The effect of oblique entry into an automotive catalyst on the flow distribution within the monolith

Automotive catalytic converters are increasingly used to reduce emissions from internal combustion engines to comply with emission regulations. Maldistributed flow across the catalyst affects its warm up light off time, ageing, and conversion efficiency. This thesis concerns flow distribution in automotive catalytic converters and methods to improve CFD predictions. Previous studies showed that modelling the monolith flow resistance using the HagenPoiseuille's formulation under predicted flow maldistribution. The predictions were improved by incorporating an additional pressure loss term..!.py2, where Y .is 2 transverse velocity just upstream of a monolith channel, for oblique entry ofthe flow into the monolith known as the entrance effect. Further improvement was.obtained by incorporating the critical angle ofattack method. However, there was no experimental evidence to support these oblique entry loss formulations. There also remained the possibility that under predictiqn offlow maldistribution might be due to the failure to predict flow in the diffuser accurately. A one-dimensional oblique angle flow rig was designed and built to measure the effect of oblique entry flow losses. in monoliths. Experiments were performed at different angles of attack (a), using different lengths of substrate and a methodology was developed to obtain the oblique flow entrance losses. The results showed that the pressure loss attributed to the entrance effect increased with the angle of attack. The entrance effect was also found to be dependent on channel Reynolds number and substrate length. The theoretical assumption of ..!.py2 predicts accurately at low 2 Reynolds number but looses its validity at high Reynolds number. From the experimental studies, an improved correlation for the entrance effect has been derived as a function of major controlling variables, i.e~, angle of .attack, length of the substrates and Reynolds number. A two-dimensional rig was designed to measure the flow field using PN in a 2-D diffuser placed upstream of two different length substrates. The results showed that the flow in;~ wide angle diffuser consisted of a central core, free shear layer and recirculation regions. The near-fiela region was· found 'similar to that of a plane jet. The flow field was found to be independent of Reynolds number. Increasing the substrate length resulted in a flattening ofthe axial profiles close to the substrate face. A CFD study was undertaken to predict maldistributed flow at the exit ofthe substrate for an axisymmetric catalyst model by incorporating the measured entrance effect correlation. A fixed critical angle of attack (flc,F) approach was used whereby the entrance effect is assumed constant for a>0<:,F. Incorporating the entrance effect with O<:,r 810 improved the prediction ofmaldistribution in the flow profiles. A 2-D CFD study was undertaken to predict the flow distribution in the diffuser and downstream of the substrate. A ~mparison of the CFD predictions in the diffuser using different turbulence models showed that all the turbulence models used in this study over predicted the width of the central core region and the V2F turbulence model. gave velocity predictions that compared best with PIV. Incorporating the entrance effect improved the predictions close to the diffuser-substrate interface and downstream ofthe substrate.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Treachery in Poetry

In this paper an attempt has been made to study treachery in its various forms, and its portrayal in some select verses from the Ghazals of the Urdu poet Ahmed Faraz. These verses exhibit the betrayal of trust and allegiance by relatives and friends. They are chosen for discussion and analysis because they succinctly unveil the intensity and depth of human relations and the complexity of the concept of treachery. Keywords: Treachery, betrayal, treason, Ghazal, friendship, relationship, enemy, opportunis

Effect of ovine luteinizing hormone antibodies on reproduction in rabbits

Call number: LD2668 .T4 1966 Q1Master of Scienc

Economy in ultimate strength design

Call number: LD2668 .R4 1967 Q

Granger-causality between macroeconomic variables and stock market index: evidence from India

The focus of the study is on the Granger-causality between stock index and macroeconomic variables in India. The relationship between macroeconomic variables and stock market returns is, by now, well-documented in the literature. In this paper we examine the long-term equilibrium relationships and Granger-causality between selected macroeconomic variables on the Mumbai Stock Exchange BSE100 Index. The standard time series techniques are applied. The paper identifies a cointegrating relationship along with the identification of the exogeneity (leading) and endogeneity(following) of the variables. The Granger-causal chain evidenced in the findings tend to indicate that the stock index is the most endogenous(dependent) variable driven by market capitalization, inflation rate, interest rate and exchange rate. The Granger-causal chain Implications of the findings are immense for the policy makers. Also the findings of this paper present an opportunity to further expand the research in this field as well as extend it to other emerging economies like India

A 6-year Cross-Sectional study on Leishmaniasis

Leishmaniasis is caused by a protozoan parasite which is transmitted by the bite of infected female phlebotomine sand-fly. Leishmaniasis is more common in poor socioeconomic conditions like poor housing, overcrowding and malnutrition. Asymptomatic Leishmania donovani infections outnumber clinical presentations, however, the predictors for development of active disease are not well known.&nbsp;Asymptomatic persons infected with the parasites causing visceral leishmaniasis (VL) usually outnumber clinically apparent cases by a ratio of 4-10 to 1. Accurate treatment and cure is mainly dependent on the factors like clinical manifestations and diagnosing the causative species among cutaneous Leishmaniasis or mucocutaneous Leishmaniasis and visceral Leishmaniasi

On the analysis and modelling of the effects of high frequency harmonics on classical synchronous generators

High frequency currents are starting to penetrate in power systems due to the rapidly increasing use of high switching frequency power electronic components. While the presence of these power electronic devices is increasing rapidly, the magnitudes of the high frequency currents generated by them are actually very low. Thus, today, research investigating their effects on the components in the power networks is very limited. In anticipation of this emerging high frequency pollution in the networks, this research focuses on modelling the effects of this phenomenon on the armature windings of classical synchronous generators, which today still represent the major source of power generation across the world. The thesis presents work on developing improved modelling tools for performance characterisation of classical wound field, salient pole synchronous generators considering the emerging high frequency pollution. It first presents a fast and accurate synchronous generator simulation model that considers space harmonics and magnetic saturation by proposing optimised lookup tables for flux linkages that make the model development process more efficient. The model is validated against experimental results and is shown to result in significant benefits and flexibility over the more common FE modelling. The thesis then proposes an improved subdomain modelling technique for accurate high frequency copper loss calculation at frequencies as high as 10kHz for round conductors, which showed a drastic improvement in the accuracy compared to the conventional subdomain model. This technique was validated experimentally and then finally both the validated modelling tools were integrated to present a comprehensive SG model that simulated the overall effects of harmonics on voltage, current, torque and high-frequency copper loss waveforms

Design and Analysis of Internal Hinge Check Valve

The advent of computers and the tremendous strides they have made in the recent times have brought the capability to model complex design and solve innumerable number of mathematical equations in a flash of time, to the desktop of the design engineer. CREO is windows based software package, which enables the design and Ansys will analyse the mechanical and other system. This project is to design 16” Class 300 Internal Hinge Swing Check Valve with compliance to BS 1868 standard. The internal hinge check valve design is to overcome the leakage issue in external hinge design. The aim is to design a check valve without puncturing the body and to assemble the whole disc sub-assembly inside the body. The design of internal hinge check valves is carried out with the help of CREO design software and subsequently analysis is done with the help of ANSYS software package

Automated Capping of Liquid Storage Bottles in Food Industry

The high speed automated production systems are employed nowadays to achieve improved quality of manufacturing accuracy with improvised and high production rates. This paper introduces a new design for the chucks which are used for capping the liquid bottles for food and beverage industry. This new chuck is designed for multi-functional purposes which reduce the time for changing the chuck if caps of different diameters are used. The power transmission to the chucks is delivered by using “Hysteresis magnetic type clutches”, for controlling and achieving smooth constant torque. The specialty of these clutches is that it offers smooth disengagement without jerks and bumps that increase its wear life compared to other ordinary clutches. The deformation and stress in the component are studied by performing the computer-aided structural analysis. With the analysis maximum deformation and maximum stress can be found out and the factor of safety can be calculated

Propose & Design an Automated Mechanical System for Capping and Water Level Measurement of Water Bottle

The purpose of this poster is to develop an automated production layout along with its design for above mentioned subject. The research work includes designing the fixture for holding the bottle while capping and three-finger self-centering gripper for placing and moving the bottle to and fro from guideways to the bottle bottom holder and vice versa. Suggesting an automated system and technology for checking the water level in bottle and effectively removing such bottles from assembly line would also be one of the objectives of this poster. Tools like automated torque wrench, precision indexing conveyor belts, three-finger self-centering grippers, three-jaw chuck (bottle holding fixture), infrared level detection sensors have been used in this system. FEA analysis of three-finger gripper and three-jaw chuck is done to verify their design. The components of this system are designed using Creo Parametric 2.0. Designed components are analyzed using ANSYS Workbench 16.0