Numerical Simulation of Flow and Heat Transfer of a Discontinuous Single Started Helically Ribbed Pipe

Abstract

In the present study, the turbulent flow field and the heat transfer in a single started helically ribbed pipe with a discontinuous rib are investigated. A large-eddy simulation (LES) technique is applied in a pipe section with cyclic boundary conditions. The aim of this study is to explain and further analyze the findings from the heat transfer measurements at such complex structures with the help of detailed flow simulations. The simulation results are validated with measurements at a Reynolds number of Re = 21,100 and a Prandtl number of Pr = 7 with water as fluid. The comparison clearly shows that the current method delivers accurate results concerning average flow field, turbulence quantities and local heat transfer. The results demonstrate that the applied method is capable of correctly simulating flows with heat transfer in complex three-dimensional structures. The overall heat transfer performance of the helically ribbed pipe with a discontinuous rib is compared to a smooth pipe and a continuous rib configuration. The impact of the interruption of the rib structure on pressure drop and heat transfer are analyzed in detail.

Numerical Heat Transfer and Fluid Flow: New Advances

“…Recently, Mousavi et al [25] described a variety of passive methods used to intensify the heat transfer process. Kugele et al [26] used the LES approach for a single-started helically ribbed pipe and validated the velocity and heat transfer between the ribs using experimental data obtained by Virgilio et al [27,28]. The authors considered an acrylic glass with two different helical turbulators inserted into the pipe.…”

“…They simulated 3D water flow in a pipe at a constant Re = 21,000 and Pr = 7.0, assuming constant thermophysical properties. Kugele et al [26] demonstrated that the LES simulations gave fairly accurate results for the flow field, the level of turbulence, and the local heat transfer coefficient. Measurements and simulations of the Nusselt number in the pipe with and without helical turbulators confirmed a significant increase in the Nusselt number.…”

“…Measurements and simulations of the Nusselt number in the pipe with and without helical turbulators confirmed a significant increase in the Nusselt number. Simulations of dynamic and thermal boundary layers performed by Kugele et al [26] shed more light on complex turbulence processes and their influence on heat transfer in helically ribbed pipes.…”