非均匀来流下TBCC变几何进气道的数值优化

为提高内并联式涡轮基组合循环发动机进气道的工作特性,设计了一种带多级楔板的扩压段二维进气道。采用数值模拟方法研究了非均匀来流对其流场特性及性能参数的影响,并与非均匀来流对常规型进气道特性的影响进行了比较。模拟结果表明:采用带多级楔板的扩压段二维进气道性能受非均匀来流影响更小,扩压段内出口流场有明显的提升;模态转换状态下,与常规型进气道相比,进气道出口总压恢复系数平均增大10%,总压畸变指数平均降低15%左右,冲压出口马赫数均小于0.41,出口温升比降低。从而使得发动机推力增加,耗油率降低,改善了TBCC发动机的性能。     

1+1/2对转涡轮的气动设计与分析

主要进行的是1 1/2轴流式对转涡轮的气动设计研究。发展了1 1/2对转涡轮的设计体系,采用基于流线曲律法的可控涡方法对1 1/2对转涡轮进行S2流面的设计,对叶型设计方面的工作进行了探索,在传统的参数法叶型设计程序的基础上发展运用bezier曲线进行叶型优化,并采用商用CFD软件开展对转涡轮S1流场和全三维粘性流场的数值计算。     

大膨胀比局部进气涡轮叶栅流场数值模拟研究

为探究局部进气对涡轮叶栅内部流场的影响机理,本文针对某大膨胀比涡轮叶栅,采用数值模拟方法,对局部进气条件下涡轮叶栅内部流场开展了详细的研究与分析,并研究了不同的出口马赫数与来流攻角下局部进气涡轮叶栅内部流动规律和机理.结果表明:局部进气导致涡轮叶栅中马赫数分布发生变化,在涡轮叶栅进口出现高马赫数区域和弓形激波,进口气流...     

混合励磁式井下涡轮发电机涡轮参数研究

随钻测井系统中井下仪器连续工作,涡轮发电机作为电源优势明显。提出了一种水力性能较高的涡轮模型形式并进行了建模研究。采用Fluent软件对不同叶片参数的涡轮模型进行紊流流场分析优化了涡轮结构。分析了流量、转速对涡轮流场的影响情况。通过地面实验验证了流量、转速、负载与涡轮发电机输出电压的关系。所建立的涡轮模型能够提高涡轮的输出功率并保证其工作寿命。用地面实验验证了仿真结果的正确性。     

基于气热固耦合的涡轮模态分析

主要研究了气热固耦合场对涡轮模态参数的影响.采用基于k-ε湍流模型理论建立了涡轮的流场模型,进行网格划分和边界条件的加载.通过气热固耦合分析计算获得了流场内部温度和压力的分布,把气动力及温度载荷映射到涡轮结构上,并在此基础上进行了涡轮模态的计算.计算结果表明,气热固耦合场主要影响涡轮结构的模态固有频率,对模态振型的影响较小.     

叶冠齿顶间隙对涡轮气动性能的影响研究

通过数值方法对某二级带冠涡轮的流场进行研究,分析了齿顶间隙对涡轮气动性能的影响。研究结果表明:泄漏流与主流掺混后形成一个涡流区,改变了叶栅上半通道的流场结构;随着齿顶间隙的增加,涡轮的流量先快速增加后趋于平缓,涡轮的效率先快速减小后趋于平缓;同时发现不同工况下,涡轮的流量和效率的变化趋势相同。     

车用涡轮增压器涡轮级流场特性的仿真研究

基于计算流体动力学两相流技术对某车用涡轮增压器涡轮级的流场特性进行了仿真研究,分析不同涡轮转速下涡轮级的废气颗粒质量浓度、废气流速、压力及温度变化规律。研究结果表明,当涡轮转速由100 000 r/min加快至140 000 r/min时,涡轮级废气颗粒质量分数呈现出降低趋势,废气颗粒分布的均匀性提高。涡轮级废气的最大流速由211.121 m/s加快至306.624 m/s,效率提高27%。随着涡轮转速的加快,涡轮级最大压力由159 771.84 Pa增大至253 244.031 Pa,温度梯度不断增大,温度分布的均匀性则有所降低。     

随钻测井用井下发电机系统的涡轮设计

对随钻测井系统中井下涡轮发电机的关键部件进行了研究.首先,建立了一种水力性能较高的涡轮模型;然后,基于计算流体力学(CFD)理论,采用Fluent软件对不同叶片参数的涡轮模型进行了紊流流场研究,并分析了流量、转速对涡轮流场的影响;最后,通过涡轮发电机地面单向水利实验验证了流量、转速、负载与涡轮发电机输出电压的关系.仿真结果表明:15叶片、叶片进口角30°以上、出口角45°以下、中弧线圆弧半径40mm以内对应的涡轮模型水力性能较好,但水力效率过高也会降低涡轮的工作寿命,因此,在一定范围内增大流量、转速对提高涡轮水力效率具有积极影响.所建立的涡轮模型能够提高涡轮的输出功率并保证其工作寿命.     

CFD在涡轮排气管增压器流场分析中的应用

本文借助三维数值模拟软件Numeca,建立了涡轮排气管增压器涡轮机的网格模型,对涡轮排气管增压器(即增压器与排气管集成)的涡轮及排气歧管内部流场分布情况进行了稳态模拟。结果表明:涡轮排气管各进出口的总压差分布不均,以2#进口进气时总压损失最大,此外,对涡轮内部流场及温度场也进行了分析,流场及温度场整体分布比较均匀,流场局部还存在一定的改善空间。可见,CFD技术对于优化涡轮增压器涡轮及排气管的设计,改善增压器性能具有很好的指导意义。     

典型燃机透平转子旋转盘结构的流动换热研究

针对实际F级燃机典型结构的透平转子旋转盘进行了流热耦合的数值模拟研究,研究其流场特性参数;根据流场模拟结果对中心进气的涡轮盘与中间盘复杂流动的换热特性进行研究计算,对实际工程应用具有一定的参考价值。     

Analysis of blade structure impact on turbine flow sensor performance

The impeller blade structure is one of the important factors affecting the performance of the turbine flow sensor. However, the underlying fluid dynamics mechanism is still not fully understood. The DN10 turbine flow sensor's internal flow field was analyzed based on computational fluid dynamics (CFD) simulations to explain the influence mechanism of blade structure on its performance. The experiment proves that the simulation method is reliable. The structural parameter η, which characterizes the shape of the impeller blade, was defined, and four turbine flow sensor structures were studied. The results suggested that the value of η affects the stability of the impeller's fluid dynamics characteristics, the velocity distribution at the impeller inlet, and the acting position and time of the wake flow behind the upstream flow conditioner. Therefore, the structural parameter influents the performance of the turbine flow sensor. With the increase of η, the characteristic curve gradually moves down, the average meter factor decreases, and the linearity error increases.     

叶轮进口宽度对液力透平性能的影响

针对叶轮进口宽度对液力透平性能影响规律的认识不足问题,建设了一开式液力透平实验台,对一单级液力透平进行了实验研究,得到了该比转速液力透平的外特性曲线。采用结构化网格技术对液力透平进行了全流场数值计算与分析,数值与实验相结合,验证了数值计算的准确性。对不同进口宽度透平叶轮的数值计算结果分析表明,随着透平叶轮进口宽度的增加最高效率点向大流量偏移,大流量时的效率逐渐增加;对于一定几何参数组合的液力透平,存在最佳叶轮进口宽度使液力透平最优工况点效率最高;透平的流量扬程曲线随叶轮进口宽度的增加变得更加平坦;透平的轴功率变化相对较小。     

变螺距井下涡轮水力性能研究

螺旋涡轮主要用于井下涡轮式交流发电机。利用CFD方法对一种变螺距涡轮的内流场作了较详细的三维紊流数值模拟，得出了丰富的内部流场信息，同时在此基础上计算出了该涡轮主要外特性曲线。变螺距涡轮与等螺距涡轮相比，叶片进口处速度变化均匀，压力损失减小，同时涡轮的压降和效率特性也有很大的改善。变螺距涡轮具有更好的水力性能，该研究为井下涡轮式发电机的性能提升和结构改进提供了有力的依据。     

工业汽轮机调节级部分进汽瞬态数值研究

针对采用喷嘴调节的汽轮机调节级效率和安全性问题,基于时均的N-S方程,采用六面体结构化网格和有限容积法,对某机组调节级内部流动进行了数值计算。给出了不同工况下调节级内部压力和速度分布图,分析了4阀开和3阀开工况下调节级内部流动。给出了动叶旋转一周扭矩的变化,并将非定常扭矩进行了傅里叶变换,得到了频谱图。研究结果表明,部分进汽使调节级内部流动不均匀,4阀开,动叶所承受最大瞬时扭矩是进汽弧段平均扭矩的2.2倍,3阀开,动叶所承受最大瞬时扭矩是进汽弧段平均扭矩的1.8倍,这可以为调节级动叶安全性校核提供参考;频谱图显示,动叶受到与转速相关的低频激振力;3阀开工况下调节级的效率比4阀开工况下降低7%。     

脉冲进气对径流涡轮转子通道内部流场影响研究

基于车用增压器涡轮的进口压力和温度是脉动变化的,本文采用Numeca软件求解进口边界条件为给定脉动总压总温的三维非定常Navier-Stokes方程组,并对相同进口条件下的涡轮转子内部流场进行分析。研究结果表明,脉冲进气条件下的涡轮特性具有强烈的非定常特征。     

Purge flow effect on aerodynamics performance in high-pressure turbine cascade

The endwall and blade film cooling systems are the typical solution adopted within gas turbines to allow further increase of turbine inlet temperature, avoiding critical material thermal damages. Due to the complex secondary flow field in the blade passage, endwall is more difficult to be cooled than blade surfaces. In the matter of fact, in endwall film cooling studies, it is necessary to investigate the interaction between coolant air and the secondary flow. In present study, the flow field of high-pressure turbine in linear cascade has been investigated by 5-holes pitot tube to reveal the secondary flows behaviour under the influenced of purge flows through a slot which is located 0.63 C_ax upstream of blade leading edge. Both measurement and numerical simulation presented almost similar trend of aerodynamics performance thus enable the authors to excute the flow visualizations accurately. The presence of newly generated vortical structures was considered to be responsible to the additional loss at higher MFR cases.     

Average Velocity Measurements in Six Automotive Torque Converters Part II: Turbine Measurements

The internal flow fields of two automotive Plexiglas torque converter turbines with three different pumps were examined. A laser velocimeter was utilized to measure the velocity flow field at the turbine inlet and mid-planes in the six different geometry combinations; the stator was the same for all combinations. The turbine geometries differed only by the inlet blade angle, while the pump geometries differed only by the exit blade angle. The torque converter was operated at three different turbine/pump rotational speed ratios: 0.065 (near stall), 0.600, and 0.800 (near coupling point). For all geometries at the inlet plane the flow is fairly uniform in the blade-to-blade direction at all speed ratios. Velocities are most uniform in the core-to-shell direction at high speed ratios, but high velocities move near the shell at lower speed ratios. At the mid-plane, at low speed ratios the velocities are significantly higher near the pressure surface but as the speed ratio increases, the gradient decreases. At low speed ratios velocities are higher near the shell but this distribution becomes uniform at higher speed ratios. In general the flow became more uniform as the speed ratio increased. Variations in the pump exit blade angle had effects on both inlet and mid-plane velocity distributions and are documented. Variations in turbine inlet blade angle altered the inlet and mid-plane flow fields, but less so than the pump variations. A clockwise circulatory secondary flow pattern at the turbine inlet plane was observed for all geometries and, conversely, counter-clockwise circulatory secondary flow patterns at the mid-plane were recorded. Resulting vorticities were found to depend on geometries and speed ratios. The turbine leading edge incidence angles were found to strongly depend on the speed ratio, ranging from positive to negative, as well as pump and turbine blade angles.     

Development of a test rig for investigating the flow field around guide vanes of Francis turbines

This paper summarizes the development of a test rig containing three guide vanes of a Francis turbine, whose flow field is set up to match with that of the actual turbine. The rig is made suitable for Particle Image Velocimetry (PIV), such that the flow field around guide vanes can be measured. It has been studied that using three consecutive guide vanes in the rig give optimum results in terms of the lab capacity and having minimum influence of the wall surrounding the guide vanes. This rig also facilitates the measurements at off-designed conditions by changing the guide vane's opening angles. The flow conduits at inlet and outlet of the vanes have been optimized using CFD, to match the velocities corresponding to the turbine's design. The rig is also made suitable for testing the guide vanes with different clearance gaps. On comparing the results obtained from the experiment with CFD on the basis of velocity and pressure measurements, it is seen that the two results are comparable.     

Performance test and component characteristics evaluation of a micro gas turbine

This study aims to analyze engine performance and component characteristics of a micro gas turbine based on detailed measurement of various parameters. A test facility to measure performance of a micro gas turbine was set up and performance parameters such as turbine exit temperature, exhaust gas temperature, engine inlet temperature, compressor discharge pressure and temperature, and fuel and air flow rates were measured. The net gas turbine performance (power and efficiency based on the gas turbine shaft end) was isolated and analyzed. With the aid of measurement based simulation, component characteristic parameters such as turbine inlet temperature, compressor efficiency, turbine efficiency and recuperator effectiveness were estimated. Behaviors of the estimated characteristic parameters with operating condition change were examined and sensitivities of estimated parameters to the measured parameters were analyzed.