Evolutionary Design of Novel Coolant Passages for Cooling a Square Substrate by Single Stream

Different designs of novel coolant (i.e., water) circuits have been proposed using a well-established constructal law to cool a square substrate made up of aluminum oxide, and subjected to a uniform wall heat flux. Five different flow-path topologies: Case-1 (umbrella-shaped), Case-2 (dumbbell-shaped), Case-3 (hexagonal-shaped), Case-4 (down-arrow-shaped), and Case-5 (up-arrow-shaped) are evolved from a single pipe embedded in the heated substrate. The best cooling pathway has been anticipated by comparing the thermo-fluid characteristics of designs. A numerical route, via Ansys R 16, has been implemented to solve the transport equations for continuity, momentum, and energy along with relevant boundary conditions. The non-dimensional temperature and pressure drop for these cases have been quantified and compared, by varying the length and Reynolds number in the range of 2-3, and 100-2,000, respectively. We observe a decrease in the dimensionless temperature and an increase in the pressure drop with Reynolds number for all the considered pathways. At Re<=500, a rapid fall in the non-dimensional temperature has been noticed; and thereafter, it looks like a plateau for all cases. For Case-4, a minimum temperature is obtained at the non-dimensional pipe length of 2.5. At Lc/L=2.5, we observe that the Case-4 provides better cooling to the substrate among all other designs. Also, the pressure drop for case 4 is not too high as compared to other designs.