scholarly journals Research on Flow Stability and Vibration of an Industrial Hydraulic Turbine

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 311
Author(s):  
Xianghui Su ◽  
Zixian Cao ◽  
Yi Li ◽  
Yuzhen Jin ◽  
Zhenji Tang
Keyword(s):  
Rotation Speed ◽  
Comprehensive Evaluation ◽  
Engineering Application ◽  
Hydraulic Turbine ◽  
Critical Issue ◽  
Angle Of Incidence ◽  
Load Pressure ◽  
Circulating Water ◽  
Water Field ◽  
Vibration Tests

Industrial hydraulic turbines, a kind of small-scaled turbine in a more compact and flexible application, are frequently used in hydrogen cracking, synthesis ammonia, and circulating water field. Besides the energy recovery efficiency, the working stability at variable speed situations is a critical issue, since its rotation speed changes with the flow parameters of the upstream. In this paper, a conventional turbine was numerically investigated under three different rotation speeds and its best efficiency points (BEPs). The velocity profiles, blade load, pressure fluctuation, and vibration features were discussed to form a comprehensive evaluation of turbine stability. The numerical results were validated through turbine external characteristic and vibration tests. The results indicate that the pressure pulsation and vibrations increase when it deviates from the rated rotation speed, but the relatively low flowrate point behaves better than the large point in the aspect of turbine stability; the main reasons are the angle of incidence and rotor circumferential vortex. The conclusions can provide significant reference for turbine hydraulic optimization and engineering application.

Determination of Key Technical Parameters of Special Hydraulic Turbine for Cooling Tower

2011 ◽  
Vol 383-390 ◽  
pp. 1386-1390 ◽  
Author(s):  
Yan Pin Li ◽  
Hai Peng Nan ◽  
Kai Chuang Duan
Keyword(s):  
Cooling Tower ◽  
Hydraulic Turbine ◽  
Working Environment ◽  
Pressure System ◽  
Technical Parameters ◽  
Circulating Water ◽  
Power Turbine ◽  
In Series ◽  
The Difference ◽  
Save Energy

The author analyzed the working environment of special hydraulic turbine for cooling tower basing on the difference between the special turbine for cooling tower and the conventional power turbine. The former works in series pressure system and the water head determined by the pipeline resistance and the property of circulating water pump of cooling tower. It is the key to transform the cooling tower system successfully and save energy to build up a series special theories which include the specific speed of turbine for cooling tower, the type of turbine, the parameters selection, the design of the flow passage and runner of turbine by effectively transforming the conventional power turbine theory to the special turbine of cooling tower.

Field Vibration Tests and Dynamic Stability Analysis of a Full-Scaled Tainter-Gate

2004 ◽  
Author(s):  
Keiko Anami ◽  
Noriaki Ishii ◽  
Charles W. Knisely
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Stability ◽  
Natural Frequencies ◽  
Hydrodynamic Pressure ◽  
Flowing Water ◽  
Rotational Vibration ◽  
Water Field ◽  
Vibration Tests ◽  
Frequency Ratios ◽  
Theoretical Analyses

This study presents results from in-air and in-water field vibration tests of a 29-ton full-scaled Tainter-gate installed on a river in Japan. These tests were conducted to confirm the validity of our theoretical analyses especially for a large value of Froude number. First, with the gate raised, an in-air experimental modal analyses, using an impact hammer and accelerometers, was conducted to determine the natural frequencies and the damping ratios for two modes of gate vibration. These two modes corresponded to the rigid body vibration of the whole gate around the trunnion pin and the streamwise rotational vibration of the skinplate. Subsequently, with the gate again lowered and exposed to flowing water, the gate vibration characteristics were carefully measured. Only weak, unsynchronized vibrations were recorded and the gate was found to be dynamically stable. A theoretical analysis developed to predict the hydrodynamic pressure, the vibration frequency ratios and the dynamic stability were applied to the full-scaled gate. The theoretical analysis correctly predicted both the measured frequency ratios and the gate’s dynamic stability.

Developing an Evaluation Framework for Solar Building from the Viewpoint of Sustainable and Ecological Cities

2013 ◽  
Vol 316-317 ◽  
pp. 171-175
Author(s):  
Kang Li Wu ◽  
Shih Tsung Yeh ◽  
Ka Yang Chu
Keyword(s):  
Decision Making ◽  
Comprehensive Evaluation ◽  
Critical Issue ◽  
Evaluation Framework ◽  
Research Approach ◽  
Cognitive Differences ◽  
Five Dimensions ◽  
Improve Energy Efficiency ◽  
Building Integrated Photovoltaics ◽  
Fitting In

How solar building and Building integrated photovoltaics (BIPV) should be implemented to improve energy efficiency while also fitting in an urban environment has become a critical issue. From the viewpoint of sustainable and ecological cities, this study develops a comprehensive evaluation framework to address this issue. By incorporating research methods involving in-depth interviews, fuzzy questionnaire survey, and AHP method, this study develops a research approach to systematically assess the key decision-making criteria in implementing BIPV. After our investigation, an evaluation framework composing of five dimensions and 27 elements is proposed and tested. The framework provides an outline that can help guide the development of solar buildings and BIPV so as not to over-emphasize on any single aspect. The research also compares the cognitive differences of the importance of the evaluation dimensions and items of the proposed framework for the two major decision-making groups (industrial expert group and the architect/urban designers group) in order to build consensus on how to implement solar building and BIPV.

INNER FLOW FIELD OF POOL MIXED BY THREE SUBMERSIBLE MIXERS

2012 ◽  
Vol 11 (02) ◽  
pp. 91-97 ◽  
Author(s):  
FEI TIAN ◽  
WEIDONG SHI ◽  
HUA JIANG
Keyword(s):  
Flow Field ◽  
Average Velocity ◽  
Large Scale ◽  
Sewage Treatment ◽  
Three Dimensional ◽  
Engineering Application ◽  
Circulating Water ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Practical Engineering

To study the agitating effect of submersible mixers in a square sewage treatment pool, the three-dimensional modeling Pro/E software was adopted to establish the physical model. The large-scale computational fluid dynamics software FLUENT6.3 was used, and the large-scale software ICEM was selected to build an unstructured tetrahedron grid of the sewage treatment pool. Next, the sewage treatment pool was numerically simulated by RNG k-ε turbulent model and move coordinate system technology. The macrofluid field and the flow field distribution of each section were analyzed to observe the efficiency of each submersible mixer. The average velocity of the fluid and the stirring volume were studied simultaneously. Results show that, under the action of three mixers, fluid of the sewage pool forms a continuous circulating water flow. The fluid is mixed adequately. The average velocity of fluid in the pool is at around 0.3 m/s, and the fluid mixing area in the pool is more than 90%, which is in agreement with the working requirements. Consequently, it can provide a reference basis for the practical engineering application of submersible mixers by using this method.

scholarly journals Evaluation of the supply capacity of livelihood service facilities in the post-epidemic era

2021 ◽  
Vol 283 ◽  
pp. 02010
Author(s):  
Ruipeng Zhang ◽  
Changquan Su ◽  
Junwei Huo
Keyword(s):  
Public Health ◽  
Comprehensive Evaluation ◽  
Central City ◽  
Final Analysis ◽  
Critical Issue ◽  
Community Living ◽  
Layout Planning ◽  
Emergency Situations ◽  
The Face ◽  
Supply Capacity

Livelihood supply security is a critical issue when a public health emergency comes, and the layout planning of existing commercial facilities in China is not yet able to meet the livelihood supply in emergency situations. Evaluating the layout plan of existing commercial facilities is the first step to optimize them. Based on the theory of community "living circle", this study takes the central urban area of Hefei City as the scope of research, uses the big data platform and GIS to analyze the accessibility of commercial facilities for people's livelihood supply, conducts comprehensive evaluation at the community level, and explores the development direction of optimizing the planning and layout of commercial facilities for people's livelihood supply in the community living circle. The final analysis concludes that the layout planning of livelihood supply commercial facilities in areas with relatively low degree of construction at the edge of the central city of Hefei is unable to meet the basic living needs of residents under normal conditions. The problem is less obvious in the core area of the central city, but is further magnified in the face of sudden public health events, and its problematic area is more obviously expanded.

scholarly journals The system design for calibrating acoustic Doppler current meter in the laboratory

2019 ◽  
Vol 283 ◽  
pp. 08001
Author(s):  
Hongxu Jiang ◽  
Yalin Li ◽  
Yongwei Liu ◽  
Dejiang Shang
Keyword(s):  
Flow Field ◽  
Laser Doppler Velocimetry ◽  
Rotation Speed ◽  
Fluid Flows ◽  
Low Noise ◽  
Resonance Phenomenon ◽  
Water Tank ◽  
Doppler Velocimetry ◽  
Circulating Water ◽  
Working Section

The Acoustic Doppler Current meter is a most commonly device for the velocity measurement of the seawater in the ocean. We had designed an equipment to calibrate the Acoustic Doppler Current meter in the laboratory, which is mainly composed of a vertical circulating water tank and a system of Laser Doppler Velocimetry. The vertical circulating water tank is the key device of the calibration equipment. The optimization of flow field is carried out by the software, CFD. The optimization of structure intensity, modal analysis and low noise is carried out by the software, ANSYS. We had also used the propeller map to design the power section of the water tank. Through the comparison of the velocity of the flow between Acoustic Doppler Current meter and LDV at the same position in the working section of the water tank, the former can be calibrated, because the wavelength of optics is much less than that of acoustics in the water. After the experimental test, we found that when the fluid flows in the vertical circulating water tank, there exists no resonance phenomenon and the velocity of the flow in the working section is approximately proportional to the rotation speed of the propeller.

Fuzzy Comprehensive Evaluation for Reconfigurable Assembly Line

2011 ◽  
Vol 108 ◽  
pp. 80-85
Author(s):  
Ming Hai Yuan ◽  
Ze Zhong Wang
Keyword(s):  
Assembly Line ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Evaluation Criteria ◽  
Engineering Application ◽  
Reference Value ◽  
Fuzzy Comprehensive Evaluation ◽  
New Combination ◽  
Weighting Method ◽  
Reconfigurable Assembly

On the basis of the analyzing of the criterion of the evaluation index, a comprehensive evaluation model for RAL (reconfigurable assembly line) is proposed based on the hierarchy analysis according to the characteristics of the RAL and the engineering application. The new combination weighting method is used to calculate the weights of every index, and the index is assessed by fuzzy synthetically evaluation. The subordinate degree of evaluation object relative to optimum reference value adopting least squares principle is regarded as the evaluation criteria. Finally, this method is demonstrated to be reasonable and effective by a simulation example.

scholarly journals An Analytical Solution for Predicting the Vibration-Fatigue-Life in Bimodal Random Processes

2017 ◽  
Vol 2017 ◽  
pp. 1-18
Author(s):  
Chaoshuai Han ◽  
Yongliang Ma ◽  
Xianqiang Qu ◽  
Mindong Yang
Keyword(s):  
Fatigue Life ◽  
Analytical Solution ◽  
Numerical Integration ◽  
Engineering Application ◽  
Critical Issue ◽  
Offshore Structures ◽  
Random Loading ◽  
Engineering Structures ◽  
Vibration Fatigue

Predicting the vibration-fatigue-life of engineering structures subjected to random loading is a critical issue for. Frequency methods are generally adopted to deal with this problem. This paper focuses on bimodal spectra methods, including Jiao-Moan method, Fu-Cebon method, and Modified Fu-Cebon method. It has been proven that these three methods can give acceptable fatigue damage results. However, these three bimodal methods do not have analytical solutions. Jiao-Moan method uses an approximate solution, Fu-Cebon method, and Modified Fu-Cebon method needed to be calculated by numerical integration which is obviously not convenient in engineering application. Thus, an analytical solution for predicting the vibration-fatigue-life in bimodal spectra is developed. The accuracy of the analytical solution is compared with numerical integration. The results show that a very good agreement between an analytical solution and numerical integration can be obtained. Finally, case study in offshore structures is conducted and a bandwidth correction factor is computed through using the proposed analytical solution.

Determination of the Weights of Evaluation Indices with Combined Weighting Model for Engineering Materials

2011 ◽  
Vol 199-200 ◽  
pp. 1912-1915
Author(s):  
Tian Yun Zhang ◽  
Kui Chen
Keyword(s):  
Comprehensive Evaluation ◽  
Back Propagation ◽  
Engineering Application ◽  
Entropy Method ◽  
Analytic Hierarchy ◽  
Model Combining ◽  
Order Preference ◽  
Bearing Materials ◽  
Engineering Materials ◽  
Propagation Network

Combined Weighting Model (CWM), a new model combining entropy method, analytic hierarchy process (AHP) and back propagation network (BPN) is discussed to determine the weights(the key parameter of comprehensive evaluation) of evaluation indices(properties) for engineering materials in this paper. Taking the selection of bearing materials as an example, the combined weights of nine kinds of evaluation indices for ten kinds of candidate materials were calculated using CWM. According to these weights, candidate bearing materials were evaluated using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The result shows that the optimal bearing material is agreed with engineering application, which means the weights obtained from CWM are reasonable and reliable, and CWM is an effective method to determine the weights of evaluation indices for engineering materials.

Sign in / Sign up

Export Citation Format

Share Document