Three major directions of this project included “Preparation and characteristic analysis of MNCBMs”, “Applicaion of AMNCBFs in the double tube heat exchanger”, and “Characteristic analysis and tribological performance evaluation of Oily micro/nano carbon-based fluid (OMNCBFs)” in 3-year to conduct an integrated research, the main research results were as follows. In the first year of this project, the micro/nanocarbon-based materials (MNCBMs) were prepared using the high-pressure combustion method (HPCM) with an isoperibol oxygen bomb calorimeter at different oxygen pressures (0.5–3.0 MPa). The prepared MNCBMs were added to water to form aqueous micro/nano carbon-based fluids (AMNCBFs) and fundamental characteristics test of AMNCBFs were conducted. The research results showed that the oxygen pressure was inversely proportional to the production rate of MNCBMs and the particle size. When the oxygen pressure was higher than 1.5 MPa, the composition of MNCBMs will have obvious diamond crystalline phase and amorphous carbon. In the second year, it was decided to use HCPM to produce MNCBMs with an oxygen pressure of 1.5 MPa. The particle size of the MNCBMs was further miniaturized by wet ball milling using a ball miller, and then made into 1.0 wt.% AMNCBFs by a two-step synthesis method and then 1.0 wt% AMNCBFs were added with 0.1 to 2.0 wt.% Gum Arabic (GA) as a dispersant. After 72 hours of sedimentation experiments, it was determined that the optimal GA concentration for 1.0 wt% AMNCBFs was 1.6 wt% (MNCBMs: GA=5:8, w/w). Finally, according to this ratio (MNCBMs: GA) further produced 0.05 wt% and 0.2 wt.% AMNCBFs as working fluids for heat transfer performance experiments of tube exchangers. In addition, the density and viscosity of 0.05 wt.% and 0.2 wt.% AMNCBFs were measured. The heat transfer performance experiment of tube heat exchanger was to measure the flow loss, pressure drop, pump power consumption, and convective heat transfer coefficient (HTC) under different heating power, sample concentration, and flow rates. The result shows 0.05 wt % AMNCBFs had better system performance. In the third year project, MNCBMs were added to refrigeration lubricant (RL) to prepare nano-carbon based refrigeration lubricants (NCRLs), and the ball milling method was used to enhance the dispersion effect of NCs in the NCRLs. Oleic acid was added to the NCRLs as a dispersant to maintain the long-term stability of the NCs in the NCRLs. The optimal ratio of NCs to oleic acid (1:1 w/w) was used to configure three MNCBMs weight concentrations (0.1, 0.5, and 1.0 wt%) of NCRLs, and the test samples consisted of an RL and three NCRLs. The anti-wear performance of the test samples was investigated using a rotary tribology tester. Through comparing the weight of the wear loss and wear scars, the optimal weight concentration of NCs was found to be around 0.5 wt%.
|Effective start/end date||2017/08/01 → 2020/10/31|
- Aqueous micro/nano carbon-based fluids (AMNCBFs)
- high pressure combustion method (HPCM)
- micro/nano carbon-based materials (MNCBMs)
- oily micro/nano carbon-based fluid (OMNCBFs)
- convective heat transfer coefficient (HTC)
- wear loss
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