基于MSP430FR6972的四声道超声波智能水表的电路设计

智能水表与传统机械水表相比,具有计量准确、使用寿命长和数据实施传输等优势。本文针对智能水表低功耗、高精度和宽量程比的需求,采用四声道换能器提高流量测量的精度,同时采用超低功耗单片机MSP430FR6972,降低水表整机功耗,该设计具有一定的市场推广和应用前景。     

一种新型低功耗无磁流量计的设计

本文介绍了一种可用于水表、热量表等仪器中的新型低功耗无磁流量传感器的设计,其中重点叙述了这种流量计的优越性,并说明了其工作原理、硬件设计以及采用低功耗16位单片机MSP430的软件设计.     

基于改进时差法的超声流量计

利用时差法的改进算法设计出超声流量计,从测量原理上提高了流量测量的精度,同时给出以MSP430单片机为核心的流量测量系统的硬件电路设计,着重叙述了超声波发射与接收电路的具体实现,并提出低功耗的设计方法.     

罗茨流量积算仪的低功耗设计

罗茨流量积算仪用于气体流量的自动化计量。本文引入天然气压缩系数Z，对理想气体状态方程进行修正，提高了流量计温压补偿的准确性。文中阐述了积算仪的硬件和软件设计方案，着重介绍积算仪低功耗设计方面的尝试；利用MSP430单片机的低功耗和高集成度的优点、软件设计的低功耗实现等。结果表明，泫系统运行稳定，检测精度高。具有一定的实用性和推广价值，适于电池供电和远程应用场合。     

低功耗智能流量计量调节仪设计与实现

论述用超低功耗单片机实现低功耗智能流量计量调节仪的实现方法,重点介绍了该仪表的硬件模块电路设计.仪表以超低功耗单片机MSP430F147为主处理器,集压力测量、流量计量控制、无线传输于一体,在电池供电时具有极低功耗.该系统已在青海油田使用,运行状态表明参数设置方便,工作稳定可靠,测量控制精度高.     

低功耗预付费热量表的研究

提出了一种基于射频卡的低功耗热量表的软、硬件设计方法。采用了Atmel公司的T5557射频卡实现预付费功能,应用目前国际上功耗最低的MSP430FW425单片机为主控制器,Pt1000为温度传感器,其流量测量部分采用无磁流量计和韦根流量传感器,提高了测量的精度和灵敏度。     

基于MSP430F4152单片机的超声波热量表的设计

一种采用时差法超声波测量流量的超声波热量表的设计,采用了低功耗单片机MSP430F4152为控制器和高精度计时芯片TDC-GP21对时间的测量来实现对温度的测量,使其成为一种具有高精度、低功耗、测量误差小和对水质要求低的新一代产品。     

基于MSP430的CAN总线智能通讯板设计

基于MSP430单片机低功耗和双口RAM高速、实时数据交换的特点,文中提出了一种以MSP430单片机为控制核心的CAN智能通讯板设计方案。该智能通讯板主要由2片MSP430单片机和双口RAM构成,通过MSP430读写双口RAM,实现CAN总线与RS-232的数据通讯。同时为了避免双口RAM的读写错误,采用了一种软件仲裁方法,实现了上位机与底层控制器之间的CAN数据的可靠通讯。     

低功耗智能涡街流量计的设计

设计了以低功耗单片机MSP430F149为核心的信号采集处理及控制单元,并配有LCD液晶显示模块、RS485通讯接口,实现了4～20mA工业电流以及瞬时流量、累积流量的测量和显示。     

超低功耗高精度智能电表的设计

介绍了基于一种超低功耗的单片机并结合一种高精度的电量计量芯片的智能电表设计方案,主控核心是采用TI公司超低功耗16位MSP430单片机MSP430F5438,配合高精度单相双电流采样电能计量芯片BL6501A,使得智能电表系统具有可靠性、高精度和实用性等优点。     

基于多流场耦合的水力风机的性能预测

针对水力风机运行过程中同时存在水流场和空气流场,常规的单流场数值计算无法直接确定水力风机的工作点及相应性能的难题,基于Fluent的UDF技术设计了一种多流场弱耦合计算方法。该方法实现了水流场和空气流场进程的同步进行和两者之间的数据交换。最后利用该耦合方法对某型水力风机进行了模拟计算,模拟性能与试验性能具有较好的一致性。该方法的提出为后续水力风机的性能优化奠定了技术基础。     

Sectional void fraction measurement of gas-water two-phase flow by using a capacitive array sensor

The sectional void fraction measurement for multiphase flow is usually influenced by flow patterns. Inspired by electrical capacitance tomography (ECT) devices applied to flow imaging (whose measured capacitance data contain both the flow pattern and sectional void fraction information), a capacitive array sensor is developed to realize two functions, flow pattern recognition and void fraction measurement, simultaneously; so that the void fraction measurement can be conducted for a certain flow pattern and the measurement accuracy can be expected to be improved. The main idea of the proposed method can be described as: firstly, the proper feature vectors are extracted from the electrical signal to identify the flow pattern (the BPNN model with GDX learning algorithm is used for flow pattern identification); and then the average of electrical signal is applied to estimates the void fraction by the corresponding calibration curve. An experimental platform of air/water two-phase flow is built (on which 3 flow patterns can be generated stably) to test the performance of the proposed method. The results support the correctness and effectiveness of the proposed method.     

Experimental study to establish an evaluating method for the responsiveness of liquid flowmeters to transient flow rates

An aim of this research work is to establish an evaluation method concerning a responsiveness of flowmeters for a transient flow rate. To this end, reference flow metering systems for the transient flow are proposed in this paper. Because a behavior of the responsiveness depends on the type of flowmeter, evaluations using different parameters, such as response time to sudden rise and sudden fall in flow rate, response to the frequency and amplitude of flow pulsation, mean characteristic and so on are needed. To achieve a precise evaluation, two reference flow metering methods for transient flow rates are proposed in this paper. One is a high-response weighing method and the other is a velocity profile measurement method using the ultrasonic pulsed Doppler method (UPDM). Since the behaviors of the transient flow rate measured by both methods show good agreement, we conclude them to be useable as a reference flow metering system.     

无轴泵喷推进器水润滑轴承间隙流水动力设计与试验

针对无轴泵喷轮毂布置式水润滑支撑/推力轴承的敞水自润滑结构,以桨叶做功后产生的高速高压流场为输入来设计轴承的润滑和冷却流动通道,形成一体化支撑/推力轴承的自循环润滑方案.鉴于桨叶水动力与轴承间隙流的耦合影响作用,提出了两者迭代的设计方法,建立了桨叶与轴承间隙水动力耦合计算模型,实现了无轴泵喷轴承间隙流量的定量计算与分析...     

水泵吸水管和进水池内三维湍流的数值模拟

建立了泵站中水泵吸水管和进水池内部三维湍流流场的数学模型,针对泵站中布置了多台机组的多个吸水管和进水池中三维流场的计算边界条件作了深入分析,提出了合理的边界条件。根据分区划分网格的思想,构造了任意形状的水泵吸水管和进水池的贴体计算网格,在任意坐标系中对三维湍流流场的控制方程进行离散,编制了水泵吸水管和进水池内部三维湍流流场数值模拟的计算程序。数值模拟计算了泵站中水泵吸水管和进水池内部三维湍流流场。在数值模拟基础上,可对泵站中水泵吸水管和进水池内部流态进行评估。     

基于水体浅层泥沙继承特性的非接触式表面流速测量技术

针对水工物理模型表面流速测量方法的技术现状,提出了一种不对流场造成破坏的新型光电非接触式表面流速测量方法。在对光束入射水体后散射光强度公式进行了推导的基础上,根据水体浅层泥沙浓度的统计继承效应,得出了经上下游浅层泥沙调制的散射光强成相关特性的结论。根据上下游散射光的相关特性,推导了流速测量公式,分析了上下游测量间距、水流流速、采样率对测量结果的影响。搭建了实验系统,在6种不同标定流速下,对0~50kg/m3六种含沙量情况下的流速进行了测量。实验结果表明,在六种不同含沙量情况下,实测流速与标定流速的一致性较好,证明理论的可行性。实验还发现,水体适量含沙能提高流速测量精度,流速相对误差能控制在8%以下。     

Study and application of discharge calibration for submerged radial gates

Sophisticated stage-discharge rating curves for radial gates are essential to modernization efforts in water conservancy and irrigation projects. However, it is a challenging hydraulic issue to accurately determine discharges through radial gates, especially when subjected to highly submerged flow conditions. According to the variation trend of jet Froude number and the mechanism of energy dissipation subjected to submerged flows, a new criterion was proposed to subdivide submerged flow into partially submerged and totally submerged flows. Thus, the three stage-discharge equations were developed for free flow, partially submerged flow and totally submerged flow, respectively. With the aid of the experimental data of single radial gate and the field data of multi-radial gates, the proposed discharge calibration method, referred to as the identification method, was tested and verified. The results indicated the discharge prediction accuracies were satisfactory, in which the mean absolute percentage errors were less than 10%. The proposed method is feasible and easily programmed.     

液压泵恒流控制的神经网络实现方法及应用研究

提出一种采用神经网络辨识负载流量原理实现液压泵恒流量调节的新方法。结合此方法,提出在种基于模糊神经网络的恒流量调节泵智能学习控制方法,并将其应用于电液比例恒流量调节轴向柱塞泵的控制,改善了该泵的控制品质。     

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.     

Measurement of vertical oil-in-water two-phase flow using dual-modality ERT–EMF system

Oil-in-water two-phase flows are often encountered in the upstream petroleum industry. The measurement of phase flow rates is of particular importance for managing oil production and water disposal and/or water reinjection. The complexity of oil-in-water flow structures creates a challenge to flow measurement. This paper proposes a new method of two-phase flow metering, which is based on the use of dual-modality system and multidimensional data fusion. The Electrical Resistance Tomography system (ERT) is used in combination with a commercial off-the-shelf Electromagnetic Flow meter (EMF) to measure the volumetric flow rate of each constituent phase. The water flow rate is determined from the EMF with an input of the mean oil-fraction measured by the ERT. The dispersed oil-phase flow rate is determined from the mean oil-fraction and the mean oil velocity measured by the ERT cross-correlation velocity profiling. Experiments were carried out on a vertical upward oil-in-water pipe flow, 50 mm inner-diameter test section, at different total liquid flow rates covering the range of 8–16 m³/hr. The oil and water flow rate measurements obtained from the ERT and the EMF are compared to their respective references. The accuracy of these measurements is discussed and the capability of the measurement system is assessed.