Use of Silver Nanoparticles Mixed With Deionized Water in a Rectangular Two-Phase Closed Thermosyphon: A Case Study of the Two-Phase Flow

Abstract

When nanofluid (NF) is used as the working fluid in a rectangular two-phase closed thermosyphon (RTPCT), the formations and heat performance of two-phase flow patterns are explored qualitatively. Silver nanoparticles were mixed with deionized water at a concentration of 0.5 wt% in the NF. Nanoparticles improved the thermal contact surface area within the base flow, allowing the base fluid to boil quickly and easily. When the working fluid was boiled, NF also demonstrated high thermal conductivity capabilities, which diffused and moved along with the dual flow patterns. As a result, these qualities improved the RTPCT's efficiency. Considering the findings of the RTPCT test at evaporation temperatures of 50, 70, and 90 o C, three flow forms are observed: bubble flow (BF), slug flow (SF), and churn flow (CF), respectively. The slug flow (SF) and the churn flow (CF) are patterns that influence the heat flux. The greatest heat flow obtained from the test is 4.78 kW/m 2 at 90°C evaporation temperatures, whereas the heat flux measured at 70°C and 50°C evaporation temperatures is 2.95 kW/m 2 and 2.74 kW/m 2 , respectively.

Archives of Thermodynamics

“…6. Upon comparing velocity and flow behaviors obtained from the tests of RTPCT with the length of the X and Y of 25.2 mm, aspect ratio of the 20 and TPCT with a diameter of 25.2 mm and aspect ratio 20 [45], results are shown in Fig. 6.…”

“…Thus, this was another reason that caused the vapor bubbles to briefly and rapidly ascended to the condenser to release the heat before flowing to the evaporator to absorb the heat again. The heat flux as obtained from the test of RTPCT with the lengths of X and Y of 25.2 mm and the aspect ratio 5 and 20, compared with that of TPCT with a diameter of 25.2 mm and the aspect ratio 5 and 20 [45] can be illustrated as per Fig. 8.…”