车用直喷式柴油机微粒排放与排气烟度、碳氢化合物排放的关系

本文针对自然吸气式车用直喷柴油机６１１０的微粒排放与排气烟度、碳氢化合物的关系进行了试验研究。结果表明，柴油机的微粒排放可按简单的经验关系式根据排气烟度和碳氢化合物排放计算，算出的值和直接通过稀释排气并用滤纸采样法测得的值吻合较好。本算式可用于确定６１１０及类似柴油机按ＥＣＥＲ４９十三工况的微粒加权比排放量，而不必用复杂的微粒测量系统。     

柴油机排气微粒过滤器的一维流体动力学模型

提出了一个一维模型来模拟柴油机排气微粒过滤器内部的流体动力学行为。在一维流体动力学模型中，将排气微粒过滤器简化成内部设有压降元件的直管，简化的直管通过突变的截面与排气管连接，直管中间的压降元件是数学意义上的一个面，没有厚度，但具有实际过滤器的全部阻力。此模型能够反映过滤器内所发生的主要现象，如压力损失、温度变小、压力波的反向与传播。此模型被添加到ＭＫ－１４程序中后，能够精确预测发动机与管路系统之间的相互作用与相互影响。模型通过试验得到了验证。     

由夏比冲击试验结果预测断裂韧性KIC转变曲线的方法

本文介绍，用Ｃｈａｒｐｙ Ｖ－切口冲击值与屈服强度值，预测低合金钢断裂韧性ＫＩＣ转变曲线的两种方法。一种方法，是使用一条各种材料ＫＩＣ／ＫＩＣ－ＵＳ和相关温度关系的主曲线；其中ＫＩＣ－ＵＳ表示上平台温度的断裂韧性值，相关温度是一个ＦＡＴＴ试验温度的负值。另一种方法，是使用一条ＫＩＣ／ＫＩＣ－ＵＳ与Ｔ－Ｔｏ关系的主曲线；且温度的改变量△Ｔ在下平台温度断裂韧性ＫＩＣ－ＬＳ和Ｃｈａｒｐｙ冲击转变曲线之间     

柴油机微粒过滤器的红外加热再生

作者对壁流式陶瓷过滤器的再生进行了研究，并在以往工作的基础上，探索出一种新的再生方法－－红外辐射加热再生。实验情况表明这种再生方法结构简单，再生效率高，可以通过改善过滤器前端的径向辐射换热有效地提高过滤陶瓷内微粒燃烧的均匀性。在实验中影响再生的各种因素进行了分析研究，初步确定了再生的基本条件。     

表面微结构对流动沸腾中核沸腾抑制因子的影响

用两根内表面微结构不同的水平光滑管环状流区流动沸腾换热实验数据，采用叠加模型分别建立了流动沸腾换热关系式，并比较它们的抑制因子。结果表明，表面微结构对抑制因子有显的影响；当表面的平均凹腔半径较大时，抑制因子明显增大。表明表面微结构改变对流动沸腾换热能起到较好的强化作用。     

采用光纤—激光技术对循环流化床内气—固两相流的颗粒浓度和速度分布的…

应用光－电检测方法测量气－固两相流中固体微粒浓度，速度，是一种十分有效和可行的方法。能实时，快速地测量到流化床中局部固体微粒的流速和浓度。对整个流化床中沿床高和某一横截面上固体微粒的流速，浓度分布情况进行了研究。图６参４     

方形分离器三维流场的测定及数值模拟

作者采用热线风速仪测量了方形分离器内部三维速度场并采用Ｋ－ε模型及应力代数模型对其内部的三维流体流动进行了数值模拟。作者还采用Ｘ型热线探头旋转法测量三维流场，提出了改进ｘ型热线探头方向特性方程的具体方法，并通过计算和实验结果的比较得出：在方形分离器内的旋风流动的计算中，Ｋ－ε模型及应力代数模型均得到比较合理的结果，与实验结果符合较好，同时应力代数模型的结果揭示了各向异性湍流的特点。图７参３     

关于燃烧监视器的开发

由于ＭＡＲＫ－Ⅱ控制系统在燃烧监视方面的不足，本文介绍一种在软件上采用ＭＡＲＫ－Ｖ的相应算法，而硬件上采用国产温度巡检仪来完善ＭＡＲＫ－Ⅱ燃烧监视功能不足的方法。     

微粒污垢沉积率的理论分析与实验研究

建立了一个小规模实验装置，利用该装置研究了微粒粒径、表面涂层类型、悬浮液温度等因素对微粒污垢沉积率的影响，得到了非常独特的实验结果。悬浮液温度在50℃时，微粒污垢沉积率最大。基于污垢附着机制对这一实验结果进行分析，理论上证实了在某一悬浮液温度微粒污垢沉积率最大，并进一步推导出了微粒污垢沉积率最大时的悬浮液温度与换热面表面自由能之间的关系式。     

NOx热力反应生成实验关系式研究

在燃烧研究中，ＮＯＸ的实验关系式一直采用０阶近似来处理，当燃烧时间较大时，这种方法误差较大。本文基于Ｚｅｌｄｏｖｉｃｈ的燃烧理论，用近似方法来获得关于ＮＯＸ０阶近似和１阶近似的实验关系式，并提出用反问题中求正规解的思想来选择确定适用于０阶实验关系式的实验数据。     

基于遗传算法的辐射特性反向研究方法

以辐射传递理论和弥散介质理论为基础,采用Pikaia遗传算法建立了物质辐射特性反向计算模型,该模型方法可以计算物质的辐射特性参数(折射率和吸收因子)、特征频率以及高频介电常数,同时确保计算结果满足Kramers-Kronig关系.通过结合实验对流体水、固体二氧化硅以及二氧化钛薄膜的反向计算分析,证明该模型方法能够准确和快速地计算物质各辐射特性参数,具有广泛的应用价值.     

铸铁锅炉扩缩通道流动与换热实验结果分析

在总结实验成果基础上，提出了烟气在铸铁锅炉扩缩通道中的流动阻力系数和对流换热系数的实验关联式，给出了公式的适用范围。同时在实验数据基础上还对扩缩通道的强化换热性能进行了计算分析，得出了最优扩缩角度。     

辐射穿透率在锅炉受热面壁温计算中的应用与研究

辐射穿透率在锅炉受热面壁温计算中很重要,但它对锅炉受热面计算壁温准确性的影响却未能引起充分的关注.从辐射穿透率的定义出发,推导出适合工程计算的公式,并将该研究结果应用于工程改造项目中,取得了良好的预期效果,在使用范围和精度上均能满足锅炉设计计算和校核计算的要求.     

Hydrothermal Characteristics of Spinel Manganese Ferrite Nanofluid in a Metal Foam Tube: Modeling of Experimental Results using Artificial Neural Network

In this research, an experimental evaluation is conducted on the hydrothermal behavior of water-based manganese ferrite nanofluid flowing in a metal foam tube. For this purpose, manganese ferrite nanoparticles are synthesized, and X-ray diffraction and scanning electron microscopy are implemented to specify the samples for determination of phase and size of nanoparticles. The effects of Reynolds number, Prandtl number, and presence of MnFe₂O₄ nanoparticles inside the water on the Nusselt number and friction factor have been studied. The experimental analysis shows that the increment of Reynolds number, Prandtl number, and nanoparticles concentration improve the heat transfer performance. The maximum of 19.1% and 10.5% increase in Nusselt number and friction factor have been achieved respectively by dispersion of 2 wt% manganese ferrite nanoparticles inside the deionized water at Reynolds number of 1,000. A hydrothermal index is proposed to consider the thermal and hydrodynamic characteristics of the nanofluid, and it is attained that the convection heat transfer improvement dominates the pressure drop in this work. According to the experimental results, the Nusselt number and friction factor of the nanofluid is modeled as a function of Reynolds number, Prandtl number, and nanoparticles concentration using artificial neural network with an acceptable precision.     

逆算法对涡轮特性柯特略尔估算的改进

以柯特略尔法为例，对在级叠加式涡轮特性计算时使用逆算法的适用性进行了讨论。证明了末级首先临界的假定在各折合级设计压比相同的条件下可自然满足；当各折合级设计压比不全相同时，给出了寻找首先临界级的判据，并提出采用顺逆结合处理临界问题的方法，突破了末级首先临界的简化假定，优化了计算步骤，提高了估算精度。     

Alternative Sensitivity Methods for Inverse Radiation Problems in a Two-Dimensional Cylindrical Enclosure

Inverse radiation problems are solved to estimate boundary temperature distributions in an axisymmetric absorbing, emitting, and scattering medium, given measured radiative quantities. To reduce the computation time required for calculating the sensitivity matrix, an automatic differentiation and Broyden combined update are adopted, and their computational precision and efficiency are compared with the result obtained by finite-difference approximation. Further, the effects of the precision of the sensitivity matrix, the magnitudes of the sensitivity coefficients, the number of measurement points, and measurement errors on the estimation accuracy are investigated using a quasi-Newton method as an inverse method. In this inverse analysis procedure, a certain function form of unknown values is not required.     

Finite element solution of radiative transfer across a slab with variable spatial refractive index

To avoid the complicated computation of ray trajectories, a finite element formulation is developed to solve the radiative transfer problem in a one-dimensional absorbing-emitting-scattering semitransparent slab with variable spatial refractive index. A problem of radiative equilibrium is taken as an example to verify this finite element formulation. The predicted temperature distributions are determined by the proposed method and compared with the data in references. The results show that the finite element formulation presented in this paper has good accuracy in solving the radiative transfer in one-dimensional absorbing-emitting-scattering semitransparent medium with variable spatial refractive index.     

Hourly vs daily method of computing insolation on inclined surfaces

Insolation on south-facing inclined planes has been computed using hourly values of total and diffuse radiation, obtained from experimental data. Such a computation procedure is then compared with the widely used method by Liu and Jordan for obtaining daily insolation on surfaces tilted toward the equator. Very small differences are noted between the results obtained by the two methods. These differences are mainly due to three factors; (a) Liu and Jordan's formulation uses a theoretical day-length while the hourly method uses day-length as incicated by the radiation data; (b) hourly method takes into account the asymmetries of total and diffuse radiation around solar noon while the daily method implicitly assumes symmetry of the same; (c) the daily method assumes uniform atmospheric transmissivity to beam radiation throughout the day. On the other hand, the hourly method assumes constant atmospheric transmissivity for one hour only.     

A fast simulation model combining with artificial neural networks for fin‐and‐tube condenser

In order to improve predicting precision and increase the computation speed of simulation for a fin‐and‐tube condenser, a novel method integrating the fundamental mathematical model with an artificial neural network (ANN) is presented. A three‐zone model is used as the basic mathematical model. An ANN maps the nonlinear relation between the distributed‐parameter model and the three‐zone one. Another ANN is involved in the present model to reflect the bias between the model and experimental results, and to improve the simulation accuracy. Practical utilization of the present model shows that the computation speed of the present model is two orders of magnitude higher than that of the distributed‐parameter model, while the precision is also improved. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(7): 551–557, 2002; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/htj.10054     

Temperature dependence of the optical band gap and refractive index of poly(ethylene terepthalate) oligomer–DDQ complex thin film

The temperature dependence of the optical band gap and refractive index dispersion of thin film of poly(ethylene terepthalate) oligomer–DDQ charge transfer complex has been investigated. The absorption edge shifts to the lower energy as consequence of the thermal annealing on film and the fundamental absorption edge corresponds to a direct energy gap. The temperature coefficient of the optical band gap for the film was found as dE_g/dT = − 3.15 × 10⁻³ eV/K. The temperature dependence of the refractive index has also been investigated and it is observed that the refractive index changes by annealing temperatures.