柴油机风扇轴强度及疲劳的分析与改进

针对某型柴油机匹配挖掘机后出现的风扇轴断裂问题,进行了强度计算及疲劳强度分析.采用Abaqus计算强度,并将应力结果作为疲劳分析软件Femfat的输入参数,进行风扇轴疲劳强度分析,通过修改风扇轴危险位置的倒角半径来优化风扇轴,满足了工程应用要求.     

耦合法在柴油机传热研究中的应用

利用流固耦合的分析方法,将柴油机气缸盖、气缸垫、气缸体、气缸套等柴油机主要零部件以及缸内气体、冷却介质作为一个耦合体,进行燃烧室部件的传热数值模拟实验。其中,冷却水侧的对流换热系数和温度由CFD软件Star-CD对整个水路进行模拟计算获得;底板火力面侧燃气的对流换热系数和温度由GT-POWER软件对缸内工作过程进行模拟获得;缸套燃气侧温度由活塞组——气缸套耦合传热模拟获得。最终的计算结果与实验数据较吻合,可以为柴油机热负荷分析和柴油机设计提供理论依据。     

燃油的喷射雾化燃烧对柴油机缸内空气流动影响的研究

将柴油机缸内气体与全体燃烧室部件(气缸盖-气缸套-活塞组)作为一个耦合体,在对耦合体进行传热数值模拟的基础上得到缸内流动计算的壁面边界条件。利用大型通用CFD软件STAR-CD及ES-ICE,在进气压缩过程流动三维瞬态数值模拟基础上,对6110柴油机喷雾燃烧过程缸内三维非稳态流动进行数值模拟研究,着重分析燃油喷射、雾化、燃烧对缸内流动的影响。研究结果表明喷雾燃烧过程中燃油的喷射流动直接影响到缸内流场的总流型,在一定空间内完全打破缸内大的旋流流场。     

多级轴流风扇的性能试验与流场分析

针对某型四级轴流风扇改进设计的需要,通过试验详细测量了风扇的总性能特性,并利用三维流体计算软件NUMECA对设计转速下的部分典型工况进行了数值模拟.研究了风扇总性能和级性能的变化,时比分析了设计工况和近失速工况的流场特征.结果表明:风扇呈现出典型跨音速风扇设计的特点,计算结果与试验数据吻合较好,设计转速下,第三级转子通道中的激波被推出通道是导致失速产生的主要原因.本文结果可为该型风扇的改进设计提供参考.     

用耦合法分析研究发动机的稳态传热

利用FLUENT分析软件对发动机的稳态传热进行了仿真模拟。以所建立的某柴油机耦合传热系统为例进行了仿真计算,得到了耦合系统(活塞、缸套、冷却水套)的温度场等相关信息。计算结果表明,用耦合法模拟柴油机活塞组、缸套和冷却水之间的稳态传热是可行的。     

16V240ZJB型柴油机气缸盖耦合场分析

用Slid Works软件建立气缸盖的实体模型;利用Simulation对建立的气缸盖实体模型进行网格划分,建立了有限元分析模型;利用数值模拟方法对16V240ZJ型柴油机气缸盖进行了有限元分析,分别计算了温度场、热应力场,分析了热—机械耦合应力场,并提出了气缸盖结构的改进建议。     

基于Simulink的柴油机仿真计算程序的研究及界面设计

在柴油机工作过程分析的基础上,利用Matlab/Simulink软件建立了柴油机的稳态仿真计算程序,实现了柴油机每个模型程序的模块化,并以某型增压柴油机为研究对象,对其不同的负荷进行仿真计算,计算结果与试验结果基本吻合,验证了编写的Simulink仿真程序的准确性。在此基础上,应用MATLAB提供的GUIDE界面设计环境,对Simulink仿真程序进行了GUI人机交换界面的设计,可通过GUI界面来控制Simulink程序以及参数的设置,并能够方便的显示出不同工况下的仿真计算结果,程序应用更加灵活快捷,提高了仿真计算的效率。     

基于MATLAB的离心风扇优化设计

利用MATLAB强大的图形处理能力和GUI集成开发环境及FORTRAN语言运算速度快、易于编制大型工程软件的特点，开发了离心风扇优化程序。并对实际风扇进行了优化计算，通过优化设计风扇的台架试验，验证了风扇优化模型及软件的工程应用价值。     

硅油风扇离合器传递扭矩计算方法的研究

本文在理论分析的基础上,建立了计算硅油风扇离合器传递扭矩的数学模型和计算公式,编制了计算程序。用该程序对硅油风扇离合器进行了计算,并在硅油风扇离合器试验台上作了专项验证试验。试验结果表明,本文提出的计算方法可以用于硅油风扇离合器的设计计算。     

车用柴油机增压匹配数值模拟研究

使用VC 和Matlab分别建立了柴油机、涡轮增压器、进排气管及中冷器的数值模型,并编制了涡轮增压器与柴油机的匹配计算程序。应用该程序对某柴油机与某径流式涡轮增压器联合工作过程进行仿真计算,得到柴油机的性能参数及与该增压器的匹配数据,最后通过试验结果对数学模型、增压器与柴油机匹配程序的可行性进行了验证。     

Thermal intensification of heat transfer characteristics on the plate‐fin heat sink with piezoelectric fan

This study applied the computational fluid dynamic (CFD) code, ANSYS Fluent for simulating the effect a piezoelectric fan installed inside the rectangular channel by numerical simulation method for transient flow field and investigating the influence of each parameter. To remove the disorganized form of energy from the electronic components, the reversible piezoelectric effect is employed to energize the piezoelectric fan. To observe the variation of fan characteristics and to predict the convective heat transfer coefficient, CFD code ANSYS Fluent 15.0 is used. The numerical simulation parameters included are Nusselt number, number of fins (n = 12 and 14), and counter‐shift (inward and outward‐phase), and distance between the upper portion of the fan tip to the front part of the low thermal reservoir. Numerical analysis was carried out to evaluate the effect of thermal flow fields on the heat sink and piezoelectric fan employed in a flow domain. the results showed that by varying the height from channel bottom to the center of piezoelectric fan improves the performance of the piezoelectric fan, piezoelectric fan swinging in a transient phenomena and also simultaneously influences fluid flow behavior on the heat source surface, the fan vibration at counter‐phase has a better rate of heat transfer than vibration in in‐phase.     

“东方红3”船机舱风机房噪声治理

以“东方红3”船为例,根据风机房布置、风机噪声特性,基于吸声、隔声和隔振原理设计了降噪方案,对风机噪声进行综合控制。实船测试表明:该方案降噪效果明显,可有效降低风机噪声对科考仪器设备采集数据的影响,及对船员工作、生活环境的影响。     

Investigation and Verification of the Aerodynamic Performance of a Fan/Booster with Through-flow Method

Through-flow method is still widely applied in the revolution of the design of a turbomachinery, which can provide not merely the performance characteristic but also the flow field. In this study, a program based on the through-flow method was proposed, which had been verified by many other numerical examples. So as to improve the accuracy of the calculation, abundant loss and deviation models dependent on the real geometry of engine were put into use, such as: viscous losses, overflow in gaps, leakage from a flow path through seals. By means of this program, the aerodynamic performance of a certain high through-flow commercial fan/booster was investigated. On account of the radial distributions of the relevant parameters, flow deterioration in this machine was speculated. To confirm this surmise, 3-D numerical simulation was carried out with the help of the NUMECA software. Through detailed analysis, the speculation above was demonstrated, which provide sufficient evidence for the conclusion that the through-flow method is an essential and effective method for the performance prediction of the fan/booster.     

Unsteady flow and mass transfer in models of stenotic arteries considering fluid-structure interaction

In this work the unsteady non-Newtonian blood flow and mass transfer in symmetric and non-symmetric stenotic arteries are numerically simulated considering the fluid-structure interaction (FSI) using the code ADINA. Blood with hyperviscosity syndrome is considered and hyperelastic Mooney–Rivlin model is used for the compliant arterial wall. The inlet boundary condition of imposed velocity or pressure is critical to obtain realistic hemodynamic results in stenotic arteries. The FSI affects significantly the hemodynamics on the stenotic arteries models, the arteries are considerably dilated and compressed due the stenosis. The stenosis severity and geometry have important influence on recirculation length, and distribution of concentration of macromolecules, such as low density lipoproteins (LDL).     

Numerical simulation of fluid–structure interaction in stenotic arteries considering two layer nonlinear anisotropic structural model

The unsteady non-Newtonian blood flow in symmetric stenotic arteries is numerically simulated considering fluid–structure interaction (FSI) using the code ADINA. A two layer hyperelastic anisotropic structural model is used for the compliant arterial wall. The pressure used as outlet boundary condition was obtained running a CFD simulation for each stenosis with a physiologically-realistic time variation of pressure at inlet for different velocities. The obtained pressure drop increases in potential form with the inlet velocity for a fixed stenosis severity. The FSI results show that the maxima velocity and WSS at throat increase in exponential form with stenosis severity. The minimum and maximum effective stress at throat for stenosis severity of S = 70% ranged between 47 kPa and 96 kPa at diastole and systole, respectively.     

基于双向流固耦合的缸体缸盖温度场模拟分析与试验研究

为了研究发动机缸体缸盖表面的温度,基于双向流固耦合分析的方法对某汽油机的缸体缸盖进行了温度场分析。首先进行CFD分析得到温度以及换热系数边界,利用ABAQUS软件进行发动机的温度分析,再把结构温度作为下一次CFD计算的边界反复迭代。最终得到准确的温度场分布。并且通过试验的手段对分析结果进行验证分析,结果表明试验结果基本与分析结果相符。     

A parametric study of forced convection in an enclosure with stationary heated cylinders

This work performs an analysis of forced convection in an enclosure with a tube bank composed of 18 stationary cylinders. One wall is allowed to transfer heat while the remaining ones are insulated. The flow is induced by one fan placed near the upper horizontal wall. Numerical and experimental comparisons are also carried out to validate the code. Temperature and velocity distributions are presented showing their effect on the Nusselt number for various Reynolds numbers. Some recirculations worked as isolation layers that made heat transfer more difficult. Some tubes were seen to change negligible heat transfer which may be taken out of the tube set. A future work on the optimization is recommended by the authors.     

Ionic liquid electrolytes compatible with graphitized carbon negative without additive and their effects on interfacial properties

Introduction of bis(fluorosulfonyl)imide (FSI) as an anion to an ambient-temperature ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium (EMI) as well as lithium (Li) cations can provide a reversible Li intercalation into a graphitized electrode, while such intercalation is completely irreversible without FSI. The surface-layer components on the graphitized electrodes, cycled in the ionic liquid electrolytes with and without FSI, were found to be chemically similar based on X-ray photoelectron spectroscopy. Ac impedance spectroscopy revealed that the resistance of the electrode charged with FSI was much lower even than that charged in a solvent electrolyte system containing ethylene carbonate (EC) and dimethyl carbonate (DMC). On the basis of these physicochemical analyses, the origins of cycleability in the presence of FSI are discussed.     

Investigation of a miniature centrifugal fan

A centrifugal fan was designed with a matching centrifugal volute flow channel in order to investigate a numerical simulation with prototype manufacturing, and to compare with experimental results. The fan configuration was developed according to a fan-design theorem. A model P-60 turbojet engine compressor blade design was adopted for the fan aerodynamic analysis and design. The results were verified using the STAR-CD code. Also, based on the findings, a miniature centrifugal fan was designed and manufactured using a CNC five axes machine. The P–Q performance curves were tested using an AMCA standard 210-85 test chamber apparatus. From the numerical analysis results, the pressure on the suction and pressure surfaces will increase gradually from the inlet to one-half the distance of the hub’s camber line, however, it will increase more rapidly afterwards. In addition, stress-concentration phenomenon occurred at the tip of the suction and pressure surfaces. In other words, the tip was more prone to damage when the fan was operated. Experiments show that the designed fan maximum flow rate Q and static pressure P were 32% and 59%, respectively, which were lower than the commercial fan data at 2000 rpm rotational speed. However, when the rotational speed was increased to 4000 rpm, the maximum flow rate Q and static pressure P were increased to 38% and 82%. This study concluded that a centrifugal fan’s static pressure at high rotational speed is higher than that of an axial-flow fan. Therefore, a centrifugal fan should be chosen if high static pressure cooling or blowing is required. This advanced research investigation is to build up the capabilities of design, analysis, manufacturing, and measurement of a centrifugal fan with an outer diameter smaller than 10 cm.     

煤矿局部通风机供电系统优化分析

供电系统是井下局部通风机运转的动力源头,确保其运行的持续稳定对于掘进作业的安全持续开展意义重大。以此为着手点,对煤矿局部通风机供电系统优化开展分析探究。结合具体工程实际,在开展事故分析的基础上,对局部通风机供电系统的优化开展分析探究,并通过现场实践进行了二次优化,实现了局部通风机运行的稳定有效,为矿井生产作业的有序进行提供了坚实保障。