A comprehensive review on double pipe heat exchangers

Growing need to develop and improve the effectiveness of heat exchangers has led to a broad range of investigations for increasing heat transfer rate along with decreasing the size and cost of the industrial apparatus accordingly. One of these many apparatus which are used in different industries is double pipe heat exchanger. This type of heat exchanger has drawn many attentions due to simplicity and wide range of usages. In recent years, several precise and invaluable studies have been performed in double pipe heat exchangers. In this review, the development procedure that this type of heat exchanger went through has been analyzed in details and the heat transfer enhancement methods in aforementioned heat exchangers have also been widely discussed. Having also tried the best to present a comprehensive research, the authors gathered information regarding the usage of these methods such as active, passive and compound methods which is worth noting that the studies concerning using passive methods in double pipe heat exchangers have been frequently cited. Moreover, various studies concerning using nanofluids in double pipe heat exchangers have been discussed in details. In this review, correlations of mostly Nusselt number and pressure drop coefficient are also presented. It is believed that this review provides new insights for further investigations. (C) 2016 Elsevier Ltd. All rights reserved.