Experimental investigations of two-phase flow measurement using ultrasonic sensors

This thesis presents the investigations conducted in the use of ultrasonic technology to measure two-phase flow in both horizontal and vertical pipe flows which is important for the petroleum industry. However, there are still key challenges to measure parameters of the multiphase flow accurately. Four methods of ultrasonic technologies were explored. The Hilbert-Huang transform (HHT) was first applied to the ultrasound signals of air-water flow on horizontal flow for measurement of the parameters of the two- phase slug flow. The use of the HHT technique is sensitive enough to detect the hydrodynamics of the slug flow. The results of the experiments are compared with correlations in the literature and are in good agreement. Next, experimental data of air-water two-phase flow under slug, elongated bubble, stratified-wavy and stratified flow regimes were used to develop an objective flow regime classification of two-phase flow using the ultrasonic Doppler sensor and artificial neural network (ANN). The classifications using the power spectral density (PSD) and discrete wavelet transform (DWT) features have accuracies of 87% and 95.6% respectively. This is considerably more promising as it uses non-invasive and non-radioactive sensors. Moreover, ultrasonic pulse wave transducers with centre frequencies of 1MHz and 7.5MHz were used to measure two-phase flow both in horizontal and vertical flow pipes. The liquid level measurement was compared with the conductivity probes technique and agreed qualitatively. However, in the vertical with a gas volume fraction (GVF) higher than 20%, the ultrasound signals were attenuated. Furthermore, gas-liquid and oil-water two-phase flow rates in a vertical upward flow were measured using a combination of an ultrasound Doppler sensor and gamma densitometer. The results showed that the flow gas and liquid flow rates measured are within ±10% for low void fraction tests, water-cut measurements are within ±10%, densities within ±5%, and void fractions within ±10%. These findings are good results for a relatively fast flowing multiphase flow

Non-invasive classification of gas–liquid two-phase horizontal flow regimes using an ultrasonic Doppler sensor and a neural network

The identification of flow pattern is a key issue in multiphase flow which is encountered in the petrochemical industry. It is difficult to identify the gas–liquid flow regimes objectively with the gas–liquid two-phase flow. This paper presents the feasibility of a clamp-on instrument for an objective flow regime classification of two-phase flow using an ultrasonic Doppler sensor and an artificial neural network, which records and processes the ultrasonic signals reflected from the two-phase flow. Experimental data is obtained on a horizontal test rig with a total pipe length of 21 m and 5.08 cm internal diameter carrying air-water two-phase flow under slug, elongated bubble, stratified-wavy and, stratified flow regimes. Multilayer perceptron neural networks (MLPNNs) are used to develop the classification model. The classifier requires features as an input which is representative of the signals. Ultrasound signal features are extracted by applying both power spectral density (PSD) and discrete wavelet transform (DWT) methods to the flow signals. A classification scheme of '1-of-C coding method for classification' was adopted to classify features extracted into one of four flow regime categories. To improve the performance of the flow regime classifier network, a second level neural network was incorporated by using the output of a first level networks feature as an input feature. The addition of the two network models provided a combined neural network model which has achieved a higher accuracy than single neural network models. Classification accuracies are evaluated in the form of both the PSD and DWT features. The success rates of the two models are: (1) using PSD features, the classifier missed 3 datasets out of 24 test datasets of the classification and scored 87.5% accuracy; (2) with the DWT features, the network misclassified only one data point and it was able to classify the flow patterns up to 95.8% accuracy. This approach has demonstrated the success of a clamp-on ultrasound sensor for flow regime classification that would be possible in industry practice. It is considerably more promising than other techniques as it uses a non-invasive and non-radioactive sensor

Aniline-Driven Liquid-Liquid Extraction for Methylamine-Water Separation: Process Simulation and Performance Evaluation

Methylamines are toxic with ammonia-like odor while aniline has a fishy odor. Both aniline and methylamines affect aquatic life and water quality if present in large concentrations in water. Nevertheless, the later, with solubility of 1120 g/L is more soluble in water than the former with solubility of 3.6 g/L at 25. Based on their difference in solubilities, liquid-liquid extraction (LLE) technique can be used to separate or remove the presence of any one of the two pollutants in water. The UNIQUAC property method in Aspen Plus V8.8 was proven to be the best method for the LLE of a water-aniline-methylamine ternary mixture after a single stage partition coefficient analysis with a mixing tank. Adopting the best model for a two-stage separation using ‘Extract’ and ‘RadFrac’ Aspen Plus model units, yielded three separate product streams that are 95.5% methylamine, 86.5% aniline and 100% water. The phase boundary, diagonal tie lines and a constant boiling point of 372.505 K showcased by the ternary phase diagram demonstrated the presence of an azeotrope and the ability of the RadFrac model to separate the mixture easily. Future demonstration on how to separate numerous ternary mixtures is recommended, as the need to treat effluents of many industries containing compounds of varying solubilities may warrant the setting up of a LLE unit. &nbsp

Application of ANN and PCA to two-phase flow evaluation using radioisotopes

In the two-phase flow measurements a method involving the absorption of gamma radiation can be applied among others. Analysis of the signals from the scintillation probes can be used to determine the number of flow parameters and to recognize flow structure. Three types of flow regimes as plug, bubble, and transitional plug – bubble flows were considered in this work. The article shows how features of the signals in the time and frequency domain can be used to build the artificial neural network (ANN) to recognize the structure of the gas-liquid flow in a horizontal pipeline. In order to reduce the number of signal features the principal component analysis (PCA) was used. It was found that the reduction of signals features allows for building a network with better performance

Non-invasive measurement of oil-water two-phase flow in vertical pipe using ultrasonic Doppler sensor and gamma ray densitometer

Oil–water two-phase flow experiments were conducted in a vertical pipe to study the liquid–liquid flow measurement using a non-invasive ultrasound Doppler flow sensor and a gamma-ray densitometer. Tap water and a dyed mineral oil are used as test the fluids. A novel Doppler effect strategy is used to estimate the mixture flow velocity in a vertical pipe based on flow velocity measured by the ultrasound sensor and the shear flow velocity profile model. Drift-flux flow model was used in conjunction phase fractions to predict the superficial velocities of oil and water. The results indicate that the proposed method estimated oil-continuous flow and water-continuous flow have average relative errors of 5.2% and 4.5%; and superficial phase flow velocities of oil and of water have average relative errors of 4.5% and 5.9% respectively. These results demonstrate the potential for using ultrasonic Doppler sensor combined with gamma densitometer for oil–water measurement

Investigation of Slug Flow Characteristicsz for Energy Harvesting Applications

The purpose of this research work is to study the characteristics of air-water slug flow for energy harvesting applications. It involves an investigation and analysis of the liquid hold-up, slug frequency and the translational velocity from conductivity rings. The experimental test was carried out with a different flow rate of the air-water slug flow in 2-inch rig horizontal pipe using a ring type conductance probe. The conductivity rings were used to obtain the slug flow characteristics. Forces were generated as a result of the fluctuating pressure of the slug flow on the entire cross-sectional area of the pipe. The acquired signal of the pressure fluctuation was used to simulate the expected outcome. The result shows that a maximum forward slug force of 30N per cross-sectional area of the pipe was obtained and 26N force of the fluctuating pressure through the cross-section was generated at the flange-end. The obtained forces can be applied to using electromagnetic or piezoelectric harvester to generate the electrical output in order to energize electro-mechanical devices

Investigation of Slug Flow Characteristics for Energy Harvesting Applications

The purpose of this research work is to study the characteristics of air-water slug flow for energy harvesting applications. It involves an investigation and analysis of the liquid hold-up, slug frequency and the translational velocity from conductivity rings. The experimental test was carried out with a different flow rate of the air-water slug flow in 2-inch rig horizontal pipe using a ring type conductance probe. The conductivity rings were used to obtain the slug flow characteristics. Forces were generated as a result of the fluctuating pressure of the slug flow on the entire cross-sectional area of the pipe. The acquired signal of the pressure fluctuation was used to simulate the expected outcome. The result shows that a maximum forward slug force of 30N per cross-sectional area of the pipe was obtained and 26N force of the fluctuating pressure through the cross-section was generated at the flange-end. The obtained forces can be applied to using electromagnetic or piezoelectric harvester to generate the electrical output in order to energize electro-mechanical devices

Thermal Characterisation of a Double Panel Concrete Radiator Based on Experimental Investigations

As heating systems are one of the most energy-intensive accessories in homes, it is crucial that radiators are both energy efficient as well as provide adequate thermal comfort. This paper presents an experimental investigation to characterise a radiator that utilises a concrete-cast heating element system. The covering of concrete enables heat output to be sustained in the room for a longer period than conventional metal-body radiators. The experimental analysis was conducted in two steps: first, the non-uniformity in the surface temperature was investigated and characterised quantitatively. Secondly, the power consumption of the radiator was monitored and related to the temperature field inside the room. It has been revealed that the temperature field is highly non-uniform. The bottom left corner of the radiator radiates a higher temperature than the rest of the surface. It has been found that the rear surface has higher thermal non-uniformity than the front surface. Results also show relationships between the transient room heating performance, measured through multiple thermocouples, and the radiator in terms of heating time and heat retention time

Role of <i style="mso-bidi-font-style:normal">Triticum aestivum</i> aqueous extract in glucocorticoid induced osteoporosis in rats

153-158Administration of aqueous extract of T. aestivum (200 and 400 mg/kg/day, po, for 30 days) and risedronate (20 <span style="font-family: Symbol;mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:"times="" roman";="" mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">mg/kg, sc, five times a week for 30 days) following methyl prednisolone sodium succinate (10 mg/kg, sc, thrice a week for 4 weeks) induced osteoporosis in Wistar rats showed an increase in the serum levels of bone mineral content markers, decrease in the serum and urinary levels of bone resorption markers. An incline in strength of femur and tibia was seen particularly with 400 mg/kg of T. aestivum. Maintenance of calcium homeostasis, formation of collagen and scavenging of free radicals can plausibly be the mode of action of aqueous extract of T. aestivum thereby combating osteoporosis induced by glucocorticoids. </span

ASSESSING COCONUT OIL PROPERTIES AS A POTENTIAL REPLACEMENT OF THE TRANSFORMER OIL

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