No description available.

No description available.

No description available.

No description available.

A research programme is described to develop an optical method to measure the instantaneous angular speed (lAS) of machinery in condition monitoring. In this research, special consideration is given to the development ofa non-contact method of measuring IAS using a laser mouse. Further development of its application to the detection ofparallel misalignment fault in condition monitoring is described. This research requires multidisciplinary design, involving the knowledge from measurement, electrical instruments, optics, mechanical engineering, majntenance engineering, modelling and programming. The research presented is a novel approach to non-contact measurement of lAS through the use of a laser mouse. Initial investigation of the characteristics of this device shows its potential for the measurement of lAS. The software application is developed to adapt the laser mouse to the Microsoft Windows operating system. Tests are carried out which show that the pixel variation acquired by the laser mouse has a linear relationship with its physical movement relative to the movement of the rotating shafts. Calibration tests show good correlation with the results of conventional, contact IAS measurement using a shaft encoder. It is concluded that using a laser mouse to measure the IAS is reliable method. An application of the IAS technique to the detection of the parallel shaft misalignment faults on a geared induction motor is described. Firstly, a mathematical model of IAS is developed for parallel misalignment. Secondly, a geared induction motor test rig is used to validate the model and to demonstrate the practical efficacy of IAS measurement by a laser mouse as a condition monitoring tool for detecting and identifying such faults. Finally, in agreement with the lAS model, the motor test rig is applied to show that parallel misalignment can be identified from the features extracted from the lAS data produced by the laser mouse. Specially, in the time domain, the amplitude of IAS waveform and the standard deviation of the IAS variation have a great increase when the parallel misalignment is occurred. The increase of the magnitude of parallel misalignment can make the amplitude of IAS waveform and the standard deviation of the IAS variation larger. In the frequency domain, the amplitude of the first component of rotational frequency appears much higher than those of the 2nd and 3rd components and has more increases, when the parallel misalignment is occurred. As the fault severity increased, the key characteristic of IAS spectra is a rise in the level of the first component of rotation frequency. The sensitivity of IAS to variations in power supply frequency and torque is also investigated using the motor test rig. It is found that variation in power supply frequency can increase in the value of the amplitude of IAS waveform and the standard deviation of IAS variation in the time domain, and can also increase in the amplitude of first component of rotational frequency in IAS spectra in the frequency domain. However, there is found to be little change in IAS with variation in torque. In conclusion, the laser mouse approach to non-contact measurement of lAS presented in this thesis can be used as an alternative to existing contact and non-contact methods, and the IAS technique can be used to identify the parallel misalignment faults in condition monitoring.

Characterisation of new filtration and wicking materials through a 'wet-bench" testing process is a requirement for many filtration companies before new products can be released to market. A reduction in this testing commitment through the application of successful computational based models, requiring minimal empirical input, would undoubtedly result in huge financial savings and reductions in testing lead times. Such models could offer total media characterisation and could also aid further insights into many filtration and wicking processes which before would have required an expensive combination of different testing procedures. In this research, a depth filtration model has been developed, based on the three-dimensional void network model Pore-Cor, The geometry of the void network is fitted, by means of an 8-dimensional Boltzmann annealed amoeboid simplex, to the porosity and percolation characteristics of stainless steel sintered filters measured by mercury intrusion porosimetry (MIP). Preferential and critical flow paths through the network are calculated via a newly developed algorithm which allows a representation of net flow within individual pore/throat clusters. Particles from an experimental size distribution are fed along these flow-biased paths, using a newly developed random-particle-selection algorithm and, when straining occurs, the flow paths are re-calculated. The model is shown usefully to reproduce experimental filtration efficiencies as a function of pressure drop, measured by single pass tests. A critique of filtration efficiency measurements is given, suggesting use of a new 'alpha efficiency' rather than standard beta efficiency. The model is currently being adapted to accept porometry as well as porosimetry data, hence avoiding the use of mercury in future testing. Further to development of the filtration model the research associated with this thesis has also investigated two related areas. One is an investigation of a hydrophilic treatment of a series of polymeric sinters using oxidizing plasma. The investigation shows an improved method of data analysis of capillary rise measurements. An optimization process for determining the correct hydrophilic treatment parameters is proposed based on the variance across sample sets, and results are interpreted with respect to the Vyon® samples analysed. Secondly an investigation of anomalous compression characteristics found in the MIP of stainless steel Sinterflo® media is presented. Hypotheses were proposed for the observed increase in media compressibility and these were investigated using the Pore-Cor void network model for comparison with other investigations of porosity and compression analysis. Preliminary results suggest increased compressibility arises from microscopic material deformities and micro-fractures found in the media.

To deduce particle size information, the majority of particle sizing techniques assume that the particles are spheres. For industrial materials, particles are rarely spherical. Non-sphericity causes discrepancies in different measurement technologies so results vary from the real characteristics of the sample. Applications like crystallisation require .shape information in addition to the size of the particles. The majority of this thesis describes results that have demonstrated that particle shape has a strong influence on particle size distribution measured by different techniques. The effect of shape on measured particle size distribution was investigated by ultrasonic attenuation spectroscopy (VAS) compared with other widely used techniques such as laser diffraction spectroscopy (LDS), microscopic image analysis (MIA) and focused beam reflectance measurement (FBRM). A strategy was applied using different chemical systems to monitor the importance of shape to measured size distribution using different techniques; fragile and non-fragile, .sp-pericaC'crystalline and irregular materials were tested. The measurements were successfully applied to laboratory crystallisation processes of different organic and inorganic chemicals In-situ monitoring of particle size evolution during crystallisation using FBRM has aroused much interest. Therefore it was important to demonstrate the dependence of measured particle size on different operating conditions and more particularly on the hydrodynamic conditions, solvent, temperature and other physical and chemical , properties of the system. In-situ measurement of maximum supersaturation during batch crystallisation and dissolution processes of different chemical systems is presented, through which nucleation kinetics of the crystallisation was retrieved. This was clemonstrated for different organic and inorganic chemical systems using FBRM as a process analytical technique (PAT). Based on crystallisation behaviour and with process analytical techniques, notably FBRM to retrieve the nucleation kinetics, the growth kinetics of different chemical systems are presented based on seeded batch cooling crystallisation. Finally future developments within this area of research are presented.

No description available.

Within the oil industry there is a need to measure and predict the form of the multiphase liquid and gas flows that are present within oil production and processing pipelines. Knowledge of the flow regimes present allows the engineer to optimise the configuration of the pipeline and downstream processes to achieve the most, economic and reliable design. The applications of these technologies are collectively known as flow assurance. Within oil production systems, one component which has received little attention is the characterisation of the multiphase flow around bends under various process conditions. To predict the flow regimes in greater details requires the development of instrumentation that can measure and characterise the flow within the pipes. To circumvent this challenge, two experimental investigations were carried out in two rigs available in the Chemical and Environmental Engineering Laboratories at the University of Nottingham. These are: (1) a 67 mm internal diameter pipe joined to a 90o bend, in which air/silicone oil flows were investigated using advanced instrumentation: Electrical Capacitance Tomography (ECT), Wire Mesh Sensor Tomography (WMS), and high-speed video. The first two provide time and cross-sectionally resolved data on void fraction. The ECT probes were mounted 10 diameters upstream of the bend whilst the WMS was positioned either immediately upstream or immediately downstream of the bend. The downstream pipe was maintained horizontal whilst the upstream pipe was mounted either vertically or horizontally. The bend (R/D = 2.3) was made of transparent acrylic resin. The superficial velocities of the air ranged from 0.05 to 4.73 ms-1 and for the silicone oil from 0.05 to 0.38 ms-1. (2) a 127 mm internal diameter riser joined to a vertical 180o bend, in which measurements of film fraction and liquid film thickness distribution for an air-water system were obtained using the electrical conductance technique. The former was measured using the ring conductance probes placed 17 and 21 diameters, respectively upstream and downstream of the bend, 45o, 90o and 135o within the bend. The latter were obtained using pin and parallel wire probes. The pin probes were used for thin films measurement whilst the parallel wire probes for thick films. The bend, made of transparent acrylic resin, has a curvature ratio (R/D = 3). The superficial velocities of the air ranged from 3.5 to 16.1 ms-1 and for the water from 0.02 to 0.2 ms-1. The experimental results for the 90o bend study reveal that bubble/spherical cap bubble, slug, unstable slug and churn flows were observed before the bend for the vertical pipe and plug, slug, stratified wavy and annular flows when the pipe was horizontal. Bubble, stratified wavy, slug, semi-annular and annular flows are seen after the bend for the vertical 90o bend, the flow patterns remained the same as before the horizontal 90o bend. These results were confirmed by the high-speed videos taken around the bend. For the vertical 180o return bend, the average film fraction was identified to be higher in straight pipes than in bends. For low liquid and higher gas flow rates, due to the action of gravity drainage, film breakdown occurs at the 45o bend. A previously proposed criterion, to determine stratification after the 90o bend, based on a modified Froude number have been shown to be valid for a liquid different from that tested in the original paper. Similarly, for the 180o return bend, the condition for which the liquid goes either to the inside or outside of the bend are identified based on published material. Variations between average liquid film thickness and bend angles are reported for the vertical 180o bend. Contrary to the conclusions reached by Hills (1973) and Anderson and Hills (1974), the liquid film thickness becomes annular flow in the 180o bend at low liquid flow rates and stratified flow at higher liquid superficial velocities. In addition, a CFD code has been used to successfully model the hydrodynamics of the slug flow pattern in a riser and vertical 90o bend, using the Volume of Fluid model based on the Eulerian approach, implemented in the commercial CFD package Star-CCM+. The modelling results are validated with the experiments and also provide more detailed information on the flow such as the velocity field.

Keywords: Computational Fluid Dynamics, Numerical Modelling, Physical Modelling, Contact Tanks, Hydrodynamics, Hydraulic Efficiency, Solute Transport, Mixing Processes, Finite Volume Method, Acoustic Doppler Velocimetry, Tracer Techniques.