Hydraulic Characteristics of the New Type Bulb Turbine With Micro-Head

2013 ◽  
Author(s):  
Lingyu Li ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Zihao Mi
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Three Dimensions ◽  
Guide Vanes ◽  
Runner Blade ◽  
Cfd Method ◽  
Bulb Turbine

The head of low-head hydropower stations is generally higher than 2.5m in the world, while micro-head hydropower resources which head is less than 2.5m are also very rich. In the paper, three-dimensional CFD method has been used to simulate flow passage of the micro-head bulb turbine. The design head and unit flow of the turbine was 1m and 3m3/s respectively. With the numerical simulation, the bulb turbine is researched by analyzing external characteristics of the bulb turbine, flow distribution before the runner, pressure distribution of the runner blade surface, and flow distribution of the outlet conduit under three different schemes. The turbine in second scheme was test by manufactured into a physical model. According to the results of numerical simulation and model test, bulb turbine with no guide vane in second scheme has simpler structure, lower cost, and better flow capacity than first scheme, which has traditional multi-guide vanes. Meanwhile, efficiency of second scheme has just little decrease. The results of three dimensions CFD simulation and test results agree well in second scheme, and higher efficiency is up to 77% which has a wider area with the head of 1m. The curved supports in third scheme are combined guide vanes to the fixed supports based on 2nd scheme. By the water circulations flowing along the curved supports which improve energy transformation ability of the runner, the efficiency of the turbine in third scheme is up to 82.6%. Third scheme, which has simpler structure and best performance, is appropriate for the development and utilization of micro-head hydropower resources in plains and oceans.

Numerical Investigations of Model Propeller Turbine Performance Under Different Guide Vane Opening

2008 ◽  
Author(s):  
Zhou Daqing ◽  
Bo Qu ◽  
Zheng Yuan
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Small Opening ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Turbine Performance ◽  
Water Head ◽  
Large Opening ◽  
Turbulent Models ◽  
Cfd Method

In the paper, CFD method is applied to investigate model propeller turbine performance under different guide vane opening. First, the whole passage geometric models of model propeller turbine have been built with 0° runner blade under five kinds of guide vane opening, and subdivided with about 1.78 million cells of unstructured mesh. Then, three dimensional turbulent flow computations are made at the water head of H = 1m and the runner speed of n = 217.4 r/min, with the two turbulent models, RNG k-ε and Spalart-Allmadas. Furthermore, the curves of moment value and axial hydraulic thrust value are plotted and compared with experimental curves, which shows that numerical results agree well with experimental data, and Spalart-Allmadas model has better precision than RNG k-ε model. Finally, the flow fields of different parts in the turbine passage are displayed and analyzed respectively under the large, normal and small guide vane opening, which shows the fact that the rotating direction of vortex in the axial diffuse of draft tube is opposite by comparing the large opening with the small opening, and the flow field is in disorder and unsteady especially under the small opening. On the whole, CFD method has many unique advantages and has played more and more important roles on the investigations of hydro turbine performance.

Minimisation of Ducted Flow Non-Uniformity Caused by Downstream Blockages

2016 ◽  
Author(s):  
M. E. Rife ◽  
F. Barbarossa ◽  
A. B. Parry ◽  
J. S. Green ◽  
L. di Mare
Keyword(s):  
Velocity Distribution ◽  
Guide Vane ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Swirling Flows ◽  
Three Dimensions ◽  
Boundary Singularity ◽  
Blade Loading ◽  
Guide Vanes ◽  
Dimensional Boundary

Flow in annular ducts is sensitive to the presence of downstream blockages which can cause flow non-uniformities propagating far upstream of the blocking body. These effects can be exacerbated in swirling flows where a cascade of uniform guide vanes is present upstream of the blockage. This work uses two- and three-dimensional boundary singularity methods to model and optimise a guide vane cascade geometry to minimise the upstream velocity distortion. Starting from a uniform cascade, the geometry is modified to provide a uniform upstream velocity distribution and minimised blade-to-blade loading in two dimensions. The new geometry is then extrapolated to a three-dimensional annulus. A three-dimensional tool is used to further modify the geometry in three dimensions to minimise the velocity distortion in the whole annulus upstream of the cascade.

Guide Vanes Inference on Hydraulic Characteristics of Tubular Pump

2011 ◽  
Author(s):  
Jin Yan ◽  
Liu Chao ◽  
Takaharu Tanaka
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Flow Fields ◽  
System Efficiency ◽  
Hydraulic Characteristics ◽  
Pump Impeller ◽  
Guide Vanes ◽  
Hydraulic Losses ◽  
Pumping System ◽  
Cfd Method

The blade number of pump guide vane is an important factor that affects hydraulic characteristics of the pumping system, since the diffusion angle after the impeller is larger than as usual. It is necessary to pay more attention for its calculation and analysis. By CFD method the numeric simulation was conducted to a bulb tubular pump with different guide vane blades and the three dimensional flow fields within whole passage of pumping system was obtained. There are five different number of guide vane blades (4 blades, 5 blades, 7 blades, 8 blades and improved 5 blades) selected for the simulation and performance prediction. The influences of the guide vanes numbers on the system performance are analyzed. The hydraulic losses increases with the increase of the number of guide vane blades while the efficiency of pumping system is not fully comply with this relationship. The system efficiency for which 5 guide vanes were adopted is higher than others with different number of guide vane blades; also the velocity and the pressure distribution of flow fields are more uniform. The system efficiency for which 5 improved guide vanes is the highest with lowest hydraulic losses. The recommended alternative of guide vane is presented for the pump impeller.

scholarly journals Load Rejection Transient Process Simulation of a Kaplan Turbine Model by Co-Adjusting Guide Vanes and Runner Blades

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3354 ◽  
Author(s):  
Huixiang Chen ◽  
Daqing Zhou ◽  
Yuan Zheng ◽  
Shengwen Jiang ◽  
An Yu ◽  
...  
Keyword(s):  
Transient Process ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Decisive Role ◽  
Axial Thrust ◽  
Guide Vanes ◽  
Kaplan Turbine ◽  
Flow Configurations ◽  
Cfd Method

To obtain the flow mechanism of the transient characteristics of a Kaplan turbine, a three-dimensional (3-D) unsteady, incompressible flow simulation during load rejection was conducted using a computational fluid dynamics (CFD) method in this paper. The dynamic mesh and re-meshing methods were performed to simulate the closing process of the guide vanes and runner blades. The evolution of inner flow patterns and varying regularities of some parameters, such as the runner rotation speed, unit flow rate, unit torque, axial force, and static pressure of the monitored points were revealed, and the results were consistent with the experimental data. During the load rejection process, the guide vane closing behavior played a decisive role in changing the external characteristics and inner flow configurations. In this paper, the runner blades underwent a linear needle closure law and guide vanes operated according to a stage-closing law of “first fast, then slow,” where the inflection point was t = 2.3 s. At the segment point of the guide vane closing curve, a water hammer occurs between guide vanes and a large quantity of vortices emerged in the runner and the draft tube. The pressure at the measurement points changes dramatically and the axial thrust rises sharply, marking a unique time in the transient process. Thus, the quality of a transient process could be effectively improved by properly setting the location of segmented point. This study conducted a dynamic simulation of co-adjustment of the guide vanes and the blades, and the results could be used in fault diagnosis of transient operations at hydropower plants.

Field Tests of Guide Vanes and Runner Blades of a Large Bulb Turbine for Output Deficiency Diagnosis

2012 ◽  
Vol 212-213 ◽  
pp. 1057-1061 ◽  
Author(s):  
Zhong Liu ◽  
Zhu Qing Huang ◽  
Shu Yun Zou ◽  
Hong De Rao
Keyword(s):  
Field Tests ◽  
Economic Loss ◽  
Hydropower Plant ◽  
Test Results ◽  
Guide Vanes ◽  
Factors Affecting ◽  
Runner Blade ◽  
Main Factors ◽  
Theoretical Analyses ◽  
Bulb Turbine

The 3# bulb turbine in Hongjiang Hydropower Plant has faced the problem of output deficiency since its commission in Sept. 2003, which caused a large economic loss. Following simple theoretical analyses on the main factors affecting the turbine’s output and efficiency, the field test schemes were determined to measure the shapes and intervals of guide vanes and runner blades of the 3#, 5# and 6# turbines. The test results discover that the average blade intervals of the 3# turbine are generally less than those of the 5# one. Suggestions on runner blade installation adjustment and combined curve modification are given.

Adaptive Geometry Representation of Turbine Vane Frames for Use in Optimization

2021 ◽  
Author(s):  
Sebastian F. Riebl ◽  
Christian Wakelam ◽  
Reinhard Niehuis
Keyword(s):  
Design Space ◽  
Cfd Simulation ◽  
A Priori ◽  
Three Dimensional ◽  
Optimization Method ◽  
Three Dimensions ◽  
Design Parameters ◽  
Adjustment Process ◽  
Turbine Vane ◽  
Integrated Concept

Abstract Turbine Vane Frames (TVF) are a way to realize more compact jet engine designs. Located between the high pressure turbine (HPT) and the low pressure turbine (LPT), they fulfill structural and aerodynamic tasks. When used as an integrated concept with splitters located between the structural load-bearing vanes, the TVF configuration contains more than one type of airfoil with sometimes pronouncedly different properties. This system of multidisciplinary demands and mixed blading poses an interesting opportunity for optimization. Within the scope of the present work, a full geometric parameterization of a TVF with splitters is presented. The parameterization is chosen as to minimize the number of parameters required to automatically and flexibly represent all blade types involved in a TVF row in all three dimensions. Typical blade design parameters are linked to the fourth order Bézier-curve controlled camber line-thickness parameterization. Based on conventional design rules, a procedure is presented, which sets the parameters within their permissible ranges according to the imposed constraints, using a proprietary developed code. The presented workflow relies on subsequent three dimensional geometry generation by transfer of the proposed parameter set to a commercially available CAD package. The interdependencies of parameters are discussed and their respective significance for the adjustment process is detailed. Furthermore, the capability of the chosen parameterization and adjustment process to rebuild an exemplary reference TVF geometry is demonstrated. The results are verified by comparing not only geometrical profile data, but also validated CFD simulation results between the rebuilt and original geometries. Measures taken to ensure the robustness of the method are highlighted and evaluated by exploring extremes in the permissible design space. Finally, the embedding of the proposed method within the framework of an automated, gradient free numerical optimization is discussed. Herein, implications of the proposed method on response surface modeling in combination with the optimization method are highlighted. The method promises to be an option for improvement of optimization efficiency in gradient free optimization of interdependent blade geometries, by a-priori excluding unsuitable blade combinations, yet keeping restrictions to the design space as limited as possible.

Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump

2011 ◽  
Author(s):  
Kai Wang ◽  
Houlin Liu ◽  
Shouqi Yuan ◽  
Minggao Tan ◽  
Yong Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Cfd Simulation ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Absolute Velocity ◽  
Operation Condition ◽  
Test Technique ◽  
Simulation Results

A double blades pump is widely used in sewage treatment industry, while at present the research on the internal flow characteristics of the double blades pump is very few. So, the CFD technology and the stereo PIV test technique are applied to study the inner flow in a double blades pump whose specific speed is 110.9. The commercial code FLUENT is used to simulate the inner flow in the double blades pump at 0.6Qd, 0.8Qd, 1.0Qd, 1.2Qd and 1.4Qd. The RNG k-ε turbulence model and SIMPLEC algorithm are used in FLUENT. According to the results of the three-dimensional steady numerical simulation, the distributions of velocity field in the impeller are obtained at the five different operating conditions. The analysis of the numerical simulation results shows that there is an obvious vortex in the impeller passage at off-design conditions. But the number, location and area of the vortex are different from each operation condition. In order to validate CFD simulation results, the stereo PIV is used to test the absolute velocity distribution in the double blades pump at Jiangsu University. The distributions of three-dimensional absolute velocity field at the above five different operating conditions are obtained by the PIV test, and the measured results are compared with the CFD simulation results. The comparison indicates that there are vortexes in impeller passages of the double blades pump under the five operating conditions. But as to the area of the vortex and the relative velocity values of the vortex core, there are some differences between the experiment results and the numerical simulation results. The research work can be applied to instruct the hydraulic design of double blades pumps.

Numerical Simulation of Three Dimensional Internal Flow of a PWR Reactor

2016 ◽  
Author(s):  
Jian Ge ◽  
Wenxi Tian ◽  
Tingting Xu ◽  
Jiesheng Min ◽  
Guofei Chen ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Physical Phenomenon ◽  
Three Dimensional ◽  
Great Influence ◽  
Flow Distribution ◽  
Internal Flow ◽  
Hydraulic Characteristics ◽  
Main Research ◽  
The Core ◽  
Internal Structures

The coolant flow in the reactor pressure vessel (RPV) lower plenum is complex due to the presence of various internal structures, which has a great influence on the flow distribution at the core inlet. In order to study the thermal hydraulic characteristics in the RPV lower plenum, many scaled down test facilities have been built for different PWR reactors such as Juliette, ACOP, and ROCOM. Although the experimental study is still a main research method, it may be not economical in some situations due to the high cost and the long study period. Compared with the experimental method, Computational Fluid Dynamics (CFD) methodology can simulate three dimensional fluid flow in complex geometries and perform parametric studies more easily. The detailed and localized thermal hydraulic characteristics which are difficult to measure during experiments can be obtained. So CFD simulation has been widely used nowadays. One of the purposes of numerical simulations of the internal flow in a RPV is to get the flow distribution at the core inlet, then to make an optimization for the flow diffusor in the RPV lower plenum to improve the core inlet flow distribution homogeneity. Appropriate optimizations for the flow diffusor depends on fully understanding the flow phenomena in the RPV lower plenum. In this paper, Phenomenon Identification and Ranking Table (PIRT) is adopted to analyze the physical phenomenon that occurs in the RPV lower plenum with the typical 900MW reactor internal structures, and the importance of the various physical phenomena and the reference parameters are ranked through expert opinions and literature review. Then a preliminary three dimensional CFD simulation for the reactor vessel is conducted. The main phenomena identified by the PIRT can be observed from the simulation results.

Based on CFX Numerical Simulation of Francis Turbine Runner

2013 ◽  
Vol 456 ◽  
pp. 207-210
Author(s):  
Fang He
Keyword(s):  
Numerical Simulation ◽  
Guide Vane ◽  
Prediction Method ◽  
Internal Flow ◽  
Francis Turbine ◽  
Flow State ◽  
Hydro Turbine ◽  
Runner Blade ◽  
Vibration Prediction ◽  
Turbine Runner

This paper presents a vibration prediction method for Francis turbine: Provided with advanced CFX software, Numerical simulation of movable guide vane and Turbine runner’s internal flow state. From the source of hydraulic vibration, Focus on numerical analysis, numerical simulation for the cutting thickness of the runner blade. After analysis of the influence of the blade of hydraulic vibration. To explore new ways for the hydro turbine control hydraulic vibration.

scholarly journals Optimization Study of Guide Vanes for the Intake Fan-Duct Connection Using CFD

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1555
Author(s):  
Juan Pablo Hurtado ◽  
Bryan Villegas ◽  
Sebastián Pérez ◽  
Enrique Acuña
Keyword(s):  
Fluid Dynamics ◽  
Energy Savings ◽  
Guide Vane ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Penetration Length ◽  
Curvature Ratio ◽  
Guide Vanes ◽  
Ventilation Shaft ◽  
Shock Loss

The connection between an intake fan and a ventilation shaft must be designed in such a way that it minimizes the energy waste due to singularity losses. As a result, the questions of which radius of curvature to use and if guide vanes have to be included need to be answered. In that case, the variables such as the number, upstream and downstream penetration length, radius of curvature, and width of the vanes, need to be defined. Although this work is oriented to mine ventilation, these questions are usually valid in other engineering applications as well. The objective of this study is to define the previously mentioned variables to determine the optimal design combination for the radius/diameter relationship (r/D). Computational fluid dynamics was used to determine the shock loss factor of seven elbow curvature ratios for a 3 m diameter duct and fan, with and without guide vanes to estimate the best performing configuration and, therefore, to maximize the fan airflow volume. The methodology used consisted of initially developing models in 2D geometries, to optimize the meshing and the CPU use, and studying separately the number of vanes, upstream and downstream penetration, radius of curvature, and width of the vanes for each curvature ratio (r/D). Then, the best-performing variable combinations for each curvature ratio were selected to be simulated and studied with the 3D geometries. The application of the guide vane designs for three-dimensional simulated geometries is presented, first without and then with guide vanes, including the shock loss factors obtained. The methodology and obtained results allowed quantifying the energy savings and to reduce the CFD simulations steps required to optimize the design of the elbow and guide vanes. The results obtained cannot be used with elbows in exhaust fans, because fluid dynamics phenomena are different.

Sign in / Sign up

Export Citation Format

Share Document