Supercritical carbon dioxide (sCO2) power cycles present promising
application prospects in spacecraft and mobile energy systems owing to their
outstanding advantages including high thermal efficiency and compact system
structure. As a key component of sCO2 heat exchange systems, the
complex capillary pipeline structure significantly influences heat transfer
performance and system stability through its internal flow distribution
uniformity. In this study, a multi-physics numerical simulation approach is
employed to establish a complex capillary pipeline model with four compartments
labeled A, B, C and D, aiming to explore the effects of different acceleration
(overload) conditions on internal flow distribution. Various acceleration cases
are considered, such as zero gravity, horizontal placement (0, 1g, 0), vertical
placement (-1g, 0, 0), (0.15g, -0.7g, 0), (5g, -3g, 0) and (8g, -3g, 0).
Meanwhile, the regulation effect of orifice plates on flow distribution is
analyzed. The results demonstrate that both the magnitude and direction of
acceleration exert remarkable impacts on the flow distribution ratio within the
pipeline. Under vertical acceleration, flow distribution among the different
branches becomes more uneven. Under high acceleration conditions, compartment A
is prone to obvious flow deviation, which deteriorates overall flow uniformity.
Orifice structures adjust flow distribution under acceleration pretty well—they
work by changing the flow resistance characteristics. The present research
provides reliable theoretical foundation and data support for the optimal design
of complex capillary pipeline structures under variable acceleration
environments.