Heat Transfer Performance Of Carbon Nanotube-Water Nanofluids In Heat Pipe

With the development of science and technology, many industrial devices are being shrinked in size. Heating or cooling technology is facing more challenge. Although various techniques such as traditional expending surface, are applied to enhance the heat transfer. The low heat transfer performance of these conventional fluids obstructs the performance enhancement. Lots of experiments show that nanofluid can intensify heat transfer. Given this background, we make detailed study at the conductivity of carbon nanofluids and performance of two-phase closed thermosyphon with carbon nanofluids in this thesis.First, Carbon nanotubes-water nanofluids are separately made by arabic method and acid mehthod. Stability and viscosity of the made carbon nanofluids are measued. The results show that carbon nanofluids made by the two methos get good stability under PH=7. Conglutination of carbon nanofluid made by arabic methed is two times larger than water's. Conglutinations of carbon nanofluids made by acid methoed and water are nearly the same.Then, conductivity of the carbon nanofluids are measured by transient two hot-wires apparatus. Results show that conductivity of carbon nanofluids is larger than base fluid water. At the same temperature, carbon nanofluids made by Arabic method is larger than carbon nanofluids made by acid method.Lastly, two-phase closed copper thermosyphons with carbon nanofluids are made. The heat transfer performance of the made thermosyphons are inveistigated. The experiment results show that the stability of carbon nanofluids does not influence the heat transfer performance of thermosyphon too much. Thermosyphon with carbon nanofluids made by Arabic method has better heat transfer ability than thermosyphons with carbon nanofluids made by Arabic method at transfer power from 100W to 500W. Thermosyphon with carbon nanofluids made by Arabic method shows better heat transfer ability than thermosyphon with water at transfer power from 100W to 700W.Additionally, research progress of nanofluids in heat transfer science is summarized. The mechanisms of stabiliy, conductivity of nanofluids are also discussed.This thesis was financially supported by the Zhejiang Province Natural Science Foundation. (No.: Y105010).