| Nanofluids are a new class of heat transfer working fluid, formed by adding nanoscalemetallic, non-metallic or the oxide solid particles into a working liquid in a certain proportionand manner. Compared with many traditional heat transfer working fluids, Nanofluids haveless heat refrigerant, higher thermal conductivity and better heat transfer performance as theworking fluid filled into a heat pipe, whose performance of heat transfer will be greatlyenhanced.SiO2-water nanofluids with good suspension stability were prepared by SiO2nanoparticles added into the water base fluid. And SiO2-water nanofluids as a heat transfer workingfluid filled into the heat pipe, SiO2-water nanofluids heat pipe is made of. This paper aims toexplore and determine the best process routes and parameters of preparation of SiO2-waternanofluids, measure the thermophysical properties of SiO2-water nanofluids, analysis andstudy many factors, causes and mechanisms on thermophysical properties of SiO2-waternanofluids. We experimented and tested the heat transfer performance of heat pipe withSiO2-water nanofluids as a heat transfer working fluid, analysised the heat transferperformance of the SiO2-water nanofluids heat pipe under the conditions of the differentgradient degree and compared with the of heat transfer performance heat pipe filled water ofeliminated ions. The main content of this paper include the following points:1、 Particle sizes of15nm,30nm and50nm, the volume fraction of0.1%0.5%SiO2-water nanofluids prepared by the two-step method. In the conditions without adding thedispersant and adjusting the pH, we analysis and the suspension stability of SiO2-waternanofluids by the measurements of the laser particle size, absorbance and zeta potential,determine preparation of the SiO2-water nanofluids the optimal ultrasonic dispersion for5hours. The suspension stability of the SiO2-water nanofluid is the best in the condition.2、 The SiO2-water nanofluids’ thermophysical property parameters——viscosity,thermal conductivity, surface tension, wettability and contact angle, the vaporization latent heat,boiling point, and saturated vapor pressure are experimented test. We research and analysis theinfluences of SiO2nanoparticles volume fraction, SiO2nanoparticles particle size and other relevant factors on the thermophysical property parameters of the SiO2-water nanofluids, andmake the mechanism explication.3、SiO2-water nanofluids heat pipe are made of SiO2-water nanofluids as a heat transferworking fluid filling into heat pipe of copper. The heat transfer performance of SiO2-waternanofluids heat pipe is experimental studied under the conditions of different gradient degree.It is found that the starting temperatures, pulse-on times and thermal resistances of SiO2-waternanofluids heat pipes are lower than heat pipe of water of eliminated ions. SiO2-waternanofluids have been greatly improved the heat transfer coefficient of heat pipe. SiO2-waternanofluids heat pipe have better heat transfer performance when it placed tilted30°.SiO2-water nanofluids have good heat transfer performance as heat transfer working fluidfilling into heat pipe. |
PDF Full Text Request