Synthesis and Characterization of Al2O3 Nanoparticles and Water-Al2O3 Nanofluids for Nuclear Reactor Coolant

A study on synthesis and characterization of Al2O3nanoparticles for water-Al2O3nanofluids as an alternative nuclear coolant has been done. The Al2O3nanoparticles were synthesized from AlCl3using sol gel method utilizing sugar as chelating agent. The Al2O3nanoparticles were mixed with water to produce nanofluids. XRD data showed that the Al2O3nanoparticles crystallize in gamma alumina with crystallite size of 5.5 nm (Debye Scherrer method). Surface area of the Al2O3nanoparticles was 90 m2/gram. Data of TEM showed that the particle size was smaller than 10 nm and the nanoparticle formed agglomerate with size of 60-100 nm. According to zeta potential data, the nanofluids were stable at pH 2.6-7.5 with zeta potential of 28-51 mV. The height of the nanofluid surface decreased about 20 % after 6 days. The thermal conductivity of the water-Al2O3nanofluids produced in this study increased about 2.4-9.7 % compared to that of water.

An Extended Reynolds Equation Including the Lubricant Inertia Effects: Application to Finite Length Water Lubricated Bearings

Water lubricated bearings used in nuclear coolant pumps and sub-sea applications exhibit large lubricant inertia forces in the magnitude order of viscous forces. To model these bearings the traditional Reynolds equation is not adequate. An extended Reynolds equation is developed in this study which takes into account the turbulence and inertia effects: both convective and temporal. The most complete form of temporal inertia which applies to the turbulent regime as well, is developed that consists of primary and secondary temporal inertia terms. The convective inertia model follows Constantinescu’s approach [1,2]. The turbulence model is also Constantinescu’s which is tuned with a CFD work. The dynamic coefficients including the lubricant added mass coefficients of a full cylindrical fixed geometry water bearing are obtained. It is observed that the convective inertia increases the load capacity and stability of the bearing. Significant lubricant added mass coefficients comparable to the shaft mass are calculated, which exhibit destabilizing effects in general.

Design of Test Bench for Flyweel of the Shaft-Seal Nuclear Coolant Pump and ANSYS Analysis

Due to the test requirements of flyweel of the shaft-seal nuclear coolant pump, design the structure of the test bench.Based on the theory of finite element analysis,use ANSYS software carries on its ststic analysis to gain the displacement and the stress form in order to check the strength and stiffness,and then carries on modal analysis to get its first six natural frequency and vibration in order to verify the rationality of design.CLC :TH122