Circular and Semi-Circular Constructal Vascular Channels for Cooling and Reduced Stresses

Abstract

In this paper, we show how the vascular channel configuration and its shape affect the mechanical strength which is simultaneously subjected to heating and mechanical load. The effect of channel cross-section on the coolant mass flow rate, peak temperature and peak stresses are documented. The material properties were defined as functions of temperature in simulations. The results show that the flow of stresses and fluid is minimum with the circular channels and 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 semi-circular channels than the circular ones if the pressure drop is less than 500 Pa for the radial design. However, the peak stress is smaller with hybrid design than the semi-circular radial 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 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. This result is in accord with the constructal law.