1027 EFFECT OF INLET FLOW CONDITION AND RUNNER SHAPE ON THE PERFORMANCE OF UNDERSHOT IMPULSE TURBINE BY VISUALIZATION OF FLOW PATTERN

2013 ◽  
Vol 2013.4 (0) ◽  
pp. _1027-1_-_1027-6_ ◽  
Author(s):  
Katayama Yusuke ◽  
Hayashi Nobuhiro ◽  
Iio Shouichiro ◽  
Ikeda Toshihiko
Keyword(s):  
Flow Pattern ◽  
Flow Condition ◽  
Impulse Turbine ◽  
Inlet Flow

Experimental Investigation of the Effect of the Probe Support Tail Structure on the Compressor Cascade Flow Field

2019 ◽  
Vol 36 (1) ◽  
pp. 9-18
Author(s):  
Honghui Xiang ◽  
Ning Ge ◽  
Jie Gao ◽  
Rongfei Yang ◽  
Minjie Hou
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Flow Condition ◽  
Test Facility ◽  
Axial Distance ◽  
Compressor Cascade ◽  
Inlet Flow ◽  
Disturbance Intensity ◽  
Cascade Flow ◽  
Tail Structure

Abstract Aiming at resolving the problem of measuring probe blockage effect in the performance experiments of high loaded axial flow compressors, an experimental investigation of the probe support disturbance effect on the compressor cascade flow field was conducted on a transonic plane cascade test facility. The influence characteristics of the probe support tail structure on the cascade downstream flow field under different operation conditions were revealed through the detailed analysis of the test data. The results show that the aerodynamic coupling effect between the upstream probe support wake and the downstream cascade flow field is very intense. Some factors, i. e. inlet Mach number, probe support tail structure, circumferential installing position of probe, and axial distance from the probe support trailing edge to the downstream cascade, are found to have the most impact on the probe disturbance intensity. Under high speed inlet flow condition, changing probe support tail structure can’t inhibit probe support disturbance intensity effectively. Whereas under low speed inlet flow condition, compared with the cylindrical probe, the elliptic probe can inhibit probe support wake loss and reduce disturbance effects on the downstream cascade flow field.

scholarly journals Infiltration and Anti-Filtration Recharge-Pumping Well and Laboratory Recharge Tests

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1834
Author(s):  
Yuxi Li ◽  
Wanglin Li ◽  
Jiapeng He ◽  
Xiaojiao Zhang ◽  
Xinyi Li
Keyword(s):  
Steady State ◽  
Flow Pattern ◽  
Theoretical Equation ◽  
Steady State Flow ◽  
Inlet Flow ◽  
State Flow ◽  
Unconfined Aquifers ◽  
Pumping Wells ◽  
Single Well

Infiltration and anti-filtration recharge-pumping wells (hereinafter, referred to as IAF recharge-pumping wells) can enable rain-flood flowing in rivers or channel recharge to aquifers, in flood periods, and pump groundwater to be utilized in non-flood periods. In this study, a round IAF recharge-pumping well and a square IAF recharge-pumping well were developed, the structure and characteristic were introduced, the calculation equations of single-well recharge quantity of IAF recharge-pumping wells, in unconfined aquifers were deduced, and the steady-state flow recharge test was conducted in the laboratory. The conclusions were as follows. The theoretical equation of the single-well recharge quantity was reasonable. Compared to existing anti-filtration recharge wells, the new IAF recharge-pumping well had stronger anti-deposit and anti-scour abilities and the single-well recharge quantity increased by 400%. Compared to the square IAF recharge-pumping well, the round IAF recharge-pumping well had a better inlet flow pattern and a larger single-well recharge quantity. With an increase in the test times, the single-well recharge quantity gradually decreased and tended to be stable. The existence of the pumping pipe had a little influence on the single-well recharge quantity.

Surrogate Models for Predicting the Performance of a Liquid-Liquid Cylindrical Cyclone Separator

2006 ◽  
Author(s):  
Jorge E. Pacheco ◽  
Miguel A. Reyes
Keyword(s):  
Flow Pattern ◽  
Mean Squared Error ◽  
Surrogate Models ◽  
Mechanistic Models ◽  
Water Mixture ◽  
Inlet Flow ◽  
Prediction Tools ◽  
Squared Error ◽  
Cylindrical Cyclone ◽  
Oil Water

Liquid-Liquid Cylindrical Cyclone (LLCC) separators are devices used in the petroleum industry to extract a portion of the water from the oil-water mixture obtained at the well. The oil-water mixture entering the separator is divided due to centrifugal and buoyancy forces in an upper (oil rich) exit and a bottom (water rich) exit. The advantages in size and cost compared with traditional vessel type static separators are significant. The use of LLCC separators has not been widespread due to the lack of proven performance prediction tools. Mechanistic models have been developed over the years as tools for predicting the behavior of these separators. These mechanistic models are highly dependent on the inlet flow pattern prediction. Thus, for each specific inlet flow pattern a sub-model has to be developed. The use of surrogate models will result in prediction tools that are accurate over a wider range of operational conditions. We propose in this study to use surrogate models based on a minimum-mean-squared-error method of spatial prediction known as Kriging. Kriging models have been used in different applications ranging from structural optimization, conceptual design, multidisciplinary design optimization to mechanical and biomedical engineering. These models have been developed for deterministic data. They are targeted for applications where the available information is limited due to the cost of the experiments or the time consumed in numerical simulations. We propose to use these models with a different framework so that they can manage information from replications. For the LLCC separator a two-stage surrogate model is built based on the Bayesian surrogate multistage approach, which allows for data to be incorporated as the model is improved. Cross validation mean squared error measurements are analyzed and the model obtained shows good predicting capabilities. These surrogate models are efficient and versatile predicting tools that do not require information about the physical phenomena that drives the separation process.

Experimental Investigation of the Influence of Inlet Distortion on the Stall Inception in a Low Speed Axial Compressor

2009 ◽  
Author(s):  
Huabing Jiang ◽  
Yajun Lu ◽  
Wei Yuan ◽  
Qiushi Li
Keyword(s):  
Flow Field ◽  
Dynamic Response ◽  
Flow Separation ◽  
Flow Condition ◽  
Axial Compressor ◽  
Flow Conditions ◽  
Inlet Flow ◽  
Stall Inception ◽  
Inlet Distortion ◽  
Compressor Performance

Inlet distortion is one of the major concerns for high maneuverability airplanes. An experiment is performed to investigate the influence of inlet distortion on the stall inception in a low speed axial compressor, where the distorted inlet flow field is simulated with a flat baffle placed upstream of the compressor. The flow field around a rotor blade is measured using 2D Digital Particle Image Velocimetry (DPIV) under both uniform and distorted inlet flow conditions. A comparison of flow fields reveals that the distorted inlet flow condition makes the compressor flow fields asymmetric. Flow separation and blockage within Distorted Sector A and Transition Sector B are more severe compared to Sector C. The distorted Sector A and Transition Sector B are the key regions that degrade compressor performance and stability. The large axial velocity makes the flow field within the Undistorted Sector C vigorous, which helps to suppress flow separation and blockage. Compressor rotor blades experience loading and unloading in a revolution period and the compressor exhibits strong dynamic response when it operates under distorted inlet flow conditions. Time-related pressure signals acquired at the rotor exit are utilized to analyze the development of the stall disturbance and the stall characteristic of the compressor. The development period of the stall disturbance is prolonged by the dynamic response of the compressor flow field under the distorted inlet flow condition. Dynamic development of the stall disturbance induced by inlet distortion reduces the compressor stall intensity. The frequency associated with the rotating stall cell is related to the rotating velocity of stall cells, which keeps the same value for uniform and distorted inlet flow conditions. Consequently, the stall inception of the compressor is influenced by the distorted inlet flow condition. The disturbance initiated in Distorted Sector A will experience development and damping when it propagates circumferentially, and might fail to survive the damping within Undistorted Sector C. Stall inception occurs only when the damping within Undistorted Sector C is insufficient to prevent its growth. The dynamic development of the disturbance can reasonably explain the influence of inlet distortion on compressor performance.

A hybrid of fast K-nearest neighbor and improved directed acyclic graph support vector machine for large-scale supersonic inlet flow pattern recognition

2021 ◽  
pp. 095441002110086
Author(s):  
Huan Wu ◽  
Yong-Ping Zhao ◽  
Tan Hui-Jun
Keyword(s):  
Pattern Recognition ◽  
Flow Pattern ◽  
Directed Acyclic Graph ◽  
Large Scale ◽  
Computational Cost ◽  
Classification Error ◽  
Support Vector ◽  
Training Set ◽  
Inlet Flow ◽  
Supersonic Inlet

Inlet flow pattern recognition is one of the most crucial issues and also the foundation of protection control for supersonic air-breathing propulsion systems. This article proposes a hybrid algorithm of fast K-nearest neighbors (F-KNN) and improved directed acyclic graph support vector machine (I-DAGSVM) to solve this issue based on a large amount of experimental data. The basic idea behind the proposed algorithm is combining F-KNN and I-DAGSVM together to reduce the classification error and computational cost when dealing with big data. The proposed algorithm first finds a small set of nearest samples from the training set quickly by F-KNN and then trains a local I-DAGSVM classifier based on these nearest samples. Compared with standard KNN which needs to compare each test sample with the entire training set, F-KNN uses an efficient index-based strategy to quickly find nearest samples, but there also exists misclassification when the number of nearest samples belonging to different classes is the same. To cope with this, I-DAGSVM is adopted, and its tree structure is improved by a measure of class separability to overcome the sequential randomization in classifier generation and to reduce the classification error. In addition, the proposed algorithm compensates for the expensive computational cost of I-DAGSVM because it only needs to train a local classifier based on a small number of samples found by F-KNN instead of all training samples. With all these strategies, the proposed algorithm combines the advantages of both F-KNN and I-DAGSVM and can be applied to the issue of large-scale supersonic inlet flow pattern recognition. The experimental results demonstrate the effectiveness of the proposed algorithm in terms of classification accuracy and test time.

scholarly journals One-dimensional Analysis of Impulse Turbine with Self-pitch-controlled Guide Vanes for Wave Power Conversion

2000 ◽  
Vol 6 (2) ◽  
pp. 151-157 ◽  
Author(s):  
M. Inioue ◽  
K. Kaneko ◽  
T. Setoguchi
Keyword(s):  
Dimensional Analysis ◽  
Flow Condition ◽  
Power Conversion ◽  
Aerodynamic Characteristics ◽  
Wave Power ◽  
Impulse Turbine ◽  
Guide Vanes ◽  
One Dimensional ◽  
Flow Rate Coefficient ◽  
Wave Power Conversion

A classical one-dimensional analysis in turbomachinery was presented to estimate aerodynamic characteristics of an impulse turbine with self-pitch-controlled guide vanes which is proposed by the authors for ocean wave power conversion. With some simplified assumptions, the efficiency vs/flow-rate coefficient curves were calculated and compared with the experimental results both in a unidirectional steady flow condition and a sinusoidally oscillating flow condition. The estimated results reveal a behavior of the actual characteristics curve of the turbine. Possibility of further improvement in efficiency was discussed from a viewpoint of specific speed and specific diameter.

Sign in / Sign up

Export Citation Format

Share Document