水口枢纽坝下水位下跌治理方案研究

在对水口枢纽坝下水位下跌原因分析的基础上，提出了解决水口坝下水位持续下跌的6种方案．根据物理模型、数学模型及船模试验结果，分析比较了各方案的通航水流条件、施工条件和工程投资，以及各方案对电站出力、水库淹没和防洪的影响，推荐了首选整治方案．     

竖井式跌水闸浅议

对竖井式跌水闸的结构、应用范围、水力计算、施工方法等方面做了简单介绍。     

水库洪水期风险调度方法

根据风险调度原理,本文提出了水库洪水期风险调度方法。首先,根据洪水期调度过程,将洪水期划分为三个阶段;其次,针对涨水段和退水段,建立了以获得效益为主的洪水调度方法。该方法适用调节性能较差的水库,且易于操作,适应性强,获得的超额效益显著。     

落震试验测试系统的研制方案

通过对我国起落架落震试验测试系统现状的分析,指出了落震试验测试系统的研制方向。     

一种多分辨率组合的模糊神经网络分类器

提出一种多分辨率组合的分类器(MRCC)模型和相应的学习算法,发展了Simpson的模糊最小最大神经网络(FMM)方法.它克服了原始模型的几个缺点:训练结果不依赖于训练样本出现的次序,超盒扩张不受一个固定的最大尺度限制.和原始模型的超盒相比较,新模型的超盒中引入了一个参数表示超盒对于训练样本的分类正确率,称为超盒置信度.新的学习算法假设样本在一定尺度下均匀分布,从而能够在线调整超盒置信度参数.新的学习算法采用多分辨率组合的方法,消除了原始算法中选择超盒最大尺度限制参数的困难.实验表明,MRCC模型与原始FMM模型相比,分类性能更好,学习算法的自适应能力更强,建立的模糊超盒数更少,并行处理能力更强.     

Effect of pressure and concentration on performance of a vertical falling-film type of absorber and generator using lithium bromide aqueous solutions

Experiments on an absorber and generator in an absorption refrigerating machine were made using a vertical falling-film type of stainless steel column. Three lithium bromid e aqueous solutions (40, 55 and 60wt% LiBr) were used as working fluid. The experimental apparatus was operated at 1.3 kPa (the pressure for a practical absorber) and 5.3 kPa (the intermediate pressure between absorber and generator). The measured absorption (evaporation) rate decreased with reducing pressure an d increasing concentration of LiBr in the falling liquid. The rate agreed with the values obtained from the analysis of heat and mass transfer in a falling film. Therefore, a falling-film type of absorber and generator can be designed and operated by a consistent method.     

食品干燥过程的扩散现象研究

本文报道了以土豆为原料的食品干燥过程只存在降速阶段的情况,并用不稳定状态扩散方程的标准解分析了实验结果;论述了干燥过程中几个变量对水分扩散速率的影响,并导出了半经验方程,以便将实验结果推广至其他的干燥条件。实验过程由计算机模拟控制,数据采集、处理、作图均由计算机完成。     

木质素悬浮液管式降膜蒸发传热研究

管式降膜蒸发器由于具有传热系数高、传热温差小等优点,已应用于多个工业领域,对管式降膜蒸发器的研究也成为近年来传热技术领域的一项重要课题.文中设计了一套管式降膜蒸发装置,以木质素悬浮液为工质,对影响降膜蒸发传热的因素进行了实验研究,通过冷膜实验测试了所设计的筛板分布器的性能,得出筛板分布器能较好地使物料在换热管内壁上成膜...     

Intensification of the G/L absorption in microstructured falling film application to the treatment of chlorinated VOC's. Part III: Influence of gas thickness channel on mass transfer

A falling film micro-absorber (FFM) is used to treat gas effluents containing a chlorinated VOC. In such operation, mass transfer can be enhanced by optimizing micro-absorber geometry and operating conditions. Firstly, the influence of gas cavity thickness and gas flow rate on absorption performances, were investigated. Experimental study is performed for a range of cavity thickness between 2 and 6 mm and gas flow rate between 45 and 390 N mL/min. Results showed a significant improvement of absorption rate when cavity thickness is reduced, especially for low gas velocities. Indeed the global mass transfer coefficient K_Ga can be multiplied by 7 when cavity thickness is divided by a factor of 3. The mass transfer is then intensified and apparatus compactness is enhanced.The modeling of gas/liquid mass transfer (Monnier and Falk, 2011) indicated that mass transport is performed mainly by diffusion. A new simulations showed an important axial dispersion in gas concentrations profile when gas flow rate and gas cavity thickness are relatively high (t_G=5–6 mm, G_V>400 N mL/min). Then, to optimize micro-absorber performances, the integration of gas turbulence promoters must be considered. The second part of this paper concerns the characterization of gas-side mass transfer in the FFM. A dimensionless correlation is developed:When compared to other relations found in literature, this correlation characterizes gas laminar flow in this kind of micro-structured device.     

Numerical simulation using boundary element method of the mechanism to enhance heat transport by solitary wave on falling thin liquid films

A boundary element method has been developed for analysing heat transport phenomena in solitary wave on falling thin liquid films at high Reynolds numbers.The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function.Consequently,velocity and temperature gradients are dliminated.and the complete formulation is written in terms of velocity and temperature,This provides considerable reduction is storage and computational requirements while improving accuracy.The non-linear equation systems of boundary element discretization are solved by the quasi-Nweton iterative scheme with Broyden‘s update.The streamline maps and the temperature distributions in solitary wave and wavy film flow have been obtained,and the variations of Nusselt numbers along the wall-liquid interface are also given.There are large cross-flow velocities and S-shape temperature distributions in the recirculating region of solitary wave.This special flow and thermal process can be a mechanism to enhance heat transport.