Automotive Science and Engineering

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If an air flow is injected into a liquid fluid, many ambulant air bubbles are formed inside the fluid. Air bubbles move inside the liquid fluid because of the buoyancy force, and the mobility of these air bubbles makes sizable commixture and turbulence inside the fluid. This mechanism was employed to enhance the heat transfer rate of a horizontal double pipe heat exchanger in this paper. However it can be used in any other type of heat exchanger. Especially, this method can be expanded as a promising heat transfer improvement technique in automotive cooling system, for instance in radiator which contains of water or other liquid fluid. Bubbles were injected via a special method. Present type of air bubbles injection and also the use of this mechanism for double tube heat exchanger have not been investigated before. Results are reported for varying bubble inlet parameters. The main scope of the present work is to experimentally clarify the effect of air bubble injection on the heat transfer rate and effectiveness through a horizontal double pipe heat exchanger.

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Considering the present business competitive scenario, the automotive industry is under pressure to achieve higher productivity. A high level of performance and quality standard could be achieved through improving the Overall Equipment Effectiveness (OEE) of the equipment in an automotive industry. Thus, the aim of this study is to investigate the performance measurement through OEE theory in an Iranian automotive industry. Data and basic information collected from the Computerized Maintenance Management System (CMMS) of the production assembly lines. In this case study, two different assembly lines such Peugeot and Sports Utility Vehicle (SUV) were studied. The results indicated that the indices such availability rate, performance and quality for Peugeot assembly line obtained an OEE value of 0.99, 0.70 and 0.38, respectively, and, these indices for SUV assembly line obtained as 0.99, 0.39 and 0.53, respectively. Statistical analysis results of net operating time parameter for two assembly lines revealed that there is significant difference in the confidence level of 5% (P-value < 0.05). In addition, the OEE index for Peugeot and SUV assembly lines gained 0.27 and 0.21 over a period of one year. Consequently, to improve the OEE in the automotive assembly lines, managing the time losses by systematic planning of manufacturing and the implementation of Total Productive Maintenance (TPM) are suggested.