Flow rate distribution in parallel heated pipes

The flow of evaporating fluids in parallel pipes, takes place in many applications such as heat exchangers, power plants, cooling systems and in the nuclear industry. It is a common knowledge that maldistribution of the flow rates may occur in evaporating liquid flowing in parallel pipes with common inlet and outlet manifolds. The theoretical model developed by Minzer et al. (2006) for the flow rate distribution is extended to a larger number of pipes and different heating conditions. Stable and unstable solutions are identified and the model predictions are experimentally validated for different configurations involving four parallel pipes. It is shown that the behavior of the system may depend on the history of the process exhibiting a hysteresis phenomenon. Transient simulations are carried out using this model in order to study the system response to finite disturbances. It was shown that transient solutions converge to the stable steady states, consistent with the linear stability analysis.