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.

Interrelation Between Mechanical Energy Supply and Flow Rate in Practical Operation of Centrifugal Pump

2004 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Energy Supply ◽  
Mechanical Energy ◽  
Rotating Flow ◽  
Centripetal Force ◽  
Impeller Blade ◽  
Flow Passage ◽  
Practical Operation ◽  
Pump Head ◽  
Fluid Particles ◽  
Remaining Time

Pump head plays an external centripetal force and balanced with imaginary centrifugal force. Fluid particles circularly forward tangential movement in the direction tangent increases with the fluid particles remaining time increase in the rotating flow passage. And fluid particles circularly forward tangential movement in the direction tangent is caused by the imaginary mechanical force perpendicular to rotational radius. Therefore, mechanical energy supply is proportional to fluid particles remaining time in the rotating flow passage of impeller blade to cause the circularly forward tangential movement.

A Consideration on Energy Transfer Mechanism Caused Between Impeller Blade and a Fluid Particle in Centrifugal Pump

2002 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Pump ◽  
Centrifugal Force ◽  
Flow Rate ◽  
Fluid Particle ◽  
Rotating Flow ◽  
Energy Transfer Mechanism ◽  
Forward Movement ◽  
Impeller Blade ◽  
Impeller Outlet ◽  
Centripetal Forces

Impeller blade’s rotational motion causes centrifugal force on fluid particle. It directs radial outward. However, the flow rate, that is, radial outward flow is not caused by centrifugal force in centrifugal pump. Tangential forward force, which is in the direction perpendicular to rotational radius, causes tangential forward movement on fluid particle under the radial balance of centrifugal and centripetal forces in the rotating flow passage of centrifugal pump and it causes the flow rate. And the head is caused by centrifugal force and equivalent to centripetal force, which acts on fluid particle radial inward. Which is equivalent to external force at the trailing edge of impeller outlet.

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.

An Investigation on Velocity Triangle Applied to Fluid Particle at Rotating Flow Passage of Impeller Blade in Centrifugal Pump

Volume 1 ◽  
2004 ◽  
Author(s):  
Takaharu Tanaka ◽  
Chao Liu
Keyword(s):  
Flow Rate ◽  
Tangential Velocity ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Rotating Flow ◽  
Impeller Blade ◽  
Flow Passage ◽  
Rotating Speed ◽  
Velocity Triangle ◽  
Fluid Particles

Although impeller blades rotational speed is kept constant for the change in flow rate, fluid particles rotating speed varies by the flow rate. Fluid particles circularly forward tangential velocity becomes zero at the maximum flow rate and the maximum at the flow rate zero. While fluid particles fundamental straightly forward tangential velocity normal to rotational radius becomes the maximum at the maximum flow rate and zero at flow rate zero.

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.

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.

scholarly journals Analysis on Centrifugal Pump Performance in Single, Serial, and Parallel

2018 ◽  
Vol 3 (2) ◽  
pp. 79
Author(s):  
Faisal Ansori ◽  
Edi Widodo
Keyword(s):  
Flow Velocity ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Mechanical Energy ◽  
Unit Weight ◽  
Centrifugal Pumps ◽  
Head Losses ◽  
Rotary Pumps ◽  
Pump Head ◽  
The Difference

The pump is a tool to provide the mechanical energy to the liquid in the pump constant fluid density and large. In terms of mechanism, the pump is divided into three types, namely, rotary pumps, pump the shaft/piston and centrifugal pumps. The use of the pump are the most widely used either in the household or in the environment industry. In the centrifugal pumps, there are losses – losses among other head losses. To find the head losses among other data needs head on the pump, the pump and the discharge flow rate of the pump. Head is defined as energy per unit weight of the fluid. The head of the unit (H) meters or feet is fluid. In the pump, the head is measured by calculating the difference between the total pressure of the suction pipe and the pipe press, when measurement is done at the same height. For single full pump openings 0,00246 m³ \ s, valve openings ¾ 0,00210 and aperture of ½ 0,00177 m³ \ s can be concluded the discharge of water at the pump the larger the opening of the valve the greater the discharge of its water. Moreover, vice versa, if the opening of the valve is getting smaller then the water debit is getting smaller. For full opening valves 3,11 m / s, for openings ¾ 2,65 m / s and ½ 2,23 m / s open valve openings. For the flow, velocity can be concluded the greater the opening of the valve the flow velocity is smaller and vice versa the smaller the opening of the valve the greater the flow rate. single centrifugal pump full valve openings 0.409 kg / cm², the opening of the valve ¾ 0,209 kg / cm² and the opening of the valve ½ 00,069 kg / cm² can be concluded the smaller the opening of the opening valve the smaller the head as well, and the greater the open valve opening, the more big head also in the can.

Theoretical Investigation on Flow Rate at the Maximum Efficiency Point in the Design of Impeller Blade in Centrifugal Pump

2004 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Centrifugal Pump ◽  
Theoretical Investigation ◽  
Flow Rate ◽  
Tangential Velocity ◽  
Maximum Efficiency ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Peripheral Velocity ◽  
Impeller Outlet ◽  
Fluid Particles

This paper presents a theoretical investigation of the flow rate at the maximum efficiency point in the design of impeller blade in centrifugal pump. An energy balance was performed at the trailing edge of impeller outlet in the rotating flow passage of centrifugal pump. The evaluation shows that, when the fluid particles straight forward tangential velocity is one third of the impeller blade’s peripheral velocity and the fluid particles circular forward tangential velocity is two third of the impeller blade’s peripheral velocity at the trailing edge of the impeller outlet, the maximum hydraulic energy output, that is, the maximum efficiency point is obtained.

An Investigation on Energy Transfer Mechanism Caused in Rotating Flow Passage of Turbomachinery: New Concept of Physical Parameters in Rectangular Coordinate System

2005 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Energy Transfer ◽  
Vertical Direction ◽  
Fluid Particle ◽  
The Other ◽  
Rotating Flow ◽  
Physical Parameters ◽  
Energy Transfer Mechanism ◽  
Rectangular Coordinate System ◽  
Flow Passage ◽  
Force Velocity

All the physical parameters, such as energy, force, velocity, and acceleration are constructed from two different kinds; one is real and the other is imaginary. Their acting directions are normal to each other. The former acts horizontal direction and causes visible kinetic movement on fluid particle. All the supplied energy is utilized and consumed. The latter acts vertical direction but does not cause any visible kinetic movement on fluid particle. All the energy transfer from mechanical to hydraulic and from hydraulic to mechanical is caused by the imaginary parameters in vertical direction.

Numerical Investigation on the Rotating Stall Characteristics in a Three-Blade Centrifugal Impeller

2016 ◽  
Author(s):  
Cao Lei ◽  
Wang Zhengwei ◽  
Xiao Yexiang ◽  
Luo Yongyao
Keyword(s):  
Flow Rate ◽  
Flow Distribution ◽  
Rotating Stall ◽  
Design Flow ◽  
Centrifugal Impeller ◽  
Propagation Mechanism ◽  
Flow State ◽  
Flow Passage ◽  
Impeller Outlet ◽  
Stall Cells

When a pump operates in part-load conditions, it is apt to form flow separations and even stall cells at the blade surfaces. In some conditions, stall cells may circumferentially propagate among the blade channels, known as rotating stall, which can affect the rotor system dynamic stability. Conventionally it is believed that the formation and circumferential propagation of stall cells is attributed to the nonuniformity of the flow state in front of the impeller inlet. In recent decades, many investigations indicate that the uneven flow field at the impeller outlet related to the asymmetric volute casing is also an important factor to induce rotating stalls. Thus the formation and propagation mechanism of rotating stalls is complex and has not been clearly understood so far. In addition, previous studies mainly focused on the rotating stalls in vaned diffusers, while it is more difficult to figure out rotating stalls in impellers for which little studies has been done. In this paper, numerical simulations are conducted for a three-blade centrifugal pump with a flow rate of 0.75Qd where Qd is the design flow rate. The SST-SAS model with a curvature correction is applied to predict the unsteady internal flows. The time-averaged pump head, efficiency and axial power agree well with the experimental results from a previous test. From the numerical results, a special rotating stall is detected in this condition. In order to verify the effect of the volute casing, a contrast simulation is also conducted without the volute casing domain. It shows that rotating stalls always occur whether there is a volute casing or not, but the distribution and motion of the stall cells are changed by the existence of the volute casing. It indicates that the nonuniform flow distribution at the impeller outlet is not an essential factor for the formation of rotating stall but accelerates the variation of stall cells. Based on the whole-flow-passage result, a stall cell in one blade channel disappears for about 2/15T (T is the duration of one revolution) when the downstream blade runs across the tongue, and the same phenomenon recurs in the upstream blade channel after 1/3T, which is unusual and worthy of investigation. The pressure fluctuations within the whole flow passage are intensified by the rotating stall more or less, especially at the middle region of pressure surface of blades, around the tongue and in the beginning of the discharge passage.

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