通过涡旋齿端面槽内安装密封机构，可以有效降低涡旋齿端面轴向间隙的泄漏。根据密封机构的工作原理，对涡旋齿内密封条进行了受力分析，详细阐述了重力和压差力载荷计算的理论依据，进一步深入研究了密封条所受力载荷的大小及分布规律。计算结果表明，压差力是密封条的最重要力载荷，是保证齿端面密封的关键作用力；沿渐开线展开角方向呈现间断式分布规律，气体压缩过程中压差力逐渐增大，使轴向间隙减小而不易产生泄漏，吸气、排气过程压差力逐渐降低，使轴向间隙增加而易产生泄漏，这将为密封机构的设计与计算提供了理论依据。

A sealing mechanism inside the scroll teeth can reduce the seal of axial clearance effectively.The force of seal element is analysed according to the working principle of sealing mechanism.The calculational process of the gravity and differential pressure force is stated detailedly.Further more,the value and distribution regularites of loading are discussed in depth.The results show that the differential pressure force is the most important one for the seal element and also the pivotal force in order to insure the sealing of scroll teeth.The distribution regularites is discontinuous along the involute angles.During the process of gas compression,the axial clearance and leakage decrease because the differential pressure force increases gradually.But it is opposite to that of the inhale and exhaust process.These will provide a theoretical basis for the design and calculation of sealing mechanism.

就现阶段国内外研究成果分析，肋片具有减小摩擦阻力及增加流动扰动等特点。平板上采用肋片减阻的效果及肋片参数对减阻的影响已相对清晰，而二维翼型上采用加装肋片后减阻效果如何变化还未可知。文章选取二维翼型S825并使用计算流体力学软件Fluent进行气动性能计算及性能分析，初步发现翼型的表面减阻效果的影响规律，得到升、阻力系数随攻角的变化关系。并用该软件计算带肋片的二维翼型的气动性能，与无肋片的翼型气动性能进行对比分析。结果显示：肋片结构在翼型表面可以产生一定的减阻效果；总阻力的计算公式为压差阻力与粘性阻力之和。由于二维翼型上加装了肋片，改变了压差阻力和粘性阻力，继而改变了总阻力的数值，产生了很好的减阻效果。

It is known that fin has the characters of reducing friction and increasing disturbance of flow. The effect of using fins to reduce friction and the influence of fin Parameters on reducing friction have been rela-tively clear, while the use of 2D airfoil’s effect has been unknown. The possibility of using fins on airfoil will be discussed in this article through Flow field simulation of 2D airfoil with fins. To the given 2D airfoil s825, Using the computational fluid dynamics software Fluent, calculation of aerodynamic performance and Perfor-mance Analysis has been performed. The law of surface drag reduction effects has initially been found and the variation of lift and drag coefficient with angle of attack has been achieved. In addition, using the soft-ware to calculate the aerodynamic performance of 2D airfoil, and taking a comparative analysis with the aero-dynamic performance of airfoil without fins. Ultimately it can be concluded:Fin structure in the airfoil sur-face can produce

扭曲舵的应用能提高推进装置的效率，文章采用了面元法来计算螺旋桨对舵的影响从而获得了不同舵剖面上的来流攻角，然后以最大附加推力为目的对舵剖面进行扭转，采用迭代处理计算了螺旋桨与桨后扭曲舵的相互干扰的水动力性能。并对设计出的扭曲舵进行了改良，将舵导边及其前缘进行扭转。计算结果表明，扭曲舵减小了压差阻力使得舵的总阻力减小，改善了舵的水动力性能，提高了桨舵系统效率；改良后的舵可更好地适应来流，同时减小了舵的摆动幅度，解决了由于叶剖面大幅摆动带来的问题。

The purpose of improving the efficiency of propulsion system can be achieved through lay-ing a twisted rudder. In order to get the inflow attack angles of every rudder section, the panel method is used to calculate the influence of the propeller on the rudder. According to the inflow attack an-gles, the sections are twisted to get the maximum additional thrust. An iterative method is used for the calculation of the hydrodynamic performance between the propeller and the aft twisted rudder with considering the interaction between them, and the results show that the twisted rudder can reduce the total resistance by reducing the pressure drag, improve the hydrodynamic performance of rudder and raise the efficiency of the propeller-rudder system. At the same time, some amendment was made in the design of twisted rudder. Through comparing the hydrodynamic performance between the two types of twisted rudder, the results show that the amendment rudder has a better matching charac-teristic with

利用GT-Power软件建立仿真模型，开展了进排气压力波动分析，针对全负荷7个稳态转速点，研究了扫气量和进排气压差的关系，确定了可用扫气转速区域。分别在最大扭矩工况和标定功率工况探讨了气门正时对发动机性能的影响规律，并提出了全负荷工况气门正时优化策略。研究结果表明：在1000～2700 r/min转速范围内，排气上止点附近存在进排气正压差区，扫气系数大于1．03；在最大扭矩工况，增大气门重叠角，可使扫气系数增加，涡前排温明显下降；在标定功率工况，排气门关闭正时在353°A T DC附近时，残余废气系数最小。基于进气量优化气门正时，在全负荷6000 r/min处，进气量提高了19％，残余废气系数降低了0．018，功率提升了21％。在最大扭矩工况附近，增压压力提高了11．7％，涡前压力增大了19．4％。

Based on the calculated model established by GT-Power software ,the intake and exhaust pressure fluctuation was analyzed .The speed range of available scavenging was determined by analyzing the relation of scavenging mass with intake and exhaust pressure difference in seven operating conditions .The effect of valve timing on engine performance was discussed in conditions of maximum torque and rated power and the optimization strategy of valve timing in full load was put forward .The results show that the positive pressure difference exists and the scavenging coefficient is 1 .03 near exhaust TDC in 1 000~2 700 r/min .In the maximum torque condition ,increasing valve overlap angle can increase the scavenging coefficient and the temperature before the turbine will decrease .In the rated power condition ,the coefficient of residual gas reaches the minimum when EVC is around 353°ATDC .After optimizing the valve timing ,the intake air mass increases by 19% ,the coefficient of re-sidual gas

为了提高工业碱木质素的利用价值,扩大碱木质素的应用范围,以工业碱木质素和聚乙烯醇为原料,以甲醛为交联剂,利用流延法制备了碱木质素-聚乙烯醇交联反应膜。通过单因素实验探索了碱木质素加入量、甲醛加入量、溶液pH值对碱木质素-聚乙烯醇(PVA,poly vinyl alcohol)反应膜透光性和透气性的影响。采用紫外可见分光光度计分析了薄膜的光学性能,压差法测定薄膜的透气性。采用SEM(scanning electron microscopy)和FTIR(Fourier transform infrared spectroscopy)方法分析反应膜的表面形貌和化学结构,利用静态接触角测量仪测定薄膜的接触角。结果表明:碱木质素加入后,在紫外光区200～400 nm薄膜的透过率为零,对紫外线全吸收,在可见光区400～800 nm薄膜透过率降低,当碱木质素与PVA质量比为1:4时,在600 nm处薄膜的透过率为16.12%;随着甲醛加入量的提高,薄膜可见光区的透光率逐渐增大;随着pH值增大,木质素逐渐溶解,pH值为9时,薄膜600 nm处薄膜透过率为20.85%。与纯PVA薄膜相比较,碱木质素加入后薄膜二氧化碳和氧气的透气性都减小;经甲醛交联后,薄膜的氧气和二氧化碳的透过量都增大;pH值由小到大变化时,碱木质素-聚乙烯醇反应薄膜对二氧化碳和氧气的透气量先增大后减小。FT-IR表征说明碱木质素-聚乙烯醇薄膜结构中有醚键生成,碱木质素和PVA发生了交联反应;电镜图片显示碱木质素-聚乙烯醇反应薄膜表面较光滑;接触角分析说明碱木质素的加入增大了薄膜与水的接触角,薄膜表面亲水性降低,并且交联反应薄膜的接触角大于共混薄膜的接触角,交联提高了薄膜的耐水性。与戊二醛相比甲醛做交联剂时碱木质素和PVA之间的交联反应程度更大,交联薄膜在可见光区的透光性更大。薄膜对紫外线吸收主要是受碱木质素的影响。碱木质素-聚乙烯醇反应膜可作为良好的紫外吸收材料,应用于地膜中。

In order to improve the utilization value of an industrial alkaline lignin and expand the application range of alkali lignin, with alkaline lignin and poly (vinyl alcohol) as the primary materials, and formaldehyde as a crosslinker, alkaline lignin/poly (vinyl alcohol) cross-linked film was prepared by casting. The effects of the dosage of alkaline lignin, formaldehyde, and the pH values on the light transmittance and gas permeability of the films were investigated one at a time for different variables. The light transmittance and gas permeability properties were measured using a double-beam UV-Vis spectrophotometer and a VAC-VBS pressure difference gas permeameter respectively. The surface morphology and chemical structure of the films were characterized by SEM and FT-IR. The results were as follows. (1) Influence of different conditions on the optical properties of the films:Alkaline lignin had a great influence on the absorbance and transmittance of films. The UV absorbance of the r