相关分析在凸轮型线测量中的应用

以凸轮加工误差的测量对象，对封闭曲线测量中测量结果的对位（相位属性的求解）方法进行研究，提出了可行的算法。较好地解决了凸轮型线及封闭曲线各测量点相位属性的求解问题。     

内燃机缸内气体流动和燃油喷雾混合的大型微机化软件包——GFFSM

本文针对内燃机缸内燃油喷雾与空气混合过程建立了气体湍流流动和燃油喷雾混合的数学模型，采用了发展的ＡＬＥ（Ａｒｂｉｔｒａｒｙ Ｌａｇｒａｎｇｉａｎ－Ｅｕｌｅｒ）法和Ｍｏｎｔｏ Ｃａｒｌｏ数值方法，开发了求解缸内工作过程三维流场的大型通用微机化软件包－ＧＦＦＳＭ。该软件包具有适用范围广、通用性好、几何适应性强和计算效率高的特点。应用结果表明，ＧＦＦＳＭ软件包具有工程实用性和较好的预测精度。     

活塞裙部的润滑分析及活塞系统2阶运动的研究

基于平均流量型分析了活塞裙部的润滑问题，并且与活塞运动方程结合求解了活塞系统２阶运动的轨迹，探讨了活塞结构参数对２阶运动 的影响，计算和比较了在不同参数下活塞初部的摩擦力。     

DF4机车内燃机组合活塞截面型线改进的探讨

对目前ＤＦ４内燃机车１６ＶＺＪ２４０组合活塞截面型线所存在的问题进行了分析和研究，提出采用二次椭圆替代目前的削边圆截面型线的方法。通过试加工和测试，取得了满意的效果。     

活塞外侧形状的椭圆度

作者对国外３４种不同类型，尺寸，结构及材料的内燃机活塞进行了外侧形状椭圆度的对比分析，引述了所得结果。简要分析，说明了国外新设计活塞选用椭圆度值的大致趋势和原因，并针对瑞士ＳＩＭ公司ＴＰＯ－１５０型活塞外形车床讨论了其椭圆度仿形加工的控制问题，提出了一项改进措施。     

高信噪比凸轮型线的设计方法

分析了三种凸轮型线的气门振动加速度自功率谱的测量结果，提出了凸轮型线动态特性的综合评价指标－－信噪比，详细讨论了几种工作段和缓冲段型线对信噪比的影响，最后阐述提高信噪比和高信噪比凸轮型线的设计方法。     

活塞二次椭圆-偏心正圆组合横向型线的计算

针对一种新型铰接活塞的二次椭圆-偏心正圆组合曲线横向型线的计算问题,通过分析,运用数值求解方法,采用MATLAB软件编程,计算出了该活塞横向型线直径收缩量。并将数值计算结果与AutoCAD作图所得直径收缩量和样品实测直径收缩量进行了对比。     

椭圆—幂函数组合凸轮动力学优化设计

本文以椭圆幂函数凸轮型线建立动力学优化设计的数学模型。在设计中将整个配气机构简化成单质点振动模型,用龙格—库塔法求解数值。为了节省机时,选用一种新的优化方法——浮动正交网格法进行优化处理。这种方法也可用于其它凸轮型线的设计。     

裙部型线对活塞裙部混合润滑特性影响的仿真分析

综合考虑了活塞裙部外形轮廓、表面波度、粗糙度、活塞裙部和缸套的热变形以及弹性变形等因素,建立了内燃机活塞裙部混合润滑数学模型,计算分析了工作状态下活塞裙部横向和纵向型线对活塞裙部混合润滑特性的影响.结果表明,裙部横向型线采用上端椭圆度小于下端椭圆度的变椭圆结构较为合适;纵向型线的中凸点位置应偏向裙部下端,以降低裙部摩擦功耗;相对于椭圆和圆曲线型线,纵向抛物线型线具有最小的摩擦功耗.     

活塞立体靠模设计软件

随着内燃机向高速、高负荷、低油耗、低排放及轻量化方向发展,对内燃机零部件的结构设计、材质选用等,逐年均有不断改进,其中活塞结构上较为突出的趋势之一是将活塞裙部制成中凸变椭圆形状.目前在活塞裙部型线设计中,工程设计人员应用活塞评价,预测活塞的工作变形或根据以往成功的设计,经过试验磨合的裙部形状,通过最小二乘法进行曲线拟合,找出其设计规律.本文介绍N阶幂函数回归和指数回归拟合方法,在活塞型线设计中的成功应用以及在此基础上本人完成的活塞中凸变椭圆立体靠模设计软件.实践证明:用最小二乘法完成的活塞立体靠模设计软件,是活塞型线的设计计算中一种行之有效的手段.     

基于遗传算法的转桨式水轮机模型参数辨识

为准确测试转桨式水轮机参数,提出了一种转桨式水轮机数学模型的新表述方法,并探讨了基于遗传算法对新表述数学模型的参数辨识。算例与实际电站参数辨识结果表明,采用辨识参数的模型输出结果与现场实测数据(样本数据)具有较好的一致性,验证了该方法的正确性及在工程实际应用中的可行性,为转桨式水轮机模型参数辨识提供了一种新方法。     

高次多项式动力凸轮优化设计及MATLAB算法实现

建立六项式动力凸轮型线的优化设计数学模型，以此为基础在MATLAB平台上开发较通用的内燃机配气凸轮优化设计程序，包括输入、输出界面和优化算法的实现，为配气凸轮设计提供了一种非常有效的手段。     

Optimization of PEMFC model parameters with a modified particle swarm optimization

In this paper, an electrochemical‐based proton exchange membrane fuel cell (PEMFC) model suitable for engineering applications is presented. In order to improve the accuracy of this model so that it can reflect the actual PEMFC performance better, its parameters are optimized by means of a modified particle swarm optimization (MPSO). The MPSO is a modified method for the PSO's inertia weight. The proposed inertia weight is calculated according to the distance of the particle's current position from the best solution of the entire swarm. The obtained results of the PEMFC model with optimized parameters agree with experimental data well. Therefore, the MPSO is a helpful and reliable technique for optimizing the model parameters and can be used to solve other complex parameter optimization problems of fuel cell models. Copyright © 2010 John Wiley & Sons, Ltd.     

Dynamic problem of fractional order thermoelasticity for a thick circular plate with finite wave speeds

This article is aimed at determining the thermoelastic displacement, stress, and temperature in a thick circular plate of finite thickness and infinite extent whose lower and upper surfaces are traction free, subjected to a given axisymmetric temperature distribution. The problem is formulated in the context of fractional order thermoelasticity theory with finite wave speeds. Integral transform technique is used to obtain the general solution in Laplace transform domain. Inversion of the Laplace transforms is done using a numerical scheme. A mathematical model is prepared for a copper material plate. Thermoelastic stresses, temperature and displacement are shown graphically and the effects of fractional-order parameters are discussed.     

An analytical solution for the field of a hysteresis motor based oncomplex permeability

A closed-form solution for the electromagnetic field distribution inside a hysteresis motor is presented. The solution is based upon Maxwell's field equations, considering the case of a circumferential-flux-type machine at synchronous speed. A hysteresis loop in the shape of an inclined ellipse is adopted. The application of the complex permeability concept to space rotating vectors is explained. A new form for the general solution of Laplace's equation is used. This new form makes it possible to obtain a proper matching between the field components at the rotor outer surface when the scalar potential function is used and the hysteresis is considered. The torque equation is developed in order to allow comparison with test results. The proposed solution is simple, accurate, and rigorous. Comparison with test results shows the accuracy of the method     

The effects of operating conditions on hydrogen production from sodium borohydride using Box-Wilson optimization technique

Sodium borohydride is the most investigated boron compound among hydrogen-carrier materials by researchers because of its stable structure, relatively high hydrogen storage capacity (NaBH₄, 10.8% hydrogen by weighing), comparatively cost-efficiency, and non-flammability. This study aims to produce hydrogen from sodium borohydride solution whose hydrolysis was carried out both in the absence of any catalysts at above 100 °C. In order to increase the rate of hydrogen production using NaBH₄ solution, the initial concentration of HCl and temperature were optimized using the Box- Wilson method. The field of the highest dehydrogenation yield was shown by drawing contour plot for the second order model. As a result of the experiments, the highest dehydrogenation yield (100%) of this solution was achieved in 3.76 M HCl concentration and at 157 °C; besides, the reaction time was the least under these conditions.     

General solution of one-dimensional,time dependent coupled heat flow systems

A new, powerful method of analysis, involving the combined use of finite integral transform and finite element techniques, is presented for the solution of time dependent heat flow systems composed of many one-dimensional elements connected through the nodes. This method leads to an eigenvalue problem which is not of the conventional Sturm-Liouville type. A procedure for the determination of the eigenvalues is described. The solution obtained is in the form of an infinite series and contains quasi-steady and transient terms. The general solution obtained can be applied in the mathematical modelling of many engineering applications such as the determination of the penetration of the daily temperature cycle into buildings, the analysis of heat transfer in array of extended surfaces in compact heat exchangers, and many others.     

全可变气门机构运动学的仿真分析

分析了BMW的N52发动机可变升程气门机构的机械结构原理,然后对机构进行运动学方程推导,得出气门升程与凸轮转角、偏心轮转角之间的数学关系,编制了发动机全可变气门升程运动学计算程序,可以用来计算全可变气门机构的运动学问题,为以后进行动力学计算作准备。     

Second-Law Analysis for an Inclined Channel Containing Porous-Clear Fluid Layers by Using the Differential Transform Method

In this study, convection in a porous medium for a laminar, incompressible, non-Darcy model flow in an inclined channel has been investigated. The flow field considered is composed of porous and clear viscous layers. The solutions are carried out for both clear fluid and porous regions by using the differential transform method (DTM). For the solutions of governing equations, constant values for some parameters such as angle of inclination (φ), porous parameter (σ), and the ratio of the heights of two layers (h) are assigned. In order to verify the applied solution technique, the results obtained are compared to the already existing ones evaluated by perturbation method. It is noticed that the results by two methods are in agreement for small values of Brinkman number (Br). However, for higher values of Br, the solutions carried out by perturbation method lose accuracy but the results of the DTM are still valid. The entropy generation number (N _s ) is derived and plotted by using dimensionless velocity and temperature profiles. One of the advantages of this study to similar studies is to give an open form series solution, which gives a tractable and easily applicable recurative form of nonlinear field equations. In similar studies, it is said that the equations are solved; however, neither solution technique nor accuracy or applicability of given technique are clear. In this work, these are well documented.     

Optimal synthesis of heat-and-power systems: the operating line method

The physical and mathematical models on which the operating line method (OLM) (H. A. Irazoqui, Chem. Engng Sci. 41, 1243–1255 (1986); P. A. Aguirre, E. O. Pavani and H. A. Irazoqui, Chem. Engng Sci. 44, 803–816 (1989)) for the optimal synthesis of heat-and-power systems is built, are discussed in depth. These models include the heat exchange ‘modes’ allowed and the general features of the type of solution sought in order to reach an optimal scheme for the total energy systems in chemical plants. A thorough development of the mathematical technique used to tackle the optimization problem is also made. This development comprises the derivation of the necessary and sufficient conditions for optimality.