2014 Fiscal Year Research-status Report
Freezing-based desalination: A molecular approach to understanding and optimisation.
| Project/Area Number |
26820059
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
CANNON James 東京大学, 工学(系)研究科(研究院), 研究員 (80648866)
|
|---|
| Project Period (FY) |
2014-04-01 – 2017-03-31
|
| Keywords | freezing / desalination / ice / water / salt / simulation / thermo-physical |
|---|
| Outline of Annual Research Achievements |
Consistent with the aim of using molecular approach, the first year of research the focus has been on understanding nano-scale fundamental interactions between molecules and their relation to important desalination liquid properties. This is important in a direct sense (desalination requires the separation of salt and water, where the interactions between molecules play a direct role) but also in an indirect sense: for example, an understanding of the relation between molecular interaction and thermal conductivity could permit the optimisation of the freezing-thawing process, while an understanding of the viscosity could lead to optimisation of energy use during pumping of the liquid around the desalination system.
Subsequently, the first year has focused on two areas. Firstly, the building up of the simulation methods and calculation code in order to understand the thermo-physical properties of liquids, and secondly, initial work to generate a clearer understanding of these properties on the nano-scale. This has produced a number of results which have been presented at domestic and international conferences.
The results have provided interesting insights into the mechanism of thermal conductivity in liquids, showing for example that conduction rather than diffusion dominates the thermal transport through water-impurity mixtures, and the molecular origins of the drop in thermal conducitivity typically experienced when mixing foreign molecules with water. Other quantities such as viscosity have also been explored, giving molecular insight into its variation during mixing.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The research is judged to be progressing smoothly. The planned purchase of a high-performance GPGPU computer has been completed, greatly enhancing the ability to carry out the calculations and analysis. The main MD simulation software, Gromacs, couples well with high performance hardware such as this. In terms of code, there was some initial work involved in building up the calculation capabilities; particularly the thermal conductivity analysis; however these are running smoothly and generating interesting results. One point that could be improved is that the thermo-physical property analysis could be more efficiently implemented, and this is something that I will be looking to improve in the short term.
|
| Strategy for Future Research Activity |
Firstly, it is important to understanding the fundamentals of freezing as a method of separation, and work in this area will involve detailed study into the freezing of water in the presence of impurities. By gaining an understanding of how foreign molecules (particularly salt) are absorbed into the solid phase from the liquid phase should give insight into what mechanisms may be invoked to prevent that happening. Understanding of such mechanisms will be instrumental to future mechanical engineering design.
Secondly, in relation to the results obtained so far regarding other thermo-physical properties, it would be interesting to generate a model to couple all of these different quantities, and furthermore to understand what trade-offs must be considered when designing such a system.
|
| Causes of Carryover |
The remaining amount was too small to be used for major enhancements to the computational resources or for attending any conferences non-local to Tokyo.
|
| Expenditure Plan for Carryover Budget |
The plan is to use the budget carried over from last year for further enhancements to the computational resources and to assist in disseminating and discussing results at major conferences.
|
