Comparative Study on Performance of Very Low Head Axial Hydraulic Turbine Using a Single Rotor and a Contra-Rotating Rotor

2015 ◽  
Vol 758 ◽  
pp. 165-172 ◽  
Author(s):  
Abdul Muis ◽  
Priyono Sutikno ◽  
Aryadi Suwono ◽  
Firman Hartono
Keyword(s):  
Comparative Study ◽  
Rotor Blade ◽  
High Efficiency ◽  
Guide Vane ◽  
Axial Flow ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
Total Power ◽  
Numerical Studies ◽  
Low Head

Studies conducted on axial flow hydraulic turbine by comparing the performance of turbines which use a single rotor and two rotors that rotate in opposite (contra-rotating). Both turbines are designed to generate energy utilizing a very low head water flow. Single rotor turbine consists of one row of guide vane and one row of rotor blade. Contra-rotating rotor turbine consists of one row of guide vane and two rows of rotor blade, which is the front rotor blade also serves as a guide vane for the rear rotor. Both of turbines are designed for the same flow and operating conditions. The results of numerical studies show that both of turbines can be applied with a fairly high efficiency, however the single rotor turbine is significantly higher. Especially for contra-rotating turbine, the total power that generated at the same operating conditions will increase because powers are resulted from both of rotors, but the effective head required will be significantly increase compare to the single-rotor turbine. These results may be used as a reference in the development of axial flow hydraulic turbine for very low head sites to expand the applications. Keywords: Single rotor, contra-rotating rotor, axial flow, very low head, hydraulic turbine.

scholarly journals Improvement of the Efficiency of the Axial-Flow Pump at Part Loads due to Installing Outlet Guide Vanes Mechanism

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Fan Yang ◽  
Hao-ru Zhao ◽  
Chao Liu
Keyword(s):  
Prediction Model ◽  
Flow Rate ◽  
High Efficiency ◽  
Guide Vane ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Ann Model ◽  
Axial Flow Pump ◽  
Flow Pump

In order to investigate the influence of adjustable outlet guide vane on the hydraulic performance of axial-flow pump at part loads, the axial-flow pump with 7 different outlet guide vane adjustable angles was simulated based on the RNG k-ε turbulent model and Reynolds time-averaged equations. The Vector graphs of airfoil flow were analyzed in the different operating conditions for different adjustable angles of guide vane. BP-ANN prediction model was established about the effect of adjustable outlet guide vane on the hydraulic performance of axial-flow pump based on the numerical results. The effectiveness of prediction model was verified by theoretical analysis and numerical simulation. The results show that, with the adjustable angle of guide vane increasing along clockwise, the high efficiency area moves to the large flow rate direction; otherwise, that moves to the small flow rate direction. The internal flow field of guide vane is improved by adjusting angle, and the flow separation of tail and guide vane inlet ledge are decreased or eliminated, so that the hydraulic efficiency of pumping system will be improved. The prediction accuracy of BP-ANN model is 1%, which can meet the requirement of practical engineering.

Noise generation in vane axial fans due to rotating stall and surge

2001 ◽  
Vol 215 (1) ◽  
pp. 57-64 ◽  
Author(s):  
M Čudina
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Noise Generation ◽  
Total Noise ◽  
Operating Stability ◽  
Partial Load ◽  
Axial Fans

A characteristic of axial flow fans is instabilities in their performance and noise in partial load operation. These instabilities are a consequence of rotating stall created in the rotor blade and/or in the guide vane cascade. At some operating conditions the rotating stall caused the appearance of a surge representing the lowest region of fan operating stability. The rotating stall and especially surge caused a steep increase in the emitted noise and lowered the performance of the fan. The present paper highlights the rotating stall generation phenomenon and its influence on the emitted total noise level and noise spectra for axial flow fans with inlet and outlet guide vanes.

Performance Study of a 1 MW Gas Turbine Using Variable Geometry Compressor and Turbine Blade Cooling

2010 ◽  
Author(s):  
Cleverson Bringhenti ◽  
Jesuino Takachi Tomita ◽  
Joa˜o Roberto Barbosa
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Turbine Blades ◽  
Axial Flow ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Variable Geometry ◽  
Performance Study ◽  
Turbine Blade Cooling ◽  
Blade Cooling

This work presents the performance study of a 1 MW gas turbine including the effects of blade cooling and compressor variable geometry. The axial flow compressor, with Variable Inlet Guide Vane (VIGV), was designed for this application and its performance maps synthesized using own high technological contents computer programs. The performance study was performed using a specially developed computer program, which is able to numerically simulate gas turbine engines performance with high confidence, in all possible operating conditions. The effects of turbine blades cooling were calculated for different turbine inlet temperatures (TIT) and the influence of the amount of compressor-bled cooling air was studied, aiming at efficiency maximization, for a specified blade life and cooling technology. Details of compressor maps generation, cycle analysis and blade cooling are discussed.

Mechanical Design and Testing of a 2.5 MW sCO2 Compressor Loop

2021 ◽  
Author(s):  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Chris Kulhanek ◽  
Meera Day Towler ◽  
Jason Mortzheim
Keyword(s):  
High Efficiency ◽  
Mechanical Design ◽  
Guide Vane ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Design Changes ◽  
Wide Range ◽  
Inlet Conditions ◽  
Design And Testing

Abstract An enabling technology for a successful deployment of the sCO2 close-loop recompression Brayton cycle is the development of a compressor that can maintain high efficiency for a wide range of inlet conditions due to large variation in properties of CO2 operating near its dome. One solution is to develop an internal actuated variable Inlet Guide Vane (IGV) system that can maintain high efficiency in the main and re-compressor with varying inlet temperature. A compressor for this system has recently been manufactured and tested at various operating conditions to determine its compression efficiency. This compressor was developed with funding from the US DOE Apollo program and industry partners. This paper will focus on the design and testing of the main compressor operating near the CO2 dome. It will look at design challenges that went into some of the decisions for rotor and case construction and how that can affect the mechanical and aerodynamic performance of the compressor. This paper will also go into results from testing at the various operating conditions and how the change in density of CO2 affected rotordynamics and overall performance of the machine. Results will be compared to expected performance and how design changes were implanted to properly counter challenges during testing.

Water Film Formation on an Axial Flow Compressor Rotor Blade

2008 ◽  
Author(s):  
Theoklis Nikolaidis ◽  
Periclis Pilidis ◽  
J. A. Teixeira ◽  
V. Pachidis
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Water Film ◽  
Inlet Guide Vane ◽  
Computational Domain ◽  
Axial Flow Compressor ◽  
Water Ingestion ◽  
Compressor Rotor ◽  
Flow Compressor

A numerical approach was used to evaluate the liquid water film thickness and its motion on an axial flow compressor rotor blade under water ingestion conditions. By post-processing blading data and using computer programs to create the blades and their computational grid, the global computational domain of the first stage of an axial flow compressor was built. The flow field within the domain was solved by CFX-Tascflow, which is a commercial CFD code commonly used in turbomachinery. The computational domain consists of an extended inlet, an inlet guide vane, a rotor and a stator blade. Having solved the flow field at Design Point, the inlet guide vane blade was re-positioned to account for changes in idle speed. At that speed, the effects of water ingestion are expected to be more significant on gas turbine engine performance. Several cases with water ingestion were studied, changing parameters like water mass and compressor rotational speed. A FORTRAN computer program was created to calculate the water film height and speed. The extra torque needed by the compressor to keep running at the same rotational speed, was also calculated. The considerable increase in torque was confirmed by experimental observations according to which water ingestion had a detrimental effect on gas turbine operation.

Effect of tip clearance on performance of contra-rotating axial flow water-jet propulsion pump

2020 ◽  
Vol 34 (10) ◽  
pp. 2050094
Author(s):  
Wei Han ◽  
Yao Liu ◽  
Chengyong Gong ◽  
Youliang Su ◽  
Pengyi Guo ◽  
...  
Keyword(s):  
High Efficiency ◽  
Axial Flow ◽  
Water Jet ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Wake Effect ◽  
Thrust Coefficient ◽  
Jet Pumps ◽  
Thrust Characteristics ◽  
Thrust Performance

Insufficient understanding of tip clearance on hydraulic and thrust performance is a major problem encountered in the design and application of the contra-rotating axial flow water-jet pumps. In order to investigate the effect of tip clearance on hydrodynamic and thrust characteristics of the pump, tip clearance coefficient [Formula: see text] is defined and scraping rate [Formula: see text] is introduced in this paper. Head coefficient and hydraulic efficiency are obtained with the numerical prediction and experiment as [Formula: see text], which are in good agreement with each other. With the increase of [Formula: see text], the saddle area of head coefficient slows down and the high efficiency zone narrows. Along the relative chord length of shroud of the rear rotor, the [Formula: see text] presents an opening down quadratic curve as [Formula: see text], and if [Formula: see text], it presents a “M” shape nearly. Comparing the two operating conditions of contra-rotating rotors and single rotor, the [Formula: see text] and wake effect of the rear rotor are enhanced and inhibited by the front rotor respectively for the interference between the two rotors, the thrust coefficient of the propulsion pump reaches the maximum when [Formula: see text].

Rotor Blade Unsteady Aerodynamic Gust Response to Inlet Guide Vane Wakes

1993 ◽  
Vol 115 (1) ◽  
pp. 197-206 ◽  
Author(s):  
S. R. Manwaring ◽  
S. Fleeter
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Unsteady Aerodynamic ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Flow Compressor

A series of experiments is performed in an extensively instrumented axial flow research compressor to investigate the fundamental flow physics of wake-generated periodic rotor blade row unsteady aerodynamics at realistic values of the reduced frequency. Unique unsteady data are obtained that describe the fundamental unsteady aerodynamic gust interaction phenomena on the first-stage rotor blades of a research axial flow compressor generated by the wakes from the inlet guide vanes. In these experiments, the effects of steady blade aerodynamic loading and the aerodynamic forcing function, including both the transverse and chordwise gust components, and the amplitude of the gusts, are investigated and quantified.

Numerical Simulation and Flow Field Measurement of High Efficiency Axial-Flow Pump

2009 ◽  
Author(s):  
De-sheng Zhang ◽  
Wei-dong Shi ◽  
Bin Chen ◽  
Xing-fan Guan
Keyword(s):  
Rotor Blade ◽  
Radial Direction ◽  
High Efficiency ◽  
Static Pressure ◽  
Axial Flow ◽  
Rotor Blades ◽  
Experimental Results ◽  
Meridional Velocity ◽  
Axial Flow Pump ◽  
Flow Pump

In order to analyze the flow characteristics of a high efficiency axial-flow pump, the behavior of the flow in an adjustable axial-flow pump bas been analyzed by numerical simulations of the entire stage based on Fluent software. The prediction data shows agreement with the experimental results. Numerical results show that the static pressure on pressure side of rotor blades increases slightly at radial direction, and remains almost constant in circumferential direction at design conditions, while it increases gradually from inlet to exit on suction side along the flow direction. The static pressure, total pressure and velocity at inlet, rotor blade exit and stator outlet were measured by five-hole probe. The experimental results show, inlet flow is almost axial and the prerotation is very small at design conditions. The meridional velocity and circulation distributions are almost uniform at rotor blades exit at design condition. The residual circulation still exists at downstream of stator, and the absolute flow angle at radial direction is almost consistent at design conditions, but Cu increases linearly from hub to tip at small flow rate conditions. To determine the influence of the hub leakage, a contrast experiment was accomplished. The measurement results show that hub leakage results in the decrease of efficiency, and the meridional velocity and circulation at rotor blade exit, especially near hub leakage region are influenced by the leakage.

scholarly journals Development of a low head tidal turbine

2018 ◽  
Vol 1 (2 (Nov)) ◽  
pp. 81-90
Author(s):  
S. Hötzl ◽  
T. Schechtl ◽  
P. Rutschmann ◽  
W. Knapp
Keyword(s):  
High Efficiency ◽  
Guide Vane ◽  
Net Energy ◽  
Transient Effects ◽  
Cfd Simulations ◽  
Design And Optimization ◽  
Runner Blade ◽  
Tidal Turbine ◽  
Low Head ◽  
Four Quadrant

Recent research has shown that four-quadrant turbines are required to achieve maximum net energy production in a tidal barrage plant. These turbines can generate electricity in both flow directions and are capable of pumping. An innovative turbine concept is being reviewed in the course of the Eurostars research project Safe*Coast. This project proposes to install a turbine in a reversible cylinder in order to allow for fourquadrant operation. To evaluate the feasibility of the concept, the authors designed a compact low head axial tidal turbine with the aid of CFD simulations. This paper presents the methods used in the design and optimization process of the turbine. It also describes numerically obtained turbine characteristics, and cavitation limits. The most critical requirements of the turbine include high efficiency in turbine and pumping mode and safe cavitation properties. By computing steady state CFD simulations of the turbine stage, an extensive set of geometries was analyzed. The authors optimized the turbine performance by adjusting the meridional section, as well as runner blade and guide vane profiles and angles along with other related parameters. Transient simulations of the whole setup, including the inlet and draft tube geometries, were performed in order to study transient effects. The final design after optimization is a three bladed axial turbine with adjustable guide vanes and a rim generator. The turbine’s symmetrical inlet and outlet geometry and its relative compactness permit its integration in a reversible cylinder. The simulation results are very positive and indicate that all the relevant design criteria are satisfied. As a result, the project will continue into a new phase in which a model of the turbine will be built for physical testing in order to verify the results and to conduct further investigations.

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