Pseudolaminar Boundary Layer on a Blunt Body Subjected to a Heterogeneous Flow

The distributions of the velocities of air and solid particles in a pseudolaminar boundary layer developing on the surface of a cylinder with a hemispherical end face are experimentally investigated. The experiments reveal a significant rise of fluctuations of the particle velocity in the wall region of the boundary layer. Data are obtained on the decrease in the particle concentration in the vicinity of the model wall compared to its value in the external flow.     

Conveying of Solid Particles in Newtonian and Non-Newtonian Carriers

This article deals with the effect of slurry composition and volumetric concentration on the flow behavior of slurries containing fine-grained and coarse-grained particles. Fluidic fly and bottom ash slurries and sand slurries were experimentally investigated. Kaolin slurries with and without a peptizing agent were used as the carrier liquid for the sand slurries to compare the effect of Newtonian and non-Newtonian carriers. The study revealed a time-dependent yield pseudo-plastic behavior of fluidic fly and fly/bottom ash slurries and the possibility of substantial reduction of the flow resistance by mechanical treatment or by the arrangement of particle size distribution. The flow behavior of fluidic ash slurries can be approximated by the Bulkley-Herschel model in the laminar region. In the turbulent region, the Wilson or Slatter models can be used. The effect of the size distribution of the sand slurry on the hydraulic gradient depends on the flow velocity. The coarse sand slurry reaches a higher hydraulic gradient than the fine sand slurry: the difference decreases with growing velocity. The highly concentrated sand-kaolin slurries show non-Newtonian behavior. When the carrier kaolin slurry is peptized, the hydraulic gradient in the laminar region becomes markedly lower, and the favorable effect vanishes in the transitional and turbulent regions. The addition of small amounts of kaolin favorably affects the flow behavior of the sand slurry.     

幂律型非牛顿流体本构常数的测量精度问题

研究了幂律型非牛顿流体本构常数的测量误差对于计算广义雷诺数、阻力系数以及建立二者实验关系的影响；指出在一定的（ｎ，ｋ）范围内，误差传播系数相当大，以致对本构测量精度要求很高。还分析了传播系数的因次和谐问题，并提出了改进本构测量的建议。     

非牛顿流体在毛细管中真实黏度的计算

在现有的有关聚合物流变学的教科书或辅导书中,对非牛顿流体中真实黏度的概念解释不清,部分内容计算上有误。文中对毛细管中非牛顿型流体的真实黏度从概念、计算方法给予了详细的解释及更正。     

The Structure of Clusters and Jets of Pulsed Plasma Expanding into Vacuum

The space-time distribution of the basic kinetic parameters of a plasma is experimentally determined under conditions of expansion of plasma clusters and jets into vacuum. It is demonstrated that the dynamics and structure of plasmoids injected by pulsed erosion plasma accelerators of the electrothermal type are characterized by two successive stages or two modes of acceleration, namely, the Joule heating of electrons in the initial region of the path and the collisionless expansion of rarefied plasma.     

Generation of a Standard Electromagnetic Field in Free Space

We derive a transfer function that relates the electric field strength in far space to the input parameter. The main stages in deriving the transfer function are described, from the formulation of the physical model of the electromagnetic field generator to the expression of the transfer function in terms of the parameters of the antenna, the electric oscillator, and the input parameter meter. Particular attention is focused on a precise, unique definition of the concepts and quantities employed.     

Mixed Convection of Non-Newtonian Erying Powell Fluid with TemperatureDependent Viscosity over a Vertically Stretched Surface

The viscosity of a substance or material is intensely influenced by the temperature, especially in the field of lubricant engineering where the changeable temperature is well executed. In this paper, the problem of temperature-dependent viscosity on mixed convection flow of Eyring Powell fluid was studied together with Newtonian heating thermal boundary condition. The flow was assumed to move over a vertical stretching sheet. The model of the problem, which is in partial differential equations, was first transformed to ordinary differential equations using appropriate transformations. This approach was considered to reduce the complexity of the equations. Then, the transformed equations were solved using the Keller box method under the finite difference scheme approach. The validation process of the results was performed, and it was found to be in an excellent agreement. The results on the present computation are shown in tabular form and also graphical illustration. The major finding was observed where the skin friction and Nusselt number were boosted in the strong viscosity.     

Heating and Melting of Paraffin in a Coaxial System under the Effect of High-Frequency Electromagnetic Radiation

The impact of a microwave electromagnetic field on the melting of paraffin in a coaxial system simulating an oil well is investigated. The schematic diagram is presented of the experimental facility for the investigation of melting of paraffin in a system consisting of an internal pipe and a coaxially arranged external pipe. In the interelectrode space of these two pipes, an electromagnetic field is induced with a frequency of 2400 MHz. It is shown that the distribution of temperature in the pipes is nonuniform, corresponding to the standing electromagnetic wave in the interelectrode space. The presence of paraffin in the interpipe space substantially accelerates the melting process in the entire coaxial system.     

Thermoelastic State of a Ferritic Layer in a Quasistationary Electromagnetic Field

The electromagnetic, temperature, and mechanical fields formed in an elastic ferritic layer under the action of an electromagnetic field induced by a quasistationary current flowing in a plane parallel to the base of the layer are determined and studied. We establish the regularities of the distributions of intensities of the fields, heat release, ponderomotive forces, temperature, and stresses (in particular, in the vicinity of resonance frequencies) in a layer of magnetically soft Ni-Zn material depending on its thickness and the parameters of external action. The accumulated results can be used for the creation and development of the modes of operation of ferritic elements in electric and electronic devices. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 3, pp. 85–95, May–June, 2005.     

Experimental Investigations of Decomposition of Gas Hydrate in a Pipe under the Impact of a Microwave Electromagnetic Field

Results are given of experimental investigations of the decomposition of propane hydrate in a microwave electromagnetic field developed in a pipe. Procedures are developed for preparing hydrate and for measuring the temperature and pressure in a model of pipeline, as well as of the volume of gas released during the decomposition of gas hydrate. The effect of increasing rate of decomposition of gas hydrate is found as compared to the natural process unassociated with the impact of electromagnetic field. The possibility is demonstrated of complete decomposition of gas hydrate in a pipe due to the impact of a microwave electromagnetic field.__________Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 4, 2005, pp. 612–617.Original Russian Text Copyright © 2005 by M. A. Fatykhov, and N. Ya. Bagautdinov.     

汽车空调电磁离合器三维静磁场有限元分析

利用APDL参数化语言建立了汽车空调电磁离合器三维有限元模型,并对其进行了三维电磁场分析,得到了离合器内部结构的磁通密度分布、皮带轮与吸盘之间的电磁吸力以及桥部个数变化对磁通密度分布和电磁吸力的影响,为离合器的优化设计提供了依据。     

超声波应用于稠油降黏的实验研究

稠油在我国已探明的储量中占比50%以上,而它的高密度、高黏度等特征使得其开采和运输的难度极大,因此,稠油降黏意义重大。超声波技术在稠油降黏的应用中已取得了一定的成效,但尚未得到现场大规模应用。为探究超声波在稠油降黏过程中的作用规律,基于室内实验设计了包括超声波发生器、流变仪、电子天平、恒温水浴等仪器组成的超声稠油降黏评价测试平台。在测试平台上,观测了超声波发生器的电功率、超声作用时间以及油样初始黏度对稠油降黏效果的影响。结果表明,只有在一定的条件下,超声波技术在稠油降黏中的应用才能取得较好的效果,说明了超声波技术对于稠油降黏以及油井的增产增注具有适用性。目前看来,超声波降黏技术在油田现场实际井中的应用及其降黏机理还需进一步深入的研究。     

A comparison between the life cycle cost of gravel and of bituminous surfacing options for feeder roads in Ghana

Feeder roads, which constitute a key component of rural transport infrastructure, play a vital role in rural development, but only 5% of the total feeder road network in Ghana has bituminous seal surfacing. The remaining 95% have either gravel or earth surfacing. However, gravel surfacing (G-S) is known to deteriorate rather rapidly necessitating expensive frequent maintenance while bituminous surfacing offers a more durable surfacing. Various life cycle cost studies have suggested that even though G-S may have lower initial construction costs, they tend to have higher life cycle costs than bituminous seal surfaced ones. However, since most of these studies are based on ideal maintenance practices, their conclusions do not reflect actual field conditions. This study seeks therefore to compare the life cycle cost of G-S with that of bituminous seal surfacing options for engineered feeder roads in Ghana using actual cost data. Data were collected from eight feeder road projects with G-S and a similar number with bituminous surfacing from six regions of Ghana completed between 2010 and 2013. The life cycle cost for each road was computed using a discount rate of 12% and an inflation rate of 15% over an analysis period of 21 years. The results for G-S are then compared with those for single bituminous seal surfacing and for double bituminous seal surfacing. The results are further compared with those from trial sections of an experimental study of Otta seal surfacing using natural gravel and using crushed rock as aggregates. The results suggest that based on the high initial construction costs of bituminous seal surfacing and actual low maintenance intervention practices, G-S remain the least cost option. The study recommends the need for alternative surfacing technology that does not involve bitumen.     

一种新型湿式金属填料过滤性能的实验研究

介绍了湿式与金属填料叠加的除尘器的结构、综合除尘机理及其它有效的功能,可有效克服传统纤维过滤器的不足。实验测试了在不同气流流速下和不同喷淋密度下除尘器的过滤性能,实验结果表明当风速1.2 m/s、喷淋密度1.0 m3/h时,湿式金属填料过滤系统除尘效率可到75%,可应用于集中式中央空调或通风系统中。     

一种新型中高温热泵混合工质的循环性能

提出了一种新的中高温热泵非共沸混合工质M.新工质ODP为0,GWP较低,输运性能优良,在90℃～110℃的冷凝温度范围,压力水平适中,有5℃～8℃的相变温度滑移,理论循环COP(性能系数)和qv(单位容积制热量)均优于传统工质CFC114.在采用HCFC22空调硬件建立的循环性能实验装置上,实现了正常水流量下冷凝器出水温度达到98℃的实验工况;最高COP达到2.8.     

Stabilization of Superconductivity by Electromagnetic Field in Narrow Channel

The results on electromagnetic field effect upon the currents at which phase-slip centers appear in a superconducting channel are given. It is shown that in the presence of external microwave field, the resistive states of superconducting channels become more stable to direct current than in zero field and, consequently, stabilization of the resistive states of the channel due to the Josephson radiation from the phase-slip centers is possible.     

电磁场作用下的金属凝固与成形

综述了电磁场在金属凝固成形过程中的主要应用及其基本原理，指出了应用计算机数值模拟方法求解材料电磁加工问题的重要性及其今后的发展方向。     

基于电磁场理论的光纤光栅孤子的理论分析

在电磁场理论基础上建立了光纤光栅孤子的矩阵传递函数进行理论分析.基于电磁场理论建立了光纤光栅中的孤子的光波传播电磁波模型,并用光波的复振幅矢量表达式描述,利用Cayley-Hamilton定理和第二类切比雪夫多项式进行化简计算.基于此数学模型的光栅反射率和透射率的数学分析,从理论上得到关于长短周期光栅和深浅度调制光栅的特性分析,并得到光栅初始位置的向前向后电场幅值差对终端孤子的电场分布的影响.此方法对进一步分析非线性光纤光栅的特性和多种形式的光纤光栅的制作有通用价值.