scholarly journals Performance Improvement of a Micro Impulse Water Turbine Based on Orthogonal Array

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Lingdi Tang ◽  
Shouqi Yuan ◽  
Yue Tang
Keyword(s):  
Performance Improvement ◽  
Orthogonal Array ◽  
Optimal Parameter ◽  
Orthogonal Experiment ◽  
Internal Flow ◽  
Experimental Result ◽  
Range Analysis ◽  
Turbine Efficiency ◽  
Water Turbine ◽  
Low Specific Speed

The study on structural design and efficiency improvement of the micro impulse water turbine with the super-low specific speed has rarely been reported in literature. In this paper, a micro impulse water turbine was optimized on the base of the orthogonal array of L18(37) with six factors. The range analysis and variance analysis were conducted to present the significance ranking of factors and the optimal combinations of factors, aiming to improve the water turbine efficiency taken as the experimental indicator in the orthogonal experiment. And then the optimal parameter combination for the water turbine was calculated by orthogonal experiment. Moreover, the internal flow field and hydraulic performance were simulated numerically to investigate the principle of performance improvement by comparing the optimized water turbine with the original. Also, the numerical method was verified by experimental result from performance tests of the original water turbine. As a result, the runner torque of the optimized water turbine was 13% higher than that of the original and the water turbine efficiency was improved by 5.8 percentage points at the rated operating condition.

scholarly journals Effect of Forming Parameters on Profile Thinning of Flexible 3D Multi-Point Stretch Bending

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1581
Author(s):  
Zhongyuan Shi ◽  
Yi Li ◽  
Jicai Liang ◽  
Ce Liang
Keyword(s):  
Numerical Simulation ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Three Dimensional ◽  
Simulation Software ◽  
Experimental Result ◽  
Range Analysis ◽  
Stretch Bending ◽  
Rectangular Profile ◽  
Aluminum Profiles

The ABAQUS finite element simulation software is used to simulate the flexible multi-point three-dimensional stretch bending process of aluminum profiles. The effect of process parameters on the web thickness of rectangular profile in flexible multi-point three-dimensional stretch bending is studied by orthogonal experiment and range analysis. The process parameters used in the experiments include pre-stretching value, post-stretching value, the number of multi-point dies and friction coefficient. The optimal combination of process parameters is obtained by numerical simulation and experimental verification. When the aluminum profile is completed flexible multi-point stretch bending according to the best parameters, the thickness thinning of outer web and inner web is the smallest. The experimental result is closed to the numerical simulated results. The effectiveness of the numerical simulation is verified by the corresponding experimental methods.

Fabrication of highly stable and durable furfurylated wood materials. Part I: process optimization

Holzforschung ◽  
2020 ◽  
Vol 74 (12) ◽  
pp. 1135-1146
Author(s):  
Wanju Li ◽  
Minghui Liu ◽  
Hankun Wang ◽  
Yan Yu
Keyword(s):  
Orthogonal Experiment ◽  
Weight Percent Gain ◽  
Weight Percent ◽  
Chinese Fir ◽  
Curing Temperature ◽  
Modulus Of Rupture ◽  
Scale Production ◽  
Range Analysis ◽  
Decay Fungi ◽  
Mold Resistance

AbstractIn order to improve dimensional stability and durability of wood, furfurylation of poplar and Chinese fir wood using newly developed furfuryl alcohol (FA) formulation combined with a common vacuum and pressure impregnation process was studied. An orthogonal experiment was designed to optimize the furfurylation process for the two wood species. The weight percent gain (WPG), equilibrium moisture content (EMC), anti-swelling efficiency (ASE), modulus of rupture (MOR), modulus of elasticity (MOE), as well as resistance to mold, decay fungi, and termites were evaluated. The results showed that nearly all the properties of the furfurylated wood could be improved to various extents. The average ASE of the furfurylated Chinese fir and poplar could reach as high as 80, 71, 92% and 79, 90, 75% in tangential and radial directions, and by volume, respectively, higher than most previously reported wood modification processes. Furthermore, the modified wood had excellent biological durability, with nearly 100% mold resistance, strong decay and termite resistance. Finally, processing parameters with 50% FA, 105–115 °C curing temperature, and 5–8 h curing time were therefore recommended for pilot-scale production of furfurylated poplar and Chinese fir wood based on range analysis.

scholarly journals Optimal Design of Slit Impeller for Low Specific Speed Centrifugal Pump Based on Orthogonal Test

2021 ◽  
Vol 9 (2) ◽  
pp. 121
Author(s):  
Yang Yang ◽  
Ling Zhou ◽  
Hongtao Zhou ◽  
Wanning Lv ◽  
Jian Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Large Scale ◽  
Internal Flow ◽  
Orthogonal Test ◽  
Centrifugal Pumps ◽  
Initial Model ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Four Levels

Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based on the combination of orthogonal testing and numerical simulation, this paper optimizes the structure of a drainage trough for a typical low-specific speed centrifugal pump, determines the priority of the various geometric factors of the drainage trough on the pump performance, and obtains the optimal impeller drainage trough scheme. The influence of drainage tank structure on the internal flow of a low-specific speed centrifugal pump is also analyzed. First, based on the experimental validation of the initial model, it is determined that the numerical simulation method used in this paper is highly accurate in predicting the performance of low-specific speed centrifugal pumps. Secondly, based on the three factors and four levels of the impeller drainage trough in the orthogonal test, the orthogonal test plan is determined and the orthogonal test results are analyzed. This work found that slit diameter and slit width have a large impact on the performance of low-specific speed centrifugal pumps, while long and short vane lap lengths have less impact. Finally, we compared the internal flow distribution between the initial model and the optimized model, and found that the slit structure could effectively reduce the pressure difference between the suction side and the pressure side of the blade. By weakening the large-scale vortex in the flow path and reducing the hydraulic losses, the drainage trough impellers obtained based on orthogonal tests can significantly improve the hydraulic efficiency of low-specific speed centrifugal pumps.

scholarly journals Laboratory Investigation of Compaction Characteristics of Plant Recycled Hot-Mix Asphalt Mixture

2021 ◽  
Vol 13 (6) ◽  
pp. 3005
Author(s):  
Jiangang Yang ◽  
Chen Sun ◽  
Wenjie Tao ◽  
Jie Gao ◽  
Bocheng Huang ◽  
...  
Keyword(s):  
Regression Model ◽  
Hot Mix Asphalt ◽  
Orthogonal Experiment ◽  
Asphalt Mixture ◽  
Material Design ◽  
Void Content ◽  
Range Analysis ◽  
Aggregate Gradation ◽  
Compaction Characteristics ◽  
Compaction Energy

In this study, the compaction characteristics of recycled hot-mix asphalt (RHMA) were evaluated using the void content (VV), compaction energy index (CEI), slope of accumulated compaction energy (K), and lock point (LP). Then, the effects of the compaction parameters, including the gradation of the RHMA, reclaimed asphalt pavement (RAP) content, temperature of gyrations, and number of gyrations, on the compaction characteristics of RHMA were investigated. An orthogonal experiment was designed and the data collected were analyzed via range analysis; then, a regression model was generated relying on a quadratic polynomial. Furthermore, the regression model was used for the comparison and prediction of the mixture’s compactability during the material design. Finally, the compaction mechanism of RHMA was discussed from the perspective of the void content of RAP particles. The results showed that a finer aggregate gradation, a higher gyration temperature, a greater number of gyrations, and a higher RAP content were effective for increasing the compactability of RHMA. The range analysis results suggest that the gradation of RHMA has the greatest influence on compactability, followed by the RAP content. The RAP aggregate cannot diffuse to a new mixture completely, so the remained RAP particle reduces the void content of RHMA. Therefore, a higher RAP content up to 50% can help RHMA to achieve the designed void content with higher efficiency.

Current Status, Design and Performance Trends for the Regenerative Flow Compressors and Pumps

2002 ◽  
Author(s):  
Mukarrum Raheel ◽  
Abraham Engeda
Keyword(s):  
Performance Improvement ◽  
Current Status ◽  
Ongoing Research ◽  
Performance Trends ◽  
The Family ◽  
Working Principle ◽  
Low Specific Speed ◽  
And Performance ◽  
Number Of Publications ◽  
Regenerative Flow

Regenerative flow compressors and pumps, hereafter called RFC/RFP have found many applications in industry; still they are the most neglected turbomachines in the family of dynamic compressors. The number of publications existing in literature is very small compared to the large number of papers about the centrifugal and axial turbocompressors. This paper gives a detail discussion of fundamentals and working principle of regenerative turbomachines. Regenerative compressors are compared with centrifugal compressors and the importance of regenerative turbomachines in low specific speed range is emphasized. The major findings of available literature on regenerative turbomachine are summarized. The current status, limitations and some of the challenges faced by RFC/RFP are assessed in context of performance improvement. The paper concludes with an overview of ongoing research and future directions to be followed for performance improvement of this neglected class of turbomachines.

scholarly journals Size reduction and performance improvement of a microstrip Wilkinson power divider using a hybrid design technique

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Behdad Jamshidi ◽  
Saeed Roshani ◽  
Jakub Talla ◽  
Sobhan Roshani ◽  
Zdenek Peroutka
Keyword(s):  
Performance Improvement ◽  
Size Reduction ◽  
Power Divider ◽  
Experimental Result ◽  
Hybrid Technique ◽  
Harmonic Suppression ◽  
Efficient Design ◽  
Quarter Wavelength ◽  
Lc Circuit ◽  
Wilkinson Power Divider

AbstractIn the design of a microstrip power divider, there are some important factors, including harmonic suppression, insertion loss, and size reduction, which affect the quality of the final product. Thus improving each of these factors contributes to a more efficient design. In this respect, a hybrid technique to reduce the size and improve the performance of a Wilkinson power divider (WPD) is introduced in this paper. The proposed method includes a typical series LC circuit, a miniaturizing inductor, and two transmission lines, which make an LC branch. Accordingly, two quarter-wavelength branches of the conventional WPD are replaced by two proposed LC branches. Not only does this modification lead to a 100% size reduction, an infinite number of harmonics suppression, and high-frequency selectivity theoretically, but it also results in a noticeable performance improvement practically compared to using quarter-wavelength branches in the conventional microstrip power dividers. The main important contributions of this technique are extreme size reduction and harmonic suppression for the implementation of a filtering power divider (FPD). Furthermore, by tuning the LC circuit, the arbitrary numbers of unwanted harmonics are blocked while the operating frequency, the stopband bandwidth, and the operating bandwidth are chosen optionally. The experimental result verifies the theoretical and simulated results of the proposed technique and demonstrates its potential for improving the performance and reducing the size of other similar microstrip components.

scholarly journals Performance Improvement of a Liquid Molten Salt Pump: Geometry Optimization and Experimental Verification

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 423 ◽  
Author(s):  
Kai Wang ◽  
Xin Lu ◽  
Yu Li ◽  
Xianghui He ◽  
Houlin Liu ◽  
...  
Keyword(s):  
Molten Salt ◽  
Performance Improvement ◽  
Pressure Fluctuation ◽  
Geometry Optimization ◽  
Internal Flow ◽  
Experimental Methods ◽  
Sharp Corner ◽  
Hydraulic Efficiency ◽  
Low Velocity ◽  
Pump Performance

In order to enhance the hydraulic efficiency of a liquid molten salt pump, the improvement on the pump was carried out through numerical and experimental methods. The internal flow field obtained by the numerical simulation was analysed. The results show that there are low-velocity area in the scroll region and large curvature of the streamline at the outlet. Geometric modification was made by trimming the back-blades of the impeller and filleting the sharp corner of the outlet pipe. The modified pump performance was verified by the experiments. The hydraulic efficiency, the pressure fluctuation, vibration characteristics between the original and modified pump were compared. The results showed that the hydraulic efficiency of the modified pump increased 7.4%. In addition, the pressure fluctuation and vibration intensity were also reduced compared with the original pump. This result shows that the geometric modification improves not only the hydraulic performance but also the structural properties.

Effects of Wet Activation Process Parameters on Surface Hydrophilicity in Silicon Direct Wafer Bonding

2012 ◽  
Vol 235 ◽  
pp. 250-253
Author(s):  
Lei Nie ◽  
Jun Xing Yu ◽  
Kun Zhang
Keyword(s):  
Wafer Bonding ◽  
Orthogonal Experiment ◽  
Volume Ratio ◽  
Holding Time ◽  
Activation Process ◽  
Analysis Method ◽  
Range Analysis ◽  
Surface Hydrophilicity ◽  
Direct Wafer Bonding ◽  
Value Range

Wet activation is a very important step in silicon direct wafer bonding process and a optimized activation process is desirable to improve the surface hydrophilicity. Therefore the pivotal parameters of activation process were investigated which were volume ratio, holding time and treat temperature. A orthogonal experiment array was designed to reveal the effects of these parameters and the experiment results were analyzed by range analysis method. The analysis results indicted among those three parameters, everyone had intimidate relationship with surface hydrophilicity, which was indexed by contact angle. And higher concentration, longer holding time and higher treating temperature in possible value range were more desirable. Based on these conclusions, optimized activation process was desigened using which void-free bonding was realized.

Influences of Splitter Blades on the Centrifugal Fan Performances

1989 ◽  
Author(s):  
Lichuan Gui ◽  
Chuangang Gu ◽  
Hongshou Chang
Keyword(s):  
Solution Method ◽  
Pressure Coefficient ◽  
Internal Flow ◽  
Experimental Result ◽  
Centrifugal Fan ◽  
Fan Performance ◽  
Load Distributions ◽  
Result Show ◽  
Engineering Practices ◽  
Approximate Solution Method

Centrifugal fan and compressors with splitter blades are widely utilized in engineering practices. A detail investigation of the influences of splitter blades on a forward-curved centrifugal fan performances is presented in the paper. The study includes two parts: experiment and numerical calculation. The experiments were produced in a specific impeller with adjustable splitter blades in order to get the performances in different conditions. The internal flow field in the impeller was calculated by means of FEASM (Finite Element Approximate Solution Method, Gu, 1984). The experimental result show that changing the circumferential positions of the splitter blades has a noticeble influence on the fan performance, the incidence of splitter blades also has a certain effect on it, and properly lengthened splitter blades can raise the total pressure coefficient. The velocity and load distributions on the blade surfaces calculated can be used to analyse the phenomena above satisfactorily.

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