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.

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.

Fundamental Energy Transfer Mechanism of Turbomachinery

2002 ◽  
Author(s):  
Takaharu Tanaka
Keyword(s):  
Energy Transfer ◽  
Centrifugal Force ◽  
Mechanical Energy ◽  
Rotational Flow ◽  
Energy Transfer Mechanism ◽  
Centrifugal Pumps ◽  
Impeller Blade ◽  
Water Turbine ◽  
Fluid Particles ◽  
Water Turbines

Fundamental mechanisms of energy transfer, which is caused between impeller blade and fluid particles in centrifugal pumps and water turbines, are discussed together with as a turbomachinery under same theoretical basement. This leads to the result that the fluid flow which directs radial outward in pump and that radial inward in water turbine are neither caused by centrifugal force nor centripetal force, but caused by tangential forward force, which acts on the impeller blade in the direction perpendicular to rotational radius. Hydraulic energies of fluid particles transferred from mechanical to hydraulic energy in pump and that to be transferred from hydraulic to mechanical energy in water turbine appear as centrifugal force FHCF in rotational flow passage.

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.

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.

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.

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.

Technique for Improving the Flow Rate Estimation Range by Using an Axial Flow Water Turbine Generator

2017 ◽  
Vol 137 (1) ◽  
pp. 30-35
Author(s):  
Hiroaki Narita ◽  
Makoto Saruwatari ◽  
Jun Matsui ◽  
Yasutaka Fujimoto
Keyword(s):  
Flow Rate ◽  
Axial Flow ◽  
Turbine Generator ◽  
Rate Estimation ◽  
Water Turbine ◽  
Estimation Range

scholarly journals Performance Characteristics in Runner of an Impulse Water Turbine with Splitter Blade

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 303
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang ◽  
Zhijun Gao
Keyword(s):  
Energy Conversion ◽  
Flow Direction ◽  
Mechanical Energy ◽  
Experimental Tests ◽  
High Energy ◽  
Negative Energy ◽  
Water Turbine ◽  
Conversion Performance ◽  
Water Turbines ◽  
Current Energy

The impulse water turbine is a promising energy conversion device that can be used as mechanical power or a micro hydro generator, and its application can effectively ease the current energy crisis. This paper aims to clarify the mechanism of liquid acting on runner blades, the hydraulic performance, and energy conversion characteristics in the runner domain of an impulse water turbine with a splitter blade by using experimental tests and numerical simulations. The runner was divided into seven areas along the flow direction, and the power variation in the runner domain was analyzed to reflect its energy conversion characteristics. The obtained results indicate that the critical area of the runner for doing the work is in the front half of the blades, while the rear area of the blades does relatively little work and even consumes the mechanical energy of the runner to produce negative work. The high energy area is concentrated in the flow passage facing the nozzle. The energy is gradually evenly distributed from the runner inlet to the runner outlet, and the negative energy caused by flow separation with high probability is gradually reduced. The clarification of the energy conversion performance is of great significance to improve the design of impulse water turbines.

A Meanline Model for Impeller Flow Recirculation

2008 ◽  
Author(s):  
Xuwen Qiu ◽  
David Japikse ◽  
Mark Anderson
Keyword(s):  
Flow Rate ◽  
Recirculation Zone ◽  
Reverse Flow ◽  
Low Flow ◽  
Suction Surface ◽  
Blade Loading ◽  
Flow Recirculation ◽  
Impeller Outlet ◽  
Active Flow ◽  
Low Flow Rate

Flow recirculation at the impeller inlet and outlet is an important feature that affects impeller performance, especially the power consumption at a very low flow rate. Although the mechanisms for this flow phenomenon have been studied, a practical model is needed for meanline modeling of impeller off-design performance. In this paper, a meanline recirculation model is proposed. At the inlet, the recirculation zone acts as area blockage to relieve the large incidence of the active flow at a low flow rate. The size of the blockage is estimated through a critical area ratio of an artificial “inlet diffuser” from the inlet to throat. The intensity of the reverse flow can then be calculated by assuming a linear velocity profile of meridional velocity in the recirculation zone. At the impeller outlet, a recirculation zone near the suction surface is established to balance the velocity difference on the pressure and suction sides of the blade. The size and the intensity of the outlet recirculation zone is assumed related to blade loading, which can be evaluated based on flow turning and Coriolis force. A few validation cases are presented showing a good comparison between test data and prediction by the model.

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