Analytical and numerical results for the dynamics of capillary pumped loops and loop heat pipes subjected to high amplitude heat load steps

Some analytical and numerical results were presented in order to clarify which are the main parameters leading the time response of CPL and LHP subjected to high amplitude heat load steps. This study actually focused on the estimation of the liquid flow rate overshoot as this peak value can be so large that it may lead to loop failures. The analytical developments assumed that the evaporator-condenser coupling which founds the CPL/LHP transient at the earliest times is based on a second-order linear system. Satisfactory agreement was observed with some data and with some simulations investigating different loop configurations even though the reliability of the analytical results depends on the reynolds number and the friction factor in the liquid line. As they provided essential information on the loop transient, these theoretical results are precious for transient numerical developments and also for the design of loops that are suitable for demanding power cycles.