wanquan Deng
Keyword(s):  
Flow Field ◽  
Velocity Distribution ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Low Pressure ◽  
External Flow ◽  
Droplet Velocity ◽  
Inlet Pressure ◽  
Outlet Section ◽  
Local Pressure

In order to study the internal flow characteristics and external droplet velocity distribution characteristics of the swirl nozzle, the following methods were used: numerical simulations were used to study the internal flow characteristics of a swirl nozzle and phase Doppler particle velocimetry was used to determine the corresponding external droplet velocity distribution under medium and low pressure conditions. The distributions of pressure and water velocity inside the nozzle were obtained. Meanwhile, the velocities of droplets outside the nozzle in different sections were discussed. The results show that the flow rate in the swirl nozzle increases with the increase in inlet pressure, and the local pressure in the region decreases because of the excessive velocity at the internal outlet section of the swirl nozzle, resulting in cavitation. The experimental results show that under an external flow field, the minimum droplet velocity occurs in the axial direction; starting from the axis, the velocity first increases and then decreases along the radial direction. Swirling motion inside the nozzle and velocity variations in the external flow field occur under medium and low pressure conditions. The relationship between the inlet pressure and the distributions of water droplets’ velocities was established, which provides a reference for the research and development of the swirl nozzle.

scholarly journals Numerical simulation and experimental research of cavitation nozzle based on equation curve

2021 ◽  
Author(s):  
Lifu Wang ◽  
Dongyan Shi ◽  
Zhixun Yang ◽  
Guangliang Li ◽  
Chunlong Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Field ◽  
High Speed ◽  
Quadratic Equation ◽  
Outer Contour ◽  
Study Results ◽  
Fluent Software ◽  
The Impact ◽  
Better Than

Abstract To further investigate and improve the cleaning ability of the cavitation nozzle, this paper proposes a new model that is based on the Helmholtz nozzle and with the quadratic equation curve as the outer contour of the cavitation chamber. First, the numerical simulation of the flow field in the nozzle chamber was conducted using FLUENT software to analyze and compare the impact of the curve parameters and Reynolds number on the cleaning effect. Next, the flow field was captured by a high-speed camera in order to study the cavitation cycle and evolution process. Then, experiments were performed to compare the cleaning effect of the new nozzle with that of the Helmholtz nozzle. The study results demonstrate that effective cavitation does not occur when the diameter of the cavitation chamber is too large. For the new nozzle, with the increase of the Reynolds number, the degree of cavitation in the chamber first increases and then decreases; the cleaning effect is much better than that of a traditional Helmholtz nozzle under the same conditions; the nozzle has the best cleaning effect for the stand-off distance of 300 mm.

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