Browsing by Author "Herle, A"

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    Experimental Investigation on Forced Convection Heat Transfer Augmentation Using Annular Blockages
    (P and R Engineering Consultancy Publication, 2015-05) Herle, A
    Abstract— Heat exchangers have several industrial and engineering applications. The design procedure of heat exchangers is quite complicated, as it needs exact analysis of heat transfer rate and pressure drop estimations apart from issues such as long-term performance and the economic aspect of the equipment. Whenever inserts are used for the heat transfer enhancement, along with the increase in the heat transfer rate, the pressure drop also increases. This increase in pressure drop increases the pumping cost. Therefore any augmentation device should optimize between the benefits due to the increased heat transfer coefficient and the higher cost involved because of the increased frictional losses. Experimental work on heat transfer augmentation using annular blockages. Inserts when placed in the path of the flow of the fluid, create a high degree of turbulence resulting in an increase in the heat transfer rate and the pressure drop. The work includes the determination of friction factor and heat transfer coefficient for various annular blockages and annular blockages having different diameter. The results of annular blockages having different diameter have been compared with the values for the plain tube. Four annular blockages (di=20%, 30%, 40% & 50% reduction in outer diameter) are used in the study.
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    Review Paper on Forced Convection Heat Transafer Augmentation Using Annular Blockages
    (Technical Journals Online, 2015-01) Herle, A
    The study of improved heat transfer performance is referred to as heat transfer enhancement, augmentation, or intensification. In general, this means an increase in heat transfer coefficient. Energy- and materials-saving considerations, as well as economic incentives, have led to efforts to produce more efficient heat exchange equipment. Common thermal-hydraulic goals are to reduce the size of a heat exchanger required for a specified heat duty, to upgrade the capacity of an existing heat exchanger, to reduce the approach temperature difference for the process streams, or to reduce the pumping power. The study of improved heat transfer performance is referred to as heat transfer enhancement, augmentation, or intensification. In general, this means an increase in heat transfer coefficient. [1] General techniques for enhancing heat transfer can be divided in three categories. One is passive method such as twisted tapes, helical screw tape inserts, rough surfaces, extended surfaces, additives for liquid and gases. The second is active method, which requires extra external power, for example mechanical aids, surface fluid vibration, use of electrostatic fields. Passive methods are found more inexpensive as compared to other group.