Analysis of thermal performance of an improved shell and helically coiled heat exchanger

Abstract

Shell and helically coiled tube heat exchangers composed from curved tubes inside a shell which are often preferred devices particularly in several applications like refrigeration, heat recovery systems, chemical processing, heat storage and food processing. Enhancing the effectiveness of heat exchangers can leads to increase in the overall efficiency of energy conversion systems. In addition, finding a simple and cost-effective method for enhancing the effectiveness of heat exchangers is a significant issue that should be taken into consideration. In this work, it is proposed to enhance the performance of a shell and helically coiled heat exchanger by utilizing a new modification. Within this context, a hollow tube integrated into the shell side and cold fluid enters the heat exchanger along this tube. The main purpose of this modification is regulating the fluid flow over the helically coiled tube and consequently obtaining more thermal energy. In this regard, the performance of a modified shell and helically coiled heat exchanger has been compared with a conventional vertical shell and helically coiled heat exchanger by using numerical simulation. The main objective of the simulation part of this study is determining suitable configuration for shell and helically coiled tube heat exchanger to obtain high thermal performance. Then, modified shell and helically coiled heat exchanger has been fabricated by considering simulation results. Finally, the performance analysis of developed heat exchanger has been experimentally conducted under different conditions to determine its behavior. The findings of this work showed the successful design of the modified heat exchanger. Generally, it can be said that integrating a hollow tube into the shell side of the heat exchanger led to regulate the fluid flow in the shell side that improved heat transfer. Overall heat transfer coefficient obtained in the range of 1600–3150 W/m2 K. Also, heat transfer coefficient of coil side in this study was obtained in the range of 5700–13,400 W/m2 K. Moreover, average difference between simulation and experimental results is 8%. © 2020 Elsevier Ltd