工业标准弯头弯管流量计研究

介绍了唐山工程技术学院研制的国家专利产品“ZLRJ—Ⅰ型智能流量热量积算仪”所用工业标准弯头弯管流量计的部分常温实验。在实验研究的基础上,重点介绍了这种流量计的一致性实验结果和统计学分析的情况,说明了应用工业标准弯头作为流量传感器的可行性。

Terminal Traffic Flow Prediction Method Under Convective Weather Using Deep Learning Approaches

In order to improve the accuracy and stability of terminal traffic flow prediction in convective weather,a multi-input deep learning(MICL)model is proposed.On the basis of previous studies,this paper expands the set of weather characteristics affecting the traffic flow in the terminal area,including weather forecast data and Meteorological Report of Aerodrome Conditions(METAR)data.The terminal airspace is divided into smaller areas based on function and the weather severity index(WSI)characteristics extracted from weather forecast data are established to better quantify the impact of weather.MICL model preserves the advantages of the convolution neural network(CNN)and the long short-term memory(LSTM)model,and adopts two channels to input WSI and METAR information,respectively,which can fully reflect the temporal and spatial distribution characteristics of weather in the terminal area.Multi-scene experiments are designed based on the real historical data of Guangzhou Terminal Area operating in typical convective weather.The results show that the MICL model has excellent performance in mean squared error(MSE),root MSE(RMSE),mean absolute error(MAE)and other performance indicators compared with the existing machine learning models or deep learning models,such as Knearest neighbor(KNN),support vector regression(SVR),CNN and LSTM.In the forecast period ranging from 30 min to 6 h,the MICL model has the best prediction accuracy and stability.

Research on traffic flow forecasting model based on cusp catastrophe theory

This paper intends to describe the relationship between traffic parameters by using cusp catastrophe theory and to deduce highway capacity and corresponding speed forecasting value through suitable transformation of catastrophe model. The five properties of a catastrophe system are outlined briefly, and then the data collected on freeways of Zhujiang River Delta, Guangdong province, China are examined to ascertain whether they exhibit qualitative properties and attributes of the catastrophe model. The forecasting value of speed and capacity for freeway segments are given based on the catastrophe model. Furthermore, speed-flow curve on freeway is drawn by plotting out congested and uncongested traffic flow and the capacity value for the same freeway segment is also obtained from speed-flow curve to test the feasibility of the application of cusp catastrophe theory in traffic flow analysis. The calculating results of catastrophe model coincide with those of traditional traffic flow models regressed from field observed data, which indicates that the deficiency of traditional analysis of relationship between speed, flow and occupancy in two-dimension can be compensated by analysis of the relationship among speed, flow and occupancy based on catastrophe model in three-dimension. Finally, the prospects and problems of its application in traffic flow research in China are discussed.

Measuring the Internal Velocity of Debris Flows Using Impact Pressure Detecting in the Flume Experiment

Measuring the internal velocity of debris flows is very important for debris flow dynamics research and designing debris flow control works. However, there is no appropriate method for measuring the internal velocity because of the destructive power of debris flow process. In this paper, we address this problem by using the relationship between velocity and kinetic pressure, as described by surface velocity and surface kinetic pressure data. Kinetic pressure is the difference of impact pressure and static pressure. The former is detected by force sensors installed in the flow direction at the sampling section. Observations show that static pressure can be computed using the formula for static water pressure by simply substituting water density for debris flow density. We describe the relationship between surface velocity and surface kinetic pressure using data from seven laboratory flume experiments. It is consistent with the relationship for single phase flow, which is the measurement principle of the Pitot tube.

Dynamic Visualization Approach of the Multiphase Flow Using Electrical Capacitance Tomography

Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualization method for the flow pattern identification,in which image reconstruction algorithms play an important role.In this paper,a generalized dynamic reconstruction model,which integrates ECT measurement information and physical evolution information of the objects of interest,was presented.A generalized objective functional that simultaneously considers the spatial constraints,temporal constraints and dynamic evolution information of the objects of interest was proposed.Numerical simulations and experiments were implemented to evaluate the feasibility and efficiency of the proposed algorithm.For the cases considered in this paper,the proposed algorithm can well reconstruct the flow patterns,and the quality of the reconstructed images is improved,which indicates that the proposed algorithm is competent to reconstruct the flow patterns in the visualization of multiphase flows.

Analysis of runoff characteristics in midstream of Yinma River

To use the water resources reasonably in the midstream of Yinma River is of great significance to Changchun City which is short of water. With the runoff data of physical measuring, the paper analyses the characteristics surface runoff of the area, by means of the groundwater flow numerical simulation, and represents the characteristics of the groundwater runoff in the area. Based on combination analyses of the two runoffs, the authors point out the problem of the water resources use in this area and bring forward a resolution of conjunctive regulation and storage of the surface water and groundwater.

With the Measuring Rod against the Floods: Ferdinand Verbiest and His Forgotten Introduction of Benedetto Castelli’s River Hydraulics to China

The monumental Studies to Fathom Principles(Qiongli xue窮理學;1683)by Ferdinand Verbiest S.J.(Nan Huairen南懷仁,1623–1688)was never printed,and its exact content is not known.A section of the only extant,though incomplete,manuscript deals with fluvial flood prevention and river control measures,a subject that until then had not cropped up in any Chinese-language work of the Jesuits.In this section,Verbiest not only described the already well-known Aristotelian theory of the origin of rivers,but also introduced to China new scientific propositions,concepts,and numerical examples originating from the seminal Renaissance work Della misura dell’acque correnti(Of the Mensuration of Running Waters;1628)by Benedetto Castelli(1578–1643).In addition,Verbiest presented to his readers some noteworthy examples of pertinent Western achievements such as the pound-lock with miter gate,and he provided them with a simple economic analysis of flood control options.The significance and possible influence of Verbiest’s text on further developments in Chinese approaches to water engineering are discussed,highlighting a hitherto largely disregarded facet of Western science and technology transfer in the field of river hydraulics and flood management.

Annual precipitation gray forecast in disaster year of Chedaren debris flow

The Chedaren ravine belongs to high-prone areas of debris flow in Jilin Province, which threaten the local people＇ s life and security seriously. The authors used the residual correction theory to amend the GM （ 1, 1 ） model and forecast annual precipitation in disaster year of the Chedaren ravine ; it provides scientific foundation for early warning of debris flow disaster in the rainy season based on weather forecast. The prediction resuits show that annual precipitation is 724.7 mm in 2009 ; the region will probably occur large-scale debris flow during the rainy season.

Experimental Acoustic Determination of the Void Fraction in Two-Phase Flow in Horizontal Pipelines

In multi-phase flows, the phases can flow and arranged in different spatial configurations in the pipe, which called flow patterns. This type of flow is found in the oil, chemical and nuclear industries. For example, in the production and transport of oil and gas, the identification of the flow patterns are essential for answering those questions which are related to the economic return of the field, such as, measuring the volumetric flow, determining the pressure drop along the flow lines, production management and supervision. In offshore production, these factors are very important. This paper presents a new method for measuring the void fraction in horizontal pipelines, taking the air as gas in water-air two-phase flow. Through acoustic analysis of the frequency response of the pipe, the method gets the parameters to changes in runoff regime, in an experimental arrangement constructed on a small scale. The main advantages are the non-intrusive characteristic and easy to implement. The paper is composed of a qualitative experimental evaluation and transducers （microphone） which are used to analyze variations in the response accompanying variations in void and flow pattern changes. Changes are imposed and controlled by a two-phase flow experimental simulation rig, including a measurement cell constituted of an external casing that can isolate the measurement from the environmental background noise fitted with acoustic pressure transducers radially arranged, and the impact of a monitored excitation mechanism. The signals which captured by the microphones are processed and analyzed by checking their frequency contents changes according to the amount of air in the mixture.

A first comprehensive evaluation of China's GNSS-R airborne campaign:part Ⅱ—river remote sensing

The Global Navigation Satellite System Reflectometry(GNSS-R) has been proven to be a powerful technique for retrieving geophysical parameters of ocean and land. Airborne GNSS-R is an important experimental platform, because it is not only needed as validation for spaceborne application, but also possesses the advantages to be capable of remote sensing of small and medium scale targets, such as rivers and lakes. This paper presents an overview of China's airborne GNSS-R campaign conducted on May 30, 2014, in Henan. The campaign has two objectives, i.e.:(1) to examine the capability of a GNSS-R payload developed by National Space Science Center,Chinese Academy of Sciences(NSSC, CAS) for airborneobservations and(2) to study the algorithms for soil moisture and river remote sensing, including altimetry and flow velocity measurement. A previous paper has presented results of soil moisture retrieval as part I, and in this paper,initial results of the Yellow River remote sensing are presented as part II. This paper presents the river altimetry results and explores a new potential application of GNSS-R technology, which is used to detect the flow velocity of the river. The river surface height results observed by code delay altimetry method were consistent with the height results of GPS dual-frequency differential positioning altimetry. The GNSS-R altimetry results showed that decimeter level heights were achieved in 1-min sliding average. Comparing with in situ measurements, the GNSSR flow velocity result was reasonable; the error was about0.027 m/s, which indicated the validity and feasibility of using GNSS-R technique to detect river flow velocity.

Breach mechanism and numerical simulation for seepage failure of earth-rock dams

In this study,a numerical model,which can capture the full process of the development of seepage passages,the collapse of dams and the failure due to overtopping,is proposed for earth-rock dams.The critical incipient velocity for the occurrence of seepage failure is derived by analyzing the forces acting on soil particles in the seepage passage.The sediment transport formula is proposed to simulate the erosion process and the evolution of breach within the dam.In this model,the grain size distribution,the compaction density and the strength of dam materials are reasonably accounted for.Furthermore,the influences of the direction of seepage paths,the slope of the dam and the velocity of water flow on the amount of erosion are also taken into consideration.The proposed model and the corresponding numerical programs are employed to simulate the development of breaches and discharge of two typical cases due to seepage failure.The development of breaches,the history of discharge and the peak flood flux predicted by the numerical models are rather comparable to the measured data,which confirms the validity of the proposed model and the feasibility of applying the model in evaluating the disaster consequences and preparing the emergency counter measurements in the case of dam collapse.