Flow Measurement and Instrumentation最新文献_第5页

Experimental investigation of dissolved oxygen improving aeration efficiency by hydraulic jumps 通过水力跃迁提高曝气效率的溶解氧实验研究

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-16 DOI: 10.1016/j.flowmeasinst.2024.102715

Saikat Mondal , Rajib Das , Subhasish Das , Sanchayan Mukherjee

The dissolved oxygen (DO) level in water is vital for water quality and supporting aquatic life. Hydraulic jumps involve rapid flow changes from super-critical to sub-critical, visible at abrupt bed slope shifts, like at spillway bases in rivers or canals. The hydraulic jump efficiently mixes oxygen from air into water and offers a cost-effective method of aeration by entraining air bubbles in the stream to improve oxygen transfer compared to traditional systems. The objective of this experimental research is to investigate the aeration performance with hydraulic jump parameters and establish correlations crucial to measuring aeration (or transfer) efficiency. Relationships between transfer efficiency, jump height, jump length, sequent depth ratio, discharge, inlet Froude number, and channel bed slope were determined. To investigate the nature of such relationships, a series of experiments were conducted in a rectangular tilt flume to test the aeration performance of forced submerged hydraulic jumps with five different discharges and five different smooth bed slopes. The inlet Froude number before the jump varied from 2.18 to 8.23. Experimental observation confirms a positive relationship between transfer efficiency and jump control parameters. During experimentation, transfer efficiency was found to vary between 9.4 % and 34 %. This research includes estimating the optimal transfer efficiency due to hydraulic jumps, which can help hydraulic engineers in building structures that can revitalize any degraded stream.

水中的溶解氧 (DO) 水平对水质和支持水生生物至关重要。水力跃迁是指水流从超临界状态向亚临界状态的快速变化，在河床坡度突变处可见，如河流或运河的泄洪道基部。与传统系统相比，水力跃迁能有效地将空气中的氧气混合到水中，并通过在水流中夹带气泡来改善氧气的传输，从而提供一种经济有效的曝气方法。这项实验研究的目的是调查水力跃层参数的曝气性能，并建立测量曝气（或传氧）效率的关键相关性。研究确定了传质效率、跃层高度、跃层长度、序深比、排水量、入口弗劳德数和河床坡度之间的关系。为了研究这些关系的性质，在矩形倾斜水槽中进行了一系列实验，以测试五种不同排水量和五种不同光滑河床坡度的强制沉没式水力跃层的曝气性能。跃流前的入口弗劳德数从 2.18 到 8.23 不等。实验观察证实，传质效率与跃层控制参数之间存在正相关关系。在实验过程中，发现转移效率在 9.4 % 到 34 % 之间变化。这项研究包括估算水力跃迁带来的最佳传输效率，这可以帮助水利工程师建造能够振兴任何退化溪流的结构。

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引用次数: 0

Development of a locating method for optical windows in shock tube 开发冲击管中光学窗口的定位方法

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-16 DOI: 10.1016/j.flowmeasinst.2024.102717

Shijie Bai, Wei Shen, Shilong Li, Xingyu Liang, Kun Wang

A method was proposed in the present study for locating single and/or multiple optical windows in shock tubes. It involved establishing a diagnostic time calculation model by transforming challenging conventional conditions into equivalent special scenarios. The method strategically balanced experimental pressure and optical window locations. Pressure-time history experiments were conducted in a shock tube to verify the reliability of the proposed locating method. An example showcased the versatility of the locating method for determining the positions of single or multiple optical windows. Lastly, the proposed locating method provided evaluation for optimizing several existing shock tube setups.

本研究提出了一种在冲击管中定位单个和/或多个光学窗口的方法。该方法通过将具有挑战性的常规条件转换为等效的特殊情况，建立了一个诊断时间计算模型。该方法从战略上平衡了实验压力和光学窗口位置。在冲击管中进行了压力-时间历史实验，以验证所建议的定位方法的可靠性。一个实例展示了该定位方法在确定单个或多个光学窗口位置方面的多功能性。最后，建议的定位方法为优化现有的几个冲击管设置提供了评估。

引用次数: 0

CFD-based flow field study and structural optimization of SAC-type ultrahigh-pressure common rail injection steady-state nozzle 基于 CFD 的 SAC 型超高压共轨喷射稳态喷嘴流场研究与结构优化

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-16 DOI: 10.1016/j.flowmeasinst.2024.102719

Hailong Ji , Ruichuan Li , Wentao Yuan , Yong Zhou , Ning Guo , Dongrun Li , Qingguang Zhang

This paper constructs and validates a fluid simulation model of fuel in an ultra-high-pressure SAC-type injector using Fluent's CFD computing tool. The effects of different nozzle parameters on the flow field characteristics of ultrahigh-pressure SAC-type nozzles under ultrahigh-pressure 200 MPa operating conditions were investigated. In the context of the study, with the increase of the nozzle diameter, the flowability of the loud nozzle is significantly improved, and the cavitation intensity extended to the outlet will be greater, which is more conducive to the atomization of the fuel. The smaller the nozzle angle, the higher the fuel flow rate, and reducing the angle is favorable to increase the fuel flow rate and mass flow rate. The increase in the inverted radius of the nozzle inlet and the significant increase in the nozzle flow characteristics help improve the nozzle's Circulation performance but are not conducive to the atomization of the fuel. The optimized structure of a Double-crossed oval spray nozzle shape is proposed to reduce the cavitation in the spray nozzle and improve the Circulation performance of the nozzle under a certain cross-sectional area of the outlet of the spray nozzle. The optimized Double-crossed oval spray nozzle mass flow rate increased by16.99 g/s compared with the original nozzle, and the cavitation in the nozzle was significantly suppressed, and the overall average circulation coefficient reached 0.9494, which is 70.23 % higher than the original nozzle, and the Circulation performance of the optimized Double-crossed oval spray nozzle was significantly improved.

本文利用 Fluent 的 CFD 计算工具构建并验证了超高压 SAC 型喷油器中燃料的流体模拟模型。研究了在 200 MPa 超高压工作条件下，不同喷嘴参数对超高压 SAC 型喷嘴流场特性的影响。从研究结果来看，随着喷嘴直径的增大，大口径喷嘴的流动性明显改善，延伸到出口的空化强度会更大，更有利于燃料的雾化。喷嘴角度越小，燃油流速越高，减小角度有利于提高燃油流速和质量流量。喷嘴进口倒半径增大，喷嘴流动特性显著增加，有利于提高喷嘴的环流性能，但不利于燃料的雾化。在喷嘴出口横截面积一定的情况下，提出了优化结构的双交叉椭圆形喷嘴形状，以减少喷嘴内的气蚀，提高喷嘴的环流性能。优化后的双交叉椭圆形喷嘴质量流量比原喷嘴提高了 16.99 g/s，喷嘴内的空化现象得到明显抑制，整体平均环流系数达到 0.9494，比原喷嘴提高了 70.23 %，优化后的双交叉椭圆形喷嘴的环流性能得到明显改善。

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引用次数: 0

Hydraulic valve design methodology for hydro turbine control system 水轮机控制系统液压阀设计方法

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-16 DOI: 10.1016/j.flowmeasinst.2024.102718

Mateusz Kosek , Dariusz Downar , Pawel Sliwinski

The control of the turbine and its equipment in a hydroelectric power plant requires the HPU (hydraulic power unit) to deliver large volumes of working fluid in a short time at specific optimum control parameters. The use of typical proportional flow control valves created by manufacturers of hydraulic components in low-pressure control systems is disadvantageous due to high pressure losses in the control chambers. This paper presents the methodology and test results while designing a hydraulic proportional valve for low pressure and high flow rate operation. CFD (computational fluid dynamics) theory was analyzed and characteristic values were determined. The validation of CFD tests through those on the test bench was carried out, correction factor was determined. A new proprietary solution was developed and a series of simulation studies were carried out to determine the flow characteristics depending on the degree of the opening of the proportional flow control valve.

水力发电厂水轮机及其设备的控制要求 HPU（液压动力单元）在特定的最佳控制参数下，在短时间内输送大量工作流体。在低压控制系统中使用由液压元件制造商制造的典型比例流量控制阀非常不利，因为控制室中的压力损失很高。本文介绍了设计低压大流量液压比例阀的方法和测试结果。对 CFD（计算流体动力学）理论进行了分析，并确定了特征值。通过试验台测试对 CFD 测试进行了验证，并确定了校正系数。开发了一种新的专有解决方案，并进行了一系列模拟研究，以确定取决于比例流量控制阀开启程度的流量特性。

引用次数: 0

Orifice erosion effect and variable gain control method for hydraulic servo spool valve 液压伺服阀芯的孔蚀效应和可变增益控制方法

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-13 DOI: 10.1016/j.flowmeasinst.2024.102714

Xinqiang Liu , Minghua Qi , Hong Ji , Fei Liu , Guang Lin , Yao Xiao

The hydraulic servo valve orifice becomes blunted due to erosion caused by solid particle contaminants in the oil, leading to a decline in the valve's static and dynamic performance. This study analyzes the working edge scanning model and proposes using a quarter-ellipse curve to fit the working edge contour for the precise calculation of the valve orifice area. Through AMESim simulation, this study investigates the relationship between valve orifice erosion and the static and dynamic characteristics of hydraulic servo slide valves and proposes a variable gain control method for addressing valve orifice erosion. Results show that the orifice area model based on the quarter elliptic curve is accurate. As erosion increases, the nonlinear area of the valve orifice curve expands, and the valve orifice degrades into a positive opening. The ratio of the long diameter to the short diameter of the ellipse is approximately linearly related to the pressure gain and leakage in the static characteristics of the hydraulic servo valve. After variable gain control, the static and dynamic characteristics of the servo valve closely resemble those of an ideal servo valve, with the maximum deviation between the flow characteristics and the ideal valve orifice approximately 1 %. Regarding pressure characteristics, the pressure drop before the zero position is below 0.2 MPa. This study establishes the internal relationship between orifice erosion and performance degradation and provides a novel approach to enhancing the erosion resistance of hydraulic servo valves.

液压伺服阀的阀嘴因油中固体颗粒污染物的侵蚀而变钝，导致阀的静态和动态性能下降。本研究分析了工作边缘扫描模型，并提出使用四分之一椭圆曲线拟合工作边缘轮廓，以精确计算阀嘴面积。通过 AMESim 仿真，本研究探讨了阀嘴冲蚀与液压伺服滑阀静态和动态特性之间的关系，并提出了解决阀嘴冲蚀问题的可变增益控制方法。结果表明，基于四分之一椭圆曲线的阀嘴面积模型是准确的。随着侵蚀的加剧，阀嘴曲线的非线性面积扩大，阀嘴退化为正开口。椭圆的长径与短径之比与液压伺服阀静态特性中的压力增益和泄漏量近似呈线性关系。经过可变增益控制后，伺服阀的静态和动态特性与理想伺服阀非常接近，流量特性与理想阀嘴之间的最大偏差约为 1%。在压力特性方面，零位前的压降低于 0.2 兆帕。这项研究确定了阀嘴侵蚀与性能下降之间的内在关系，为增强液压伺服阀的抗侵蚀能力提供了一种新方法。

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引用次数: 0

Design of a high-precision linear regulating ball valve 高精度线性调节球阀的设计

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-11 DOI: 10.1016/j.flowmeasinst.2024.102708

Zhe Zhao , Yongguang Liu , Xiaohui Gao , Saisai Tong

In this paper, a high-precision linear regulating ball valve is designed from four aspects: positioning accuracy, sealing performance, flow area and flow coefficient. A mathematical expression for the relationship between spool thickness, incision angle and flow coefficient was developed. The correlation matrix

P

between the structural parameters and the flow coefficient is obtained by surface fitting. The structural parameters under linear requirements are further determined by determining the P matrix. A more accurate linearization of the flow characteristics was achieved. The CFD data showed that the error of the optimized flow rate with respect to the ideal linear data was less than 0.15 kg/s. The average error was reduced by 43.8% when compared with the minimum error of different structures. The variance decreased by about 58.2% compared to the minimum variance for different structures. The final flow test of the optimized ball valve was carried out. The error between the flow test data and the CFD data is less than 0.14 kg/s and the maximum relative error is about 6.58%.

本文从定位精度、密封性能、流通面积和流量系数四个方面设计了一种高精度线性调节球阀。建立了阀芯厚度、切口角度和流量系数之间关系的数学表达式。通过曲面拟合得到了结构参数与流量系数之间的相关矩阵 P。通过确定 P 矩阵，进一步确定了线性要求下的结构参数。实现了更精确的流动特性线性化。CFD 数据显示，优化后的流量与理想线性数据的误差小于 0.15 kg/s。与不同结构的最小误差相比，平均误差减少了 43.8%。与不同结构的最小方差相比，方差减少了约 58.2%。对优化后的球阀进行了最终流量测试。流量测试数据与 CFD 数据之间的误差小于 0.14 kg/s，最大相对误差约为 6.58%。

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引用次数: 0

Projection segmentation-based image recognition technology for automatic reading of gas meter 基于投影分割的图像识别技术用于自动读取燃气表

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-11 DOI: 10.1016/j.flowmeasinst.2024.102707

Yuanming Zhang , Xiaoxiao Huo , Qilun Lu , Guoyu Chen , Liangyong Hu

In view of the shortcomings of the existing gas meter reading methods, this paper introduces an automatic reading method and calibration device based on the projection segmentation method, which uses the color difference between the character part and the rest part of the last code wheel of the gas meter counter to realize image recognition of the turned characters, and then calculates the cumulative volume indication of gas meter based on the number of turned characters. The pixel projection value scanned by the camera device at the horizontal centerline of the last code wheel changes alternately when the code wheel rotates. The proposed projection segmentation method does not require recognition of specific characters, simplifying the algorithm and making it suitable for most calibration devices. Experiments show that the accuracy rate of the proposed method is 100% even under low-light conditions, which is a great improvement compared with the traditional character recognition method. Additionally, the reading resolution of the proposed method is improved by 10 times compared with the existing photoelectric sampling method and template matching method, and the total calibration time can be reduced by 6.7%–58.7%, which significantly enhances the calibration efficiency.

针对现有燃气表读数方法的不足，本文介绍了一种基于投影分割法的自动读数方法和校准装置，该方法利用燃气表计数器最后一个码轮的字符部分与其余部分的色差实现翻转字符的图像识别，然后根据翻转字符的个数计算燃气表的累计量指示。当编码轮旋转时，摄像装置在最后一个编码轮水平中心线上扫描到的像素投影值会交替变化。所提出的投影分割方法无需识别特定字符，简化了算法，适用于大多数校准设备。实验表明，即使在弱光条件下，所提方法的准确率也能达到 100%，与传统的字符识别方法相比有了很大改进。此外，与现有的光电采样法和模板匹配法相比，所提方法的读取分辨率提高了 10 倍，总校准时间可缩短 6.7%-58.7% ，大大提高了校准效率。

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引用次数: 0

Flow inferential measurement for proportional control valves by combining wavelet denoising and a dual-attention-based LSTM network 结合小波去噪和基于双注意力的 LSTM 网络，为比例控制阀提供流量推断测量功能

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-11 DOI: 10.1016/j.flowmeasinst.2024.102713

Yue Xu, Gang Yang, Baoren Li, Zhe Wu, Zhixin Zhao, Zhaozhuo Wang

Accurate flow inferential measurement enables accurate real-time acquisition of the flow rate for hydraulic systems, effectively replacing conventional expensive and space-consuming flowmeters. However, the high nonlinearity and complexity of valve flow pose significant challenges for achieving accurate flow inferential measurements. To address this issue, this paper proposes a novel method based on wavelet denoising and a dual-attention-based long short-term memory (DA-LSTM) network. The DA-LSTM network is innovatively proposed to learn the flow mapping relationship, and incorporates the intervariable attention mechanism and the variable self-attention mechanism to enhance learning performance. Additionally, considering the presence of noise contamination in the measurement datasets, the wavelet thresholding denoising method is employed to increase the data quality. Furthermore, the real-time performance of the proposed method is also considered. The trained model is validated against test datasets, and is also compared to three other neural network-based flow estimation methods. The experimental results demonstrate that the proposed method accurately realizes the flow inferential measurement of the proportional control valve, with a mean square error percentage of 0.6494 %. This establishes a robust foundation for accurate flow control of proportional control valves.

精确的流量推断测量能够准确实时地获取液压系统的流量，有效地取代了传统的昂贵且耗费空间的流量计。然而，阀门流量的高度非线性和复杂性给实现精确的流量推断测量带来了巨大挑战。为解决这一问题，本文提出了一种基于小波去噪和双注意长短期记忆（DA-LSTM）网络的新方法。创新性地提出了 DA-LSTM 网络来学习流量映射关系，并结合了可变注意机制和可变自我注意机制来提高学习性能。此外，考虑到测量数据集中存在噪声污染，采用了小波阈值去噪方法来提高数据质量。此外，还考虑了建议方法的实时性能。根据测试数据集对训练好的模型进行了验证，并与其他三种基于神经网络的流量估算方法进行了比较。实验结果表明，所提出的方法准确地实现了比例控制阀的流量推断测量，均方误差百分比为 0.6494%。这为比例控制阀的精确流量控制奠定了坚实的基础。

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引用次数: 0

Flow regime discrimination and methodology for calculating discharge in trapezoidal sluice gates 梯形水闸的水流状态判别和排水量计算方法

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-10 DOI: 10.1016/j.flowmeasinst.2024.102710

Wanshang Meng , Lin Li , Shuaijie Zhao , Pengcheng Li

This study introduces a novel trapezoidal sluice gate designed for water division and flow control within irrigation networks featuring canals with trapezoidal cross-sections. Experiments were conducted on trapezoidal channels with side slopes of m = 1.5, 1.75, and 2.0, using trapezoidal sluice gates at various gate openings, upstream water depths, and downstream depths. A total of 411 experimental sets were conducted to study methodologies for discerning between free flow and submerged flow conditions and for determining discharge rates. A method was proposed to distinguish flow patterns of trapezoidal sluice gates: submerged flow occurs when the downstream channel depth (h_t) exceeds the submergence threshold (H_t'), while free flow is indicated when h_t is less than H_t'. The formula for calculating H_t' was derived, along with formulas for computing discharge rates under free flow and submerged flow conditions for trapezoidal sluice gates. The results revealed that the average relative errors of the formulas obtained through the partition method and the submergence coefficient correction method were 2.24 % and 5.37 %, respectively, demonstrating high accuracy and reliability. The scale effects on the flow regimes and formulas of discharge rates are also discussed. Findings from this study enhance the understanding of the hydraulic characteristics of trapezoidal sluice gates, which hold significant implications for the adoption and intelligent management of such gates in irrigation areas, offering a viable solution for selecting appropriate water gate configurations in irrigation systems.

本研究介绍了一种新型梯形水闸，设计用于以梯形横截面渠道为特色的灌溉网络中的分水和流量控制。实验在边坡为 m = 1.5、1.75 和 2.0 的梯形渠道上进行，使用不同闸门开度、上游水深和下游水深的梯形水闸。共进行了 411 组实验，以研究区分自由流和潜流条件以及确定排水率的方法。提出了一种区分梯形水闸水流模式的方法：当下游河道水深（ht）超过淹没临界值（Ht'）时为淹没水流，而当 ht 小于 Ht' 时为自由水流。推导出了 Ht' 的计算公式，以及梯形水闸在自由流和淹没流条件下的排水率计算公式。结果表明，通过分区法和淹没系数修正法得到的公式的平均相对误差分别为 2.24 % 和 5.37 %，显示了较高的准确性和可靠性。此外，还讨论了尺度对水流状态和排泄率公式的影响。本研究的结果加深了人们对梯形水闸水力特性的理解，对灌区采用和智能管理此类水闸具有重要意义，为灌溉系统中选择合适的水闸配置提供了可行的解决方案。

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引用次数: 0

Dynamics and experimental study of a novel proportional directional valve with displacement feedback groove controlled by high-speed switching valves 由高速开关阀控制的带位移反馈槽的新型比例换向阀的动力学和实验研究

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Flow Measurement and Instrumentation

Pub Date : 2024-10-09 DOI: 10.1016/j.flowmeasinst.2024.102711

Ruihao Zhao , Weifeng Chai , Yang Zhang , Xiang Yuan , Zisheng Lian , Huiting Shi

The intelligence of hydraulic roof support is an important guarantee for unmanned fully mechanized coal mining face. The water-based medium proportional directional valve is the main factor that restricts the intelligent realization of support system. The support control valve needs to meet the 2/3 (two-position three-way) structure, taking into account both manual and electro-hydraulic control functions. The current water-based proportional valve does not satisfy the structural or functional demands of the support system. In this paper, a novel 2/3 water-based proportional directional valve is presented based on the displacement-flow feedback principle, which has two control modes: manual on-off control and electro-hydraulic proportional control. The proportional valve comprises two main valve spools and two pilot valves. The pilot valve is composed of a 2/3 on-off valve with manual operation capability and a high-speed switching valve group controlled by PWM (Pulse Width Modulation). The mathematical model of the proportional valve is established, and the experimental system is built to verify the characteristics of proportional valve. The proportional valve can meet the special functional requirements of the support. In the proportional control mode, the adjustment of spool displacement is regulated through the modulation of PWM duty ratio, resulting in effective control performance of the proportional valve. Furthermore, the discontinuous flow of the high-speed switching valve causes the pressure fluctuation of the pilot hydraulic bridge. Increasing the carrier frequency of PWM can reduce the amplitude of control chamber pressure and spool displacement fluctuation. The findings of the study can offer valuable insights for the continued advancement and enhancement of water-based proportional valves used in hydraulic roof support systems.

液压顶板支护的智能化是煤矿无人化全机械化采煤工作面的重要保障。水基介质比例换向阀是制约支护系统智能化实现的主要因素。支护控制阀需满足2/3（二位三通）结构，兼顾手动和电液控制功能。目前的水基比例阀无法满足支撑系统的结构和功能需求。本文介绍了一种基于位移-流量反馈原理的新型 2/3 位水基比例换向阀，它具有手动开关控制和电液比例控制两种控制模式。比例阀由两个主阀芯和两个先导阀组成。先导阀由一个具有手动操作功能的 2/3 开关阀和一个由 PWM（脉宽调制）控制的高速开关阀组组成。建立了比例阀的数学模型，并搭建了实验系统来验证比例阀的特性。该比例阀可满足支架的特殊功能要求。在比例控制模式下，通过调制 PWM 占空比来调节阀芯位移，从而实现了比例阀的有效控制性能。此外，高速切换阀的不连续流量会导致先导液压桥的压力波动。提高 PWM 的载波频率可以减小控制室压力和阀芯位移波动的幅度。研究结果为继续改进和提高液压顶棚支撑系统中使用的水基比例阀提供了宝贵的启示。

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引用次数: 0