scholarly journals Influence of meridional plane shape on performance and internal flow of high head contra-rotating small hydroturbine

2021 ◽  
Vol 1909 (1) ◽  
pp. 012044
Author(s):  
Takuji Hosotani ◽  
Toru Shigemitsu ◽  
Yuki Kawaguchi ◽  
Takuya Inamoto ◽  
Takeru Ishiguro ◽  
...  
Keyword(s):  
Internal Flow ◽  
Meridional Plane ◽  
Plane Shape ◽  
High Head

scholarly journals Analysis of Flow Within Pump Impeller of Torque Converter

1996 ◽  
Author(s):  
Hoshio Tsujita ◽  
Shimpei Mizuki ◽  
Eiji Ejiri
Keyword(s):  
Coordinate System ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Internal Flow ◽  
Torque Converter ◽  
Flow Patterns ◽  
Speed Ratio ◽  
Meridional Plane ◽  
Pump Impeller ◽  
Simple Method

It is difficult to measure flow patterns within rotating elements of a torque converter due to the complicated construction. Therefore, the numerical calculation is considered to be an effective tool to know the internal flow. Three-dimensional incompressible turbulent flow within a pump impeller of an automotive torque converter was analyzed numerically at three different speed ratios, 0.02, 0.4 and 0.8 under the same inlet boundary condition. The speed ratio was defined as the ratio of rotating speed of the turbine impeller to that of the pump. The governing equations using the k-ε model in the physical component tensor form were solved with a boundary-fitted coordinate system fixed on a rotating impeller. The solution algorithm was the SIMPLE method applied to the curvilinear coordinate system. The computed results were compared with those obtained experimentally by an oil film flow visualization technique for the pressure, suction, core and shell surfaces. Moreover, the results at three different speed ratios were examined in detail in order to clarify the behavior of secondary flow patterns. The computed results showed good agreement with the experimental results and clarified the behavior of the complicated flow patterns. The secondary flow patterns were strongly influenced by the correlation between the intensities of the Corinlis force (COF) and the centrifugal force due to the passage curvature in the meridional plane (CMF).

scholarly journals Optimization of Pump Hydraulic Performance Based on the Response Surface Method

2018 ◽  
Author(s):  
Shengli Xu ◽  
Shaowei Zhong ◽  
Haixin Zhao
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Computational Cost ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Hydraulic Performance ◽  
Design Parameters ◽  
Meridional Plane ◽  
Hydraulic Efficiency ◽  
Surface Method

This paper studies the optimization method of pump hydraulic performance based on the response surface method. A parametric model of impeller and diffuser is established. Three-dimensional optimization is carried out on the basis of the initial model obtained by one-dimensional design method. We select the pump hydraulic efficiency and the head as objective function and constraint function. Response surface models are constructed to analyze the relationship between the objectives and the design variables, and the global optimization of hydraulic performance is realized. According to the internal flow characteristics of pump, this paper proposes the strategy of two steps optimization, which aims at meridional plane and blade shape, respectively, to solve the problem of large numbers of design parameters and computational cost. The optimization results show that the hydraulic efficiency of pump increased by 3.7%, and the head is nearly the same.

Numerical Study of the Internal Flow Field Characteristics in Mixed Flow Turbines

2002 ◽  
Author(s):  
D. Palfreyman ◽  
R. F. Martinez-Botas
Keyword(s):  
Flow Field ◽  
Cell Density ◽  
Numerical Study ◽  
Internal Flow ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Test Facility ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Radial Turbine

Presented is a numerical investigation of the characteristics of the internal flow field of a high-speed low-pressure ratio mixed flow turbine of 95.14 mm tip diameter. A commercial computational fluid dynamics (CFD) code has been successfully employed. This has been carefully validated to experimental data taken from a turbine test facility at this institution. A comparison to gated (in phase with the turbine rotation) Laser Doppler Velocimetry measurements at the turbine trailing edge and total to static efficiencies at various operating conditions, was made showing good agreement. Details of the internal flow field from a numerical study using a 393,872 cell density model are presented. These details have been compared to a radial turbine of similar geometry and performance characteristics, also analyzed using the same cell density and analysis and boundary conditions. The flow field was found to be highly three-dimensional with the tip leakage vortex as the dominant secondary flow feature. The tip clearance flow was found to be significantly influenced by the relative motion of the shroud wall, which suppressed the development of a vortex within the mainstream passage particularly in the inducer region. Comparison to the radial turbine has shown noticeable differences concentrated in the inducer region where the greater Coriolis acceleration in the radial turbine is more influential in the development of secondary flows. Considerable loss is observed localized at the blade leading edge tip region along the full length of the blade pitch; this is associated with the increased streamline curvature in the meridional plane.

Meridional shape design and the internal flow investigation of centrifugal impeller

2016 ◽  
Vol 231 (23) ◽  
pp. 4319-4330 ◽  
Author(s):  
Yan Wang ◽  
Quanlin Dong ◽  
Yulian Zhang
Keyword(s):  
Velocity Distribution ◽  
Medial Axis ◽  
Design Method ◽  
Internal Flow ◽  
Centrifugal Impeller ◽  
Shape Design ◽  
Meridional Plane ◽  
Centrifugal Fan ◽  
Constraint Equations ◽  
Meridional Shape

This paper describes an inverse design method for calculating the shape of meridional plane of centrifugal impeller. This design method permits the shroud and hub contours to be indirectly calculated by medial axis contour and constraint equations. The design process is computationally inexpensive and can conveniently modify the shroud and hub shapes as the design’s demand. Based on this design method, new constraint equations are used for a new shape design of meridional plane that lead to a uniform velocity distribution in the inlet of impeller. Numerical simulations are employed to investigate the fluid flows of centrifugal fan. After validation of the numerical strategy, the pressure and velocity distributions in centrifugal fan are illustrated. The numerical results show that the inlet performance is improved and the velocity distribution is more uniform. Furthermore, in order to understand the flow mechanism inside the centrifugal fan, the secondary flow in the blade passage and velocity distribution at the shroud and hub have been carried out a detailed investigation and study.

Optimization of the Meridional Plane Shape Design Parameters in a Screw Centrifugal Pump Impeller

2021 ◽  
Vol 24 (4) ◽  
pp. 15-25
Author(s):  
Thi Hong Minh Hoang ◽  
Viet Anh Truong ◽  
Ujjwal Shrestha ◽  
Young-Do Choi
Keyword(s):  
Centrifugal Pump ◽  
Design Parameters ◽  
Shape Design ◽  
Meridional Plane ◽  
Pump Impeller ◽  
Plane Shape ◽  
Centrifugal Pump Impeller

Investigations on the Flow Pattern and Aerodynamic Performance of Last Stage and Exhaust Hood for Large Power Steam Turbines

2012 ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Xin Yan ◽  
Zhenping Feng ◽  
Hiroharu Ohyama ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Static Pressure ◽  
Flow Behavior ◽  
Internal Flow ◽  
Aerodynamic Performance ◽  
Meridional Plane ◽  
Computational Domain ◽  
Exhaust Hood ◽  
Large Power ◽  
Last Stage

The aerodynamic performance and internal flow behavior of the last stage and exhaust hood for large power steam turbine was numerically investigated using commercial CFD software ANSYS-CFX. The computational domain includes all stator and rotor blades of last stage and exhaust hood including bracing tubes and strengthening plates. The Reynolds-Averaged Navier-Stokes (RANS) solution was utilized to analyze aerodynamic performance of last stage and static pressure recovery coefficient of exhaust hood. For comparison, the internal flow pattern of the individual exhaust hood was also analyzed without consideration of the last stage effects. The static pressure and Mach number distribution at the meridional plane of the last stage was illustrated. The velocity vector distribution at different cross sections in the exhaust hood with and without consideration of the last stage influence was compared. In addition, the static pressure and pressure loss contours distribution in the exhaust hood were also studied. The obtained results show that the outflow of the last stage can significantly influence the aerodynamic performance and flow pattern of the exhaust hood. To obtain a reliable prediction of the aerodynamic performance of the exhaust hood, it is necessary to consider the interaction between the last stage and exhaust hood.

scholarly journals A Quasi-Three Dimensional Calculation System for the Flow Within Transonic Compressor Blade Rows

1985 ◽  
Author(s):  
W. J. Calvert ◽  
R. B. Ginder
Keyword(s):  
Data Transfer ◽  
Three Dimensional ◽  
Internal Flow ◽  
Compressor Blade ◽  
Meridional Plane ◽  
End Effects ◽  
Transonic Compressor ◽  
Calculation System ◽  
Set Up ◽  
Transonic Fan

A calculation system has been set up to predict both the internal flow field and the overall performance of a transonic compressor blade row. The system iterates between an inviscid-viscous time-marching blade-to-blade (S1) treatment and a streamline curvature throughflow calculation for the pitchwise-averaged flow in the meridional plane (S2). A blade geometry package and a data transfer/display program are used to link the S1 and S2 methods to give a semi-automatic convergence procedure. The only empirically-based correlation or correction required is an extra loss imposed near the blade hub and tip to allow for end effects. The system has been applied to a high bypass ratio transonic fan rotor near design point. The converged solution was in good agreement with the measured performance.

Investigation of the natural ventilation of wind catchers with different geometries in arid region houses

2020 ◽  
Vol 14 (3) ◽  
pp. 7109-7124
Author(s):  
Nasreddine Sakhri ◽  
Younes Menni ◽  
Houari Ameur ◽  
Ali J. Chamkha ◽  
Noureddine Kaid ◽  
...  
Keyword(s):  
Arid Region ◽  
Natural Ventilation ◽  
Reduction Rate ◽  
Internal Flow ◽  
Climatic Conditions ◽  
Maximum Pressure ◽  
Ventilation Technique ◽  
Window Position ◽  
The One ◽  
Flow Velocities

The wind catcher or wind tower is a natural ventilation technique that has been employed in the Middle East region and still until nowadays. The present paper aims to study the effect of the one-sided position of a wind catcher device against the ventilated space or building geometry and its natural ventilation performance. Four models based on the traditional design of a one-sided wind catcher are studied and compared. The study is achieved under the climatic conditions of the South-west of Algeria (arid region). The obtained results showed that the front and Takhtabush’s models were able to create the maximum pressure difference (ΔP) between the windward and leeward of the tower-house system. Internal airflow velocities increased with the increase of wind speed in all studied models. For example, at Vwind = 2 m/s, the internal flow velocities were 1.7, 1.8, 1.3, and 2.5 m/s for model 1, 2, 3, and 4, respectively. However, at Vwind = 6 m/s, the internal flow velocities were 5.6, 5.5, 2.5, and 7 m/s for model 1, 2, 3, and 4, respectively. The higher internal airflow velocities are given by Takhtabush, traditional, front and middle tower models, respectively, with a reduction rate between the tower outlet and occupied space by 72, 42, 36, and 33% for the middle tower, Takhtabush, traditional tower, and the front model tower, respectively. This reduction is due to the due to internal flow resistance. The third part of the study investigates the effect of window (exist opening) position on the opposite wall. The upper, middle and lower window positions are studied and compared. The air stagnation or recirculation zone inside the ventilated space reduced from 55% with the lower window to 46% for the middle window and reached 35% for the upper window position. The Front and Takhtabush models for the one-sided wind catcher with an upper window position are highly recommended for the wind-driven natural ventilation in residential houses that are located in arid regions.

Experimental and Numerical Analysis of a Motorcycle Air Intake System Aerodynamics and Performance

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
M. A. Abd Halim ◽  
N. A. R. Nik Mohd ◽  
M. N. Mohd Nasir ◽  
M. N. Dahalan
Keyword(s):  
Combustion Process ◽  
Three Dimensional ◽  
Engine Performance ◽  
Internal Flow ◽  
Rapid Expansion ◽  
Navier Stokes ◽  
Turbulent Fluctuation ◽  
Ansys Fluent ◽  
Induction System ◽  
Acceleration And Deceleration

Induction system or also known as the breathing system is a sub-component of the internal combustion system that supplies clean air for the combustion process. A good design of the induction system would be able to supply the air with adequate pressure, temperature and density for the combustion process to optimizing the engine performance. The induction system has an internal flow problem with a geometry that has rapid expansion or diverging and converging sections that may lead to sudden acceleration and deceleration of flow, flow separation and cause excessive turbulent fluctuation in the system. The aerodynamic performance of these induction systems influences the pressure drop effect and thus the engine performance. Therefore, in this work, the aerodynamics of motorcycle induction systems is to be investigated for a range of Cubic Feet per Minute (CFM). A three-dimensional simulation of the flow inside a generic 4-stroke motorcycle airbox were done using Reynolds-Averaged Navier Stokes (RANS) Computational Fluid Dynamics (CFD) solver in ANSYS Fluent version 11. The simulation results are validated by an experimental study performed using a flow bench. The study shows that the difference of the validation is 1.54% in average at the total pressure outlet. A potential improvement to the system have been observed and can be done to suit motorsports applications.

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