Thesis
Experimental study of a pulsating heat pipe using nanofluid as a working fluid
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/106582
Abstract
In this study, as a passive energy conversion/transport device, the performance of a pulsating heat pipe (PHP) using silver nanofluid (pure water as the base) with a concentration of 0.1% by volume is experimentally investigated. The goal is to characterize the performance of the heat pipe by the use of a nanofluid as a working fluid. The operating temperature of the PHP varies from 35 °C to 266 °C, with the power rates of 61 W, 87 W, and 119 W. Experiments with fill ratios of 30%, 40%, 50%, 60% and 70% were conducted. Several thermocouples along the pipe are used to measure the surface and fluid temperatures to calculate the heat transfer performance in the evaporator and condenser sections as well as the overall PHP performance. Experiments with pure water as the working fluid and the nanofluid were conducted and their performance was compared by measuring the thermal resistance. The results for pure water showed the thermal resistance decreased as the fill ratio was increased except for the lowest power rate of 61W. The non-monotonic response for the 61W can be explained by the relatively large subcooling in the condenser section compared to the other power rates of 87 W and 119 W. Also, dry out occurred with high power input and low fill ratio and therefore the highest thermal resistance is obtained at those operating conditions. Similar trends were observed when the working fluid was the nanofluid. One main difference is the lowest thermal resistance overall was at a power rate of 87 W whereas for water it was at 119 W. A combination of larger subcooling and superheat at 119 W compared to 87 W can explain the lower performance. Comparing the nanofluid and pure water, improvement by the use of nanofluid in only 6 out of the 15 different operating conditions was observed. A further look at the fluid temperatures in the condenser section showed what effect the silver nanoparticles had on the PHP; it reduced the subcooling by the improved thermal conductivity of the fluid.
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Details
- Title
- Experimental study of a pulsating heat pipe using nanofluid as a working fluid
- Creators
- Miguel Ángel González
- Contributors
- Yoon Jo Kim (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525389101842
- Language
- English
- Resource Type
- Thesis