Flow-rate Characteristics Measurement of Regulators Based on the Pressure Response in an Isothermal Tank

Regulators are important components in pneumatic system, and their flow-rate characteristics are the key parameters for designers. According to the correlatively international standard and national standard of China, which describe the flow-rate characteristics measurement method of pneumatic regulators, the pressure and the flow are measured point by point, and then the flow-rate characteristics curve is plotted point to point. This method has some disadvantages, such as equipment complexity, much air consumption, and low efficiency. To settle the problems presented above, this paper puts forward a new high efficient and energy saving flow-rate characteristics measurement method of regulators, which is based on the pressure response when charging and discharging to an isothermal tank without any flow meters. The measurement principle, the system and the steps are introduced. And the tracking differentiator is used for the data processing of the pressure difference. Two typical kinds of regulators were experimentally investigated, and their flow-rate characteristics curves were obtained with the new and the conventional method, respectively. Comparatively, it＇s proved that this new method is feasible because it is not only able to meet the demand of the measurement precision, but also to save energy and improve efficiency. Compared to the conventional method, the new method takes only about 1/10 amount of time and consumes about only 1/30 amount of air. Hopefully it will be able to serve as an international standard of flow-rate characteristics measurement method of regulators.

A Study into Blood Flow, Heart Rate Variability, and Body Surface Temperature While Listening to Music

In this study we examined the relaxing effects of listening to music on a total of 12 women aged from their 20s to their 40s by measuring their blood flow, heart rate variability, and their body surface temperature. As a result, We found that there was a tendency for the volume of blood flow to the fingertips to significantly increase when listening to classical music, but there was a variety of changes in blood flow between each age group for healing music and J-Pop music. When measuring heart rate it was found that the LF/HF value, which is an index for the autonomic nervous system which shows tension and stress, fell significantly when listening to each type of music. Lastly, there was a trend for body surface temperature to rise when listening to classical or healing music, a rise which was particularly significant when listening to healing music. This study shows that a relaxing effect can be expected for all indices when listening to classical music. However, for healing music and J-Pop, personal musical preferences seemed to have an effect and the results were varied.

A numerical simulation strategy for a compressor’s underlying axisymmetric characteristic and its application in body force model

Accurate prediction of the aerodynamic response of a compressor under inlet distortion is crucial for next-generation civil aircraft,such as Boundary Layer Ingestion(BLI)silent aircraft.Therefore,research on the Body Force(BF)model plays a significant role in achieving this objective.However,distorted inlet airflow can lead to varying operating conditions across different spatial locations of the compressor,which may cause some regions to operate outside the stability boundary.Consequently,the accuracy of BF model simulations might be compromised.To address this issue,this paper proposes a numerical simulation strategy for acquiring the steady axisymmetric three-dimensional flow field of a compressor operating at low mass flow rates,which is known as the Underlying Axisymmetric Pressure Rise Characteristic(UAPRC).The proposed simulation accounts for two different rotor speeds of a transonic compressor and identifies initial positions in the flow field where deterioration occurs based on prior experimental investigations.Moreover,simulation results are incorporated into the BF model to replicate hub instability observed in experiments.Obtained results demonstrate that this strategy provides valid predictions of the UAPRC of the compressor,thereby addressing the limitations associated with the BF model.

横摇晃荡对矩形工船养殖舱内流场与颗粒物去除的影响

深远海养殖工船游弋式养殖是现代海洋渔业发展的一个重要的方向。基于FLOW-3D软件探究了横摇运动对舱内流场特征的影响,并在此基础上计算了不同横摇工况下流场中废弃颗粒物的去除情况。结果显示:控制横摇周期一定,随着横摇角度从0°增加到2°,舱内流速略有增加。而当横摇角度从2°增加到7°时,舱内流速出现大幅增加,v_(50%)从0.171 m/s增加到0.477 m/s;同时横摇角度的增大也使流速的整体分布更加离散。横摇角度幅值2°以内工况的流动均匀性指数主要集中在0.8~0.85,当横摇角度幅值增加到3°后,养殖舱流动均匀性显著降低,养殖舱内水体流动均匀性指数均小于0.8。当横摇角度幅值一定时,横摇周期缩短,养殖舱内流速急剧增大,各工况流速的v_(50%)与其他分位数呈线性增长趋势而舱内水体的流动均匀性变化并不显著。对于养殖舱内废弃固体颗粒物的去除,在横摇周期和颗粒物自身属性一定时,整个过程分为效果相反的前后两个阶段:从颗粒物投放进入流场至投放后的1 000 s内,横摇角度幅值越小,其去除速率越高;此后直至整个算例的计算结束,横摇角度越大,颗粒物去除速率越高。而横摇周期对养殖舱内颗粒物的去除排出基本没有影响,各个工况颗粒物去除的达标时间极为接近。

液氢贮罐内过热蒸气不同质量流量泄放过程模拟

以液氢工厂中贮存液氢的液氢贮罐为研究对象,选择液氢、气液相界面、蒸气三个区域合适的控制方程,建立了可模拟从自增压到泄放后回到初始压力过程的三区模型。模拟了充液率为50%的10 m3液氢贮罐从自增压-泄放后回到初始压力的周期过程。在特定泄放时间,不同泄放质量流量条件下,对比了液氢贮罐内贮罐压力、饱和液氢和过热蒸气的质量流量和温度以及液氢体积随时间的变化特性。结果表明:泄放过热蒸气质量流量大小随泄放时间增大不断减小;泄压时间越短,泄放后过热蒸气温度越接近初始温度;进入泄放阶段,蒸发液氢质量流量发生了明显激增,增大幅度随泄放时间增大而减小。

不同加载速率下矸石胶结充填体破坏规律细观研究

基于室内单轴压缩试验,使用颗粒流软件建立了数值模型并标定微观参数,研究了不同加载速率下矸石胶结充填体试样的应力应变曲线规律、微裂纹数量、破坏过程以及微观位移场变化规律。结果表明:随着加载速率的不断增大,试样的峰值强度及弹性模量均不断增加;试样生成的微裂纹数量与加载速率成正比,微裂纹-应变曲线分为裂纹未萌生、裂纹快速增长、裂纹数量稳定3个阶段;试样的破坏过程分为压缩密实、弹性变形、塑性破坏以及残余变形4个阶段;试样微裂纹两侧颗粒发生不同形式的组合破坏,包括拉伸破坏、剪切破坏以及拉伸和剪切共同作用的混合破坏。

关于延长制盐蒸发装置生产周期的研究分析

在制盐蒸发装置生产管理过程中对延长装置生产周期的主要影响因素进行了研究分析,本文针对加热室管内流速、卤水杂质、管内料液固液比、末效真空度等进行优化、探索、追求,从而达到延长制盐蒸发装置生产周期的目标,提高了设备生产能力和产量。

离子型稀土开采过程中导流井井周矿体颗粒脱落运移临界流速研究

离子型稀土是我国独具特色、世界罕见的矿产资源,主导了全球的中重稀土供给,具有配分齐全、高科技应用元素多与综合利用价值大的特点。但离子型稀土开采过程中易出现井壁坍塌,进而造成边坡失稳。本文分析了导流井井周矿体颗粒受力状态,建立了矿体颗粒脱落运移临界流速计算模型,研究了不同影响因素下矿体颗粒脱落运移临界流速。结果表明,矿体颗粒脱落运移的临界流速随颗粒半径、排列角度、摩擦系数的增大而增大。静电力受浸矿液浓度的影响,但其对矿体颗粒脱落运移临界的影响不大。此外,浸矿液粘度增大能够显著降低临界流速。本研究能够为离子型稀土安全高效开发提供理论与技术支撑。

方体定向穿刺置管抽吸引流术治疗原发性脑干出血的效果分析

目的:探究方体定向穿刺置管抽吸引流术治疗原发性脑干出血的效果。方法:选取2021年3—12月钦州市第一人民医院神经外科收治的原发性脑干出血患者60例为研究对象,随机分为观察组和对照组,各30例。观察组接受方体定向穿刺置管抽吸引流术治疗,对照组接受开颅血肿清除引流术治疗。比较两组死亡率、预后情况和神经功能恢复情况。结果:观察组死亡率低于对照组,差异有统计学意义(P=0.0283);治疗1、3、6、12个月后,观察组格拉斯哥预后量表评分高于对照组,差异有统计学意义(P<0.0001);治疗1、3、6、12个月后,观察组改良Rankin量表评分低于对照组,差异有统计学意义(P<0.05)。结论:方体定向穿刺置管抽吸引流术可有效治疗原发性脑干出血,可促进神经功能恢复,改善预后。

不锈钢废水站废水最终排放流量测量失准问题研究

为解决不锈钢冷轧废水站废水最终排放流量测量数据波动大及小流量废水无法准确测量问题,从巴歇尔槽的组成、标准巴歇尔槽构造尺寸、标准巴歇尔槽流量计算、巴歇尔槽前标准长度设计要求、巴歇尔槽安装位置密封情况五方面进行分析研究,采用排除及比对方法,得出巴歇尔槽前入口液面波动及安装固定位置密封性差两个影响因素,最终从减少巴歇尔槽前液面波动性和对安装位置进行密封两个方面提出解决措施。

水力负荷和填料对华南冬季条件下潮汐流人工湿地去除氨氮的影响

供氧不足是导致传统人工湿地硝化速率和水力负荷低的关键因素。此外,低温条件下微生物活性下降会进一步加剧该问题。针对上述情况,构建两组供氧能力强的潮汐流实验柱,在华南冬季条件下考察水力负荷和填料对系统NH_(4)^(+)-N去除效率的影响。结果表明,NH_(4)^(+)-N去除负荷与水力负荷成正比。以沸石与碎石混合填充的潮汐流实验柱(TFCW-Z)对NH_(4)^(+)-N的平均去除率(67.20%~77.28%)显著高于以碎石填充的实验柱(TFCW-G)NH_(4)^(+)-N平均去除率(43.23%~51.77%)(p<0.05)。在日平均温度为6~19.5℃,水力负荷为4 m/d条件下,TFCW-Z出水中NH_(4)^(+)-N质量浓度始终低于黑臭水体标准值8 mg/L,此时NH_(4)^(+)-N平均去除率为67.20%,NH_(4)^(+)-N平均去除负荷高达47.96 g/(m2·d),表明潮汐流人工湿地在华南地区黑臭水体治理中具有良好的应用前景。

Flow rate limitation in open wedge channel under microgravity

A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computa- tional Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dim- ensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.

规则波条件下的多液舱浮体动力响应特性研究

为了研究多液舱浮体的动力响应特性,基于势流理论进行多液舱浮体动力响应的频域分析。首先考虑不同的网格尺寸开展网格敏感性分析,随后针对规则波中单液舱浮体开展建模计算并与相关试验结果进行对比验证。最后分析多液舱浮体的动力响应特性,并探讨载液量及载液类型对浮体动力响应的影响。研究发现:液舱对浮体横荡的影响较小,对横摇的影响较大,垂荡响应与全系统自重有关;横摇响应曲线的峰值大小及峰值数量与液舱的载液类型存在一定关联。

直通式袋式除尘器流量分配计算流体动力学方法研究

介绍了能有效降低设备运行能耗、提高滤袋寿命的直通式袋式除尘器及其箱体气体流通结构,并利用CFD方法对箱体流量分配和气流分布进行数值模拟,给出了实现箱体流量合理分配的气流分布板结构调整方法和参数。计算结果与模型试验、现场测试结果吻合较好。

垂直流人工湿地系统对污水磷的净化效果

用煤灰渣人工土壤和风车草组成的垂直流人工湿地系统对化粪池出水中总磷和无机磷的去除率分别达到75 %— 92 %和 73%— 92 % ,其处理出水中总磷和无机磷浓度大部分低于 1mg/L ,达到了城市污水二级生化处理的二级排放标准。垂直流煤灰渣人工湿地系统对磷的去除作用主要有 :物理作用、化学吸附与沉淀作用和微生物同化作用以及植物摄取等作用 ,其对化粪池出水中总磷的去除率分别为 2 2 .8%、5 0 %— 6 5 %和 1%— 3%。

流量对河水滴灌重力沉沙过滤池内流速分布的影响

为研究流量对河水滴灌重力沉沙过滤池流速分布规律的影响,该文对5种不同流量下的水沙两相流流场进行了数值模拟。通过对不同流量下流速沿程分布规律、流速沿水深方向分布规律及水沙分离效率的对比与分析,可知河水滴灌重力沉沙过滤池的适宜流量范围为0.05~0.2 m3/s,进水流量越小,流速变化幅度也就越小,越有利于泥沙沉降,水沙分离效率不小于72.5%。不同流量下沉淀池中流速沿程变化规律可分成3个阶段:流速迅速增加阶段、流速缓慢减小阶段和流速迅速减小阶段。清水池中流速方向与沉淀池的相反,流速沿程减小。受进水口、出水口和固体边界,以及侧向溢流堰的影响,不同流量下河水滴灌重力沉沙过滤池中的流速沿水深方向分布规律有差别。当流量为0.05和0.1 m3/s时,远离进水口、出水口及侧向溢流堰的位置,流速沿水深方向的分布规律包含流速迅速增加、流速缓慢减小和流速恒定3个阶段,而清水池则只包括流速迅速增加和流速恒定阶段。研究可对大首部的应用提供参考。

淬火槽中介质流速的测量及流速场的模拟

为了研究淬火槽中流速场的分布状态 ,提高流体均匀性 ,采用超声波多普勒流速测定仪对螺旋桨搅拌状态下的介质流速进行了测量 ,用有限元法对流速场进行了模拟 ,并根据模拟结果对均流片的设置进行了改进。结果表明 ,试验选用的超声波多普勒流速测定仪及其测量方法适合于测量工业淬火槽的介质流速 ;

三棱柱阻流体无阀压电泵的设计与试验

以三棱柱阻流体为无移动部件阀,结合3D打印技术的快速一体成型特点,设计并制作了以压电振子为动力源的三棱柱阻流体无阀压电泵。分析了该无阀压电泵的工作原理、理论流量和振子振动特性,推导出了它的的流量表达式。利用有限元法对三棱柱阻流体的流阻特性进行了仿真模拟,由其内部压强分布及进出口流速情况,定性分析了三棱柱阻流体的正反向流阻大小。最后,使用3D打印机制作了该无阀泵的试验样机,并进行了流阻和流量测量试验。试验结果表明:三棱柱阻流体具有正反向绕流流阻不等的特性,当驱动电压为550V,驱动频率为8 Hz时,该压电泵的输出流量达到最大,为29.8mL/min。结果证明了该三棱柱阻流体无阀压电泵具有良好的输送流体的能力。

大型LNG地上全容储罐的冷却技术研究

大型常压LNG储罐是LNG接收站中极其重要的单元设备,占有很高的投资比例,其正式启用时对调试工作的技术要求较高,而LNG储罐调试工作最关键和最危险的环节就是冷却。为此,详细介绍了国内LNG接收站常用16×104m3常压LNG储罐的冷却过程,分析了LNG储罐冷却前应具备的条件及注意事项,讨论了LNG储罐冷却过程中的压力控制、冷却介质(LNG)供应及流量控制、冷却过程的监控及冷却速率控制等调试技术,指出了冷却过程容易出现管线位移过大、法兰泄漏等问题,并给出了相应解决方法。研究成果对国内其他LNG项目具有借鉴意义。

炼油厂酸性水罐区排放气量分析计算

为确定酸性水罐区排放气治理装置规模,建立了罐区排放气量的计算方法并进行了计算。酸性水罐区排放气包括大呼吸、小呼吸和来水中低碳烃的汽化。目前,A炼油厂酸性水罐区最大大呼吸排气速率为240 m3/h;最大小呼吸排气速率为212 m3/h;来水中低碳烃的汽化速率为20 m3/h;合计最大气体排放速率为472m3/h。日排气量为6 427 m3/d。