海底扇朵叶沉积构型研究进展

作为深海沉积体系中主要的沉积储层类型之一,海底扇朵叶沉积具有重要的科研价值和极大的油气资源潜力,因此一直是世界深海沉积研究的热点。在近60年的研究历程中,学术界在海底扇朵叶概念、沉积模式及成因机制等方面取得了重要进展,同时也产生了一定分歧,尤其是在海底扇朵叶体系内部构型研究方面仍存在较多争议和不足。本文阐述了海底扇朵叶沉积内部的构型要素类型及特征,总结并分析了海底扇朵叶体系构型级次划分方案及不同级次构型单元的空间分布样式与定量规模。在此基础上,指出了今后的研究有必要对不同学者的朵叶构型分级概念作细致的对比梳理,在统一构型级次的基础上明确不同地质条件或主控因素对海底扇朵叶构型发育模式的控制作用,能够建立相对统一的、可对比的、定量构型知识库,从而更好地指导深水油气勘探开发过程中的朵叶储层构型表征。

长叶野扇花化学成分研究

目的:研究长叶野扇花化学成分研究。方法:通过硅胶柱色谱、Sephadex LH-20葡聚糖凝胶色谱和制备薄层色谱等方法进行分离纯化,根据波谱数据与文献对照鉴定其化学结构。结果:从长叶野扇花全草提取物中分离得到了13个化合物,分别鉴定为:清香桂碱D(1)、(20S)-20-(N,N-dimethylamino)-3β-tigloylamino-5α-pregn-11β-ol(2)、salignenamide D(3)、funtuphyllamine B(4)、(+)-irehine(5)、富贵草碱G(6)、sarcorine(7)、海南野扇花碱A(8)、sarchookloide B(9)、邻苯二甲酸二戊酯(10)、(3S,5R,6S,7E,9R)-5,6-epoxy-3,9-dihydroxy-7-megastigmene(11)、erythro-guaiacylglycerol-β-coniferyl ether(12)、isolariciresinol(13)。结论:以上化合物均为首次从该植物中分离得到,其中,化合物4、6、10~13为首次从该属植物中分离得到。

国产玉叶金花属(茜草科)的三个新异名(英文)

澄清了中国产玉叶金花属Mussaenda 2种1变型的分类学位置, 分别将胀管玉叶金花M. inflata Hsue & H. Wu、异形玉叶金花M. anomala Li和灵仙玉叶金花M. pubescens Ait. f. forma clematidiflora Chun ex Hsue & H. Wu作为粗毛玉叶金花M. hirsutula Miq.、大叶白纸扇M. esquirolii Lévl.和玉叶金花M. pubescens Ait. f.的新异名处理。

风电混合动力微型车设计

电动车由于电池技术的制约下,续航里程还无法达到理想水平。本论文旨在设计一款风电混合动力微型车,以达到降低行驶耗能,充分利用发电能源来提高电动车的续航里程。根据国内外文献和实际测量研究分析,本文从风能发电机结构、风能回收率与车速关系以及制作简单的汽车模型,从而实现风电混合动力微型车的设计。

微型电机定子自动组装工艺的研究与设计

每台空调的摆叶扇安装有至少4个微型步进电机同步上下或左右扫描,因此空调行业对微型步进电机需求巨大。针对空调摆叶扇家电微型步进电机定子目前的生产工艺落后和生产效率低下现状,对定子自动组装代替手动组装进行了可行性研究,通过定子铁心工艺改进和CAD设计方法,提出了一种微型电机定子自动组装工艺和设计方案。依据该设计方案制造的自动设备,满足了定子的生产效率和品质提升要求,响应了政府“机器换人”的科技创新计划。

EFFECT OF TIP CLEARANCE ON PERFORMANCE AND FLOW FIELD OF SMALL SIZED HIGH SPEED CENTRIFUGAL FAN

A centrifugal fan with the high speed and compact dimensions is studied numerically and experimentally. The centrifugal fan consists of a shrouded impeller rotating at 34 000 r/min with a small tip clearance 0.7 mm to the fixed outer casing. Computational models with/without the tip clearance are built and the κ-ω shear stress transport （SST） turbulence model and the unstructured mesh are applied to the numerical simulation for unsteady solutions. The overall performance is measured on a standard experimental bench and the major flow feature of each component inside the centrifugal fan is numerically investigated. In the presence of the tip clearance due to the difference of static pressure between leading and trailing edges of the clearance, i. e. , leading and trailing edges of the impeller, a strong return flow exists inside the clearance passage and re-circulates the main stream inside the impeller passage, and produces the strong flow interaction, thus changing the flow field and influencing the overall performance.

Numerical Simulation on Ice Shedding Phenomena in Turbomachinery

In the jet engine, icing phenomena occur primarily on the fan blades, the FEGVs （fan exit guide vanes）, the splitter, and the low-pressure compressor. Accreted ice disturbs the inlet flow and causes large energy losses. In addition, ice accreted on a fan rotor can be shed from the blade surface due to centrifugal force and can damage compressor components. This phenomenon, which is typical in turbomachinery, is referred to as ice shedding. Although existing icing models can simulate ice growth, these models do not have the capability to reproduce ice shedding. In the present study, we develop an icing model that takes into account both ice growth and ice shedding. Furthermore, we have validated the proposed ice shedding model through the comparison of numerical results and experimental data, which include the flow rate loss due to ice growth and the flow rate recovery due to ice shedding. The simulation results for the time at which ice shedding occurred and what were obtained using the proposed ice shedding model were in good agreement with the experimental results.

基于CFD模拟的新型径向流搅拌桨设计

用CFD软件模拟了3种传统径向流搅拌桨—平直叶式、半圆管式和非对称抛物线式搅拌桨的功率消耗和泵送能力等搅拌性能,研究了不同桨叶结构和尺寸对搅拌桨功率准数和泵送能力的影响,设计扇环抛物面桨叶结构,比较了新型桨与传统桨的功率准数、泵送效率等搅拌性能和轴向投影面积率的差异.结果表明,桨叶外缘顶点曲率增大可减小功率准数和提高泵送效率,轴向高度减小可使功率准数降低但对泵送效率提升不大.基于空间自由曲面设计的带有新型非对称扇环抛物面桨叶的搅拌桨操作性能最佳,比非对称抛物线式搅拌桨功率准数下降30.8%,泵送效率提高22.6%.新型搅拌桨轴向投影面积率比非对称抛物线式搅拌桨增加21.5%,能用于气液分散操作.

Leading Edge Film Cooling Enhancement for an Inlet Guide Vane with Fan-Shaped Holes

This paper describes the improvement of leading edge film cooling effectiveness for a turbine inlet guide vane by using fan-shaped film cooling holes. The modification details are presented in comparison with the base-line configuration of cylindrical holes. Numerical simulations were carried out for the base-line and modified configurations by using CFX, in which the k-ε turbulence model and scalable wall function were chosen. Contours of adiabatic film cooling effectiveness on the blade surfaces and span-wise distributions of film cooling effectiveness downstream the rows of cooling holes interested for the different cooling configurations were compared and discussed. It is showed that with the use of fan-shaped cooling holes around the leading edge, the adiabatic film cooling effectiveness can be enhanced considerably. In comparison with the cylindrical film cooling holes, up to 40% coolant mass flow can be saved by using fan-shaped cooling holes to obtain the comparable film cooling effectiveness for the studied inlet guide vane.

Numerical and Experimental Investigation on Aerodynamic Performance of Small Axial Flow Fan with Hollow Blade Root

To reduce the influence of adverse flow conditions at the fan hub and improve fan aerodynamic performance, a modification of conventional axial fan blades with numerical and experimental investigation is presented. Hollow blade root is manufactured near the hub. The numerical and experimental results show that hollow blade root has some effect on the static performance. Static pressure of the modified fan is generally the same with that of the datum fan, while, the efficiency curve of the modified fan has a different trend with that of the datum fan. The highest efficiency of the modified fan is 10% greater than that of the datum fan. The orthogonal experimental re- suits of fan noise show that hollow blade root is a feasible method of reducing fan noise, and the maximum value of noise reduction is about 2 dB. The factors affecting the noise reduction of hollow blade root are in the order of importance as follows： hollow blade margin, hollow blade height and hollow blade width. The much smoother pressure distribution of the modified fan than that of the datum fan is the main mechanism of noise reduction of hollow blade root. The research results will provide the proof of the parameter optimization and the structure de- sign for high performance and low noise small axial fans.

Effects of a Kind of Non-smooth Blade on the Performance of an Axial Fan

This paper presents an experimental investigation of effects of a kind of streamwise-grooved blade on the performance of an axial-flow fan. The flow field at 25% chord downstream from the trailing edge at hub was measured using a 5-hole pressure probe at different mass-flow conditions. The fan performance of the groove blades was compared with that of the smooth blades. The measurement results indicate that： （ 1 ） the non-smooth blades increase mass flow of the fan at the same throttle conditions except a near stall condition; （2） the non-smooth blades reduce the relative total pressure loss in the rotor passage and increase the fan＇s total pressure rise at the test mass-flow conditions except the near stall condition; （3） Negative benefits are obtained at a near stall condition when the smooth blades are replaced by the non-smooth ones. The fan mass flow decreases 0.9% while the total-pressure rise decreases 2.4% at the near stall condition.

Heat Transfer and Performance Characteristics of Axial Cooling Fans with Downstream Guide Vanes

This study examines experimentally the effect of stators on the performance and heat transfer characteristics of small axial cooling fans. A single fan impeller, followed by nine stator blades in the case of a complete stage, was used for all the experimental configurations. Performance measurements were carried out in a constant speed stage performance test rig while the transient liquid crystal technique was used for the heat transfer measurements. Full surface heat transfer coefficient distributions were obtained by recording the temperature history of liquid crystals on a target plate. The experimental data indicated that the results are highly affected by the flow conditions at the fan outlet. Stators can be beneficial in terms of pressure drop and efficiency, and thus more economical operation, as well as, in the local heat transfer distribution at the wake of the stator blades if the fan is installed very close to the cooling object. However, as the separation distance increases, enhanced heat transfer rate in the order of 25% is observed in the case of the fan impeller.

Factors Affecting Small Axial Cooling Fan Performance

Many factors such as outer diameter, hub ratio, blade numbers, shape and stagger angle affect the performance of small cooling fans. A small cooling fan was simulated using CFD software for three blade stagger angles （30.5°, 37.5°, 44.5°）and obtained the internal flow field and the static characteristics. Research indicated that the stagger angle has an obvious effect on the static characteristics of a fan. For flow rates below 0.0104 mVs, total pressure is the greatest when the stagger angle is 37.5°; flow rates higher than 0.0104 m^3/s, the total pressure is greatest when the stagger angle is 44.5° For the same flow rates, the velocity at inlet of pressure surface increases with in- creasing stagger angle, but the change of velocity on the suction surface is very small. For one model, vortices and the speed of revolution surfaces decrease with tip clearance increasing. But for other three models, increasing the stagger angle, the vortex intensity and speed of revolution surfaces at same height tip clearance increases, simultaneously, the position of vortex offset from the top of the rotor blade to the suction surface.

Unsteady Flow at Low Flow-rate Region in a Semi-open Propeller Fan (Velocity Fluctuation outside of Blade Tip)

In order to clarify the unsteady flow fields at low flow-rate region with positive gradient on pressure-flow-rate curve,the experimental investigation was carried out at rotor inlet and outside of rotor blade tip without casing in a semi-opened propeller fan using a hot-wire anemometer.A single I-type hot-wire probe was used,and the data obtained were processed by the use of phase-locked averaging,ensemble averaging and FFT analyzing.The flow fields at rotor inlet and outside of rotor blade tip were discussed mainly using the results from distributions of velocity fluctuations and power spectrum density.It was found from these results that there are the two types of different periodical fluctuations and both of those frequencies were not the same of rotor rotating frequency(RRF;15Hz).One was observed at relatively high flow-rate region at relatively downstream area in measurement and its frequency was approximately 7Hz(47% of RRF).The other was observed at relatively low flow-rate region at relatively upstream area in measurement and its frequency was approximately 10Hz(67% of RRF)".As the velocity fluctuations with the flow fields are rapidly increased by the former fluctuation,it is thought that its fluctuation is the trigger of blade stall.