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Journal of Drainage and Irrigation Machinery Engin
 
2014 Vol.32 Issue.2
Published 2014-02-25
article
Article
93 Optimization design and test study on automobile cooling pumps
Yuan Shouqi, Zhang Tingting, Zhang Jinfeng, Liu Jianrui, Pei Bing
Six impeller hydraulic parameters with obvious effects on the performance,β2, b2, D2, Z, D0 and φ were analyzed for an automobile cooling pump with specific speed ns=59, and an auxiliary factor e was also considered. According to the original values, two sets of parameters were designed, and two levels were chosen. According to the orthogonal table L8(27)designed, eight design schemes of impeller were obtained. Steady simulations of the flow in the pump was carried out by Ansys-CFX12.1. Taking head and efficiency at design point as performance target as well as flow rate, head and efficiency at best efficiency point, based on range analysis and comparative analysis of inner flow, the impeller parameters were optimized. The calculated and experimental performance results have been obtained for both the optimized and the original impellers. The results show that the optimized impeller improves the hydraulic efficiency of the pump, and the high efficiency range is widen when more flat head curve can be obtained. The discussion shows that orthogonal method on the pump design is feasible and the numerical simulation is reliable. The combined design method will improve pump performance conveniently, and testing pump performance on the basis will shorten development period and improve work efficiency. 
2014 Vol. 32 (2): 93-97 [Abstract] ( 1940 ) [HTML 1KB] [ PDF 2868KB] ( 1680 )
98 Structure optimization of annular jet pumps
Zeng Qinglong,, Long Xinping,, Xiao Longzhou,, Lü Qiao,
With the method of DOE(the design of experiment method)and CFD, the optimum structure parameters combination of an annular jet pump(AJP)was mainly investigated for the maximum efficiency. The AJP model designed by previous researchers, with the area ratio 1.75, was adopted as the simulation prototype. The experimental data of the performance were used to validate the simulation results. Based on DOE, four main factors, namely the flow ratio q, the relative throat length lt, the included angles of the suction chamber α and the diffusion angle in diffuser β, were selected for the optimization of the efficiency, and series of experiments were carried out to study the inner flow of pump with different structure parameters combination. Then, the significance of structural parameters to the AJP performance was ascertained and the optimum structure parameters combination was obtained by means of statistic software package. The results confirmed the availability and effectiveness of the method that the maximum efficiency 36.3% from DOE is nearly the same with the corresponding results 35.8% from CFD. Moreover, among all the main structural parameters impacting on AJP performance, the influence of the relative throat length is considerably greater than that of the included angle of the suction chamber and the diffusion angle in diffuser. It can be concluded that the effects of two-factor interactions are more significant than that of one factor acting alone. The basis for the further optimization and determination of reasonable working range of AJP is provided.
2014 Vol. 32 (2): 98-102 [Abstract] ( 1810 ) [HTML 1KB] [ PDF 977KB] ( 1968 )
103 Effect of blade leading edge shape on sediment erosion of blade in double-suction centrifugal pumps
Qian Zhongdong, Zhang Kai, Wang Zhiyuan, Xue Jun
In order to improve the anti-abrasion characteristics of pumps, the water flow and movement of silt in a double-suction centrifugal pump was simulated using an Euler-Lagrange multiphase flow model. The erosion rate of blade was predicted with a particle erosion model and the influence of the four different blade leading edge shapes on the erosion rate was analyzed. The results show that the blade leading edge and the blade trailing edge are usually severely destroyed by sediment erosion, and the average erosion rate on the suction side is always greater than that on the pressure side. The relative velocity and the incidence angle are the two major factors that influence on the erosion rate of blade, and are able to be controlled by changing the blade leading edge shape. The relative velocity near the blade leading edge appears uniform after cutting the tip area of the blade leading edge, and the erosion rates at both the blade leading edge and the blade trailing edge are decreased while the pump head is also decreased. Sediment erosion of the blade is effectively controlled and the pump head is slightly increased while cutting the tip side of the blade trailing edge as well as increasing the incidence angle near the hub.
2014 Vol. 32 (2): 103-107 [Abstract] ( 1798 ) [HTML 1KB] [ PDF 26105KB] ( 1230 )
108 Analysis of influence factors on flow rate characteristics in gear pump
Kong Fanyu, He Yuyang, Zheng De, Zhang Hui, Xia Bin
In order to research the important influence factors of the coefficient of the flow rate pulsation φ on the external gear pump, the analytic way of deducing and simulation was adopted. By deducing the formulation of the coefficient of flow rate pulsation, the relationship between gear number, press angle and φ were analyzed. A numerical simulation of the transient flow field of the gear pump was performed by using the moving boundary condition and dynamic mesh method with k-ε turbulent model, and the relationships among the loading pressure,the clearance and the φ were achieved. The result shows that the coefficient of flow rate pulsation will decrease with the increasing of the gear number z or the pressure angle α. It is good for improving the flow rate characteristic of the gear pump. Furthermore, the gear number makes a very similar function in improving the flow characteristics with the pressure angle′s function. On the other hand, the coefficient of the flow rate pulsation will also decrease with the loading pressure p or the clearance δ increasing. The exaggerated loading pressure and clearance δ will lead to the volumetric efficiency decreasing, and this characteristics should be attached great importance in pump design procedure.
2014 Vol. 32 (2): 108-112 [Abstract] ( 1919 ) [HTML 1KB] [ PDF 1479KB] ( 2999 )
113 Numerical analysis on influence of guide vanes on performance of centrifugal pump acting as hydraulic turbine
Yang Junhu, Gong Zhaohui, Xia Shuqiang, Luo Kaikai, Li Hailong
In order to study the effects of guide vanes on the performance of a centrifugal pump acting as hydraulic turbine, CFD software was adopted to simulate the flow field of the pump as turbine which was designed with and without guide vanes. The results show that guide vanes could improve the efficiency, increase the flow rate at the best efficiency point and decrease the required pressure head. Internal flow field analysis shows that the velocity field is improved, and the number of vortexes as well as the size decreases. The static pressure distributions at the inlet of impeller increases. The analysis of velocity moment distribution shows that the variation amplitude of velocity moment with guide vanes is smaller, and symmetrical distribution and smooth change of velocity moment can be found on the ring surface of impeller inlet. When the number of guide vanes is eleven, the variation amplitude of velocity moment is the lowest. With the guide vanes, the injection conditions of impeller and the operation stability are improved.The results are instructive to the optimization design of pumps as turbines.
2014 Vol. 32 (2): 113-118 [Abstract] ( 1620 ) [HTML 1KB] [ PDF 2183KB] ( 1813 )
119 Experimental study on flow of mixed flow pumps
Lu Jinling, Guo Pengcheng, Feng Jianjun, Deng Jia, Luo Xingqi
Mixed flow pumps are widely used in many fields,and the performance of a whole pump is affected by the flow in the impeller to a great extend. To make clear the flow phenomena in mixed flow impellers under design and off-design flow rate conditions, a mixed flow unshrouded impeller was ma-nufactured, and the flow in the impeller at design and off-design flow rates was measured by particle image velocimetry(PIV). In the experiment, the volute was specially designed and manufactured by transparent material. The distribution of time-average relatively velocity from the experiment shows that velocity near blade pressure surface at design flow rate decreases and then increases from inlet to outlet of the impeller, when the velocity near blade suction surface increases and then decreases. The velocity near the suction surface decreases from hub to casing, and the minimal velocity appears near the casing and suction surface. Near the impeller outlet, the relative velocity near blade pressure surface varies a little alone the span direction; and back-flow phenomena can be found at passage outlet near casing and mid-span sections at partial flow rates. To clarify the effect of asymmetrical volute geometry on the velocity distribution, the flow in passages at different impeller relative positions to the volute tongue was tested and the results show that the velocity distributions in different passages are similar.
2014 Vol. 32 (2): 119-124 [Abstract] ( 2007 ) [HTML 1KB] [ PDF 2926KB] ( 1622 )
125 Working conditions diagnosis of surface-driving progressive cavity pump wells based on support vector machine
Liu Guangdong
The frequent faults of surface-driving progressive cavity pump(PCP)wells limit their further development. In order to improve the economic benefits and management level of surface-driving progressive cavity pump wells, a diagnosis method of working conditions of surface-driving PCP well based on support vector machine was proposed. The condition types of PCP wells were subdivided into 10 categories as outputs, and 8 variables were selected as inputs which can represent operation situation of oil wells. Sample sets were established based on the already existing failure oil wells of Jinjia oilfield in Dongsheng group company, and 45 classifiers were built using voting method. Best C and g were determined by three methods including grid optimization, genetic algorithm and particle swarm optimization. The Libsvm toolbox called by Matlab was used to establish and train the SVM model, and 15 PCP wells of Jinjia oilfield in Dongsheng group company were diagnosed to verify the SVM model, and the comparison between support vector machine and artificial neural network was conducted. The results show that the diagnosed working conditions of 14 PCP wells by the SVM method are in accord with their actual working conditions, with an accuracy of 93.33%. Compared to artificial neural network(88.9%), the SVM is more accurate, which is superior for small sample problems, and is a feasible diagnosis method for PCP wells.
2014 Vol. 32 (2): 125-129 [Abstract] ( 2176 ) [HTML 1KB] [ PDF 1030KB] ( 1507 )
130 Energy conversion mechanism of screw centrifugal pump under single-phase
Quan Hui, Li Rennian, Su Qingmiao, Han Wei, Cheng Xiaorui, Shen Zhengjing
In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, the internal flow in fluid machinery is analyzed theoretically. Based on Eulerian equation adopted, the fluid energy in the impeller was divided into the dynamic pressure and static pressure head, which provides a theoretical foundation for the application of numerical simulation on analyzing the internal flow and the acting ability of various impeller fragments. Navier-Stokes equation and standard k-ε equation turbulence model are used to simulate the screw centrifugal pump internal flow. Taking water as medium, the flow filed including pressure and velocity was simulated under design condition. The monitoring points were taken at screw centrifugal impeller tip and hub, and dynamic head and static head change at the segments between the monitoring points were obtained to analyze the energy conversion capability along the impeller. The results show that the energy of fluid of the screw centrifugal pump is provided by helical segments, and the front helical segments of the impeller played a multi-level role. The impeller makes fluid from axial to radial completion of the transition, in which fluid velocity of axial changes from large to small while radial velocity is vise versa.
2014 Vol. 32 (2): 130-135 [Abstract] ( 1632 ) [HTML 1KB] [ PDF 5679KB] ( 1733 )
136 Characteristics of energy dissipation and pressure within inner energy dissipaters of tooth block
Zhang Ting, Tian Chun, Li Yongye, You Zhiqiang, Fan Pan
Combining the common inner dissipation way of the orifice and the plug in water pipe or spillway with the dissipation way in free flow, the inner energy dissipater of tooth block was proposed, and the tooth block with different area contraction ratio by physical modeling experiment was studied to analyze its conveyance capacity, dissipation ratio, pressure changes along the tube and the characteristics of fluctuating pressure. The results show that the conveyance capacity of tooth block dissipater is mainly determined by the energy dissipater′s shape and size. The conveyance capacity is proportional to the area contraction ratio, while the energy dissipation ratio is opposite. The time-averaged pressure of schemes drops suddenly in contraction section, then gradually rises and returns to stability, and their recovering length is almost the same. The maximum point of pressure fluctuation appears at 1 time tunnel diameter away from outlet of the tooth block, and decreases rapidly along the tube, and then becomes stability after 4 times tunnel diameter. The tooth block with area contraction ratio of 0.471 2 has a better capacity of resisting cavitation than others as its pulsating strength is small, and its distribution of the probability density is approximate to Gauss distribution.
2014 Vol. 32 (2): 136-139 [Abstract] ( 1533 ) [HTML 1KB] [ PDF 1341KB] ( 1884 )
140 Design of embedded electro-hydraulic servo synchronous system
Wang Hongjie, He Xiaolin, Li Deyou, Zhao Junlong, Li Zheng,
Reasonable control method and high-performance measurement and control system can effectively enhance the synchronization accuracy of electro-hydraulic servo system, which is of great significance for improving the performance of cylindrical valve and governor of a turbine. Considering the characteristics of synchronous multi-loop system, an improved control method was proposed to add controller to each circuit for signal pre-processing. The measurement and control system is based on PXIe embedded platform, combining the advantage of embedded R-T controller and synchronization data acquisition card to gain efficient control over the system and the software employed by LabVIEW is responsible for data collecting and processing. Preliminary test was made on the two-cylinder synchronous system. The results show that this hydraulic system works well and achieves the design requirement. System′s synchronous errors reduce from 0.40 mm to 0.15 mm and meet the requirement. The design reflects that embedded system is superior in the control of synchronous system as its high speed and reliability, it can effectively improve the control accuracy of the cylinder valve and speed governor.
2014 Vol. 32 (2): 140-145 [Abstract] ( 1360 ) [HTML 1KB] [ PDF 2386KB] ( 1734 )
146 Dynamic characteristics and aerodynamic performance of vertical axis wind turbine
Gao Wei,, Li Chun, Ye Zhou, Nie Jiabin
The flow field of a vertical axis wind turbine(VAWT)is a typical unsteady large separation flow, which exhibits strong dynamic characteristics. Because of the complexity of aerodynamic perfor-mance for VAWT,it will result in more errors when common engineering algorithms is used to estimate VAWT′s performance. Firstly, the transient flow fields of four NACA symmetric airfoil series on H-type VAWT with different thickness were calculated based on the sliding mesh technique. And the relationship between airfoil dynamic stall and bound vortex generation and development were studied in detail. The range of phase angle when rotor dynamic stall occurs has been obtained and simultaneously the flow mechanism in the airfoil dynamic stall zone was explained preferably at the small tip speed ratio conditions. At the same time, the results also show that airfoil dynamic and static characteristics are very different for a running VAWT, thus the lift-drag coefficient calculation method has been proposed. Secondly, it was also been calculated that the changing trends of four airfoils blade torsion moment, wind electrical power and wind energy utilization coefficient change with the tip speed ratio. The results show that the thickness of airfoil for the blade torsion moment, wind electrical power and wind energy utilization coefficient has great influence. Therefore, the influence of geometry parameters on aerodynamic characteristics should be consided, such as airfoil thickness and rotary dynamic parameter for the design and development of H-type VAWT.
2014 Vol. 32 (2): 146-150 [Abstract] ( 1486 ) [HTML 1KB] [ PDF 3437KB] ( 2625 )
151 Application of magnetic fluid seal in hydraulic turbine shaft
Yu Zhenyan, Zhang Wei
At present the main shaft sealing device of hydraulic turbine is easy to wear and tear, and the leakage is great. In order to solve it, the magnetic fluid seal with the advantages of no contact, no wear, self-healing, long life and so on would be used on the turbine shaft. The oil-based oxide ferromagnetic fluid suitable for sealing water medium was used as sealing material and NdFeB permanent magnet material with high magnetic properties and low prices was used to provide an external magnetic field.Through simulation analysis by using analysis software of electromagnetic field, it is shown that the seal ability is the worst and first to seal fail in the places close to the shaft side in the axial seal and close to the magnetic conductor side in the radial seal, the parameters of the sealing device such as tooth and seal gap have great effect on the sealing performance which is stronger in a certain range of values of tooth and gap.Based on the result above and the characteristics of the turbine shaft seal, the magnetic fluid sealing device with rectangle tooth combined of axial and radial was designed for turbine, while number of axial total poles is 48, the radial is 20-24, the sealing pressures Δp>0.5 MPa.
2014 Vol. 32 (2): 151-155 [Abstract] ( 1499 ) [HTML 1KB] [ PDF 1734KB] ( 2152 )
156 Formula of power function in logarithm form for groundwater irrigation water quality assessment
Zhang Duanmei,, Liang Xiujuan, Li Qinwei
In order to establish a scientific and rational model for irrigation water quality evaluation which can be used simply and effectively, a formula of power function in logarithm form was proposed. Particle swarm optimization(PSO)was used to optimize the parameters in the formula, and the formula for irrigation water quality evaluation applicable to the multi index was obtained. The water quality datum of Alar Reclamation Area, Yuli County in Xinjiang, Pingluo County in Autonomous Region County were taken as examples. The results show that the evaluation results of the formula were basically in accord with those obtained by other evaluation methods including comprehensive hazard coefficient method, fuzzy comprehensive evaluation method and catastrophe theory. The groundwater of Alar Reclamation A-rea in Xinjiang and Pingluo County in Autonomous Region County were suitable for agricultural irrigation, and shallow groundwater of irrigated plains in Yuli County of Xinjiang was not suitable for long-term direct irrigation. The formula of irrigation water quality evaluation has the advantages that it is simple and convenient, and irrigation water quality evaluation results can be quickly obtained. In this way, a new effective approach for agricultural irrigation water quality assessment was suggested.
2014 Vol. 32 (2): 156-161 [Abstract] ( 1518 ) [HTML 1KB] [ PDF 1137KB] ( 2094 )
162 Analysis and multivariate regression model for energy consumption of small-scale sprinkler irrigation machine
Tu Qin, Li Hong, Wang Xinkun, Hu Bin, Tang Pan
In order to investigate the impacts of configuration parameters on the energy consumption of small-scale sprinkler irrigation machine, an orthogonal design of four factors on three levels conside-ring effect of interactions was employed. The influences of pipe diameter, sprinkler spacing, number of sprinklers and working pressure of sprinkler head together with the interactions between them on the energy consumption of the sprinkler irrigation machine typed 4.4CP-45 were analyzed based on the energy consumption calculation model. A multivariate regression model for the computation of energy consumption was established. The results indicate that the impact of working pressure of the sprinkler head comes first, followed by that of pipe diameter, and the impact of number of sprinklers is also obvious. The impact of sprinkler spacing is manifested in the interactions with the other factors. Among four major interaction items, the interaction between sprinkler spacing and number of sprinklers is the most notable, interactions between pipe diameter and number of sprinklers, sprinkler spacing and pipe diameter, sprinkler spacing and working pressure of sprinkler head come in order. Therefore, the interactions between factors cannot be neglected in the configuration of sprinkler systems. Based on the comparison analysis, the optimal combination of parameters for configuration of the sprinkler machine is obtained, with the parameters of sprinkler spacing 15m, pipe diameter 80mm, number of sprinklers 9, working pressure of the sprinkler head 0.25MPa. The specific energy consumption of the system is 4.53 kW·h/(mm·hm2), 22.6% lower than that before optimization and 1.0% lower than that without consideration of interactions between factors, and the configuration parameters are comparatively more acceptable to the customers in practice. The multiple correlation coefficient and coefficient of determination of the multivariate regression model is 0.88 and 0.774 respectively, thus the model is reliable. The discussion may provide a reference for the design and performance evaluation of sprinkler systems. 
2014 Vol. 32 (2): 162-166 [Abstract] ( 1470 ) [HTML 1KB] [ PDF 1500KB] ( 1468 )
167 Research on removal effects of pond wetland system on nitrogen and phosphorus in paddy field drainage
Wu Jun,, Cui Yuanlai, Zhao Shujun, Tong Xiaoxia,
To determine the removal effects of lotus pond wetlands on nitrogen and phosphorus(N&P)in the paddy field drainage, an in-situ field experiment was conducted in Jiangxi Central Irrigation Experimental Station. The main goal of the experiment is to determine the best area ratio β of lotus pond wetlands to farmlands(most paddy field)and the best WRT(water retention time)for effective N&P reduction. Results show that, lotus wetlands have significant effects on N&P reduction, taking removal rate index of TN,NH+4-N,NO-3-N,TP as targets. The removal rates were generally increased with WRT extend at the first three to four days after drainage water putting in, and the increase of removal rates weren't obvious after that, which means the best WRT is three days. Lotus wetlands during seedling formation or flowering fruit bearing growing stage have much better removal effects on N&P than rhizome bearing growing stage. Based on the datum of seedling formation and flowering fruit bearing growing stage, the removal efficiency of TN,NH+4-N,NO-3-N were in sequence of SD1>SD2>SD3. Although the difference between SD1 and SD2 was not significant, they were both much higher than SD3. The removal effects on phosphorus had no significant difference among the three different β wetlands. Considering both economic and N&P removal efficiency, 1∶6 of SD2 is the best β in local area. With three days WRT in SD2, the average removal rate of TN,NH+4-N,NO-3-N and TP is respectively 72.5%,71.7%,55.6% and 69.5% during seedling formation and flowering fruit bearing growing stage of lotus. 
2014 Vol. 32 (2): 167-172 [Abstract] ( 1340 ) [HTML 1KB] [ PDF 1273KB] ( 1604 )
173 Analysis of production efficiency of irrigation districts based on DEA method:Take Jiangsu province as an example
Cao Xinchun,, Wu Pute,,, Wang Yubao,, Zhao Xining,, Liu Jing
Most agricultural production efficiency evaluations of irrigation district are based on single input and output index now. We used data envelopment analysis(DEA)method and set the input and output index system which can represent the characterization of production efficiency, after that we compared the relative production efficiency of 35 irrigation districts in Jiangsu using the CCR model as an example. Results showed that the comprehensive efficiency of Jiangsu province was not high; The differences between irrigation area were large; The average value of the comprehensive efficiency of Jiangsu was 0.634; Three irrigation districts were DEA effective; The popularization and utilization of agricultural production technology in different region were at the same rate; The imbalance of relative production efficiency of irrigation districts was mainly caused by the unreasonable production scale; We can increase the production efficiency of DEA ineffective irrigation area by reducing the input;The effective irrigation area, water resources and agricultural population we can saved in all the DEA ineffective irrigation districts were accounts for 20.7%,13.3% and 9.4% respectively by improving production efficiency when compared with the input. The comparison of the relative DEA efficiency can provide a new method for irrigation production efficiency improvement and the calculation of agricultural water saving potential.
2014 Vol. 32 (2): 173-178 [Abstract] ( 1238 ) [HTML 1KB] [ PDF 1133KB] ( 1540 )
179 Response of grapes growth by alternate partial root-zone drip irrigation
Wang Weihua, Li Shuqin, Wu Zhongdong
As the shortage of water resources in the extreme arid region, field experiments of grapes were studied, and alternate partial root zone drip irrigation mode was considered to analyze the grape ecological indicators and water distribution on root zone. The results show that the changes of grape shoot relative growth rate and leaf area index with time can be described by Logistic model. The leaf area indexes of alternate drip irrigation and conventional drip irrigation don't have significant differences analyzed by single factor analysis of variance. That means no significant effect of alternate drip irrigation on the main organ of plant namely the grape leaf exists. Under the joint action of soil evaporation, root absorption, gravitational potential and the water potential gradient, soil moistures of furrow and ridge raise alternately by alternate drip irrigation. And the change of soil moisture can be mainly found in the 0-60 cm soil layer. Results show that, water consumption and soil evaporation of grape irritated by alternate drip irrigation were less than by conventional drip irrigation, and the efficiency of water utilization was improved at the same time. The study provides scientific references for the water saving irrigation in extremely arid areas.
2014 Vol. 32 (2): 179-184 [Abstract] ( 1463 ) [HTML 1KB] [ PDF 1250KB] ( 1485 )
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