scholarly journals Study of Circulation Drive in High-Speed Rotating Flow Field

2018 ◽  
Vol 186 ◽  
pp. 01001
Author(s):  
Xu Fan ◽  
Bo Ran
Keyword(s):  
Flow Field ◽  
Numerical Computation ◽  
High Speed ◽  
Influence Factors ◽  
Internal Flow ◽  
Rotating Flow ◽  
Factors Affecting ◽  
Cause Of Formation

In the rotor with high speed, there is a certain axial circulation in the internal gas, which is necessary to analyze the cause of formation and influence factors for understanding better the internal flow field. There are many factors affecting the axial circulation. Different circulation drives have different effects on the flow field. In this paper, numerical computation with N-S equations is used to compute the flow field parameters and analyze the mechanism of the flow field. The influence of the temperature of the end cap on the flow field is mainly disscussed. By comparing and analyzing the streamline shape and the size of vortex region under different temperature drive, an effective method is provided for the study of axial circulation in the highspeed rotating flow field.

scholarly journals Analysis and control of flow at suction connection in high-speed centrifugal pump

2017 ◽  
Vol 9 (1) ◽  
pp. 168781401668529 ◽  
Author(s):  
Wen-wu Song ◽  
Li-chao Wei ◽  
Jie Fu ◽  
Jian-wei Shi ◽  
Xiu-xin Yang ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
High Speed ◽  
Internal Flow ◽  
Orifice Plate ◽  
Centrifugal Pumps ◽  
Pressure Area ◽  
Negative Effect ◽  
And Control ◽  
Experimental Data Analysis

The backflow vortexes at the suction connection in high-speed centrifugal pumps have negative effect on the flow field. Setting an orifice plate in front of the inducer is able to decrease the negative effect caused by backflow vortexes. The traditional plate is able to partially control the backflow vortexes, but a small part of the vortex is still in the inlet and the inducer. Four new types of orifice plates were created, and the control effects on backflow vortexes were analyzed. The ANSYS-CFX software was used to numerically simulate a high-speed centrifugal pump. The variations of streamline and velocity vectors at the suction connection were analyzed. Meanwhile, the effects of these plates on the impeller pressure and the internal flow field of the inducer were analyzed. Numerically, simulation and experimental data analysis methods were used to compare the head and efficiency of the high-speed pumps. The results show that the C-type orifice plate can improve the backflow vortex, reduce the low-pressure area, and improve the hydraulic performance of the high-speed pump.

Analysis of the Behavior of Droplet Impinging on a Curved Dry Wall in a Rotating Flow Field

2020 ◽  
Author(s):  
Shuo Ouyang ◽  
Zhenqin Xiong
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Nuclear Power ◽  
Rotating Flow ◽  
Droplet Deformation ◽  
Wind Speeds ◽  
Boundary Information ◽  
Different Diameters ◽  
The Impact ◽  
Steam Separator

Abstract Steam water separator is the core equipment of nuclear power plant. It is very vital for improving the efficiency of the steam separator to study the impact characteristics between the droplets and the curved dry wall of the steam separator under the action of the rotating air flow. In this paper, the characteristics of droplet impinging on the dry wall in the rotating flow field are analyzed by establishing a visualization experimental device. A high-speed camera was used to capture the impact of droplets with different diameters on the dry wall of a non-wetting curved surface at different gas velocities. At the same time, using image processing tool in MATLAB to obtain image boundary information. The characteristics of spreading factor, droplet deformation factor and initial diffusion velocity of droplets impacting the surface dry wall under different wind speeds are studied.

Study on the Turbulent Injury Principle of Blood in the High-Speed Spiral Blood Pump

2011 ◽  
Vol 393-395 ◽  
pp. 992-995
Author(s):  
Zhong Yun ◽  
Chuang Xiang ◽  
Xiao Yan Tang ◽  
Fen Shi
Keyword(s):  
Shear Stress ◽  
Flow Field ◽  
Blood Cell ◽  
Turbulent Flow ◽  
Red Blood Cell ◽  
Blood Cells ◽  
High Speed ◽  
Internal Flow ◽  
Blood Pump ◽  
Turbulent Flow Field

The strongly swirling turbulent flow in the internal flow field of a high-speed spiral blood pump(HSBP), is one of important factors leading to the fragmentation of the red blood cell(RBC) and the hemolysis. The study on the turbulent injure principle of blood in the HSBP is carried out by using the theory of waterpower rotated flow field and the hemorheology. The numerical equation of the strongly swirling turbulent flow field is proposed. The largest stable diameter of red blood cells in the turbulent flow field is analyzed. The determinant gist on the red blood cell turbulent fragmentation is obtained. The results indicate that in the HSMP, when turbulent flow is more powerful, shear stress is weaker, the vortex mass with energy in flow field may cause serious turbulent fragmentation because of the diameter which is smaller than the RBC’s. The RBC’s turbulent breakage will occur when the Weber value is larger than 12.

Detailed Flow Investigations Within a High-Speed Centrifugal Compressor Impeller

1976 ◽  
Vol 98 (3) ◽  
pp. 390-399 ◽  
Author(s):  
D. Eckardt
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
High Speed ◽  
Internal Flow ◽  
Suction Side ◽  
Turbulence Structure ◽  
Wake Interaction ◽  
Compressor Impeller ◽  
Channel Curvature ◽  
Relative Flow

Detailed accurate measurements of velocities, directions, and fluctuation intensities were performed with a newly developed laser velocimeter in the internal flow field of a radial discharge impeller, running at tip speeds up to 400 m/s. Relative flow distributions are presented in five measurement areas from inducer inlet to impeller discharge. The impeller flow pattern, which coincides largely with potential-theory calculations in the axial inducer, becomes more and more reversed when the flow separates from the blade suction side, developing a rapidly increasing wake in the radial impeller. The observed secondary flow pattern and effects of channel curvature and system rotation on turbulence structure are discussed with respect to separation onset and jet/wake interaction.

Numerical Simulation of the Flow in a Large-Scale Thrust Bearing

2010 ◽  
Author(s):  
Hong-Jie Wang ◽  
Ru-Zhi Gong ◽  
De-Ping Lu ◽  
Zhong-De Wu ◽  
Feng-Chen Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Large Scale ◽  
Thrust Bearing ◽  
Cfd Simulation ◽  
Internal Flow ◽  
Heat Radiation ◽  
Heavy Load ◽  
Cfd Method ◽  
Water Turbines

Thrust bearing is a key component of large-scale water turbine. It closely relates to the efficiency of large-scale water turbines, and even determines whether the large-scale turbine can operate normally. With the development of the capacitance of water turbines, thrust bearing will develop to the direction of high speed and heavy load. The structure, strength, lubrication and the characteristic of heat radiation of large-scale thrust bearing were often researched in the past. To study the flow condition of the large-scale thrust bearing and analyze the load characteristics, CFD simulation was carried out on the model of thrust bearing. In this study, CFD method was used to simulate the internal flow field of the large-scale thrust bearing. The model researched was a thrust bearing for 1000MW water turbines. The diameter of the thrust bearing was over 5.8 meters, and the maximum thrust load of the bearing can reach to 60MN. The thin gap between the runner and the pad was usually neglected in the published CFD calculations of thrust bearing. But the thin gap was taken into account in this investigation. 1/12 of the model was used as the computational field and periodic boundary was used in the calculation. The standard κ-ε turbulence model was used to simulate the thrust bearing model, and the flow field in the thrust bearing was obtained. The thin gap between the runner and the pad is a wedge. The pressure and velocity distribution in the thrust bearing and thin gap was calculated respectively with conditions of different thin gaps and different rotational speeds of runner. After that, the relationship between carrying capacity and the size of clearance or the speed of the runner through analyzing the data has been obtained from the results of the calculation.

Numerical Analysis of Internal Flow Field in an Impeller with the Time Marching Method

2011 ◽  
Vol 94-96 ◽  
pp. 1476-1480
Author(s):  
Cai Hua Wang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Internal Flow ◽  
Centrifugal Impeller ◽  
Three Dimensional Flow ◽  
Vector Distribution ◽  
Time Marching ◽  
Marching Method

Centrifugal compressors are power machineries used widely. Fully understanding of the complex three-dimensional flow field is very important to design higher pressure ratio, higher efficiency centrifugal compressor. In this paper, time marching method is adopted to solve the three-dimensional viscous N-S equations under the relative coordinate system. The internal flow field of the “full controllable vortex” high speed centrifugal impeller is analyzed and the medial velocity vector distribution and the development of the velocity of each section in the impeller are showed. From the figures, it can be seen that the “wake” phenomenon, such as Ecckart described, caused by the curvature, Coriolis force and the boundary layer is exist

Aerodynamic Characterisation of Ramjet Missile through Combined External-internal Computational Fluid Dynamics Simulation

2016 ◽  
Vol 66 (6) ◽  
pp. 624 ◽  
Author(s):  
Anand Bhandarkar ◽  
Souraseni Basu ◽  
P. Manna ◽  
Debasis Chakraborty
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Internal Flow ◽  
Dynamics Simulation ◽  
Navier Stokes ◽  
Navier Stokes Equations

<p>Combined external-internal flow simulation is required for the estimation of aerodynamic forces and moments of high speed air-breathing vehicle design. A wingless, X-tail configuration with asymmetrically placed rectangular air intake is numerically explored for which experimental data is available for different angles of attack. The asymmetrically placed air intakes and protrusions make the flow field highly three-dimensional and existing empirical relations are inadequate for preliminary design. Three dimensional Navier Stokes equations along with SST-kω turbulence model were solved with a commercial CFD solver to analyse the combined external and internal flow field of the configuration at different angles of attack. Estimated aerodynamic coefficients match well with experimental data and estimated drag coefficient are within 8.5 per cent of experimental data. Intake performance parameters were also evaluated for different angles of attack.</p>

Performance improvement of a high-speed aero-fuel centrifugal pump through active inlet injector

2020 ◽  
pp. 095441002096096
Author(s):  
Jia Li ◽  
Xin Wang ◽  
Wancheng Wang ◽  
Yue Wang
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Turbulence Model ◽  
High Speed ◽  
Flow Direction ◽  
Active Flow Control ◽  
Turbulence Models ◽  
Internal Flow ◽  
Geometrical Parameters ◽  
Centrifugal Pumps

This paper presents a high-speed aero-fuel centrifugal pump with an active inlet injector for an aero-engine aiming at regulating the internal flow field and improving overall hydraulic performance. Unlike most of the existing centrifugal pumps for aero-engines, an injector is designed and integrated with the pump to accomplish the active flow control. Firstly, by employing the energy equation in the pump, reasonable geometrical parameters of the injector are calculated. Then, a validation study is conducted with three known turbulence models, showing that simulations with the RNG κ- ε turbulence model can accurately predict the head and efficiency of the experimental pump. Finally, simulation results with the determined turbulence model are discussed. The results show that the static pressure is uniformly distributed inside the impeller, the volute and the injector. The flow field is significantly ameliorated by improving the pressure inside the suction pipe and controlling the flow direction via the injector. Furthermore, the head and efficiency of the designed pump with an active inlet injector are improved compared to the one without an injector.

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