Modeling of Laser Ablation and Plume Chemistry in a Boron Nitride Nanotube Production Rig

• US 20130144576A1
• Filed: 11/09/2012
• Published: 06/06/2013
• Est. Priority Date: 11/10/2011
• Status: Abandoned Application

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Fay, Catharine C., Gnoffo, Peter A.
• Application Number:
  US13/673,360
• Publication Number:
  US 20130144576A1
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]
• CPC Class Codes: G16C 20/10 Analysis or design of chemical reactions, syntheses or processes

Abstract

A pressurized vapor condensation (PVC) process for production of Boron Nitride Nanotubes (BNNT) is modeled utilizing a modified hypersonic flow solver. The results of the modeling may be utilized to adjust operating parameters of the PV process of BNNT production rig. Utilizing the modeling reduces the time and expense associated with setup of a BNNT production rig.

Claims

1. A method of providing operational parameters for a boron nitride nanotube production rig, the method comprising:

providing a computer simulation of a high temperature, pressurized vapor condensation boron nitride nanotube production process;

utilizing the computer simulation to optimize at least one operating parameter of the high temperature, pressurized vapor condensation boron nitride nanotube production process to thereby facilitate formation of boron nitride nanotubes;

utilizing information concerning the one operating parameter from the simulation to set up a boron nitride nanotube production rig.

2. The method of claim 1, wherein:

creating a computer simulation of a high temperature, pressurized vapor condensation boron nitride nanotube production process includes providing thermodynamic and transport property data sets for the boron species B, BN, and B₂.

3. The method of claim 2, wherein:

the simulation includes setting a surface energy balance equation under a laser radiation source based on equilibration of atomic boron vapor pressure with a liquid boron source.

4. The method of claim 3, wherein:

the simulation utilizes momentum equations having buoyancy terms.

5. The method of claim 4, wherein;

the simulation includes a porous wall boundary condition to mimic a pressure relief valve in the system to maintain constant pressure as mass and energy are added to the system.

6. The method of claim 1, wherein:

the simulation comprises modifying a hypersonic flow solver to account for the conditions present during a high temperature, pressurized vapor condensation boron nitride nanotube production process.

7. The method of claim 1, wherein:

the production process utilizes a pressurized chamber, and the one operating parameter comprises pressure in the chamber.

8. The method of claim 1, wherein:

the production process utilizes a pressurized chamber, and the one operating parameter comprises a flow rate of a gas into the pressurized chamber.

9. The method of claim 8, wherein:

the gas comprises nitrogen.

10. The method of claim 1, wherein:

the one operating parameter comprises an amount of power provided by a laser.

11. The method of claim 1, wherein:

the one operating parameter comprises temperature in the chamber.

12. The method of claim 1, wherein:

the production process includes feeding a bundle of boron fibers into a pressurized chamber, and the one operating parameter comprises a rate at which the bundle of boron fibers are fed into the pressurized chamber.

13. The method of claim 1, wherein:

experimental observation is utilized in conjunction with the computer simulation to optimize at least one operating parameter of the high temperature, pressurized vapor condensation boron nitride nanotube production process.

14. A method of modeling laser ablation and plume chemistry of a boron nitride nanotube production process, the method comprising:

providing a hypersonics flow solver;

modeling a pressurized chamber by forming a grid of discrete elements corresponding to the walls of a pressurized chamber;

including boron species to thermodynamic and transport data sets of the hypersonics flow solver, the boron species comprising B, BN, and B₂;

modifying the hypersonics flow solver to provide an energy balance that takes into account energy from a laser radiation source;

executing the hypersonics flow solver to generate a plume and to determine the effect of changes in the production process.

15. The method of claim 14, including:

setting the chamber pressure at a value in the range of approximately 0-800 psig.

16. The method of claim 15, including:

setting a power level supplied from the laser in the range of approximately 0.05-5.0 KW.

17. The method of claim 14, wherein:

the hypersonics flow solver includes momentum equations; and

including;

providing buoyancy terms in momentum equations of the hypersonics flow solver.

18. The method of claim 14, wherein:

the model includes a porous wall boundary condition to simulate a pressure relief valve in the system to maintain constant pressure as mass and energy are added to the system.

19. The method of claim 14, including:

utilizing the solver to determine a mass fraction of BN in the plume.

20. The method of claim 14, including:

utilizing the solver to determine a flow rate of at least a selected one of BN, B, and B₂ in the plume.