An investigation of the exergy and first and second laws by two-phase numerical simulation of various nanopowders with different diameter on the performance of zigzag-wall micro-heat sink (ZZW-MHS)

In this paper, a novel heat sink (HS) with zigzag walls is simulated and exergy analysis is performed. $$\mathrm{CuO}$$ / $${\mathrm{H}}_{2}\mathrm{O}$$ and $${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$$ / $${\mathrm{H}}_{2}\mathrm{O}$$ nanofluids are employed as coolants. HS consists of two main parts, including the main body and the aluminum door. In the main part, there are micro-channels with zigzag walls. The application of zigzag-wall micro-heat sink (ZZW-MHS) is cooling of different energy systems. The control volume method is used for numerical simulations, and the SIMPLE algorithm is employed for coupling velocity and pressure fields by use ANSYS FLUENT. A two-phase mixture method is used to simulate nanofluid flow. The volume percentage of nanoparticles is considered to be 0.1 and 2%, where the Reynolds number is changed in the range of 500 and 1500. The main purpose and innovation of the work is to focus and analyze the exergy and efficiency of the laws of thermodynamics. The results showed that increasing the Reynolds number decreases the amount of out exergy and gain exergy and increases the amount of lose exergy. The addition of nanoparticles, especially copper oxide, reduces the amount of out exergy. The addition of nanoparticles also reduces the amount of lose exergy. The addition of nanoparticles, especially the addition of copper oxide nanoparticles to water, reduces the efficiency of the first and second laws of thermodynamics. The efficiency values of the second law of thermodynamics when 0.1% alumina and 4% copper oxide are added to water are 0.1 and 0.2%, respectively. Also, increasing the Reynolds number reduces the efficiency of the first and second laws of thermodynamics, so that in the case of using water, increasing the Reynolds number can reduce the efficiency of the second law by up to 4%.