用涡轮流量计测量多相流流量

对涡轮流量传感器进行了理论分析,给出了涡轮流量计仪表常数的计算方法,讨论了获得较大固有仪表常数K0时涡轮传感器结构参数(如叶片数、涡轮半径、口径等)的优化组合问题,通过多相流动实验,总结出K0与流动密度之间的实验关系,由此给出用涡轮流量计测量多相流的半理论半经验公式,并在油井多相流量测量中得到了实际应用,符合较好.     

液体涡轮流量传感器叶轮几何参数定量优化方法

以降低传感器特性受被测液体粘度变化的影响为目的，提出了液体涡轮流量传感器叶轮的多参数定量优化方法。该优化方法以叶片顶端间隙与管道半径之比、轮毂半径与叶片顶端半径之比、叶片均方根平均半径位置的叶片安装角、叶片顶端的叶栅实度为传感器叶轮的几何特征参数；传感器用同一仪表系数测量高粘度和低粘度2种液体，以线性度误差最大值为目标函数；以约束条件下n维极值的复形调优法为优化算法。     

磁轴承涡轮流量传感器的探讨

对不同结构的磁轴承涡轮流量传感器进行了比较综合,发现采用被动磁轴承结合机械约束,实现传感器内部可动部件叶轮的部分悬浮,是减小轴与轴承之间机械摩擦阻力、降低轴和轴承的磨损,从而提高传感器的灵敏度,增加传感器使用寿命的一条思路。提出了采用两个轴向磁化的径向磁轴承结合两个球头轴尖支撑的涡轮流量传感器结构,并进行了理论分析和参数计算。对研制磁轴承涡轮流量传感器过程中遇到的问题,进行了初步探讨。     

应用双光纤传感器的涡轮流量计结构、特性及试验研究

本文叙述了将反射型光纤传感器与传统的涡轮流量测量原理相结合,进行具有双光纤传感器的涡轮流量计的实验研究。与传统的内磁式涡轮流量计相比具备了正反流量测量的性能。实验研究结论表明：应用双光纤传感器涡轮流量计可进行双向流量测量,两个流量信号经鉴别电路实现了双向流动的检测。对于单向流量测量,也可通过流量计算机的算法消除因水击产生的脉动流造成涡轮往复震动而引起的计量误差。扩展了涡轮流量计的量程比,不存在内磁式传感器在低流速时与涡轮叶片产生磁阻而引起的误差。     

井下涡轮发电机叶片改型与优化设计

为提高涡轮叶片效率和涡轮发电机的输出功率,提出一种叶片改型与优化设计的方法。分别对导轮型线和涡轮翼型进行改型,通过不同叶型的导轮和涡轮组合的CFD流场分析,研究不同结构的导轮对涡轮性能的影响,从中选择出高效率、大扭矩的叶轮组合,基于BP神经网络和Fmincon函数与遗传算法结合的方法对叶片进行优化分析,并对比试验数据验证了此方法的可行性。优化结果表明单级涡轮的效率增加了4.74%,最大工作效率由初始的64.824%提高至79.4%,提升了约14.6%,理想输出功率增加了274.7 W。     

解决D100叶轮加工中切削变形的对策

TWLQ系列涡轮气体流量计是一款用于天然气等气体介质瞬时流量和累积流量测量的仪表。TWLQ-100型涡轮气体流量计的核心部件是D100叶轮,其工作原理是将叶轮置于被测流体中,当介质流经流量计时,由于叶轮叶片与流过的介质之间存在一定夹角,流体对叶轮产生转动力矩,使叶轮克服机械摩擦阻力矩和流动阻力矩而旋转,以叶轮的旋转速度来反映流量的大小。因此,叶轮的几何形状、尺寸及动平衡将直接影响涡轮气体流量计的性能和使用寿命。     

小口径液体涡轮流量传感器数学模型的研究

针对磁阻力矩对小口径涡轮流量传感器性能影响较大,而对其定量计算又相当困难的问题,提出了利用计算流体力学(CFD)仿真获取磁阻力矩及轴与轴承间的摩擦力矩之和(T_M)的方法,建立适用于小口径液体涡轮流量传感器的数学模型。利用完善后的数学模型对4种不同结构的10 mm口径涡轮流量传感器性能进行预测,并与实验结果进行对比分析。结果表明:利用数学模型预测的特性曲线与实验结果趋势相同,数值相近,平均仪表系数最大误差1.2%,线性度误差相差0.12%。     

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。     

电动燃油泵流道数值仿真及结构改进研究

针对电动燃油泵流道内液体流动规律复杂,工作效率需要改善的问题,运用Fluent软件对燃油泵内部流场进行仿真分析。基于雷诺时均N-S方程和标准K-∑湍流模型以及标准壁面函数法,采用三维非结构四面体网格划分方法,对包括不同叶片数、不同叶片夹角和不同叶轮厚度的燃油泵结构模型进行了数值模拟,得到了燃油泵内部流场压力云图和流线图。以燃油泵叶轮结构参数为变量,出口流量为目标函数,通过对仿真结果进行了数值拟合,得到了叶轮叶片数,叶片夹角,叶轮厚度和出口流量的一般规律。并通过燃油泵台架实验,对优选的燃油泵性能进行了验证。研究结果表明,实验数据与仿真结果基本吻合,且改进后的燃油泵流量提高了2.5%左右,其工作性能得到改善。     

分流叶片周向位置对离心叶轮性能及内部流动的影响

利用商用计算流体力学软件包NUMECA FINE/TURBO对Krain叶轮内部三维粘性流场进行了数值模拟研究。重点分析了分流叶片不同周向位置对该叶轮内部流动和性能的影响,得出了不同周向位置时的叶轮效率、压比随质量流量变化关系,结合对叶轮内部流场的详细分析,给出了适合此半开式离心叶轮分流叶片周向位置的最佳设计方案。研究结果表明:分流叶片不同周向位置对叶轮流道流场影响明显,当偏向主叶片吸力面一侧时可以有效提高叶轮效率。     

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.     

Dynamic performance analysis of turbine flow sensor based on CFD simulations

The research on the dynamic performance of flowmeters has great significance for the accurate measurement of flow onsite. A simulation method for dynamic characteristics of turbine flow sensor was proposed in this study. This method was used to investigate the dynamic performance of three turbine flow sensors with different diameters. The amplitude-frequency characteristic, phase-frequency characteristic, transfer function, and step response are analyzed based on the results of the simulation. The results indicate that turbine flow sensors can be analyzed as a first-order system. The frequency of pulse flow is the main factor affecting the sensor's performance. The phase difference increases as the frequency increases, and the maximum phase difference reaches 50°. The gain of the small-diameter turbine flow sensor is susceptible, while the phase difference and time constant of the large-diameter turbine flow sensor are susceptible. For step flow, the time constant generated by the negative step is larger than that by the positive step. The analysis results provide bases for evaluating the dynamic performance of turbine flow sensors used online.     

The effect of runner blade loading on the performance and internal flow of a Francis hydro turbine model

As a core component of a hydropower station, hydro turbines play a vital role in the integration of a power station. Research on the technology of hydro turbine is continuously increasing with the development of water electricity. It is effective and successful to design a Francis turbine runner blade with good performance by one-dimensional hydraulic design method. For the one-dimensional hydraulic design, the runner blade angle at leading and trailing edges can be defined by calculation of Euler’s head. Design of the runner blade profile at several cross sections is needed to design a runner shape. In this study, there are three different blade loadings conducted to compare the internal flow characteristics and performance. The result shows that the front loading achieves the best efficiency in comparison to other loadings, which is good at suppressing the loss at draft tube.     

Performance studies on cavitation-resistance turbine flow sensor based on experiment and CFD simulation

Under the technical requirements of expanding measurement range and suppressing cavitation of flow sensors, the performance of a novel cavitation-resistance turbine flow sensor is taken as the research objective in this article. Based on theoretical analysis, a three-dimensional flow field CFD model of the turbine flow sensor with Realizable k-ε turbulence model and Schnerr&Sauer cavitation model is established. The cavitation tunnel experiment is performed to obtain the sensor characteristics. Finally, simulation and experiment results is analyzed and the feasibility of the CFD simulation of the sensor flow field is proved. The results show that this novel turbine flow sensor has the ability to resist cavitation, and the critical cavitation number σ_cr of the turbine flow sensor is below 0.4. Under a wide range of cavitation number (0.33~ σ ~1.6), Reynolds number(5 × 10⁴~ Re ~8 × 10⁵)and inflow angle α(−5°~ α~ 5°), the measurement meets the requirements.     

双层翼叶片几何参数对水平轴风力机气动性能影响研究

为了提高风力机的气动性能，基于NREL Phase Ⅵ水平轴风力机叶片，设计出的一种双层翼叶片。通过计算流体力学的方法，在不同来流风速下，对比分析了双层翼叶片与按比例缩放各叶高处弦长的NREL Phase Ⅵ水平轴风力机叶片的扭矩与弯矩，研究了叶片实度的影响，发现实度增加并不是双层翼叶片的气动性能优于原始NREL Phase Ⅵ风力机叶片的主要原因。对不同弦长比、垂直距离及水平距离的大小叶片所组成的双层翼结构进行数值模拟研究，利用流线图着重分析了大小叶片水平距离对风力机气动性能的影响，总结了气动性能随双层翼叶片几何参数的变化规律，发现在15 m/s至25 m/s的风速下，选择较大弦长比、较大垂直距离或者较小水平距离的双层翼叶片可得到较高的扭矩值，但弯矩值也会随之增加。     

基于内流场分析的液力变矩器改型设计

为了提高液力变矩器的外特性,使其与发动机匹配良好,利用CFD软件对液力变矩器内流场进行三元流场数值计算和分析,在此基础上根据性能要求对原有变矩器作改型设计,改进了叶型进出口角、骨线形状和厚度分布等参数,以期得到分布合理的内流场,从而使改型后的变矩器具有符合要求的更优的外特性。改型后的液力变矩器具有更高的效率和与发动机匹配更优的泵轮容量系数,试验结果与计算结果非常吻合,改型设计效果良好。     

涡轮流量传感器在旋转来流中的特性研究

本文对涡轮流量传感器在旋转来流中的特性进行了理论和实验研究。利用涡轮流量传感器的数学模型,给出了涡轮转速、仪表常数与来流旋转角之间的理论关系式。计算了来流旋转强度及上游直管段长度变化时,仪表常数的变化情况。设计了能获得不同来流旋转强度的旋转发生器,并获得了大量的实验数据。实验结果与理论计算值在较大的流量范围内甚为吻合。     

基于Pro/E软件平台的混流式水轮机转轮叶片形状拟合

根据混流式水轮机叶片设计方程，基于Pro／ENGEINEER软件设计平台，对混流式水轮机叶片进行了形状拟合，得到了叶片拟合形状，完全符合叶片加工的工艺要求，也为研制水轮机修复专用机器人提供了研制条件。     

Analytical investigation of an inductive flow sensor with arc-shaped electrodes for water velocity measurement in two-phase flows

An inductive flow sensor with spot-shaped electrodes (IFS-SE) is sensitive to the shape of the flow profile and is restricted to be used to measure the flow rate of axisymmetric single-phase flows in a circular pipe. In many cases of application, it is not possible to provide a fully developed flow profile. Therefore, the inductive flow sensor has to cope with flow profiles that are not fully developed. To improve the accuracy, an inductive flow sensor with a pair of arc-shaped electrodes flush-mounted on the internal surface of an insulating section of a pipe is proposed in this article to investigate the characteristics of vertical gas-water two-phase flows. The effect of the flow profile on the inductive flow sensor is analyzed. A key contribution of the present work is to estimate the relationship between the induced voltage and the velocity of the conductive phase in two-phase flows. The estimation is achieved by the analytical calculation of magnetic-inductive equations through the method of variables separation. The analytical solution is compared with the results from an ideal model and from numerical simulation. Experiments are conducted to calibrate the inductive flow sensor with arc-shaped electrodes (IFS-AE). It is noted that the proposed IFS-AE can be adopted to obtain the velocity of the conductive phase in two-phase flows by measuring the voltage induced on the arc-shaped electrodes.