Numerical investigation of heat transfer in intensive cooling tubes with turbulence bushes

The heat transfer in intensive cooling tubes with turbulence bushes is studied numerically. Based on experimental data, a two-dimensional, two-phase heat transfer model was developed, which describes the coupled temperature fields in the wire and the annulus. Due to the very high wall temperature of the wire and the special flow conditions, convection-controlled film boiling occurs, in which the heat transfer depends mainly on the parameters of single-phase convection. The asymmetric turbulent flow is described by an appropriate one-dimensional model. In order to investigate shape variations of the bushes, additional experiments or two-dimensional flow simulations are required. Therefore, further modeling is focused on the single-phase heat transfer considering the two-dimensional flow. This numerical model is also validated by experimental results. The numerical experiments show the mechanism of the shape influence of the turbulence bushes on the pressure drop and the heat transfer coefficient. They permit optimization of newly designed turbulence bushes and deliver the characteristic bush parameters for the two-phase model.