量纲法分析Kenics静态混合器的压力降关系

介绍了一种新型的静态混合器压力降关系式,该关系式考虑了混合单元的长径比,提高了压力降关系式的可靠性以及计算精度.采用量纲法分析Kenics静态混合器的压力降特性的研究表明,该静态混合器的压力降特性可以通过摩擦因数、雷诺数以及混合单元长径比这3个无因次群来描述.     

GCL的气体渗透性研究

GCL作为垃圾填埋场封盖系统的主要复合材料，其气体渗透性是一种很重要的性质，也是决定垃圾填埋场成败的关键。气体渗透分为平流和扩散两种过程，根据雷诺数来判别这两种渗透过程的基本准则，给出了平流与扩散过程中气体渗透量的计算公式；总结了影响GCL透气性的主要因素，包括外部气压、GCL的含水量以及与其共同作用的土工膜的完好程度，并简略分析了这些因素影响GCL透气性的原因。     

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准确判别井内液体的流态，对钻井优化设计和施工，保证注水泥顶替质量是非常重要的。文中介绍了以层流稳定性现象理论为基础提出的5个使用较广的流态判别准则－雷诺数（Re)、稳定性参数Z、稳定性参数K、稳定性参数X和稳定性参数Y。通过对这5个流态判别准则的分析与对比，认为雷诺数、稳定性参数Z与K都存在不足，而稳定性参数X、Y更具合理性。建议将稳定性参数X、Y进行推广，使它们能够用于其它非牛顿液体圆管流、同心环空流，偏心环空流的流态判别。     

矿浆雷诺数与紊流建模

本文提出了一种新的非牛顿流体矿浆的紊流建模理论，它是在Cape·Technikon和开普敦大学共同研究之下，基于一个新的雷诺数公式提出的。这个新的雷诺数公式有利于选矿这一重要领域中矿浆紊流理论建模的解决。     

涡街流量计及其应用

介绍了涡街流量计的工作原理、分类、特点，以及选型和应用中所需注意的事项。     

天然气混合气体粘度和雷诺数计算研究

为了探讨天然气混合气体粘度和雷诺数的计算方法,依据具体工程实例,给出了已知组分和平均流量天然气混合气体动力粘度、运动粘度和雷诺数的计算实例.并对粘度计算误差和雷诺数计算中体积流量的取值方法可行性进行了分析.同时给出了用C Builder程序实现的人机界面.程序运行表明,这套方法的计算结果满足该系统对天然气流动状态及计量误差分析的要求.     

单颗粒泥沙沉速公式的对比研究

结合大量的相关研究成果,简要总结了国内外泥沙沉速的研究现状,就单颗粒泥沙在静止水体中的沉降情况对各家泥沙沉速公式进行了分类,并进行了对比分析.结果表明,单颗粒泥沙的沉降特性已基本明确,其中Raudkivi、Cheng和Wu泥沙沉速公式的计算准确程度较高.     

层状燃烧有机热载体锅炉炉膛最高液膜温度计算方法探讨

介绍了一种计算层状燃烧有机热载体锅炉炉膛最高液膜温度的方法以及该计算方法的思路及计算实例。     

Feasibility of pulse combustion in micro gas turbines

In gas turbines, a fast decrease of efficiency appears when the output decreases; the efficiency of a large gas turbine (20…30 MW) is in the order of 40 %, the efficiency of a 30 kW gas turbine with a recuperator is in the order of 25 %, but the efficiency of a very small gas turbine (2…6 kW) in the order of 4…6 % (or 8…12 % with an optimal recuperator). This is mainly a result of the efficiency decrease in kinetic compressors, due to the Reynolds number effect. Losses in decelerating flow in a flow passage are sensitive to the Reynolds number effects. In contrary to the compression, the efficiency of expansion in turbines is not so sensitive to the Reynolds number; very small turbines are made with rather good efficiency because the flow acceleration stabilizes the boundary layer. This study presents a system where the kinetic compressor of a gas turbine is replaced with a pulse combustor. The combustor is filled with a combustible gas mixture, ignited, and the generated high pressure gas is expanded in the turbine. The process is repeated frequently, thus producing a pulsating flow to the turbine; or almost a uniform flow, if several parallel combustors are used and triggered alternately in a proper way. Almost all the compression work is made by the temperature increase from the combustion. This gas turbine type is investigated theoretically and its combustor also experimentally with the conclusion that in a 2 kW power size, the pulse flow gas turbine is not as attractive as expected due to the big size and weight of parallel combustors and due to the efficiency being in the order of 8 % to 10 %. However, in special applications having a very low power demand, below 1000 W, this solution has better properties when compared to the conventional gas turbine and it could be worth of a more detailed investigation.     

Three-dimensional numerical simulation of the movement of the flexible body under different constraints

For the large deformation of the flexible body may cause the fluid grid distortion,which will make the numerical calculation tedious,even to end,the numerical simulation of the flexible body coupling with the fluid is always a tough problem.In this paper,the flexible body is under two kinds of constrained conditions and the ratio of length-diameter is 1：30.The Reynolds number of the airflow is 513,belonging to the area of low Reynolds number.The control equations of the coupling of flexible body with airflow are built and the adaptive grid control method is adopted to conduct the three-dimensional numerical simulation of the movement of the flexible body.The numerical results show that it is possible to simulate the characteristics of the flexible body＇s movement in the low Reynolds number airflow when the appropriate control equations are modeled and suitable equation-solving method is adopted.Unconstrained flexible body would turn over forward along the airflow＇s diffusion direction,while constrained flexible body in the flow field will make periodic rotation motion along the axis of the flexible body,and the bending deformation is more obvious than that of unconstrained flexible body.The preliminary three-dimensional numerical simulation can provide references for further research on the characteristics of the yam movement in high Reynolds number airflow.