This research investigated the thermal performance of various horizontal closed-loop oscillating heat-pipe systems with check valves (HCLOHPs/CVs). Numerous test systems were constructed using copper capillary tubes with assorted inner diameters, evaporator lengths, and check valves. The test systems were evaluated under normal operating conditions using ethanol, R123, and distilled water as working fluids. The system's evaporator sections were heated by hot water from a hot bath, and the heat was removed from the condenser sections by cold water from a cool bath. The adiabatic sections were well insulated with foam insulators. The heat-transfer performance of the various systems was evaluated in terms of the rate of heat transferred to the cold water at the condenser. The results showed that the heat-transfer performance of an HCLOHP/CV system could be improved by decreasing the evaporator length. The highest performance of all tested systems was obtained when the maximum number of system check valves was 2. The maximum heat flux occurred with a 2 mm inner diameter tube, and R123 was determined to be the most suitable working fluid.
This study aimed to investigate the application of a Heart Shaped Glass Spoon Loop Oscillating Heat Pipe (HSGS/LOHP) made of a glass tube. The results showed that HSGS/LOHP can be practically used for stirring hot coffee in a cup. At the working substance filling rates of 80 and 60%, slug and annular flows of the working substance pattern were found while at 40% only the slug flow was found. The maximum mean lengths of the slug and annular flows of the working substance were 0.0259 and 0.00443 m which occurred at the working substance filling rate of 80% at the evaporator temperatures of 40℃, the average velocity was the highest for every working substance filling rate at the evaporator temperatures 70°C. The slug and annular flow patterns had maximum speeds of 0.00171 and 0.00111 m/s when tested at the 40% and 60% working substance filling rates, respectively. The working substance at the evaporator temperature of 40℃ and the filling rate of 80% had the highest buoyancy force and moment of inertia of 4.90 ± 0.25 kN and 901.77 ± 45.08 Tm2·kg, respectively.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.