Two-phase flow experiments with coriolis mass flow metering using complex signal processing

Two-phase (gas/liquid) flow is common in many industrial applications but its measurement remains challenging for Coriolis mass flow meters (CMFM), especially for high Gas Void Fraction (GVF). In this paper, we present experimental results applying previously developed complex signal processing techniques for tracking the rapidly changing sensor signals generated by two-phase flow. The techniques are implemented in a new System-on-Chip (SOC) prototype transmitter connected to a commercial Coriolis flow tube. Experiments have been carried out over a range of single phase and two-phase (water/air) flows. The signal tracking as well as mass flow rate and density measurement performance is compared with that of a laboratory version of a commercial Coriolis transmitter with two-phase flow capability. The result shows that the complex bandpass algorithms, coupled with flowtube control algorithms, reduce the standard deviation of the mass flow measurement by a factor of 3 or more in 50% of the experiments undertaken. For the density measurement, the corresponding reduction in standard deviation is by a factor of 6

High precision Coriolis mass flow measurement applied to small volume proving

This paper discusses Small Volume Provers (SVPs), used in the oil and gas industry to validate the performance of custody transfer meters. Recently Coriolis mass flow meters have been introduced for custody transfer; while these offer reduced maintenance requirements over traditional PD and turbine meters, proving Coriolis flow meters using SVP is challenging. This paper presents SVP results for a Coriolis meter which matches or exceeds the most stringent requirements for custody transfer. This is achieved in part by using a novel signal processing technique which reduces the dominant component of the measurement noise, associated with so-called Coriolis mode vibration, with negligible loss of dynamic response. © 2006 Elsevier Ltd. All rights reserved

A new method for measuring fuel flow in an individual injection in real time

Knowledge of fuel mass injected in an individual cycle is important for engine performance and modeling. At the moment, such measurements are not possible on-engine or in real-time. In this paper, a new method using Coriolis flow meters (CFMs) and a new, patented, signal processing technique, known as the Prism, is introduced. CFMs are extensively used for flow measurement both in the automotive industry and further afield, and when coupled with the Prism have the potential to make these challenging high-speed measurements. A rig-based feasibility study was conducted injecting very small quantities of diesel (3 mg) at pressures of up to 1000 bar at simulated engine speeds of up to 4000 rpm. The results show that these small quantities can in principle be measured. The results also reveal a previously unknown behaviour of CFMs when measuring very low flow rates at high speed. The study concludes that by combining high-resonant frequency flow tubes with the Prism technology in a new instrument—the Fast Next Generation Coriolis (Fast-NGC) flow meter—it will be possible to measure individual injector flow rates on-engine in real-time

Drought Resistance of Vegetation and Its Change Characteristics before and after the Implementation of the Grain for Green Program on the Loess Plateau, China

Drought affects the growth and productivity of vegetation, and the analysis of drought resistance of vegetation can help ecological and environmental protection and sustainable development in drought-prone areas. The Loess Plateau (LP) is a drought-prone area in China with an extremely fragile ecological environment. This study analyzed the drought resistance of vegetation across different climate regions and vegetation biotypes, explored the characteristics of changes in vegetation drought resistance before and after the implementation of the Grain for Green Program (GGP), and evaluated the relative contribution of climatic factors and human activities to the change in drought resistance of vegetation. The following conclusions are obtained. (1) The drought resistance of vegetation on the LP basically showed a spatial pattern of increasing from northwest to southeast with the degree of aridity. The vegetation in the semi-humid and arid regions showed the strongest and weakest drought resistance, respectively. (2) The drought resistance of vegetation on the LP mainly showed an increasing trend since the GGP was implemented, but there were differences in different climatic zones. In semi-humid regions, the drought resistance of vegetation mainly showed a weakening trend, while in arid and semi-arid regions, it mainly showed an increasing trend. There were differences between vegetation biotypes as well; the drought resistance of forest and grassland showed a different trend in different climatic zones, while that of crops in all climatic zones showed an increasing trend. In the area with cropland returned, the drought resistance tended to increase where crops turned to forests, but the area where crops turned to grassland showed a weakening trend. (3) The positive contribution of climate change and human activities leads to the enhancement of drought resistance of vegetation in most areas of the LP, and the weakening of drought resistance of vegetation in semi-humid regions is dominated by the negative contribution of climate change. The negative contribution of human activities is the main reason for the decrease in drought resistance of vegetation in the area of returning cropland to grassland. This study can provide a reference for ecological protection and high-quality development of the LP

Coriolis mass flow metering for wet gas

Most two-phase applications for Coriolis mass flow metering are for low Gas Void Fraction (GVF) conditions, i.e. where the process fluid is essentially liquid with relatively low levels of entrained air or gas. There are particular challenges associated with metering wet gas, where the GVF exceeds 95%. Established wet gas metering techniques are typically based on a differential pressure-type device (for example an orifice plate or V-cone). It is well-known that such devices over-read compared to a dry gas calibration; equations to correct the reading are available if the degree of gas "wetness" is known. For Coriolis mass flow metering of wet gas, two approaches are described. The natural extension of the low GVF techniques is to map the observed mass flow and density readings onto estimates of the flow rates of the gas and liquid components. The alternative is to use the Coriolis meter to estimate the degree of gas "wetness" (e.g. the Lockhart-Martinelli number) and to apply a conventional correlation (e.g. Murdock or Chisholm) to a differential pressure flow reading. A prototype Coriolis-based wet gas meter is described, together with results from laboratory trials at CEESI in Colorado, and from extended field trials at BP's Wamsutter gas field in Wyoming

Identification and Characterization of Sex-Biased miRNAs in the Golden Pompano (<i>Trachinotus blochii</i>)

The golden pompano (Trachinotus blochii) is a marine fish of considerable commercial importance in China. It shows notable sexual size dimorphism; the growth rate of females is faster than that of males. Therefore, sex-biased research is of great importance in T. blochii breeding. However, there have been few studies on sex differentiation and mechanisms underlying sex determination in T. blochii. MicroRNAs (miRNAs) play crucial roles in sex differentiation and determination in animals. However, limited miRNA data are available on fish. In this study, two small RNA libraries prepared from the gonads of T. blochii were constructed and sequenced. The RNA-seq analysis yielded 1366 known and 69 novel miRNAs with 289 significantly differentially expressed miRNAs (p gata4, foxo3, wt1, and sf1 genes were found to be regulated by bta-miR-2898; esr2 and foxo3 by novel_176, and ar by oar-let-7b. Quantitative real-time polymerase chain reaction analysis of selected mRNAs and miRNAs validated the integrated analysis. This study established a set of sex-biased miRNAs that are potential regulatory factors in gonadal development in T. blochii. These results provide new insight into the function of miRNAs in sex differentiation and determination in T. blochii and highlight some key miRNAs for future studies