ABSTRACT

The main contents of this thesis includes the design and construction of a natural convection & radiation heat transfer equipment. With this equipment the heat transfer rate from a body by different modes can be found. The emissivity and the heat transfer coefficient of the body can also be determined. The total heat supplied to the element (heating element) is transferred in three modes. Heat transfer by conduction process can easily be measured. If the element  in very low pressure or in a vacuum then the heat transfer by convection process become negligible and the total heat transfer by radiation process can be easily determined. And thus emissivity of the element can be determined. It was assume that the G.I sheet was mild steel. And the pressure vessel was made by G.I sheet. But when the vessel was making vacuum, air pressure squeezed the vessel and the equipment failed. Then it was necessary to analysis the case of failure. Moreover, the analysis of the G.I sheet by universal testing machine, it was seen that the properties (hardness, toughness, stress, etc...) of the sheet was not same the mild steel properties. Then necessary to analyze the case of tangential, compression & buckling where the equipment failed. As a result of analysis, buckling was the main cause of failure. In order to eliminate this failure, the properties of the sheet have to consider first.This work will help the beginner who wants to proceed in this field.

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ABSTRACT

DI diesel engine vehicles are becoming popular because of their friendly behavior to the environment as it emits lower CO₂ . The main cause of it is that it consumes relatively smaller amount of fuel than a gasoline engine vehicle. But this increases both regulated and unregulated emissions like No_x, PM, exhaust odor and others. The regulated emissions are No_x, PM etc and unregulated emissions is the exhaust odor. Most diesel engine researches put their attention to reduce the regulated emissions. The attention of the authors is to reduce the unpleasant exhaust odor of DI diesel engines at idling. Among the various exhaust emission problems of DI diesel engine, odor is still a prominent emission problem. Reduction of exhaust odor can be done mainly in three ways. One of them is to optimize the engine parameters. But researches have been shown that the reduction of odor is not significant. The other is that the use of alternative fuels. Some alternative fuels can reduce the exhaust odor significantly but the cost is much higher than diesel fuel. The one is to use the catalyst system. The catalyst system hence cannot be applied at idling and at low temperature operation. The other is the absorption type system like water-washing system. By EGR, NOx reduces but PM emission increases, with which odorous emission increases. For this reason, EGR and Water- Washing System is used to improve emissions by reducing NOx & odor. Odorous emissions seems to be reduced using EGR, While reading is taken directly. This is due to the reason that EGR reduces the speed of exhaust gas. For this reason, indirect odor assessment is done, from which it is found that odor increases with the increase in EGR. The water washing system can be applied at idling and at low temperature operation. Since the emission of exhaust odor at idling at low temperature operation is higher than any other engine condition, and exhaust gas temperature is much lower at idling and low speed operation, the water washing system can be used. Some previous researches have shown that odor can be reduced greatly by washing the exhaust gas by water. Since there are no proper systems to reduce the exhaust odor at idling, this thesis report focuses on the water washing system. In the water washing system the exhaust was first passed through EGR system and then through water. Also, experiments were performed with EGR only and water washing only. From these experiments, it was found that odor reduced to 1point (a significant odor reduction) by using total setup (combination of EGR and water-washing). But individual components could not able to reduce the odor significantly.    

 

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