A study on heat transfer during thermoplastic composite tape lay-up process

A study on heat transfer during thermoplastic composite tape lay-up process was done. To investigate the relation between major process variables, experiments as well as numerical simulations were performed. A small-scale tape lay-up system was built. A hot nitrogen torch was used to heat the prepreg tape. Right after the torch, a compaction roller was located to bond the prepreg plies. Temperatures inside the composite at four different locations through the thickness were measured, using thermocouples. Experiments were done for different process conditions. Numerical simulations also were performed, using the finite element code developed in this study. A numerical code was run for the same conditions as the experiment. Close agreement was observed between the numerical results and the experimental data.     

Supersonic COIL with angular jet singlet oxygen generator

Supersonic Chemical Oxy-iodine Laser has been developed using a Singlet Oxygen Generator (SOG) with a novel approach. Generated singlet oxygen is taken out of the SOG at an angle of 40° to avoid the problem of carry over of droplets, which is one of the major drawbacks of horizontal system. The system has been operated up to 22 mmol/s chlorine flow rates. Chlorine utilization and singlet oxygen observed have been more than 90% and 60%, respectively. The observed maximum output power was 350 W, thus yielding a chemical efficiency of 17.5%.     

炸药爆轰驱动超高速击波管的数值摸拟

 高能炸药（HE）柱壳沿轴向传播的稳定态爆轰，在置于炸药柱壳内部的泡沫塑料（工作流体）中产生很强的轴向击波，达到极高的压力和能量密度。适当设计，可使工作流体的流动接近一稳定态，与炸药爆轰以相同的相速度前进。击波阵面后的工作流体可用Nozzle流动方程很好地描述^[1]，Nozzle收缩段中的流动不受散开段流动的影响。利用这一性质，可以设计出达到极高压力和能量密度的超高速击波管，并且不受管壁物质强度的限制。数值模拟计算给出了上述稳定态物理图象，并显示出开始阶段轴向击波的形成过程及其后对稳定态的逼近，计算结果及物理图象与理论分析符合得很好。     

Comparative Study of Flow Characteristics Inside Plasma Torch with Different Nozzle Configurations

A numerical analysis of the influence of different nozzle configurations on the plasma flow characteristics inside D.C plasma torches is presented to provide an advanced nozzle design basis for plasma spraying torches. The assumption of steady-state, axis-symmetric, local thermodynamic equilibrium, and optically thin plasma is adopted in a two-dimensional modeling of plasma flow inside the plasma torch. The PHOENICS software is used for solving the governing equations, i.e. the conservation equations of mass, momentum, and energy along with the equations describing the K-epsilon model of turbulence. The calculated arc voltages are consistent with the experimental results when arc current, gas inflow rate, and working gas are the same as the experimental parameters. Temperature, axial velocity contours inside plasma torches, profiles along the torch axis and profiles at the outlet section are presented to show the plasma flow characteristics. Comparisons are made among those torches. The results show that torches with different anode nozzle configurations produce different characteristics of plasma flows, which suggest some important ideas for the advanced nozzle design for plasma spraying. In order to validate the model and to show its level of predictivity, a comparison of the model with experimental results encountered in the literature is presented in the last part.     

半干法烟气脱硫喷嘴的雾化特性研究

利用FAM型衍射式激光测粒仪，对双流体石灰浆液雾化喷嘴的雾化特性进行了试验研究，得到了预测雾滴平均粒径的经验公式，分析了气耗率、石灰浆液浓度等参数对雾化粒径分布和雾化角的影响规律。结果表明，气液质量比增大，浆液液滴平均直径(SMD)减小；浆液浓度增加，液滴平均直径增加。气液质量比在0.05～0.3的范围内可获得良好的雾化效果，雾化粒径一般在20 μm～100 μm。喷嘴的雾化角较小，一般在20°～25°之间。气液质量比增加，雾化角减小；而石灰浆浓度对雾化角影响较小。     

Application of instantaneous nebulization dispersive liquid-phase microextraction combined with HPLC for the determination of chalcone and isoflavone in traditional Chinese medicines

A simple and rapid instantaneous nebulization dispersive liquid-phase microextraction method was developed, and combined with high-performance liquid chromatography for determination of the contents of seven analytes in traditional Chinese medicines. In this study, using the sprinkler device to achieve instantaneous synchronous dispersion and extraction, only one spray can rapidly achieve the concentration and enrichment of seven kinds of chalcone and isoflavones. The key factors affecting the extraction efficiency were optimized including the type and volume of extractant, the pH and salt concentration of the sample phase, and the number of dispersion. Under the optimal conditions, the enrichment factor of the target analytes ranged from 103.1 to 180.9, with good linearity and correlation coefficients above 0.9970. The limits of detection ranged from 0.02 to 0.15 ng/mL, with good accuracy (recoveries 91.1 to 108.9%) and precision (relative standard deviations 1.5–7.1%). This method has short extraction time (2 s), low organic solvent consumption and high enrichment effect, so it has a wide application prospects.     

气枪喷嘴高速射流的除水效率研究

为揭示喷嘴除水的机理并进而对气枪喷嘴进行改进和优化设计,本文提出了利用图像分析处理对小尺度气枪喷嘴高速冲击乘风破浪的除水效率的研究方法。该方法将有效除水面积作为衡量喷嘴除水效率的标准,从面实现了对喷嘴整体除水效率的定量测量,并利用该方法对影响气枪喷嘴除水效率的各种因素（一次侧压力,喷嘴到平板的距离和射流攻角）进行了研究,并将实验结果与用热线风速仪及总压探头测量的结果进行了比较,得到冲击射流在平板水平速度分量是蚊蝇 嘴除尘除水效率的决定性因素等结论。     

空心旋转液体射流初始阶段特性的实验研究

以空心旋转射流的理论模型为基础［１］,通过实验对旋流喷嘴射流特性做进一步深入的研究,特别是实际射流形状的变化规律及喷嘴初始参数的变化规律．结果表明,旋流喷嘴的初始参数和空心射流内外表面压力差是决定射流形状的主要因素。     

Determinated of Trace Amounts of Mercury by Non-Disperse Atomic Fluorescence Method

Abstract

A rapid and sensitive cold vapor method for the determination of trace mercury by non-disperse atomic fluorescence measurement is proposed. Mercury vapor generated from solution was swept into the nozzle (the funnel type of glass tube) by nitrogen, and the atomic fluorescence (AF) of mercury in the gas mixture was detected by a non-dispersive AF method using a solar-blind photomultiplier. The detection limit obtained was 0.5 ng per 5 ml sample solution.     

3D numerical simulation of compressible swirling flow induced by means of tangential inlets

The objective of the present work is to predict compressible swirl flow in the nozzle of air‐jet spinning using the realizable k–ε turbulence model and discuss the effect of the nozzle pressure. The periodic change of flow patterns can be observed. The recirculation zone near the wall of the injectors upstream increases in size and moves gradually upstream, whereas the vortex breakdown in the injector downstream shifts slowly towards the nozzle outlet during the whole period. A low axial velocity in the core region moves gradually away from the centerline, and the magnitude of the center reverse flow and the area occupied by it increase with axial distance due to the vortex breakdown. From the tangential velocity profile, there is a very small free‐vortex zone. With increasing nozzle pressure, the velocity increases and the location of vortex breakdown is moved slightly downward. However, the increase in the velocity tends to decline at nozzle pressure up to a high level. Copyright © 2008 John Wiley & Sons, Ltd.