Internal Flow Characteristics of Cross-Flow Hydraulic Turbine With the Variation of Nozzle Shape

2007 ◽  
Author(s):  
Young-Do Choi ◽  
Jea-Ik Lim ◽  
You-Taek Kim ◽  
Young-Ho Lee
Keyword(s):  
Flow Characteristics ◽  
Cross Flow ◽  
Internal Flow ◽  
Close Relation ◽  
Hydraulic Turbine ◽  
Impulse Turbine ◽  
Runner Blade ◽  
Turbine Performance ◽  
Nozzle Shape ◽  
The Cross

The purpose of this study is to examine the optimum configuration of nozzle shape to further optimize the cross-flow hydraulic turbine structure and improve the performance. The results show that CFD analysis for the cross-flow turbine can be adopted as a useful method to examine the internal flow and turbine performance in detail. Pressure on the runner blade in Stage 1 and velocity at nozzle outlet have close relation to the turbine performance. The performance characteristics of cross-flow turbine have both impulse turbine and reaction turbine simultaneously.

scholarly journals Attenuation of Cross-Flow Fan Noise Using Porous Stabilizers

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Huanxin Lai ◽  
Meng Wang ◽  
Chuye Yun ◽  
Jin Yao
Keyword(s):  
Cross Flow ◽  
Sound Radiation ◽  
Internal Flow ◽  
Considerable Effect ◽  
Front Wall ◽  
Performance Curve ◽  
Fan Noise ◽  
Aerodynamic Performances ◽  
The Cross ◽  
Cross Flow Fan

This paper presents a qualitative analysis of controlling the cross-flow fan noise by using porous stabilizers. The stabilizer was originally a folded plate. It is changed into a porous structure which has a plenum chamber and vent holes on the front wall. In order to investigate the influences of using the porous stabilizers, experiments are carried out to measure the cross-flow fan aerodynamic performances and sound radiation. Meanwhile, the internal flow field of the fan is numerically simulated. The results show that the porous stabilizers have not produced considerable effect on the cross-flow fan's performance curve, but the noise radiated from the fan is strongly affected. This indicates the feasibility of controlling the cross-flow fan noise by using the porous stabilizers with selected porosity.

Inter-Blade Vortex Characteristics With the Blockage Effects of Runner Blade in a Francis Hydro Turbine Model

2019 ◽  
Author(s):  
Seung-Jun Kim ◽  
Jin-Hyuk Kim ◽  
Young-Seok Choi ◽  
Yong Cho ◽  
Jong-Woong Choi
Keyword(s):  
Flow Rate ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Operating Conditions ◽  
Low Flow ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Performance Reduction ◽  
Turbine Model ◽  
Low Flow Rate

Abstract This study presents the numerical analysis on the inter-blade vortex characteristics along with the blockage effects of runner blade in a Francis hydro turbine model with various flow rate conditions. The turbine model showed different flow characteristics in the runner blade passages according to operating conditions, and inter-blade vortex was observed at lower flow rate conditions. This inter-blade vortex can lead to performance reduction, vibration, and instability for smooth operation of turbine systems. The previous study on blockage effects on various runner blade thickness, showed its influence on hydraulic performance and internal flow characteristics at low flow rate conditions. Therefore, the inter-blade vortex characteristics can be altered with the blockage effects at low flow rate conditions in a Francis hydro-turbine. For investigating the internal flow and unsteady pressure characteristics, three-dimensional steady and unsteady Reynolds-averaged Navier-Stokes calculations are performed. These inter-blade vortices were captured at the leading and trailing edges close to the runner hub. These vortex regions showed flow separation and stagnation flow while blockage effects contributed for decreasing the inter-blade vortex at low flow rate conditions.

Numerical Investigation of a Banki Turbine in Transient State: Reaction Ratio Determination

2012 ◽  
Author(s):  
Sergio D. Croquer ◽  
Jesus de Andrade ◽  
Jorge Clarembaux ◽  
Freddy Jeanty ◽  
Miguel Asuaje
Keyword(s):  
Numerical Models ◽  
Flow Characteristics ◽  
Cross Flow ◽  
Turbulence Models ◽  
Transient State ◽  
Major Influence ◽  
Small Scale ◽  
Complex Flow ◽  
Impulse Turbine ◽  
Reaction Ratio

Cross-Flow Turbines (CFT) also known as Banki Turbines, are often considered for small scale hydroelectric generation. They are known for their simple construction, maintenance and operation, which means they incur in lower CAPEX and OPEX when compared to other types of turbines. However, they also tend to have a modest efficiency (82% [1–3]), hence they are not considered for big scale operations. Little is known about the flow characteristics inside the runner of the CFT. The objective of this investigation is to better understand the flow inside CFTs using Computational Fluid Dynamics (CFD) tools. Steady and Transient State simulations were performed for a CFT at an specific speed NS = 45. SST and κ–ε turbulence models were compared in terms of simulation requirements and obtained results. A proposed runner-nozzle interface, considering real CFT existent gap between these two components (free space) was evaluated as well. Results were compared to available experimental data. Maximum, numerically calculated efficiency deviation from reported experimental global efficiency was 15%. Pressure and velocity profiles along nozzle outlet, energy transfer stages location and CFT reaction ratio values were addressed. Results were compared in terms of runner-nozzle interface (gap vs no-gap), turbulence model (SST vs κ–ε) and calculation regime (steady vs transient regime). Only calculation state (steady vs transient) was found to have major influence over results. Transient state calculations better representing complex flow inside the CFT. Obtained degrees of reaction (no runner-nozzle gap, SST, transient state) were 0.12 and 0.08, for 1st and 2nd stages respectively. Hence the CFT is defined, according to this numerical models, as an impulse turbine.

The Influence of Non-Uniform Impeller on the Cross Flow Fan Noise

2016 ◽  
Vol 693 ◽  
pp. 251-256
Author(s):  
Zhi Qiang Yang ◽  
C.J. Wu
Keyword(s):  
Pressure Fluctuations ◽  
Flow Characteristics ◽  
Cross Flow ◽  
Internal Flow ◽  
Broadband Noise ◽  
Aerodynamic Noise ◽  
Air Conditioner ◽  
Fan Noise ◽  
Power Spectral ◽  
Cross Flow Fan

The aerodynamic noise of a cross flow fan with uneven blade spacing in room air-conditioner was simulated by computational aerodynamic acoustics (CAA) method. It is detailed to analyze the vorticity distribution of the flow field and the power spectral density of measured points’ pressure fluctuations, and the results demonstrate the non-uniform impeller used in this paper can significantly improve internal flow characteristics. Thus the broadband noise got reduced.

scholarly journals A Double Nozzle Cross Flow Turbine Fluid Flow Dynamics

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Corvis L. Rantererung ◽  
Sudjito Soeparman ◽  
Rudy Soenoko ◽  
Slamet Wahyudi
Keyword(s):  
Fluid Dynamics ◽  
Fluid Flow ◽  
Turbine Blade ◽  
Mechanical Energy ◽  
Water Discharge ◽  
Cross Flow ◽  
Flow Dynamics ◽  
Runner Blade ◽  
Turbine Performance ◽  
Turbine Runner

The dynamics of fluid flow are very important to the process of converting water energy into mechanical energy at the nozzle double runner cross flow turbine blade. Fluid dynamics of a jet of water from a nozzle release energy as the water crosses the cross flow turbine runner. This research aims to improve turbine performance and the effectiveness of fluid flow dynamics that drive cross flow turbine runner blades using double nozzles. The method of research using a cross flow turbine with double nozzle is a combination of vertical and horizontal nozzles. The turbine runner casing and blade are made of transparent acrylic material so that the flow dynamics can be observed directly. The laboratory scale double nozzle cross flow turbine is comprised of 24 blades, 3 mm thick, 40 mm long and 200 mm runner blade diameter. Test the performance of the turbine by measuring rotation, torque, and power, and by photographing the dynamics of the fluid flow that drives the turbine runner blade. The results of the study found that the visualization of the dynamics of fluid flow in turbines with double nozzles is more regular, evenly distributed, focused, and directed, moving the turbine runner blade cross flow so as to be able to increase turbine performance higher. The highest double nozzle cross flow turbine performance is 6.04 Watt power and 81.68% efficiency, at a water discharge of 0.22 liters /s.

scholarly journals Frequency modelling and dynamic identification of cross-flow water turbines

2021 ◽  
pp. 354-354
Author(s):  
Daniel Stroita ◽  
Adriana Manea
Keyword(s):  
Power Plants ◽  
Dynamic Properties ◽  
Cross Flow ◽  
Hydraulic Turbine ◽  
Point Of View ◽  
Complex Flow ◽  
Dynamic Identification ◽  
Hydro Power ◽  
The Cross ◽  
Hydro Power Plants

The Cross-Flow turbines cover from the point of view hydraulic power the running domain of some well-known turbines such as Pelton, Francis or Kaplan. This type of turbine has a simple construction, long life and low execution cost, which makes it very suitable for on and off grid small to medium hydro power plants. It is quite difficult to establish an exact theoretical dynamic model for this type of turbines, due to the complex flow phenomenon (bi phase flow water and air). In order to obtain the exact dynamic behavior of the hydraulic machine, experimental dynamic identification will be done. In automation, the dynamic properties, represent the fundamental characteristic of the object which must be regulated. When the dynamic properties of the regulated object are obtained experimentally, we analyze the characteristics of the transient regime, which appears because of the application at the system inlet of some stochastic or deterministic signals (sine waves for our case). The hydraulic turbine is modeled as an informational quadrupole having the inlet parameters the movement of the wicket gate and the turbine head and outlet parameters the torque and the speed. In this paper it will be presented the frequency modelling of the cross flow turbine and the validation of the mathematical model through experimental dynamic identification.

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