Taimoor Asim

Computational Fluid Dynamics based Fault Simulations of a Vertical Axis Wind Turbines

Due to depleting fossil fuels and a rapid increase in the fuel prices globally, the search for alternative energy sources is becoming more and more significant. One of such energy source is the wind energy which can be harnessed with the use of wind turbines. The fundamental principle of wind turbines is to convert the wind energy into first mechanical and then into electrical form. The relatively simple operation of such turbines has stirred the researchers to come up with innovative designs for global acceptance and to make these turbines commercially viable. Furthermore, the maintenance of wind turbines has long been a topic of interest. Condition based monitoring of wind turbines is essential to maintain continuous operation of wind turbines. The present work focuses on the difference in the outputs of a vertical axis wind turbine (VAWT) under different operational conditions. A Computational Fluid Dynamics (CFD) technique has been used for various blade configurations of a VAWT. The results indicate that there is significant degradation in the performance output of wind turbines as the number of blades broken or missing from the VAWT increases. The study predicts the faults in the blades of VAWTs by monitoring its output.

Capacity Testing and Local Flow Analysis of Geometrically Complex Trims Installed Within a Commercial Control Valve

Industrial control valves often handle flows with very high pressure drops (conditions often referred to as severe service). In order to cope with these pressure drops, geometrically complex valve trims with many stages of pressure loss, are designed to prevent undesirable side effects such as cavitation, excessive noise or erosion. These effects are maintained under control by gradually decreasing the pressure in each stage of pressure letdown of the trim. There are many different product designs for control valve trims produced by different manufacturers. One such design uses cylindrical obstructions in the flow field to control the pressure drop. The design of these trims is based on their capacity (Cv) values. With the advent of advanced computational tools, such as Computational Fluid Dynamics, it has become possible to test these trims in flow conditions which are difficult to achieve in laboratories, but do exist in real time functioning of the trims. Hence, this study presents capacity testing and local flow analysis of a complex geometry trim, installed within a commercial control valve for severe service. The results show that the capacity of this particular design of trim decreases as the valve opening position decreases.

A Study on Optimal Sizing of Pipeline Transporting Equi-sized Particulate Solid-Liquid Mixture

Pipelines transporting solid-liquid mixtures are of practical interest to the oil and pipe industry throughout the world. Such pipelines are known as slurry pipelines where the solid medium of the flow is commonly known as slurry. The optimal designing of such pipelines is of commercial interests for their widespread acceptance. A methodology has been evolved for the optimal sizing of a pipeline transporting solid-liquid mixture. Least cost principle has been used in sizing such pipelines, which involves the determination of pipe diameter corresponding to the minimum cost for given solid throughput. The detailed analysis with regard to transportation of slurry having solids of uniformly graded particles size has been included. The proposed methodology can be used for designing a pipeline for transporting any solid material for different solid throughput.

Pressure Drop in Capsule Transporting Bends Carrying Spherical Capsules

One of the most important parameters in designing a capsule transporting pipeline is the pressure drop in the pipes carrying capsules and associated pipe fittings such as bends etc. Capsules are hollow containers with typically cylindrical or spherical shapes flowing in the pipeline along with the carrier fluid. The dynamic behavior of a long train of capsules depends on the behavior of each capsule in the train and the hydrodynamic influence of one capsule on another. Researchers so far have used rather simplified empirical and semi-empirical correlations for pressure drop calculations, the range and application of which are fairly limited. Computational Fluid Dynamics (CFD) based techniques have been used to analyze the effect of the presence of solid phase in hydraulic bends. A steady state numerical solution has been obtained from the equations governing turbulent flow in pipe bends carrying spherical capsule train consisting of one to four capsules. The bends under consideration are of 45° and 90° with an inner diameter of 0.1m. The investigation was carried out in the practical range of 0.2 ≤Vb≥ 1.6 m/sec. The computationally obtained data set over a wide range of flow conditions has been used to develop a rigorous model for pressure drop calculations. The pressure drop along the pipe bends, in combination with the pressure drop along the pipes, can be used to calculate the pumping requirements and hence design of the system.

Effect of the Length and Diameter of a Cylindrical Capsule on the Pressure Drop in a Horizontal Pipeline

Capsule pipeline research involves the study of the flow in a pipe of a long train of spherical or cylindrical capsules (hollow containers) filled with minerals or other materials including hazardous liquids. The behavior of the capsule train will depend upon the behavior of each capsule in the train and the hydrodynamic influence of one capsule on another. Designers are in need of a general correlation to calculate pressure drop in a capsule pipeline. Researchers, so far, have used rather simplified empirical and semi-empirical correlations for pressure drop calculations, the range and application of which is fairly limited. A mathematical correlation developed for pressure drop in cylindrical capsule of equi-density as its carrying medium is presented here. Based on Computational Fluid Dynamics (CFD) a numerical solution has been obtained from the equations governing the turbulent flow around a concentric cylindrical capsule in a hydraulically smooth pipe section. The diameter of the pipe used in present study is 0.1m while that of capsules are in the range of 50-80% of the pipe diameter. The investigation was carried out in the practical range of 0.2 ≤Vb≥ 1.6 m/sec. The computationally obtained data set over a wide range of flow conditions have then been used to develop a rigorous model for pressure drop. Using this model the pressure drop along the pipeline can be computed which then can be used to calculate pumping requirements.

Development of an Integrated Connectedness Model to evaluate the effectiveness of Teaching and Learning

Use of blended learning system in a structured manner results in achieving higher order skills in cognitive domain. However, there is a need to quantify skills improvements as the students go through lower level skills to higher level skills. To ascertain this progression, it is necessary to develop a mathematical model of learning which can indicate the effectiveness of teaching and learning methods on skills improvement. In this study, mathematical learning model has been developed, which predicts the students’ knowledge, depending on the amount of instruction they receive. It is expected that this model will enable development of direct correlation between teaching and learning methods, and the skills level attained by the students. The model is applied for different categories of learning. Parameters in the model are determined after least-square fitting has been applied on observed student learning data.

Numerical Analysis of a Railway Compartment Fire

Trains are considered to be the safest on-land transportation means for both passengers and cargo. Train accidents have been mainly disastrous, especially in case of fire, where the consequences are extensive loss of life and goods. The fire would generate smoke and heat which would spread quickly inside the railway compartments. Both heat and smoke are the primary reasons of casualties in a train. This study has been carried out to perform numerical analysis of fire characteristics in a railway compartment using commercial Computational Fluid Dynamics code ANSYS. Non-premixed combustion model has been used to simulate a fire scenario within a railway compartment, while Shear Stress Transport k-ω turbulence model has been used to accurately predict the hot air turbulence parameters within the compartment. The walls of the compartment have been modelled as no-slip stationary adiabatic walls, as is observed in real life conditions. Carbon dioxide concentration (CO2), temperature distribution and air flow velocity within the railway compartment has been monitored. It has been observed that the smoke above the fire source flows to both sides of the compartment. The highest temperature zone is located downstream the fire source, and gradually decreased with the increase in the distance from the fire source. Hence, CFD can be used as an effective tool in order to analyse the evolution of fire in railway compartments with reasonable accuracy. The paper also briefly discusses the topical reliability issues.

Performance Comparison of a Vertical Axis Wind Turbine Using Commercial and Open Source Computational Fluid Dynamics Based Codes

Computational Fluid Dynamics (CFD) is a very effective tool to analyse the flow characteristics within and around different mechanical artifacts such as automotive vehicles, turbomachines etc. CFD based analysis provides beneficial information about the flow behavior within a component, hence reducing the costs involved in the design process of that component. This has led the researchers to develop an Open Source CFD code, commonly known as Open Field Operation and Manipulation, or OpenFOAM. The development of OpenFOAM has made scientific research in the field of fluid dynamics available for almost no cost. Designers who rely on commercial CFD packages are hesitant on using Open Source CFD codes because of accuracy. They need to be convinced by proving its simulation capability as compared to any commercial CFD package. Hence, this study investigate the flow phenomenon in the vicinity of a Vertical Axis Wind Turbine (VAWT), using such open source code combinations that yields reasonably accurate results, which can be compared against any commercial CFD code.

Development of an Information Quality Framework for Mechanical Engineering Modules with Enhanced Treatment for Pedagogical Content

The technology based learning systems have capability to comply with diverse requirements of all the stakeholders in the modern education system. In technology based modules, such as those taught in Mechanical Engineering courses, the psychomotor content takes precedence over other domains of teaching and learning. Effective integration of pedagogical content within the Mechanical Engineering modules is of utmost importance for effectiveness in teaching and learning processes in these modules. Published literature is limited in this regard, and hence, the present study focuses on developing a novel an information quality framework for Mechanical Engineering modules, through which an enhanced treatment has been provided to the pedagogical content, in order to meet the educational goals and the industrial requirements worldwide. The novel information quality framework developed in the present study can be used as a guideline for measuring the effectiveness of Mechanical Engineering modules.

Optimisation of a Horizontal Capsule Transporting Pipeline carrying Cylindrical Capsules

Pipelines carrying fluids and slurries are quite common. The third-generation pipelines carrying spherical or cylindrical capsules (hollow containers) filled with minerals or other materials including hazardous liquids are rather a new concept. These pipelines need to be designed optimally for commercial viability. An optimal design of such a pipeline results in minimum pressure drop in the pipeline. This corresponds to minimum head loss and hence minimum pumping power required to drive the capsules and the transporting fluid. This study uses a rigorous approach to predict pumping cost based on Computational Fluid Dynamics (CFD) and hence optimize the design of the capsule transporting pipelines. Pressure drop relationship developed has been incorporated to calculate the pumping requirements for the system. Based on the least-cost principle, a methodology has been developed for the determination of the optimal diameter of cylindrical capsule carrying hydraulic pipeline. This procedure can be applied to obtain the optimal size of the capsule pipeline for minimum pumping and capital costs.