TY - JOUR
T1 - Thermal Regulation in Thin Vascular Systems: A Sensitivity Analysis
AU - Nakshatrala , K. B.
AU - Adhikari , K.
JO - Communications in Computational Physics
VL - 2
SP - 427
EP - 466
PY - 2024
DA - 2024/03
SN - 35
DO - http://doi.org/10.4208/cicp.OA-2023-0166
UR - https://global-sci.org/intro/article_detail/cicp/22978.html
KW - Sensitivity analysis, adjoint state method, thermal regulation, microvascular systems, active cooling, countercurrent heat exchange.
AB - <p style="text-align: justify;">One of the ways natural and synthetic systems regulate temperature is via
circulating fluids through vasculatures embedded within their bodies. Because of the
flexibility and availability of proven fabrication techniques, vascular-based thermal
regulation is attractive for thin microvascular systems. Although preliminary designs
and experiments demonstrate the feasibility of thermal modulation by pushing fluid
through embedded micro-vasculatures, one has yet to optimize the performance before translating the concept into real-world applications. It will be beneficial to know
how two vital design variables—host material’s thermal conductivity and fluid’s heat
capacity rate—affect a thermal regulation system’s performance, quantified in terms of
the mean surface temperature. This paper fills the remarked inadequacy by performing adjoint-based sensitivity analysis and unravels a surprising non-monotonic trend.
Increasing thermal conductivity can either increase or decrease the mean surface temperature; the increase happens if countercurrent heat exchange—transfer of heat from
one segment of the vasculature to another—is significant. In contrast, increasing the
heat capacity rate will invariably lower the mean surface temperature, for which we
provide mathematical proof. The reported results (a) dispose of some misunderstandings in the literature, especially on the effect of the host material’s thermal conductivity, (b) reveal the role of countercurrent heat exchange in altering the effects of design
variables, and (c) guide designers to realize efficient microvascular active-cooling systems. The analysis and findings will advance the field of thermal regulation both on
theoretical and practical fronts.</p>