Dynamic thermal response modelling of turbulent fluid flow through pipelines with heat losses

The dynamic thermal behaviour of pipe systems is important in many heating, cooling and process systems and is further complicated where radial heat transfer and the thermal capacity of the pipe are significant. In this study, the ability of three forms of discretized one-dimensional models in prediction of the dynamic thermal response of pipelines considering the longitudinal dispersion of turbulent fluid flow were examined. Furthermore, a model is proposed combining features of plug-flow and discrete stirred tank representations that take into account the thermal capacitance of the pipe material as well as radial heat transfer. This combination enables the proposed model to simultaneously handle the simulation of momentum and energy balance as well as simulation of the longitudinal dispersion in pipelines. The proposed model is further compared to experimental measurements. The results elucidated that the proposed model is not only able to capture the outlet temperature changes due to a step change in the very good agreement against the measurement data but also offers advantages in reduced computational expense.