Detached-eddy simulation of the flow behavior in the shell-side of the coil tube bundle in turbulent flow

Abstract

The coil tube bundle of Coil-wound heat exchanger (CWHE) is densely arranged, resulting in a complex flow domain in the shell. And Flow-induced vibration (FIV) is a common phenomenon in working situations where coil tubes are submerged in the oncoming flow. Understanding the flow and FIV characteristics of the shell-side plays a significant key in engineering issues, such as the design of coil tube bundle arrangements and safety verification of heat exchangers. This paper presented a detailed investigation of flow in the shell-side of the three-layer coil tube bundle with Detached eddy simulation (DES), whose validity was verified by comparison with the experimental results. Eight calculated cases of inlet flow rates from 0.01 m3/s to 0.15 m3/s with an interval of 0.02 m3/s were set up to determine that the flow domain of the shell-side is turbulent. The flow was found to form flow channels between adjacent layers, while variable eddy currents appeared around coil tubes. Subsequently, the gap transverse flow velocity was predicted and the calculation correlation was proposed. Furthermore, spectral and wavelet analyses were carried out to investigate the time-frequency data of fluctuating velocities in the flow, to bring to light vortex shedding frequencies and to capture St with respect to this tube bundle arrangement.