THE EFFECT OF COOLING ON MECHANICAL AND THERMAL STRESSES IN VASCULAR STRUCTURES

Year 2018, , 1855 - 1866, 20.12.2017

Erdal Çetkin

https://doi.org/10.18186/journal-of-thermal-engineering.382916

Cited By: 3

Abstract

Here, we show how the
vascular channel configuration and its shape affect the mechanical strength
which is simultaneously subjected to heating and mechanical load. The material
properties were defined as functions of temperature. The effect of channel
cross-section on the coolant mass flow rate, peak temperature and peak stresses
are documented. The results show that the resistances to flow of stresses and
fluid is minimum with the circular channels while the resistance to the heat
flow is the smallest with semi-circular channels. In addition, morphing the
vascular design provides almost the smallest resistance to the heat flow with
circular channels (0.3% difference in the peak temperature). This shows that
even the convective resistances are the smallest with circular-cross section,
overall thermal resistance is smaller in semi-circular design for the fixed
fluid volume. The peak stress is smaller with hybrid design than the parallel
designs for the entire pressure drop range. In addition, the effects of
mechanical load, heating rate and reference temperature on the stress distribution
are also documented. Furthermore, the thermal and mechanical stresses are also
documented separately, and then compared with the coupled solution cases. The
chief result of this paper is that for a coupled system minimizing only one of
the resistance terms is not sufficient, all the resistances considered
simultaneously in order to uncover the best performing design. In coupled
solutions, we documented the simulation results with temperature dependent
material properties and the resistances to the heat and fluid flow is affected
by the mechanical deformations. In addition, the results show that the designs
should be free to vary, the unexpected designs can be the best performing
designs for the given parameters and constraints. Therefore, the design parameters
based on the experience does not always yield the best performing designs as
the objectives and constraints vary.

Keywords

Vascular, Cooling, Thermal Expansion, Smart Features

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