ROLLS-ROYCE舵机操作模式功能选择故障分析及处理

舵机是控制船舶的前进方向,其重要性不言而喻。现我局8 000k W类型船舶的舵机及控制系统皆采用ROLLSROYCE的产品。本文着重介绍ROLLS-ROYCE SR722-FCP型舵机操作模式系统原理,以及对该系统发生故障使部分操作模式失效的原因进行分析和处理,为其他船舶发生类似故障时提供参考。

极致奢华的完美呈现 全新劳斯莱斯幻影Rolls-Royce Phantom上市

北京时间2017年10月15日,劳斯莱斯全新幻影车型在中国正式上市,新车是幻影家族的第八代产品,而现款第七代幻影的首次发布还是在2003年。全新幻影基于劳斯莱斯全新铝制奢华架构打造,在降低自身整备质量的同时,车身刚性增强30%。此外,新车不仅保持了幻影家族一贯的奢华感,更将前沿电子配置引入其中,值得一提的是,该车还换装了全新的6.75升V12双涡轮增压发动机,替代了此前的同排量自然吸气版本。

舍我其谁的王者 全新一代劳斯莱斯幻影Rolls-Royce Phantom

北京时间2017年7月28日凌晨,劳斯莱斯全新幻影车型在英国正式发布,新车是幻影家族的第八代产品,而现款第七代幻影的首次发布还是在2003年。全新幻影基于劳斯莱斯全新铝制奢华架构打造,在降低自身整备质量的同时,车身刚性增强30%。此外,新车不仅保持了幻影家族一贯的奢华感,更将前沿电子配置引入其中,值得一提的是,该车还换装了全新的6.75升V12双涡轮增压发动机,替代了此前的同排量自然吸气版本。据悉,新车有望在2018年初上市。

Design and Verification for Dual⁃mode CDFS and High⁃Load Compressor with a Large Flow Regulation Range

This paper presents the design and verification of the dual-mode core driven fan stage(CDFS)and high-load compressor with a large flow regulation range.In view of the characteristics of large flow regulation range of the two modes and high average stage load coefficient,this paper investigates the design technology of the dual-mode high-efficiency compressor with a large flow regulation range and high-load compressor with an average stage load coefficient of 0.504.Building upon this research,the design of the dual-mode CDFS and four-stage compressor is completed,and three-dimensional numerical simulation of the two modes is carried out.Finally,performance experiment is conducted to verify the result of three-dimensional numerical simulation.The experiment results show that the compressor performance is improved for the whole working conditions by using the new design method,which realizes the complete fusion design of the CDFS and high-pressure compressor(HPC).The matching mechanism of stage characteristics of single and double bypass modes and the variation rule of different adjustment angles on performance are studied comprehensively.Furthermore,it effectively reduces the length and weight of compressor,and breaks through the key technologies such as high-load compressor with the average load factor of 0.504.These findings provide valuable data and a methodological foundation for the development of the next generation aeroengine.

Impacts of Using Al_(2)O_(3)Nano Particle to Compressor Oil on Performance of Automobile Air Conditioning System

This work involves an experimental study on the performance of automobile air-conditioning systems by adding Al_(2)O_(3)nanoparticles to oil compressors to investigate their impacts on the enhancement of the speed cooling of refrigeration systems and to compare it with the system operated using only oil.The Al_(2)O_(3)nanoparticles have been added to the oil compressor for different ranges ofmass concentration(Ф=0.1%,Ф=0.15%andФ=0.2%).The stability of Al_(2)O_(3)nanoparticles has been tested by direct observation for different time periods.The results indicated that the air conditioning systemthat operated by using Al_(2)O_(3)-oil was better than the system that operated with pure oil.ForФ=0.2%,the results indicated that the cooling speed and the efficiency of the system operated with Al_(2)O_(3)-oil are increased by 13%and 18%,respectively,as compared to the pure oil system.This study shows that the thermos-physical properties of refrigerant oil are enhanced by 15%whenФis increased.

Preparation and property of seal coating for gas turbine compressor

Double-layer structure of seal coating which consisted of a Ni5Al bond coating and a Ni25 graphite top coating were prepared on steel substrate of gas turbine compressor cylinder block.Bond coating was prepared by atmospheric plasma spraying and top coating was prepared by flame spraying.The microstructure,mechanical properties and abradability of the coating were characterized by scanning elec-tron microscope(SEM),hardness tester,universal testing machine,thermal shock testing machine and abradability testing machine.The res-ults show that the overall spraying structure of the seal coating is uniform,the nickel metal phase is the skeleton supporting the entire coat-ing,and the coating is well bonded without separation.The seal coating has a bonding strength of not less than 7.7 MPa,excellent thermal stability,and thermal shock resistance cycle numbers at 500℃more than 50;the scratch length,deepest invasion depth and wear amount of the coating increase with rise of test temperature,with almost no coating adhesion,indicating that the seal coating has excellent abradability.

Experimental and Numerical Investigation of Micro Tip Injection in a High‑Speed Axial Compressor Rotor

A series of experiments and numerical simulations are carried out in a high-speed axial compressor to systematically investigate the influence and underlying flow mechanisms of micro tip injection on enhancing compressor stability.Different geometric structures of micro tip injection have been investigated,including the axial positions of injector port,injected mass flow rate and injector diameter.First,seven designed micro tip injection structures and one solid wall casing are tested in the compressor test rig to elucidate the influence of different micro tip injection parameters on the compressor stability.Then,numerical simulations are conducted to analyze the underlying flow mechanisms of micro tip injection with different design parameters on enhancing the compressor stability.The experimental and numerical investigation reveal that when the injection port is located upstream of the low-speed region,the compressor stability is significantly enhanced.The tip injection with larger injected mass flow can obtain higher stall margin improvement.Smaller injector diameter produces higher injection momentum and velocity,contributing to greater improvement on the compressor stability.

Study on a High Precision Inter-stage Flow Field Test System for Axial Compressors

The accurate parameters measurement of the flow field between the stages for axial compressors is a significant demand.This paper proposes an axial compressor inter-stage flow field high-precision test system,which mainly consists of a probe motion scanning mechanism,fully automated test control software,and data processing methods.Iterative correction is applied to the original readings obtained from the scanning tests to enhance testing accuracy.Using this test system,detailed tests are conducted on a 1.5-stage subsonic axial compressor under different operating conditions.The test results effectively captured the impact of surface roughness and tip clearance variations on compressor performance.The distribution characteristics of parameters measured in inter-stage sections can characterize the effects of blade wake area and changes in aerodynamic performance at different blade heights.The developed test system can be extended to multi-stage compressors.

Numerical Study of Co-flow Jet Control on Corner Separation in Compressor Cascade

The design objectives of modern aircraft engines include high load capacity,efficiency,and stability.With increasing loads,the phenomenon of corner separation in compressors intensifies,affecting engine performance and stability.Therefore,the adoption of appropriate flow control technology holds significant academic and engineering significance.This study employs the Reynolds-averaged Navier-Stokes(RANS)method to investigate the effects and mechanisms of active/passive Co-flow Jet(CFJ)control,implemented by introducing full-height and partial height jet slots between the suction surface and end wall of a compressor cascade.The results indicate that passive CFJ control significantly reduces the impact of corner separation at small incidence,with partial-height control further enhancing the effectiveness.The introduction of active CFJ enables separation control at large incidence,improving blade performance under different operating conditions.Active control achieves this by reducing the scale of corner separation vortices,effectively reducing the size of the separation region and enhancing blade performance.

优化数据生成算法的往复压缩机故障诊断研究

为解决实际生产中存在的往复压缩机故障信息样本缺失、样本不平衡等引起的长尾分布所造成故障诊断不准确的问题,提出一种基于经优化的对抗生成网络(Generative Adversarial Network,GAN)的方法,该方法在既保证样本质量又增强样本数量的情况下,应用改进的卷积神经网络(Convolutional Neural Networks,CNN)进行故障诊断分类。首先对往复压缩机一维故障数据进行整理并通过小波变换生成故障时频图;然后构建适应于样本的LS-SAGAN框架模型并利用原始故障时频图训练模型,生成满足实验数量的时频图;最后通过经天鹰算法优化CNN进行快速准确的故障诊断。将实验方法与其他方法进行效果对比验证,结果表明,所提方法在故障诊断中的平均准确率达到99.6%,相较其他分类方法分类效果明显提高。

转子尖部角区分离对高负荷压气机性能影响的实验与数值研究

为了探究转子尖部角区分离对高负荷压气机性能及内部流场的影响,以设计负荷系数为0.46的单级高负荷压气机为研究对象,通过实验与数值计算研究了转子叶尖间隙为0.6%与1.3%叶高的两种情况下高负荷压气机级特性与内部流场细节,分析了转子尖部角区分离对于高负荷压气机性能的影响规律及其流动机制。结果表明,转子叶尖间隙为0.6%叶高时,小流量工况下转子尖部吸力面出现了明显的角区分离;而转子叶尖间隙为1.3%叶高时,小流量工况下转子尖部流动由泄漏流主导。随着小间隙下转子尖部角区分离的增强,转子尖部堵塞与损失剧烈增长;同时,由于转子吸力面径向迁移的增强,小流量工况下转子近轮毂区域损失降低、负荷升高。相应地,压气机级总压升随流量减小表现出“先平缓,再升高,最后快速下降”的特点,级效率随着小流量工况总压升的进一步升高快速下降。

天然气管线计划性放空回收数值仿真模拟

天然气中甲烷的温室效应强度远高于二氧化碳,消除或减少输气管线放空作业中的天然气排放对实现双碳目标具有重要意义。为此,针对需计划性放空的输气管线,分别对采用下游压气站离心压缩机和移动式往复压缩机的2种天然气回收过程以及传统冷放空过程建立了瞬态仿真模型,并对放空回收所需总时间、放空气量、回收气量等参数进行了对比分析。研究结果表明:(1)采用隐式中心差分法求解这些模型,获得的回收时长、排放时长、回收气量、排放气量等参数与相应的TGNET软件仿真结果及放空过程实际数据的偏差均在±8%以内;(2)针对放空气回收过程的仿真模型,离心压缩机和往复压缩机需要考虑进行边界条件的转换;在放空过程的模拟中,需要考虑立管出口处压力和流速边界条件的转换;(3)针对输气管线计划性放空提出了3种天然气回收方案,其中方案1利用下游压气站的离心压缩机,方案2利用移动式往复压缩机,方案3为方案1和方案2的组合,即先用下游压气站的离心压缩机进行回收,当其进口压力降至允许最低值时,再切换至移动式往复式压缩机继续回收过程。结论认为:(1)方案1的回收时长最短但回收率最低,方案2的情况刚好相反,而方案3的回收率与方案2相近但回收时长介于方案1和方案2之间;(2)针对阀室间管线放空气回收方案的选择,离心压缩机与往复式压缩机结合进行回收的方案,可同时兼顾回收时长和回收效率,具有较好的经济性和可行性,因而具有较好的综合效果。

考虑接触间隙的压缩机柔性转子扭振特性研究

往复式压缩机曲轴系扭振会引起烧瓦及轴系断裂等重大问题,为掌握压缩机转子系统扭振响应,提出了一种考虑衬套-销轴碰撞间隙、曲轴-轴承油膜间隙的压缩机柔性转子系统扭振动力学求解方法,为避开曲轴系固有频率提供了一种新的思路及方法。基于多体动力学理论以及Hertz接触理论,求解了含碰撞间隙下曲轴系扭振动力学响应,分析表明,曲轴系第4列曲柄销的扭振幅值最大,扭转角位移幅值为0.051°,动态角速度峰值为156.026 rad/s。基于此,考虑了曲轴-轴承油膜间隙,利用有限差分法及超松弛迭代法计算滑动轴承油膜压力,并通过压力扰动法求解轴承动态特性系数,综合考虑衬套-销轴碰撞间隙和曲轴-轴承油膜间隙对曲轴系动态响应的影响,开展了考虑预应力下的曲轴系模态分析,并对比分析了考虑油膜间隙和不考虑油膜间隙下曲轴系的共振情况。结果表明,考虑油膜间隙后曲轴系第3、8阶固有频率分别降低了44.64%、21.23%,且在同一转速范围带内,考虑综合间隙下曲轴系共振转速点减少,2阶临界转速降低了38.55%,共振的概率增大。

低雷诺数轴流压气机叶型气动优化

为研究低雷诺数下轴流压气机叶型优化设计方法,本文验证了准三维求解器MISES对于低雷诺数流动的预测精度,对于V103叶型计算得到的转捩位置与实验值偏差小于5%,证实了其在低雷诺数流动中的可用性;基于多圆弧(MCA)叶型程序,利用增强精英保留遗传算法,搭建轴流压气机叶型准三维气动优化设计平台;以总压损失系数为优化目标,出口气流角为约束条件,对V103叶型进行了低雷诺数单点和高低雷诺数综合优化设计。结果表明:低雷诺数单点优化后,抑制了叶型层流分离泡现象,总压损失系数减小31.31%,性能显著改善;高低雷诺数综合优化后叶型在高雷诺数和低雷诺数下总压损失分别减小了3.05%和3.03%。本文研究结果证明了所发展工具的有效性和考虑雷诺数叶型优化的可行性。

基于地铁车辆空压机出口压力空气含水量影响因素分析的正交试验设计方法

[目的]地铁列车空压机出口压力空气干燥度是一个非常重要的指标。如果压力空气中含水量高,就会影响各用风设备的性能,进而影响行车安全。上海轨道交通运维人员在汛期对某些线路列车进行检修时发现,列车供风管路中存在液态水,这是因压力空气中含水量过高而造成的。需要在现有条件下,研究如何调整维修策略,进而改善空压机在汛期的干燥能力。[方法]通过正交试验设计方法,设计了用于分析空压机出口压力空气含水量影响因素的试验方案,给出了使用田口方法分析数据进而确定主要影响因素的方法。[结果及结论]运用该试验方案进行试验,能够分析出影响列车空压机出口压力空气含水量的主要因素,运维人员可据此结论制定适用于汛期的列车空压机维修策略。该正交试验设计方法也可以推广应用至城市轨道交通其他设备运维策略的完善与优化工作之中。

基于改进布谷鸟搜索算法的压气机特性曲线预测

为了提高压气机特性曲线的预测精度和边界工况点的泛化能力,本文提出了一种改进布谷鸟搜索算法优化BP(ICS-BP)的模型,应用于某轴流压气机流量-压比特性预测方法研究,并对比分析了采用传统BP、遗传算法优化BP(GA-BP)、布谷鸟搜索算法优化BP(CS-BP)、径向基函数神经网络(RBF)、极限学习机(ELM)、自优化支持向量机(MSVM)和ICS-BP模型的预测结果。分析显示,ICS-BP模型整体预测结果的相对误差最小,普遍在±1%以内,评价指标展现出最高的精度和鲁棒性,预测结果具有最佳的泛化能力,且优化后的模型解决BP易陷入局部最优的问题;ELM和RBF模型运行速度较快的情况下依然具有良好的整体预测精度,但对于边界工况点预测效果欠佳,适用于对时间成本要求高的场景。针对7F重型燃气轮机和NASA74A型号压气机特性曲线,通过ICS-BP模型预测的压比特性精度较高,整体预测结果的平均绝对百分误差分别为1.129%和0.590%,进一步验证了其在特性预测方面的优势。

Aerodynamic Design and Analysis of a Low-reaction Axial Compressor Stage

There is introduced a new low-reaction, highly-loaded axial compressor design concept which is coupled with boundary layer suction method. The characteristic features of the concept are made clear through its comparison with the MIT boundary layer suction compressor. Also are pointed out the potential applications of this concept as well as its key technological problems. Based on this concept, a single-stage, low-reaction and low-speed axial compressor is constructed in association with analysis and computation of boundary layer suction on vanes with the aid of a three-dimensional numerical approach. The results attest to the effectiveness of this way to control separation in blade cascades by the boundary layer suction and the feasibility of this proposed design concept.