Conservation Low of Centrifugal Force and Its Application to Fluid Flow in Turbomachinery

2006 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Fluid Flow ◽  
Centrifugal Force ◽  
Rotational Motion ◽  
Constant Angular Velocity ◽  
Axis Of Rotation ◽  
Impeller Outlet ◽  
Pump Head ◽  
Rotational Motions ◽  
The Difference ◽  
Circular Line

Theoretical pump head is discussed and the conservation low is introduced on Centrifugal force. Theoretical head obtained by the application of conservation law on fluid flow in rotating flow passage is formed as the difference between the head obtained at the impeller outlet and that at impeller inlet. Conservation low of Centrifugal force due to fluid particles rotational motion at constant angular velocity says that the magnitude of Centrifugal force caused by the rotational motion along the outside circular line is constructed from those caused by the rotational motions along two different kinds circular lines. One is that caused by the rotational motion along the inside circular line whose rotational center locates at the axis of rotation. And the other is that caused by the rotational motion along the circular line whose circular line touches internally with the outer circular line and locates its rotational center on the inside circular line.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Vol 127 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a ringlike wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions, namely, one with and one without this ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a Ring-like wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions — namely, one with and one without this Ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back-flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

Fluid Particle’s Rotational Speed at the Trailing Edge of Impeller Outlet of Centrifugal Pump

2003 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Force ◽  
Flow Rate ◽  
Mechanical Energy ◽  
Fluid Particle ◽  
Rotating Flow ◽  
Centripetal Force ◽  
Impeller Blade ◽  
Flow Passage ◽  
Impeller Outlet ◽  
Pump Head

Mechanical force caused by mechanical energy acts real and imaginary forces on impeller blade. Therefore, impeller blade moves in the direction of real force, straightly forward in the direction of tangent perpendicular to rotational radius and the direction of imaginary force, circularly forward in the direction of tangent perpendicular to rotational radius. Former real movement causes on fluid particle radial outward movement, resulting to flow rate Q. Latter imaginary movement causes on fluid particle a rotational motion under the external centripetal and imaginary centrifugal force, resulting to pump head. Pump head is equivalent to external centripetal force and balanced with imaginary centrifugal force in the rotating flow passage.

Fluid Particles Straightly Forward and Circularly Forward Movements in the Direction of Tangent at Trailing Edge of Impeller Outlet in Centrifugal Turbomachinery

2003 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Force ◽  
Flow Rate ◽  
Rotational Motion ◽  
Mechanical Energy ◽  
Centripetal Force ◽  
Impeller Outlet ◽  
Water Turbine ◽  
Fluid Particles ◽  
Centripetal Forces ◽  
Acting Force

Flow rate, which is caused in the direction radial outward in pump and radial inward in water turbine, is caused by the fluid particles straightly forward tangential movement in the direction of acting force perpendicular to impeller blades rotational radius. Impeller blades rotational motion is caused under the radial balance of centrifugal and centripetal forces. Centrifugal force is caused by the transferred energy from mechanical to hydraulic energy in pump and from hydraulic to mechanical energy in water turbine. Centripetal force is equivalent to discharge head in pump and equivalent to suction head in water turbine.

Experiments and mechanistic modeling of viscosity effect on a multistage ESP performance under viscous fluid flow

2021 ◽  
pp. 095765092110149
Author(s):  
Yi Shi ◽  
Jianjun Zhu ◽  
Haoyu Wang ◽  
Haiwen Zhu ◽  
Jiecheng Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Viscous Fluid ◽  
Prediction Error ◽  
Flow Direction ◽  
Fluid Viscosity ◽  
Oil Viscosity ◽  
Viscous Fluid Flow ◽  
Viscosity Effect ◽  
High Production Rate ◽  
Pump Head

Assembled in series with multistage, Electrical Submersible Pumps (ESP) are widely used in offshore petroleum production due to the high production rate and efficiency. The hydraulic performance of ESPs is subjected to the fluid viscosity. High oil viscosity leads to the degradation of ESP boosting pressure compared to the catalog curves under water flow. In this paper, the influence of fluid viscosity on the performance of a 14-stage radial-type ESP under varying operational conditions, e.g. rotational speeds 1800–3500 r/min, viscosities 25–520 cP, was investigated. Numerical simulations were conducted on the same ESP model using a commercial Computational Fluid Dynamics (CFD) software. The simulated average pump head is comparable to the corresponding experimental data under different viscosities and rotational speeds with less than ±20% prediction error. A mechanistic model accounting for the viscosity effect on ESP boosting pressure is proposed based on the Euler head in a centrifugal pump. A conceptual best-match flowrate QBM is introduced, at which the impeller outlet flow direction matches the designed flow direction. The recirculation losses caused by the mismatch of velocity triangles and other head losses resulted from the flow direction change, friction loss and leakage flow etc., are included in the model. The comparison of model predicted pump head versus experimental measurements under viscous fluid flow conditions demonstrates good agreement. The overall prediction error is less than ±10%.

scholarly journals Study of internal corrosion on the turning angles in steel pipes

2021 ◽  
Vol 225 ◽  
pp. 01004
Author(s):  
Bauyrzhan Manapbayev ◽  
Bazartai Alimbayev ◽  
Erkegali Amanbayev ◽  
Arman Kabdushev ◽  
Zhangazy Moldamuratov
Keyword(s):  
Fluid Flow ◽  
Centrifugal Force ◽  
Average Rate ◽  
Internal Corrosion ◽  
Steel Pipes ◽  
Corrosion Propagation

Corrosive damages can lead to accidents on pipelines in various industries. Therefore, the main objective of the work is to study the peculiarities of propagation of internal corrosion on turning angles in steel pipes. The paper substantiates the primary importance of the propagation of corrosion on turning angles in steel pipes. It has been identified that in curvilinear areas, the rate of corrosion propagation depends on the rate of fluid flow, on the number of ions, and also on the effect of centrifugal force. The authors studied the average rate of corrosion propagation on the turns in steel pipes. Thus, the results obtained showed that the location of steel pipes affect the rate of corrosion propagation inside the pipes.

IMPORTANCE OF 3D VEHICLE HEAT EXCHANGER MODELING

2021 ◽  
pp. 1-10
Author(s):  
Michal Schmid ◽  
Fatih Bozkurt ◽  
Petr Pašcenko ◽  
Pavel Petržela
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Coolant Temperature ◽  
Inlet Temperature ◽  
Vehicle Simulation ◽  
Velocity Magnitude ◽  
Primary Fluid ◽  
The Difference ◽  
Inlet Conditions

Abstract The work demonstrates, via a comprehensive study, the necessity of using a 3D CFD approach for heat exchanger (HTX) modelling within underhood vehicle simulation. The results are presented as the difference between 1D and 3D CFD approaches with a focus on auxiliary fluid (e.g. coolant) temperature prediction as a function of primary fluid (e.g. air) inlet conditions. It has been shown that the 1D approach could significantly underpredict auxiliary fluid inlet temperature due to neglecting the spatial distribution of primary fluid velocity magnitude. The resultant difference in the auxiliary fluid flow HTX inlet temperature is presented and discussed as a function of the Uniformity Index (UI) of the primary fluid flow velocity magnitude. Additionally, the 3D HTX model's importance is demonstrated in an industrial example of full 3D underhood simulation.

Interrelation Between Fluid Particles Rotational Motion in Rotating Flow Passage of Centrifugal Pump and Overall Efficiency

Volume 3 ◽  
2004 ◽  
Author(s):  
Takaharu Tanaka ◽  
Chao Liu
Keyword(s):  
Centrifugal Pump ◽  
Rotational Motion ◽  
Rotating Flow ◽  
Energy Losses ◽  
Trailing Edge ◽  
Flow Passage ◽  
Impeller Outlet ◽  
Overall Efficiency ◽  
Fluid Particles ◽  
The Way

Main purpose of investigation has been put on the hydraulic energy losses caused in the rotating flow passage of centrifugal pump. Result of discussion shows that fundamental poor efficiency is brought by the fluid particles poor rotational motion at the trailing edge of impeller outlet, including the rotational motion caused in the flow passage between impeller blades rather than the hydraulic energy losses caused in the rotating flow passage. Therefore, our main purpose of investigation has to be put on the way rather to the fluid particles rotational motion caused at the trailing edge of impeller outlet and that caused between impeller blades.

ANALISIS NILAI HAMBATAN TOTAL DENGAN PERUBAHAN SARAT KAPAL KM. KENDHAGA NUSANTARA 6

2020 ◽  
Vol 21 (1) ◽  
pp. 21-25
Author(s):  
Budi Utomo ◽  
Sulaiman Sulaiman
Keyword(s):  
Fluid Flow ◽  
Experimental Method ◽  
Calculation Method ◽  
Loading Condition ◽  
Total Resistance ◽  
Ship Resistance ◽  
The Difference ◽  
Resistance Value

The calculation of total resistance value is important of ship because  affects the speed of fluid flow that occurs, as well as the speed of the ship.So that in the designing new ships, sea trials are needed to find out whatever the preparedness of the ship is planned. The purpose is to obtain the value of the total resistance and the coefficient of ship resistance KM. Kendhaga Nusantara 6 uses the calculation method for each ship draught/loading condition. The Method used is experimental method with numerical value approach, Denny Mumford theory and Froude's number. The results show that the largest Total Resistance (Rt) is 5646,02 kN, it was found when speed of ship was 12 knots and draught ship 3,5 meters, with a coefficient value (Ct) of 7,757 x 10-3. The difference in value (Ct) is 0,032x10-3 or 0.41%, and it is still in the criteria because it is below 5%.

Studies on Micropump/Minipump Using Rotational Motion of Magnetic Material Balls

2013 ◽  
Author(s):  
Hiroshige Kumamaru ◽  
Fuma Sakata ◽  
Akira Ohue ◽  
Kazuhiro Itoh ◽  
Yuji Shimogonya
Keyword(s):  
Magnetic Material ◽  
Flow Rate ◽  
Cross Sections ◽  
Rotational Motion ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Numerical Analyses ◽  
Closed Channel ◽  
Pump Head ◽  
Inner Diameter

Experiments and numerical analyses have been performed on micropumps/minipumps using rotational motion of magnetic material balls. In the pumps, magnetic material balls and nonmagnetic materials balls rotate in a closed channel loop, and a part of the balls acts as a piston and the remaining part of the balls serves as a valve. Experiments have been carried out on two pumps, i.e. a smaller pump and a larger pump with channel cross-sections of ∼1 mm and ∼2 mm inner diameter, respectively. The maximum flow rate achieved and the maximum pump head obtained are ∼500 μl/min and ∼70 Pa, respectively, for the smaller pump, and ∼2000 μl/min and ∼150 Pa, respectively, for the larger pump. Numerical analyses have been performed by dividing the pumping loop into a piston channel and a valve channel. The numerical analyses overestimate the flow rate obtained in the experiments, except for the region of larger pump heads in the larger pump.

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