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质量漏和传质不可逆性对化学泵循环性能的影响 总被引：1，自引：0，他引：1
建立不可逆化学泵循环模型，揭示质量传递不可塑性和质量漏对其性能的影响，导出循环的泵能率与性能系数间的优化关系，在此基础上进一步讨论循环的其它优化特性，所得结论可为质量交换器，电化学、光化学、固态设备及燃油泵等设备的优化设计提供新的理论指导。 相似文献
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循环水泵作为汽轮发电机组电力生产的重要辅机,其振动安全对电力生产可靠性影响显著。由于泵内水流的水动力学作用以及轴系的立式不稳定结构,都导致了凝结水泵和循环水泵复杂多样的振动故障。这些故障通常涉及泵内流体激振、结构共振、轴系失稳、机械磨损、安装质量以及多种故障的耦合。下面通过实际故障案例介绍分析这些故障的特征、振动机理以及处理方案。 相似文献
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研究在非线性传热情况下,热阻和有限速率过程对卡诺热泵性能的影响.导出了最佳泵热率与致热系数之间的关系,并进行了讨论. 相似文献
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介绍工程塑料泵的改造实践。针对工程塑料泵在净化的洗渣工序压滤中存在轴封容易磨损而泄漏、叶轮的金属件与叶轮母体容易脱落而失效等问题进行了详细的分析,并提出了改造措施。经改造后轴封及叶轮的性能得到了有效的改善。 相似文献
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介绍锥形鱼尾三翼螺旋泵吸反循环钻头结构特点,分析多年对泵吸反循环钻头研制、改进探讨及成型;不同钻头结构,碎岩方式不同,取得的不同效果;概述锥形鱼尾三翼螺旋泵吸反循环钻头在三、四纪地层各类大口径工程钻进中深井应用实例。 相似文献
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本文主要讨论变量泵在双护盾硬岩掘进机TBM主推进系统上的应用和控制。TBM为一种高能耗的工程机械,液压泵作为液压系统的核心元件,其技术水平和性能的的高低,在很大的程度上决定了主机的整体性能和质量。因此,为了减小能耗,使动力元件和负载之间达到功率的最佳匹配,选择适合的变量泵及其控制方式尤为重要。 相似文献
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A performance index consisting of a Chebyshev absolute maximum functional plus terminal and integral cost is applied to the optimal control of dynamical systems. First-order necessary conditions are derived for a large class of systems. Utilizing the necessary conditions, analytic examples are worked in demonstrating many of the properties of this class of systems. 相似文献
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利用变分法导出量子力学系统中一类最优控制问题的方程组，并使用具有最优搜索步长的开关变尺度法对最优控制问题进行数值迭代求解，最后在自旋1/2粒子上进行了系统仿真实验，验证了本文方法的有效性，同时对性能指标中参数的不同选择对整个最优控制效果影响的一般规律进行了分析。 相似文献
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In this paper the problem of memoryless discrete time detection of a constant signal in additive φ-mixing noise is considered. The fidelity criterion is taken to be the asymptotic relative efficiency. The optimal detector nonlinearity is approximated by a polynomial, and the statistical knowledge required for the design of the detector is the family of joint moments of the noise, resulting in a very simple design procedure for the detector. It is shown that the performance of this detector can be made arbitrarily close to that of the optimal memoryless detector for a large class of noises. 相似文献
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Yi-Yuan Li Sara Ying Zhang Jason Zheng Jiang Simon Neild 《Journal of The Franklin Institute》2019,356(14):7836-7854
Vibration suppression capabilities of linear passive vibration absorbers, such as traditional tuned mass damper (TMD), and recently proposed inerter-based vibration absorbers, have been studied for multiple mechanical systems. In particular, significant performance advantages have been obtained with a specific device making use of both inerter and mass elements, namely the tuned mass damper inerter (TMDI). However, there are still countless mass-included inerter-based configurations that have not been studied, which can potentially provide more preferred dynamic properties. In this paper, an immittance-function-layout (IFL) is introduced, which can cover a large range of topological connection possibilities with both mass and inerter elements. With the recently proposed structural immittance format, a systematic approach is established to identify the most beneficial IFL type mass-included inerter-based configurations with pre-determined number of each element type. Vibration suppression performance with single-IFL type device and two parallel-connected IFLs (i.e. dual-IFL) type devices are investigated in this paper. Three optimal configurations are identified for mitigating the maximum inter-storey drift of an example 3-storey building model subjected to base excitation. With this 3-storey building model, results show that, for the optimum single-IFL configuration, the performance improvement is 7.3% compared with the optimum TMDI, and with identified beneficial dual-IFL configurations, up to 34.9% performance advantages are obtained. Furthermore, consistent performance gains are shown under real-life earthquake inputs and with a 10-storey building model using identified absorber configurations. 相似文献
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The usual use of fractals involves self-similar geometrical objects to fill a space, where the self-similar iterations may continue ad infinitum. This is the first paper to propose the use of self-similar mechanical objects that fill an alloted space, while achieving an invariance property as the self-similar iterations continue (e.g. invariant strength). Moreover, for compressive loads, this paper shows how to achieve minimal mass and invariant strength from self-similar structures. The topology optimization procedure uses self-similar iteration until minimal mass is achieved, and this problem is completely solved, with global optimal solutions given in closed form. The optimal topology remains independent of the magnitude of the load. Mass is minimized subject to yield and/or buckling constraints. Formulas are also given to optimize the complexity of the structure, and the optimal complexity turns out to be finite. That is, a continuum is never the optimal structural for a compressive load under any constraints on the physical dimension (diameter). After each additional self-similar iteration, the number of bars and strings increase, but, for a certain choice of unit topology shown, the total mass of bars and strings decreases. For certain structures, the string mass monotonically increases with iteration, while the bar mass monotonically reduces, leading to minimal total mass in a finite number of iterations, and hence a finite optimal complexity for the structure. The number of iterations required to achieve minimal mass is given explicitly in closed form by a formula relating the chosen unit geometry and the material properties. It runs out that the optimal structures produced by our theory fall in the category of structures we call tensegrity. Hence our self-similar algorithms can generate tensegrity fractals. 相似文献
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根据熊彼特关于"创新是‘新的生产函数的建立’,即‘企业家对生产要素之新的整合’"这一经典定义,构建了创新绩效函数W_i=F_i(X_1,X_2,……X_n),其中(X_1,X_2,……X_n)为企业拥有的n个创新要素,W_i为创新绩效。本文研究(1)发现在创新绩效函数中,F_i为(X_1,X_2,……X_n)的整合方式,表示在企业各种创新要素保持不变的情况下,只对这些要素进行不同整合就会为企业带来不同创新绩效,而技术创新模式正是对创新要素进行整合的方式,因此F_i即是技术创新模式。(2)提出如何选择企业最优技术创新模式的原理,即在企业(X_1,X_2,……X_n)不变条件下,能为企业带来最大创新绩效W~*的技术创新模式,就是该企业最优技术创新模式F~*_i。由于F~*_i具体关系式不易清晰界定,故本文将F~*_i的求解过程视为一个黑箱,对其进行了整体拟合。(3)根据最优创新模式选择原理,在建立并评价X、Y、Z、W、F_i的基础上,构建了企业最优技术创新模式选择模型。(4)收集川酒企业样本数据,实证分析川酒企业最优技术创新模式选择过程。 相似文献
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The present paper proposes a numerical approach to a linear optimal control problem with a quadratic performance index. In this technique, the time interval is divided into a number of time segments and all of the unknown functions which appear in the performance index are either interpolated linearly with respect to time or assumed to be constant in each time segment. The augmented performance index is discretized within each time element through the ordinary finite element technique.The main advantage of the present method is as follows: all of the necessary conditions for the performance index to be stationary can be expressed in the form of algebraic equations and the performance sequence of the state variables can be eliminated. As a result, the optimal control problem is reduced to the simple one of finding the sequence of control variables alone, which minimizes the quadratic performance index.A general formulation of the method is given and simple numerical examples are shown to demonstrate the effectiveness of the technique. 相似文献
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This study introduces a novel particle inerter system (PIS) designed for vibration mitigation of structures. The new system comprises an inerter subsystem, a spring, and a tuned particle element, where the spring is used for tuning the particle element and the inerter subsystem is set for energy absorption and dissipation. The structural performance and the vibration mitigation effect of the PIS are assessed in terms of displacement and acceleration responses. An optimal design method is developed for a PIS under a performance-oriented design framework. Following the criterion of lightweight control, the added mass of the PIS is minimized under the constraints of target displacement and acceleration responses. A parametric analysis is performed and the robustness of the PIS for seismic response mitigation is verified. Design cases are carried out for the illustration of the proposed design method. The results show that the structural displacement and acceleration responses can be reduced significantly with the help of a PIS. Compared with the particle tuned mass damper with the same parameters, both the energy absorption and dissipation effects of the PIS are increased and the relative displacement response of the container in the PIS is reduced by the inerter subsystem. Under the same performance target, the required physical mass of the container and particles in the PIS is minimized and is significantly smaller than that of the conventional particle tuned mass damper. 相似文献
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In this paper, the impacts from both cyber and physical attacks are analyzed for a class of networked control systems via a delta operator approach. A comprehensive attack model involving randomly occurred deception attack, denial-of-service attack and physical attack is established. The multi-tasking optimal control strategy is developed in the delta-domain such that the individual cost function for each player is minimized. For quantifying the impacts from attacks, an ?-Nash equilibrium is employed to describe the performance degradation. An explicit upper bound for the ?-Nash equilibrium is provided such that the maximum performance-loss induced by the considered all-around attacks is estimated. Some convex optimization algorithms are provided to compute an upper bound of the ?-Nash equilibrium. Finally, a numerical example is presented to illustrate the validity of the design scheme. 相似文献