Design of conical helical coil heat exchanger for waste heat recovery system

Helical tubes are universally used in chemical reactors, ocean engineering, heat exchangers, piping system and many other engineering applications. It has been long recognized that heat transfer characteristic of helical tubes are much better than that of straight ones because of the occurrence of secondary fluid flow in planes normal to the main flow inside the helical structure. In the present study an experimental investigation of heat transfer in cone shaped helical coil heat exchanger is reported for various Reynolds number. The purpose of this study is to design and fabricate a non-previously implemented shell and cone shaped helical coil and fitted with a twin cylinder diesel engine to recover waste heat from the exhaust gas to heat water. A “C” program was developed for the easiness of the design and an AutoCAD model of the design was made. For the fabrication of the coil, copper tubes were used. To evaluate the designed value various temperatures have taken for various mass flow rate of the water. The results show that the design value are having a good agreement with the experimentally obtained value. It was found that the heat transfer rates are 1.18 to 1.38 times more for the cone shaped helical coil than that of simple helical coil.