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Stochastic back analysis of permeability coefficient using generalized Bayesian method
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作者 Zheng Guilan Wang Yuan +1 位作者 Wang Fei Yang Jian 《Water Science and Engineering》 EI CAS 2008年第3期83-92,共10页
Owing to the fact that the conventional deterministic back analysis of the permeability coefficient cannot reflect the uncertainties of parameters, including the hydraulic head at the boundary, the permeability coeffi... Owing to the fact that the conventional deterministic back analysis of the permeability coefficient cannot reflect the uncertainties of parameters, including the hydraulic head at the boundary, the permeability coefficient and measured hydraulic head, a stochastic back analysis taking consideration of uncertainties of parameters was performed using the generalized Bayesian method. Based on the stochastic finite element method (SFEM) for a seepage field, the variable metric algorithm and the generalized Bayesian method, formulas for stochastic back analysis of the permeability coefficient were derived. A case study of seepage analysis of a sluice foundation was performed to illustrate the proposed method. The results indicate that, with the generalized Bayesian method that considers the uncertainties of measured hydraulic head, the permeability coefficient and the hydraulic head at the boundary, both the mean and standard deviation of the permeability coefficient can be obtained and the standard deviation is less than that obtained by the conventional Bayesian method. Therefore, the present method is valid and applicable. 展开更多
关键词 permeability coefficient stochastic back analysis generalized Bayesian method variable metric algorithm
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Symmetry Groups and New Exact Solutions to (2+1)-Dimensional Variable Coefficient Canonical Generalized KP Equation 被引量:7
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作者 ZHANG Li-Hua LIU Xi-Qiang BAI Cheng-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3X期405-410,共6页
In this paper, the modified CK's direct method to find symmetry groups of nonlinear partial differential equation is extended to (2+1)-dimensional variable coeffficient canonical generalized KP (VCCGKP) equation... In this paper, the modified CK's direct method to find symmetry groups of nonlinear partial differential equation is extended to (2+1)-dimensional variable coeffficient canonical generalized KP (VCCGKP) equation. As a result, symmetry groups, Lie point symmetry group and Lie symmetry for the VCCGKP equation are obtained. In fact, the Lie point symmetry group coincides with that obtained by the standard Lie group approach. Applying the given Lie symmetry, we obtain five types of similarity reductions and a lot of new exact solutions, including hyperbolic function solutions, triangular periodic solutions, Jacobi elliptic function solutions and rational solutions, for the VCCGKP equation. 展开更多
关键词 (2+1)-dimensional variable coefficient canonical generalized KP (VCCGKP) equation modified CK's'direct method symmetry groups Lie symmetry similarity reductions new exact solutions
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SIMILARITY REDUCTIONS FOR 2+1-DIMENSIONAL VARIABLE COEFFICIENT GENERALIZED KADOMTSEV-PETVIASHVILI EQUATION 被引量:1
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作者 闫振亚 张鸿庆 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第6期645-650,共6页
With the aid of MATHEMATICA, the direct reduction method,vas extended and applied in 2 + 1-dimensional variable coefficient generalized Kadomtsev-Petviashvili equation( VCGRPE). As a result, several kinds of similarit... With the aid of MATHEMATICA, the direct reduction method,vas extended and applied in 2 + 1-dimensional variable coefficient generalized Kadomtsev-Petviashvili equation( VCGRPE). As a result, several kinds of similarity reductions for VCGKPE are obtained which contain Painleve I, Painleve II and Painleve ni reductions. 展开更多
关键词 variable coefficient generalized Kadomtsev- Petviashvili equation direct reduction method similarity reduction
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Direct Reduction and Exact Solutions for Generalized Variable Coefficients 2D KdV Equation under Some Integrability Conditions 被引量:2
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作者 M.H.M.Moussa RehabM.El-Shiekh 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第4期551-554,共4页
Based on the closed connections among the homogeneous balance (HB) method and Clarkson-KruSkal (CK) method, we study the similarity reductions of the generalized variable coefficients 2D KdV equation. In the meant... Based on the closed connections among the homogeneous balance (HB) method and Clarkson-KruSkal (CK) method, we study the similarity reductions of the generalized variable coefficients 2D KdV equation. In the meantime it is shown that this leads to a direct reduction in the form of ordinary differential equation under some integrability conditions between the variable coefficients. Two different cases have been discussed, the search for solutions of those ordinary differential equations yielded many exact travelling and solitonic wave solutions in the form of hyperbolic and trigonometric functions under some constraints between the variable coefficients. 展开更多
关键词 direct reduction method the generalized variable coefficients 2D KdV equation exact solutions
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New Multiple Soliton-like and Periodic Solutions for (2+l)-Dimensional Canonical Generalized KP Equation with Variable Coefficients 被引量:3
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作者 ZHANG Li-Hua LIU Xi-Qiang BAI Cheng-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5X期793-798,共6页
In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit ... In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit exact solutions, which contain multiple soliton-like and periodic solutions, are obtained for the (2+1)-dimensional OGKP equation with variable coetffcients. 展开更多
关键词 (2+1)-dimensional canonical generalized (CGKP) equation with variable coefficients tanh function method Riccati equation soliton-like and periodic solutions
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Exact Solutions of Generalized Burgers-Fisher Equation with Variable Coefficients 被引量:1
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作者 陈博奎 闵松强 汪秉宏 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第3期443-449,共7页
The generalized Riccati equation vational expansion method is extended in this paper. Several exact solutions for the generalized Burgers-Fisher equation with variable coefficients are obtained by this method, and som... The generalized Riccati equation vational expansion method is extended in this paper. Several exact solutions for the generalized Burgers-Fisher equation with variable coefficients are obtained by this method, and some of which are derived for the first time. It is concluded from the results that this approach is simple and efficient even in solving partial differential equations with variable coefficients. 展开更多
关键词 generalized Riccati equation rational expansion method generalized variable coefficient Burgers-Fisher equation exact solution
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Similarity Solutions for Generalized Variable Coefficients Zakharov-Kuznetsov Equation under Some Integrability Conditions 被引量:1
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作者 M.H.M.Moussa Rehab M.El-Shiekh 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第10期603-608,共6页
In this paper, the symmetry method has been carried over to the generalized variable coefficients Zakharov- Kuznetsov equation. The infinitesimal symmetries and the optimal system are deduced and from this optimal sys... In this paper, the symmetry method has been carried over to the generalized variable coefficients Zakharov- Kuznetsov equation. The infinitesimal symmetries and the optimal system are deduced and from this optimal system seven basic fields are determined, and for every vector field in the optimal system the admissible forms of the coefficients are found and this also leads us to transform the given equation into partial differential equations in two variables. After using some referenced transformations the mentioned partial differential equations eventually reduce to ordinary differential equations. The search for solutions to those equations has yielded many exact solutions in most cases. 展开更多
关键词 symmetry method the generalized variable coefficients Zakharov-Kuznetsov equation exact solutions
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Wronskian and Grammian Solutions for Generalized (n + 1)-Dimensional KP Equation with Variable Coefficients
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作者 Hongwei Fu Yang Song Juan Xu 《Applied Mathematics》 2012年第2期154-157,共4页
The generalized (n + 1)-dimensional KP equation with variable coefficients is investigated in this paper. The bilinear form of the equation has been obtained by the Hirota direct method. In addition, with the help of ... The generalized (n + 1)-dimensional KP equation with variable coefficients is investigated in this paper. The bilinear form of the equation has been obtained by the Hirota direct method. In addition, with the help of Wronskian technique and the Pfaffian properties, Wronskian and Grammian solutions have been generated. 展开更多
关键词 generalized Variable coefficient (n + 1)-Dimensional KP Equation HIROTA Bilinear method WRONSKIAN SOLUTION Grammian SOLUTION
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Generalized Likelihood Ratio Tests for Varying-Coefficient Models with Censored Data
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作者 Rong Jiang Wei-Min Qian 《Open Journal of Statistics》 2011年第1期19-23,共5页
In this paper, we extend the generalized likelihood ratio test to the varying-coefficient models with censored data. We investigate the asymptotic behavior of the proposed test and demonstrate that its limiting null d... In this paper, we extend the generalized likelihood ratio test to the varying-coefficient models with censored data. We investigate the asymptotic behavior of the proposed test and demonstrate that its limiting null distribution follows a distribution, with the scale constant and the number of degree of freedom being independent of nuisance parameters or functions, which is called the wilks phenomenon. Both simulated and real data examples are given to illustrate the performance of the testing approach. 展开更多
关键词 VARYING coefficient Model generalized LIKELIHOOD RATIO Test Local Linear method Wilks Phenomenon CENSORING
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A General Calculating Method of Rotor’s Torsional Stiffness Based on Stiffness Influence Coefficient 被引量:1
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作者 Danmei Xie Wangfan Li +3 位作者 Ling Yang Yong Qian Xianbo Zhao Zhigang Gao 《Engineering(科研)》 2010年第9期698-704,共7页
In order to develop a general calculating rotor’s torsional stiffness based on stiffness influence coefficient for different rotor assembling, the calculation method of the torsional stiffness influence coefficient o... In order to develop a general calculating rotor’s torsional stiffness based on stiffness influence coefficient for different rotor assembling, the calculation method of the torsional stiffness influence coefficient of equal thickness disc is researched in this paper at first. Then the torsional stiffness influence coefficient λ of equal thickness disc is fit to a binary curved face and a calculation equation is obtained based on a large quantity of calculating data, which lays the foundation for research on a general calculating method of rotor torsional stiffness. Thirdly a simplified calculation method for equivalent stiffness diameter of stepped equal thickness disc and cone disc in the steam turbine generators is suggested. Finally a general calculating program for calculating rotor’s torsional vibration features is developed, and the torsional vibration features of a verity of steam turbine rotors are calculated for verification. The calculating results show that stiffness influence coefficient λ of equal-thickness disc depends on parameters of B and H, as well as the stiffness influence coefficient λ;and discs with complex structure can be simplified to equal-thickness discs with little error by using the method suggested in this paper;error can be controlled within 1% when equivalent diameter of stiffness is calculated by this method. 展开更多
关键词 ROTOR DISC generAL CALCULATING method Torsional STIFFNESS STIFFNESS Influence coefficient
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EXACT SOLUTIONS FOR GENERAL VARIABLE-COEFFICIENT KdV EQUATION 被引量:8
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作者 Liu Xiqiang Jiang SongGraduate School, China Academy of Engineering and Physics, P.O. Box 2101, Beijing 100088 Dept. of Math., Liaocheng Teachers Univ., Shandong 252000. Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beiji 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第4期377-380,共4页
By asing the nonclassical method of symmetry reductions, the exact solutions for general variable coefficient KdV equation with dissipative loss and nonuniformity terms are obtained. When the dissipative loss and non... By asing the nonclassical method of symmetry reductions, the exact solutions for general variable coefficient KdV equation with dissipative loss and nonuniformity terms are obtained. When the dissipative loss and nonuniformity terms don't exist, the multisoliton solutions are found and the corresponding Painleve II type equation for the variable coefficient KdV equation is given. 展开更多
关键词 general variable coefficient KdV equation nonclassical method of symmetry reduction exact solution.
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Seepage simulation of high concrete-faced rockfill dams based on generalized equivalent continuum model 被引量:6
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作者 Shou-kai Chen Qi-dong He Ji-gang Cao 《Water Science and Engineering》 EI CAS CSCD 2018年第3期250-257,共8页
This research focused on the three-dimensional(3 D) seepage field simulation of a high concrete-faced rockfill dam(CFRD) under complex hydraulic conditions. A generalized equivalent continuum model of fractured rock m... This research focused on the three-dimensional(3 D) seepage field simulation of a high concrete-faced rockfill dam(CFRD) under complex hydraulic conditions. A generalized equivalent continuum model of fractured rock mass was used for equivalent continuous seepage field analysis based on the improved node virtual flow method. Using a high CFRD as an example, the generalized equivalent continuum range was determined, and a finite element model was established based on the terrain and geological conditions, as well as structural face characteristics of the dam area. The equivalent seepage coefficients of different material zones or positions in the dam foundation were calculated with the Snow model or inverse analysis. Then, the 3 D seepage field in the dam area was calculated under the normal water storage conditions, and the corresponding water head distribution, seepage flow, seepage gradient, and seepage characteristics in the dam area were analyzed. The results show that the generalized equivalent continuum model can effectively simulate overall seepage patterns of the CFRD under complex hydraulic conditions and provide a reference for seepage analysis of similar CFRDs. 展开更多
关键词 Concrete-faced ROCKFILL dam(CFRD) generalized equivalent CONTINUUM model Node virtual flow method Fractured rock mass SEEPAGE field SEEPAGE coefficient
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Fuzzy Varying Coefficient Bilinear Regression of Yield Series
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作者 Ting He Qiujun Lu 《Journal of Data Analysis and Information Processing》 2015年第3期43-54,共12页
We construct a fuzzy varying coefficient bilinear regression model to deal with the interval financial data and then adopt the least-squares method based on symmetric fuzzy number space. Firstly, we propose a varying ... We construct a fuzzy varying coefficient bilinear regression model to deal with the interval financial data and then adopt the least-squares method based on symmetric fuzzy number space. Firstly, we propose a varying coefficient model on the basis of the fuzzy bilinear regression model. Secondly, we develop the least-squares method according to the complete distance between fuzzy numbers to estimate the coefficients and test the adaptability of the proposed model by means of generalized likelihood ratio test with SSE composite index. Finally, mean square errors and mean absolutely errors are employed to evaluate and compare the fitting of fuzzy auto regression, fuzzy bilinear regression and fuzzy varying coefficient bilinear regression models, and also the forecasting of three models. Empirical analysis turns out that the proposed model has good fitting and forecasting accuracy with regard to other regression models for the capital market. 展开更多
关键词 FUZZY VARYING coefficient BILINEAR Regression Model FUZZY Financial Assets YIELD LEAST-SQUARES method generalized Likelihood Ratio Test Forecast
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New Exact Solutions to (2+1)-Dimensional Variable Coefficients Broer-Kaup Equations
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作者 ZHU Jia-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3X期393-396,共4页
In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. The... In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. These solutions include Weierstrass function solution, solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. Because of the three or four arbitrary functions, rich localized excitations can be found. 展开更多
关键词 variable coefficient generalized projected Ricatti equation method (2+l)-dimensional variable coefficients Broer-Kaup equations Weierstrass function solution solitary wave solution trigonometric function solution
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PainlevéAnalysis of Higher Order Nonlinear Evolution Equations with Variable Coefficients
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作者 Wang Yuan 《Chinese Quarterly Journal of Mathematics》 2021年第2期196-203,共8页
There is a close relationship between the Painlevéintegrability and other integrability of nonlinear evolution equation.By using the Weiss-Tabor-Carnevale(WTC)method and the symbolic computation of Maple,the Pain... There is a close relationship between the Painlevéintegrability and other integrability of nonlinear evolution equation.By using the Weiss-Tabor-Carnevale(WTC)method and the symbolic computation of Maple,the Painlevétest is used for the higher order generalized non-autonomous equation and the third order Korteweg-de Vries equation with variable coefficients.Finally the Painlevéintegrability condition of this equation is gotten. 展开更多
关键词 Higher order generalized non-autonomous equation Third order Korteweg-de Vries equation with variable coefficients Painlevéanalysis method
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A New 2 + 1-Dimensional Integrable Variable Coefficient Toda Equation
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作者 Yanan Huang Junhong Yao Ting Su 《Journal of Applied Mathematics and Physics》 2021年第8期2152-2158,共7页
In this paper, a new integrable variable coefficient Toda equation is proposed by utilizing a generalized version of the dressing method. At the same time, we derive the Lax pair of the new integrable variable coeffic... In this paper, a new integrable variable coefficient Toda equation is proposed by utilizing a generalized version of the dressing method. At the same time, we derive the Lax pair of the new integrable variable coefficient Toda equation. The compatibility condition is given, which insures that the new Toda equation is integrable. To further analyze the character of the Toda equation, we derive one soliton solution of the obtained Toda equation by using separation of variables. 展开更多
关键词 The generalized Dressing method Variable coefficient Toda Separation of Variables
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基于反射系数谱的配电电缆局部缺陷识别定位
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作者 赵洪山 郭潇镁 +1 位作者 马利波 王艳 《华北电力大学学报(自然科学版)》 CAS 北大核心 2024年第4期9-17,共9页
传统配电电缆在局部缺陷识别与精准定位上灵敏度较差,位置范围识别受到限制,为解决现有技术在配电电缆缺陷诊断上存在的不足,提出一种基于反射系数谱的配电电缆局部缺陷识别定位方法。首先依据电缆分布参数模型,获得配电电缆完好状态与... 传统配电电缆在局部缺陷识别与精准定位上灵敏度较差,位置范围识别受到限制,为解决现有技术在配电电缆缺陷诊断上存在的不足,提出一种基于反射系数谱的配电电缆局部缺陷识别定位方法。首先依据电缆分布参数模型,获得配电电缆完好状态与存在局部缺陷段的反射系数谱,然后利用广义正交积分法,将反射系数谱的虚部从频域转换到空间域,建立积分诊断图,得到具有直观性的定位图谱,根据积分诊断图实现配电电缆局部缺陷的识别与精准定位,方法适用于同时存在多处电缆缺陷的情况。最后,在实验室50 m长的配电电缆上制作老化与破损两种缺陷,用于验证所提方法的有效性。仿真和实验结果表明,该方法对不同缺陷情况均具有较高的识别精度,定位误差小于0.15 m。 展开更多
关键词 反射系数谱 分布参数 局部缺陷 广义正交积分法 配电电缆
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n 的多项式为系数的幂级数和函数注记
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作者 张奇业 王创坤 徐宇鑫 《大学数学》 2024年第1期99-107,共9页
研究了以n的多项式为系数的幂级数的和函数的求解问题,给出了这类幂级数和函数的一种求解方法,并得到了其和函数的通用计算公式,通过实例验证了公式的正确性.文中还得到了两个关于组合数的等式.
关键词 幂级数 多项式系数 和函数 通用形式 数学归纳法
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考虑主轴疲劳载荷的虚拟同步双馈风电场有功功率分布式优化方法
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作者 王瀚博 刘颖明 +3 位作者 王晓东 郭国先 王黎明 王瑛玮 《电网技术》 EI CSCD 北大核心 2024年第9期3643-3652,I0036,I0037,共12页
为降低风电场内各台基于虚拟同步发电机控制策略的双馈风电机组在响应电网功率指令值变化时所承受的主轴疲劳载荷,提出一种基于改进惩罚系数的交替方向乘子法的考虑主轴疲劳载荷的有功功率分布式优化方法。在推导可量化表征机组有功功... 为降低风电场内各台基于虚拟同步发电机控制策略的双馈风电机组在响应电网功率指令值变化时所承受的主轴疲劳载荷,提出一种基于改进惩罚系数的交替方向乘子法的考虑主轴疲劳载荷的有功功率分布式优化方法。在推导可量化表征机组有功功率指令值与其主轴力矩之间关系的离散化模型基础上,以各台机组的主轴力矩波动总和最小作为目标函数,并根据机组运行状态设定目标函数的约束条件。为分担风电场中央控制器的计算压力,基于改进惩罚系数的交替方向乘子法将目标函数拆解为主函数(中央控制器)和多个子函数(本地控制器)的分布式优化结构,各本地控制器通过在线优化各台机组有功功率指令值以实现主轴疲劳载荷的降低。最后,仿真结果验证了所提优化方法的优越性。 展开更多
关键词 风电场 主轴疲劳载荷 虚拟同步发电机 改进惩罚系数的交替方向乘子法 分布式优化方法
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二级射流真空发生器的结构参数优化设计 被引量:1
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作者 詹友基 吴晋泽 郑天清 《液压与气动》 北大核心 2024年第7期44-52,共9页
为提升二级射流真空发生器的真空度和引射系数,建立以空气为介质的二级射流真空发生器仿真模型,通过仿真模型获取相关性能数据。在此基础上,运用响应面法构建二级射流真空发生器结构参数对其真空性能影响的拟合数学模型,以真空度和引射... 为提升二级射流真空发生器的真空度和引射系数,建立以空气为介质的二级射流真空发生器仿真模型,通过仿真模型获取相关性能数据。在此基础上,运用响应面法构建二级射流真空发生器结构参数对其真空性能影响的拟合数学模型,以真空度和引射系数为优化目标,通过求解拟合数学模型,确定了二级射流真空发生器的最优结构参数组合。结果表明:优化后二级射流真空发生器的真空度增加了13.9%,引射系数增加了26.3%。 展开更多
关键词 多级真空发生器 结构优化 引射系数 真空度 响应面法
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