Operational Principles of a Pump-Augmented Loop Heat Pipe with Auxiliary Evaporators

This paper introduces pump-augmented loop heat pipes (PA-LHPs), which is a relatively novel sub-class of two-phase devices with capillary structures, more powerful and versatile than conventional LHPs. The LHP reservoir-evaporator assembly controls the system operating temperature and provides capillary pressure potential for the fluid circulation in the LHP flow contour. A mechanical pump added to the liquid return line circulates fluid through the second flow contour with auxiliary flow-through evaporators, as well as through the condenser shared by the two flow contours. Some results of the numerical simulation were obtained for an ammonia PA-LHP selected for this study. The predictions indicate that such PA-LHP can operate in a stable manner under power variations on the LHP and auxiliary evaporators. Unlike conventional LHPs, PA-LHPs with auxiliary evaporators can acquire thermal energy from multiple distributed heat sources.