Flow Meter Method Research Articles

Signal processing method of ultrasonic gas flowmeter based on transit-time mathematical characteristics

To address the issue of timing errors caused by attenuation and jitter in the echo signal with the conventional threshold method, this paper presents a signal processing method for ultrasonic gas flow meters based on the mathematical characteristics of transit time. First, an improved weighted recursive filtering algorithm based on the mathematical characteristics of transit time is proposed. Then,based on the aforementioned filtering algorithm, a feedback-type threshold adjustment method has been proposed. Finally, the results for the flow meter meeting the performance criteria for a Class 1 accuracy ultrasonic gas flow meter at range of 2∼300 m3/h. This signal processing technique can be implemented at comparatively low cost on existing conventional fixed-threshold flow measurement infrastructures, with the potential to significantly improve accuracy and reliability.

Design of Three-Dimensional Characteristics of Perforated Plate for Liquid Nitrogen Balanced Flowmeter

To design the two-dimensional structural parameters of the core throttling component, i.e., the perforated plate for a liquid nitrogen (LN2) balanced flowmeter, this paper presented an orthogonal experiment scheme with three parameters, three factors, and three interactions, combined with the three-dimensional CFD numerical simulation. The constructed mixture multi-phase flow numerical model considers the complex cavitation effect of LN2 with a thermal effect. A DN40 balanced flowmeter and an LN2 flowrate test setup based on a standard flowmeter were constructed, and the measured flowrate data were used to evaluate the CFD model. Based on the optimized two-dimensional structure and the validated numerical model, the influence of the three-dimensional thickness of the perforated plate on the flow and pressure drop coefficient was investigated. It was found that there are two throttling forms as the thickness increases, resulting in two pressure-changing characteristics. The formation mechanism was explained by analyzing the turbulence intensity distribution. Finally, the final flow coefficient, pressure drop coefficient, and upper limit of measurement due to the cavitation were analyzed and obtained. The results provide a feasible parameter design method for the cryogenic balanced flow meters.

The development of the ultrasonic flowmeter sensors for mass flow rate measurement: A comprehensive review

A two-phase flow measuring device whose measurement system does not disturb the flow pattern, real-time measurement, and non-destructive measurement or non-intrusive model is a typical tool for an ideal situation. One measuring instrument that meets these criteria is an ultrasonic flow meter. Ultrasonic sensors can measure the velocity of fluid flow in pipelines. It has the advantage of high accuracy and reproducibility and does not make direct physical contact with the fluid in the pipe. Low fabrication costs and fast response make ultrasonic flowmeters widely used for two-phase flow measurements in both horizontal and vertical orientations. The void fraction or liquid holdup and velocity are the two most essential parameters for flow monitoring. The Time of Flight (ToF) method is mainly used for measurements in several ultrasonic flowmeter methods. In the present manuscript, the introductory section of this review explains the advantages of using the Time of Flight (ToF) method and its basic principles. This review also discusses research on measuring velocity and flow rate, differences in intrusive and non-intrusive measurement methods, parameters that affect ultrasonic measurements, and finally, measuring film thickness using non-intrusive methods.

A Fault Diagnosis Method for Ultrasonic Flow Meters Based on KPCA-CLSSA-SVM

To enhance the fault diagnosis capability for ultrasonic liquid flow meters and refine the fault diagnosis accuracy of support vector machines, we employ Levy flight to augment the global search proficiency. By utilizing circle chaotic mapping to establish the starting locations of sparrows and refining the sparrow position with the highest fitness value, we propose an enhanced sparrow search algorithm termed CLSSA. Subsequently, we optimize the parameters of support vector machines using this algorithm. A support vector machine classifier based on CLSSA has been constructed. Given the intricate data collected from ultrasonic liquid flow meters for diagnostic purposes, the approach of employing KPCA to decrease data dimensionality is implemented, and a KPCA-CLSSA-SVM algorithm is proposed to achieve fault diagnosis in ultrasonic flow meters. By using UCI datasets, the findings indicate that KPCA-CLSSA-SVM achieves fault diagnosis accuracies of 94.12%, 100.00%, 97.30%, and 100% in the four flow meters, respectively. Compared with the Bayesian classifier diagnostic algorithm, this has been increased by 4.18%. And compared with support vector machine diagnostic algorithms improved by the SSA, it has increased by 2.28%.

Study on the water detection using the flowmeter method at low temperatures

To prepare for the lunar water exploration in the Chinese Lunar Exploration Project IV, a new apparatus for studying characteristics of the water vapor conductance and water detection at low temperatures was built based on the flowmeter method, and the performance of the miniature time-of-flight mass spectrometer (TOF-MS) for water detection in the range −20 to 20 °C was measured. The through-put within the range of 3 × 10−9–9 × 10−6 Pa m3 s−1 was provided at temperatures in the range −60 to 20 °C. The conductance of the orifice with a diameter of 21 µms for three gases (N2, Ar, and H2O) was measured at low temperatures. The diameter change of the metal orifice caused by the cold contraction in the molecular flow state is the main factor affecting the conductance, and the viscosity characteristic of gas in the viscous flow state is the main factor affecting the conductance. Therefore, the conductance of the orifice increases with the decreasing temperature when the through-put is high. In addition, the water vapor can be stably supplied by the orifice under low temperatures, and the conductance of water vapor through the orifice is measured through the on-line method and the time-ratio method. The adsorption rate and amount of water vapor on the metal surface increase with the decreasing temperature, hence the concentration of water molecules in the test dome significantly decreases as the temperature decreases. Finally, the through-put of water vapor of 8.75 × 10−8 Pa m3 s−1 was detected by the miniature TOF-MC at −20 °C on the apparatus.

Pumping performance analysis of negative ion based neutral beam injector cryosorption pump prototype

A cryosortion pump creates a vacuum gradient environment in the process of neutral beam generation and transmission. Its pumping performance is related to the neutral beam quality. Here, the structural design and manufacturing method of the cryosorption pump were demonstrated based on the actual needs of negative ion based neutral beam injector (NNBI).Then,in order to verify the rationality of cryosorption pump's design, the test system of the cryosorption pump test prototype was built based on the flow-meter method to perform experiments to study the factors affecting the pumping performance. The results show that the prototype's stable pumping performance under different temperature, vacuum pressure, gas composition and the important characteristics of effective pumping speed for hydrogen and its isotopic gasses. The maximum error between the actual and the theoretical pumping speeds is maintained within 35%. The physical mechanism that temperature fluctuation and impurity gas helium can obviously affect the pumping performance of the cryosorption pump is revealed.It is concluded that the cryosorption pump prototype has excellent pumping performance, verifying the rationality of the structural design and providing a reference for the performance evaluation of a NNBI cryosorption pumps.

Research on the hydrogen consumption of fuel cell electric vehicles based on the flowmeter and short-cut method

Energy consumption is essential for evaluating the competitiveness of fuel cell electric vehicles. A critical step in energy consumption measurement is measuring hydrogen consumption, including the mass method, the P/T method, and the flowmeter method. The flowmeter method has always been a research focus because of its simple operation, low cost, and solid real-time performance. Current research has shown the accuracy of the flowmeter method under specific conditions. However, many factors in the real scenario will influence the test result, such as unintended vibration, environment temperature, and onboard hydrogen capacity calibration. On the other hand, the short-cut method is also researched to replace the run-out method to improve test efficiency. To evaluate whether the flowmeter method basing on the short-cut method can genuinely reflect the hydrogen consumption of an actual vehicle, we research and test for New European Driving Cycle (NEDC) and China Light-Duty Vehicle Test Cycle (CLTC) using the same vehicle. The results show that the short-cut method can save at least 50% of the test time compared with the run-out method. The error of the short-cut method based on the flowmeter for the NEDC working condition is less than 0.1%, and for the CLTC working conditions is 8.12%. After adding a throttle valve and a 4L buffer tank, the error is reduced to 4.76% from 8.12%. The test results show that hydrogen consumption measurement based on the flowmeter and short-cut method should adopt corresponding solutions according to the scenarios.

Thermal performance and mold discoloration of thermally modified wood containing bio‐based phase change material for heat storage

AbstractThe work presents the results of thermal performance and mold discoloration of thermally modified wood‐based composites incorporating multicomponent fatty acids as a bio‐based phase change materials (BPCM). Thermally modified Scots pine (TMP), beech (TMB), and spruce (TMS) sapwood were impregnated with a multicomponent mixture of linoleic acid and coconut oil fatty acids at a ratio of 20:80. Samples with different BPCM uptakes were analyzed in the temperature range typical for building indoor conditions. Leakage tests were conducted and revealed that the maximum leakage for all the samples is 3% to 5%. T‐history and heat flowmeter methods were used to evaluate the thermal characteristic of the composites. The incorporation of BPCM into thermally modified woods (TMWs) resulted in significant thermal mass improvements, expressed by the ability of the composites to store excessive energy in terms of latent heat and keep the temperature constant for long time. The specific heat capacity of the TMWs was around 2 J/g K, which increased to 4 to 8 J/g K after impregnation with BPCM, depending on the impregnation uptake. Results showed also that TMB has higher thermal conductivity than TMP and TMS, while incorporating of BPCM into these materials resulted in even improved thermal conductivity. Results showed that the thermal conductivity of TMP increased after incorporation of BPCM from 0.06 W/m K to 0.1 and 0.14 W/m K for TMP/BPCM with 48% and 95% uptake respectively. Mold tests showed that BPCM encapsulated in TMWs is less susceptible to mold discoloration compared to untreated wood.

Research on measuring method of pumping speed for miniature sputter ion pump

In this work, a new calibration apparatus, which employs the flowmeter method and the orifice method, was developed to get the low pumping speed of the miniature sputter ion pump (SIP), and the two methods were compared in the measurement of the low pumping speed. A low pumping speed of the order of 10-4 m3 s−1 was calibrated in the pressure range of 10-6 Pa to 10-2 Pa, and the combined standard uncertainty was 4.5–8.8% for nitrogen. The measurement results of the spinning rotor gauge (SRG) and the extractor gauge (IE514) were contrasted, and it can be found that the measurement error of the extractor gauge is obvious. Hence a method to measure the pumping speed and the outgassing rate of the extractor gauge is introduced, and the influence of the extractor gauge on the measurement was evaluated in the pressure range of 10-6 Pa to 10-4 Pa. The low pumping speed of the miniature SIP, which is a single-cylinder diode SIP, was calibrated in these high purity gases (N2, He, and Ar), and the flowmeter method performs better than the orifice method.

Optimization of the Tracer Particle Addition Method for PIV Flowmeters

When a PIV flowmeter is used to measure a large flow of natural gas, the flow field fluctuation and particle distribution have a significant influence on the measurement accuracy and the particle injection mode plays a key role in the flow field fluctuation and particle distribution. To improve the measurement accuracy of PIV flowmeters, the method of filling tracer particles in single pipes, multiple pipes, and L pipes of a natural gas DN100 pipeline under high-pressure working conditions was compared and analyzed through numerical calculation and testing. The results show that the disturbance distance of filling particles in L pipes was the shortest, but the particle distribution area was small, whereas the flow metering error was large. By shortening the intersection distance between the L tube injection flow field and the main flow field, the problem that the particles failed to fill the test area was effectively solved, and the peak turbulence intensity at the intersection of the flow field decreased from 13.4% to 8%. Furthermore, the optimized structure was used to measure a flow of 100–600 m3/h with different flow rates. The relative error between the flowmeter and the ultrasonic flowmeter was approximately 2%, and the metering deviation was significantly improved.

An alternative analysis method for evaluating electromagnetic flowmeter performance

AbstractThe weight function method (WFM) is compared with the magnetohydrodynamics (MHDs) coupled solver approach for single‐point and multipoint magnetic flowmeters downstream of a distorted flow created by a long radius 90‐degree elbow. A review of the literature appears to indicate that researchers who are interested in magnetic flowmeter accuracy and performance either have been unaware of or not capable of analyzing magnetic flowmeters using the WFM. The study examines whether any differences are apparent between modeling the single‐point electrodes and omitting the electrodes from the model. The results of the study indicate differences less than 0.50% between the WFM and the MHD approach. The results also demonstrate that for single‐point flowmeters, modeling the electrodes is not necessary. This research eliminates the barrier of deriving a weight function to model magnetic flowmeters.Article Impact StatementAn alternative analysis method for magnetic flowmeters enables more researchers to evaluate their performance.

The hydraulic architecture of an arborescent monocot: ontogeny-related adjustments in vessel size and leaf area compensate for increased resistance.

Bamboos are arborescent monocotyledons that have no secondary growth, but can continually produce conduits with diameters appropriate to the current size of the plant. Here, we studied bamboo hydraulic architecture to address the mechanisms involved in compensating for the increase in hydraulic resistance during ontogeny. We measured the hydraulic weighted vessel diameters (Dh ) at different distances from the apex along the stem of Bambusa textilis. The hydraulic resistance of different components and individuals of different heights were quantified using the high-pressure flowmeter method. The Dh showed tip-to-base widening with a scaling exponent in the range of those reported for trees. Although theoretical hydraulic conductivity decreased from base-to-tip, leaf-specific conductivity did not change. Leaves contributed the most to the whole-shoot hydraulic resistance, followed by the leaf-bearing branches. Roots contributed c. 13% to whole-plant resistance. Interestingly, taller individuals showed lower whole-shoot resistance owing to an increased number of resistances in parallel (side-branches), while leaf-specific resistance was independent of plant size. Tip-to-base vessel widening and height-independent constant leaf-specific conductance could be mechanisms for hydraulic optimization in B.textilis. Similar patterns have also been found in woody plants with secondary growth, but this bamboo exhibits them without secondary growth.

Study on hydrogen emission performance of FCEV

Hydrogen leakage and emission will bring adverse effects to the environment and human health. When it enters a certain concentration range, it will bring the potential explosion. Hydrogen emissions from fuel cell vehicles can be divided into two sources: normal operation of the system and leakage under abnormal circumstances. This paper mainly uses the flowmeter method to measure the hydrogen emission from fuel cell electric vehicle（FCEV）. The different emission characteristics of different types of FCEV under idle and steady cycle conditions were analyzed. The hydrogen emission levels of different types of FCEV under idle and cycle conditions were verified by analyzing and processing the experimental data through a certain amount of hydrogen emission tests of FCEV.

A simple and easy-implemented time-of-flight determination method for liquid ultrasonic flow meters based on ultrasonic signal onset detection and multiple-zero-crossing technique

Determination of time-of-flight (TOF) is crucially importantin liquid ultrasonic flow meters. There are some deficiencies of previous TOF detection methods in practical applications. Inspired by our last work and the knowledge of clustering algorithms, we proposed a TOF determination method based on ultrasonic signal onset (USO) detection and multiple-zero-crossing technique to solve cycle-skip problem caused by waveform change. This method categorizes the ultrasonic and the noise signal, and identifies the rough position of USO. A time value from the obtained zero-crossing time values is selected as the TOF. The main advantage of the proposed method is the high insensitivity towards waveform change, i.e., the effect ofamplitude characteristics changeon TOF detection is negligible. Numerical experiments were done to evaluate the performance of the proposed method and its anti-noise ability. Experimental validation on a liquid ultrasonic flow meter showed the proposed method is capable of obtaining the accurate TOF.

Simplified Method of Discharge Measurement for Micro-Hydropower Capacity Assessment: A Case Study for a Small-Scale Agricultural Irrigation Canal

Discharge flow rates were used to assess and determines the hydropower capacity of water source. It is known that the procedure for discharge measurement using common methods requires multiple parameters. These parameters were measured respectively to determine the water power. In reality, water flow may not the same in the succeeding times. Therefore, parameters should be measured simultaneously will give a more relevant water profile assessment. Likewise, these common methods are not feasible during heavy water flow. With these, the study develops two things; 1.) the adjustment factors of different common methods in measuring water discharge, and 2.) the simplified method of weir method. The simplified approach of weir method measures the water discharged by measuring the overflow head of water above the weir crest. A simultaneous data observation was performed in the experiment to develop the simplified approach of weir method and derived adjustment factors of each method. The result shows that 3-point method of current flow-meter and float method gives almost the same as true discharge value. The true discharge value of the simplified method of weir method is multiplied by the adjusted factor equal to 0.81.

Analysis and improvement of the hot disk transient plane source method for low thermal conductivity materials

The hot disk transient plane source (TPS) method is a widely used standard technique (ISO 22007–2) for characterizing the thermal properties of materials, especially the thermal conductivity, k. Despite its well-established reliability for a wide variety of common materials, the hot disk TPS method is also known to suffer from substantial systematic errors when applied to low-k thermal insulation materials, because of the discrepancies between the idealized model used for data analysis and the actual heat transfer process. Here, we present a combined numerical and experimental study of the influence of the geometry of the hot disk sensor on the measured k value of low-k materials. We demonstrate that the error is strongly affected by the finite thickness and thermal mass of the sensor's insulation layer as well as the corresponding increase of the effective heater size beyond the radius of the embedded metal heater itself. We further numerically investigate the dependence of the error on the sample thermal properties, confirming that the errors are worse in low-k samples. A simple polynomial correction function is provided based on the numerical error analysis, which converts the apparent (erroneous) result from a standard hot disk TPS measurement to a more accurate value of k. To experimentally validate the conclusions from numerical simulations, standard polyimide (Kapton) sensors are systematically optimized (thinned) by etching and used to measure low-k materials, including a standard polystyrene foam, a commercial Airloy® x56 aerogel, and a commercial Hydrophobic Silica Disk aerogel from Aerogel Technologies, LLC. The experimental results clearly demonstrate the strong influence of the sensor thickness. The k results of these samples obtained using either the optimized sensor or the pristine sensor then corrected with the corresponding polynomial correction functions are in good agreement with the values measured independently using a steady-state heat flowmeter (HFM) method: whereas the raw values measured with the pristine sensor are in error by 35% and 40% compared to the HFM reference values for the Airloy® x56 and the hydrophobic aerogel, respectively, the correction function greatly reduces those errors to <2% and <4%. This study reveals the detailed mechanisms of the systematic error in the hot disk TPS method for low-k samples, and shows that both the numerical correction to a pristine sensor and/or using an optimized (thinned) sensor are capable of providing highly accurate values of thermal conductivity for such materials.

Review of flow regime in CFB standpipe and circulation rate measurement

The classification and characteristics of flow regimes in a circulating fluidized bed standpipe were briefly described. Based on the flow characteristics, several measuring methods of circulating flow rate in standpipe were introduced, including accumulation method, time-of-descent measurements, particle motion detection method, flowmeter method, and correlation method. Advantages and disadvantages of these methods were compared. It can be seen that at present, all measurement methods have some defects, which need to be further studied and improved.

Single-shot photoacoustic microscopy of hemoglobin concentration, oxygen saturation, and blood flow in sub-microseconds

We present fast functional optical-resolution photoacoustic microscopy (OR-PAM) that can simultaneously image hemoglobin concentration, blood flow speed, and oxygen saturation with three-pulse excitation. To instantaneously determine the blood flow speed, dual-pulse photoacoustic flowmetry is developed to determine the blood flow speed from photoacoustic signal decay in sub-microseconds. Grueneisen relaxation effect is compensated for in the oxygen saturation calculation. The blood flow imaging is validated in phantom and in vivo experiments. The results show that the flow speed can be measured accurately in sub-microseconds by comparing the dual-pulse flowmetric method with photoacoustic Doppler flowmetry. Wide-field OR-PAM of hemoglobin concentration, blood flow speed, and oxygen saturation are demonstrated in the mouse ear. This technical advance enables more biomedical applications for fast functional OR-PAM.

Influence of the Thermal Field on Static Behaviour of Sandwich Structures

In this paper, numerical and experimental studies on the influence of the thermal field on behavior of the structure of sandwich plates in three points bending is analysed. Various materials are used so for skins. For the core only extruded polystyrene, with various thicknesses is used. The thermal conductivity n was determined by using the Hilton B480 unit, based on the heat flowmeter method described in ISO 8301:1991. We have been analyzed 12 cases of composite sandwich structures. The results obtained by experimental determination and numerical simulation of all cases of modeling are compared and certain differences occurred on the analyzing of influence of the thermal field on the bending characteristics of sandwich structures.

Application Research on Testing Efficiency of Main Drainage Pump in Coal Mine Using Thermodynamic Theories

The efficiency of a drainage pump should be tested at regular intervals to master the status of the drainage pump in real time and thus achieve the goal of saving energy. The ultrasonic flowmeter method is traditionally used to measure the flow of the pump. But there are some defects in this kind of method of underground coal mine. This paper first introduces the principle of testing the main drainage pump efficiency in coal mine using thermodynamic theories, then analyzes the energy transformation during the process of draining water, and finally derives the calculation formulae of the pump efficiency, which meet the on-site precision of engineering. On the basis of analyzing the theories, the protective sleeve and the base of the temperature sensor are designed to measure the water temperature at inlet and outlet of the pump. The efficiencies of pumps with two specifications are measured, respectively, by using the thermodynamic method and ultrasonic flowmeter method. By contrast, the results show that thermodynamic method can satisfy the precision of the testing requirements accuracy for high-flow and high-lift drainage pump under normal temperatures. Moreover, some measures are summed up to improve the accuracy of testing the pump efficiency, which are of guiding significance for on-site testing of the main drainage pump efficiency in coal mine.